Subjects

Subjects

More

Protein Synthesis: RNA Polymerase, Translation Steps, and Splicing

View

Protein Synthesis: RNA Polymerase, Translation Steps, and Splicing

RNA polymerase II plays a crucial role in eukaryotic transcription, working with general transcription factors to initiate and carry out gene expression. This process involves complex steps including initiation, elongation, and termination. Following transcription, mRNA processing occurs through intron removal and exon splicing. Translation then synthesizes proteins using ribosomes in a multi-step process involving initiation, elongation, and termination.

5/7/2023

769

Translation: The Process of Translocation

Translocation is a crucial step in the elongation phase of translation, following peptide bond formation. During translocation:

  1. The ribosome shifts along the mRNA in a 3' direction.
  2. The deacylated tRNA in the P site moves to the E (exit) site.
  3. The peptidyl-tRNA in the A site shifts to the P site.
  4. The A site becomes vacant, ready to accept the next aminoacyl-tRNA.

This process repeats multiple times, depending on the length of the mRNA being translated. Each cycle of translocation moves the ribosome one codon further along the mRNA, allowing for the sequential addition of amino acids to the growing polypeptide chain.

Highlight: Translocation is powered by GTP hydrolysis and facilitated by elongation factors, ensuring the precise movement of the ribosome along the mRNA.

Example: Think of translocation as a conveyor belt in a factory. As each part (amino acid) is added to the product (protein), the belt moves forward to bring the next part into position.

The repetitive nature of translocation enables the ribosome to efficiently synthesize proteins of varying lengths, from short peptides to large, complex proteins.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

RNA Polymerase II and Transcription Initiation

RNA polymerase II is a key enzyme in eukaryotic transcription, responsible for synthesizing messenger RNA (mRNA) from DNA templates. The transcription process begins with initiation, where RNA polymerase II attaches to the promoter region of a gene. This attachment is mediated by transcription factors, which help form the transcription initiation complex.

A crucial element in eukaryotic transcription initiation is the TATA box, a specific promoter sequence that plays a vital role in forming the transcription initiation complex. The complex consists of RNA polymerase II and various general transcription factors, working together to begin the process of gene expression.

Vocabulary: The TATA box is a DNA sequence found in the promoter region of many eukaryotic genes, typically located about 25-35 base pairs upstream of the transcription start site.

Highlight: The transcription initiation complex, comprising RNA polymerase II and transcription factors, is essential for the accurate and efficient start of gene transcription in eukaryotes.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Ribosomes: The Protein-Making Machinery

Ribosomes are the cellular structures responsible for protein synthesis. They consist of two main subunits:

  1. Large subunit
  2. Small subunit

These subunits work together to facilitate the translation of mRNA into proteins. The ribosome's structure allows mRNA to feed through it, enabling the step-by-step assembly of amino acids into a polypeptide chain.

Definition: Ribosomes are complex molecular machines found in all living cells, responsible for synthesizing proteins by translating messenger RNA (mRNA) into amino acid sequences.

Highlight: The diameter of a ribosome is approximately 10 nanometers, making it one of the largest molecular complexes in the cell.

The ribosome's role in protein synthesis is crucial, as it interprets the genetic instructions encoded in mRNA molecules that were originally transcribed from DNA in the nucleus. This process of translating genetic information into functional proteins is a fundamental aspect of the central dogma of molecular biology.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Steps of Translation: Peptide Bond Formation

The translation process involves several key steps, with peptide bond formation being a critical part of elongation. During this stage:

  1. The amino acid in the P (peptidyl) site of the ribosome forms a peptide bond with the amino acid in the A (aminoacyl) site.
  2. This bond formation is catalyzed by the peptidyl transferase activity of the large ribosomal subunit.
  3. The process occurs after codon recognition and before translocation.

Example: Imagine the ribosome as a molecular assembly line. The P site holds the growing protein chain, while the A site brings in the next amino acid. When these two amino acids are correctly positioned, they are joined together like linking two train cars.

Vocabulary: Peptide bond - A chemical bond formed between the carboxyl group of one amino acid and the amino group of another, creating the backbone of proteins.

This step-by-step process of peptide bond formation is crucial for the accurate synthesis of proteins based on the genetic information encoded in mRNA.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Transcription Initiation Complex in Eukaryotes

The transcription initiation complex in eukaryotes is a sophisticated assembly of proteins that forms at the promoter region of a gene. This complex includes:

  1. RNA polymerase II: The main enzyme responsible for transcribing protein-coding genes.
  2. General transcription factors: Proteins that assist RNA polymerase II in recognizing the promoter and initiating transcription.
  3. TATA box: A specific DNA sequence in the promoter that serves as a binding site for transcription factors.

The formation of this complex occurs in a step-wise manner:

  1. Transcription factors bind to the TATA box and other promoter elements.
  2. RNA polymerase II is recruited to the promoter.
  3. Additional factors assemble, creating the complete initiation complex.

Vocabulary: General transcription factors are a group of proteins required for the initiation of transcription in eukaryotes. They include TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH.

Highlight: The assembly of the transcription initiation complex is a highly regulated process that ensures genes are expressed at the right time and in the right amount.

This intricate process of complex formation is crucial for the precise control of gene expression in eukaryotic cells, allowing for the fine-tuning of cellular responses to various stimuli and developmental cues.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

DNA vs. RNA: Structural Differences

DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) are both nucleic acids, but they have several key structural differences:

  1. Sugar component:

    • DNA contains deoxyribose
    • RNA contains ribose (has an extra OH group)
  2. Nucleobases:

    • DNA: Adenine (A), Guanine (G), Cytosine (C), Thymine (T)
    • RNA: Adenine (A), Guanine (G), Cytosine (C), Uracil (U) instead of Thymine
  3. Structure:

    • DNA is typically double-stranded
    • RNA is usually single-stranded
  4. Stability:

    • DNA is more stable due to its double-stranded nature
    • RNA is less stable and more prone to hydrolysis

Vocabulary: Nucleobases are the nitrogen-containing biological compounds that form the building blocks of nucleic acids (DNA and RNA).

Highlight: The structural differences between DNA and RNA reflect their distinct roles in the cell. DNA serves as the stable storage of genetic information, while RNA acts as a more versatile molecule involved in gene expression and regulation.

These structural differences are crucial for the distinct functions of DNA and RNA in cellular processes, including genetic storage, transcription, and translation.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Ribosome Structure and Function

Ribosomes are complex molecular machines essential for protein synthesis. The large subunit of the ribosome contains three crucial binding sites:

  1. A site (Aminoacyl-tRNA binding site): This is where new aminoacyl-tRNAs enter the ribosome.
  2. P site (Peptidyl-tRNA binding site): This site holds the growing polypeptide chain attached to a tRNA.
  3. E site (Exit site): This is where deacylated tRNAs leave the ribosome after delivering their amino acids.

The process of translation involves the coordinated use of these sites:

  1. The first tRNA binds directly to the P site.
  2. Subsequent aminoacyl-tRNAs enter through the A site.
  3. Peptide bonds form between amino acids in the P and A sites.
  4. Deacylated tRNAs exit through the E site.

Definition: Aminoacyl-tRNA is a tRNA molecule that has been charged with its specific amino acid, ready to deliver it to the growing polypeptide chain during translation.

Highlight: The precise arrangement of these binding sites in the ribosome allows for the accurate and efficient translation of mRNA into proteins, a fundamental process in all living cells.

This intricate structure of the ribosome enables the complex process of protein synthesis, ensuring the correct sequence of amino acids is assembled based on the genetic code.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Ribonucleic Acid (RNA): Structure and Function

RNA is a crucial molecule in cellular processes, particularly in gene expression. Key features of RNA include:

  1. Structure: Single-stranded molecule that can form various shapes and lengths
  2. Location: Found in both the nucleus and cytoplasm, depending on the type of RNA
  3. Composition: Made up of nucleotides, each consisting of:
    • Sugar (Ribose)
    • Phosphate group
    • Nitrogenous base (Adenine, Guanine, Cytosine, or Uracil)

RNA plays diverse roles in the cell:

  • Messenger RNA (mRNA): Carries genetic information from DNA to ribosomes
  • Transfer RNA (tRNA): Brings amino acids to ribosomes during protein synthesis
  • Ribosomal RNA (rRNA): Forms part of the ribosome structure

Vocabulary: Nucleotide - The basic structural unit of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.

Highlight: The versatility of RNA in terms of structure and function makes it a key player in various cellular processes, from gene regulation to protein synthesis.

The unique properties of RNA, including its ability to form complex secondary structures, enable it to perform a wide range of functions in the cell, making it essential for life as we know it.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

mRNA Processing: Intron Removal and Exon Splicing

Before pre-mRNA leaves the nucleus, it undergoes crucial processing steps:

  1. Intron Removal: Non-coding sections (introns) are removed from the pre-mRNA.
  2. Exon Splicing: Coding sections (exons) are joined together to form the mature mRNA.

This process, known as RNA splicing, is a critical step in gene expression in eukaryotes. Key points include:

  • Introns are often referred to as "junk" DNA, although they may have regulatory functions.
  • Exons contain the actual genetic information for protein synthesis.
  • Alternative splicing can occur, where exons are combined in different ways to produce various protein isoforms from a single gene.

Definition: Alternative splicing is a process by which different combinations of exons are included in the mature mRNA, allowing a single gene to code for multiple protein variants.

Highlight: RNA splicing significantly increases the complexity of the eukaryotic proteome, allowing for greater diversity of proteins from a limited number of genes.

This sophisticated process of mRNA processing enables eukaryotic cells to fine-tune gene expression and increase protein diversity, contributing to the complexity of higher organisms.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Protein Synthesis Overview

Protein synthesis is a fundamental cellular process that translates genetic information from nucleic acids into functional proteins. This process involves two main stages:

  1. Transcription: The synthesis of mRNA from a DNA template in the nucleus.
  2. Translation: The synthesis of proteins from mRNA using ribosomes in the cytoplasm.

Key components involved in protein synthesis include:

  • DNA: The genetic blueprint containing instructions for protein synthesis
  • RNA polymerase: Enzyme responsible for transcribing DNA into RNA
  • mRNA: Carries genetic information from DNA to ribosomes
  • tRNA: Brings amino acids to the ribosome during translation
  • Ribosomes: Cellular structures where protein synthesis occurs

Highlight: Protein synthesis is a highly regulated process that ensures the correct proteins are produced at the right time and in the right amounts, crucial for proper cellular function and organism development.

Understanding the intricacies of protein synthesis is essential for comprehending how genetic information is expressed and how cells respond to their environment and developmental cues.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Transcription Elongation: RNA Polymerase II in Action

During the elongation phase of transcription, RNA polymerase II plays a crucial role in synthesizing the RNA transcript. The process involves several key steps:

  1. DNA Unwinding: RNA polymerase II unwinds the DNA double helix, breaking the hydrogen bonds between base pairs.

  2. Strand Separation: The enzyme separates the DNA strands, exposing the template strand.

  3. Base Pairing: Incoming RNA nucleotides pair with complementary DNA nucleotides on the template strand.

  4. RNA Synthesis: RNA polymerase II catalyzes the formation of phosphodiester bonds between nucleotides, elongating the RNA chain in a 5' to 3' direction.

Highlight: RNA polymerase II moves along the DNA template strand in a 3' to 5' direction, synthesizing the complementary RNA strand in a 5' to 3' direction.

Example: If the DNA template strand reads 3'-TACGTA-5', the corresponding RNA sequence will be 5'-AUGCAU-3'.

This process continues until RNA polymerase II reaches a termination sequence, resulting in the production of a complete RNA transcript that is complementary to the DNA template strand.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Understanding Genes: The Blueprint for Proteins

A gene is a fundamental unit of heredity, defined as a section of DNA that codes for a specific protein. Key points about genes include:

  1. One Gene, One Protein: Generally, each gene contains the information to produce one specific protein.

  2. Gene Structure: Genes consist of coding regions (exons) interspersed with non-coding regions (introns).

  3. Protein Coding: The genetic code within a gene determines the sequence of amino acids in the protein it encodes.

  4. Human Genome: Humans have approximately 30,000 protein-coding genes.

Highlight: While the "one gene, one protein" concept is a useful simplification, modern understanding recognizes that alternative splicing and other mechanisms can allow a single gene to produce multiple protein variants.

Example: A gene for eye color contains the instructions for producing melanin, the pigment that determines eye color. Different versions (alleles) of this gene can result in various eye colors.

Understanding the structure and function of genes is crucial for comprehending how genetic information is stored, transmitted, and expressed in living organisms.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Translation Initiation: The First Step in Protein Synthesis

The initiation phase of translation is a crucial step in protein synthesis, involving several key components and processes:

  1. Ribosomal Assembly: The small and large ribosomal subunits come together at the 5' end of the mRNA.

  2. Start Codon Recognition: The ribosome scans the mRNA in a 5' to 3' direction to locate the start codon (AUG).

  3. Initiator tRNA: The first tRNA, carrying methionine, attaches directly to the P site of the ribosome, unlike subsequent tRNAs which enter through the A site.

  4. First Amino Acid: Methionine is always the first amino acid in the newly synthesized protein, though it may be removed later in some cases.

Vocabulary: The start codon (AUG) is a specific sequence of nucleotides that signals the beginning of a protein-coding sequence on the mRNA.

Highlight: The precise positioning of the ribosome at the start codon is crucial for ensuring that the correct reading frame is established for accurate protein synthesis.

This intricate process of translation initiation sets the stage for the subsequent elongation phase, where the protein will be assembled one amino acid at a time based on the mRNA sequence.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Understanding Codons in Protein Synthesis

Codons are fundamental units of genetic code that play a crucial role in translating mRNA into proteins. Key points about codons include:

  1. Definition: A codon is a sequence of three nucleotides on the mRNA that specifies a particular amino acid or a stop signal.

  2. Codon Diversity: There are 64 different possible codons in the genetic code.

  3. Amino Acid Coding: Of the 64 codons, 61 code for amino acids, while 3 are stop codons that signal the end of protein synthesis.

  4. Redundancy: Multiple codons can code for the same amino acid, a feature known as the degeneracy of the genetic code.

Example: The codon AUG codes for methionine and also serves as the start codon, initiating protein synthesis.

Highlight: The genetic code is nearly universal across all living organisms, with only minor variations in some species, highlighting its fundamental importance in biology.

Understanding codons is essential for comprehending how genetic information is translated into the amino acid sequences that form proteins, a process central to the expression of genetic traits and the functioning of all living cells.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Transcription Termination: Ending the RNA Synthesis

The termination phase of transcription is a crucial step that signals the end of RNA synthesis by RNA polymerase II. This process involves several key elements:

  1. Termination Sequence: RNA polymerase II continues transcription until it encounters a specific termination sequence in the DNA.

  2. Hairpin Loop Formation: The termination sequence often leads to the formation of a hairpin loop structure in the newly synthesized RNA.

  3. Intrinsic Mechanism: In many cases, termination occurs through an intrinsic mechanism where the hairpin loop causes the RNA polymerase to pause and eventually release the RNA transcript.

  4. RNA Release: The completed RNA molecule is released from the DNA template and the RNA polymerase.

Vocabulary: A hairpin loop is a secondary structure in single-stranded nucleic acids where the strand folds back on itself to form a loop, resembling a hairpin.

Highlight: Proper transcription termination is essential for producing functional RNA molecules of the correct length and preventing interference with downstream genes.

This termination process ensures that each gene is transcribed accurately and independently, contributing to the precise control of gene expression in eukaryotic cells.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

View

Can't find what you're looking for? Explore other subjects.

Knowunity is the # 1 ranked education app in five European countries

Knowunity was a featured story by Apple and has consistently topped the app store charts within the education category in Germany, Italy, Poland, Switzerland and United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the # 1 ranked education app in five European countries

4.9+

Average App Rating

13 M

Students use Knowunity

#1

In Education App Charts in 11 Countries

950 K+

Students uploaded study notes

Still not sure? Look at what your fellow peers are saying...

iOS User

I love this app so much [...] I recommend Knowunity to everyone!!! I went from a C to an A with it :D

Stefan S, iOS User

The application is very simple and well designed. So far I have found what I was looking for :D

SuSSan, iOS User

Love this App ❤️, I use it basically all the time whenever I'm studying

Can't find what you're looking for? Explore other subjects.

Knowunity is the # 1 ranked education app in five European countries

Knowunity was a featured story by Apple and has consistently topped the app store charts within the education category in Germany, Italy, Poland, Switzerland and United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the # 1 ranked education app in five European countries

4.9+

Average App Rating

13 M

Students use Knowunity

#1

In Education App Charts in 11 Countries

950 K+

Students uploaded study notes

Still not sure? Look at what your fellow peers are saying...

iOS User

I love this app so much [...] I recommend Knowunity to everyone!!! I went from a C to an A with it :D

Stefan S, iOS User

The application is very simple and well designed. So far I have found what I was looking for :D

SuSSan, iOS User

Love this App ❤️, I use it basically all the time whenever I'm studying

View

Protein Synthesis: RNA Polymerase, Translation Steps, and Splicing

Protein Synthesis: RNA Polymerase, Translation Steps, and Splicing

RNA polymerase II plays a crucial role in eukaryotic transcription, working with general transcription factors to initiate and carry out gene expression. This process involves complex steps including initiation, elongation, and termination. Following transcription, mRNA processing occurs through intron removal and exon splicing. Translation then synthesizes proteins using ribosomes in a multi-step process involving initiation, elongation, and termination.

5/7/2023

769

Translation: The Process of Translocation

Translocation is a crucial step in the elongation phase of translation, following peptide bond formation. During translocation:

  1. The ribosome shifts along the mRNA in a 3' direction.
  2. The deacylated tRNA in the P site moves to the E (exit) site.
  3. The peptidyl-tRNA in the A site shifts to the P site.
  4. The A site becomes vacant, ready to accept the next aminoacyl-tRNA.

This process repeats multiple times, depending on the length of the mRNA being translated. Each cycle of translocation moves the ribosome one codon further along the mRNA, allowing for the sequential addition of amino acids to the growing polypeptide chain.

Highlight: Translocation is powered by GTP hydrolysis and facilitated by elongation factors, ensuring the precise movement of the ribosome along the mRNA.

Example: Think of translocation as a conveyor belt in a factory. As each part (amino acid) is added to the product (protein), the belt moves forward to bring the next part into position.

The repetitive nature of translocation enables the ribosome to efficiently synthesize proteins of varying lengths, from short peptides to large, complex proteins.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

RNA Polymerase II and Transcription Initiation

RNA polymerase II is a key enzyme in eukaryotic transcription, responsible for synthesizing messenger RNA (mRNA) from DNA templates. The transcription process begins with initiation, where RNA polymerase II attaches to the promoter region of a gene. This attachment is mediated by transcription factors, which help form the transcription initiation complex.

A crucial element in eukaryotic transcription initiation is the TATA box, a specific promoter sequence that plays a vital role in forming the transcription initiation complex. The complex consists of RNA polymerase II and various general transcription factors, working together to begin the process of gene expression.

Vocabulary: The TATA box is a DNA sequence found in the promoter region of many eukaryotic genes, typically located about 25-35 base pairs upstream of the transcription start site.

Highlight: The transcription initiation complex, comprising RNA polymerase II and transcription factors, is essential for the accurate and efficient start of gene transcription in eukaryotes.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Ribosomes: The Protein-Making Machinery

Ribosomes are the cellular structures responsible for protein synthesis. They consist of two main subunits:

  1. Large subunit
  2. Small subunit

These subunits work together to facilitate the translation of mRNA into proteins. The ribosome's structure allows mRNA to feed through it, enabling the step-by-step assembly of amino acids into a polypeptide chain.

Definition: Ribosomes are complex molecular machines found in all living cells, responsible for synthesizing proteins by translating messenger RNA (mRNA) into amino acid sequences.

Highlight: The diameter of a ribosome is approximately 10 nanometers, making it one of the largest molecular complexes in the cell.

The ribosome's role in protein synthesis is crucial, as it interprets the genetic instructions encoded in mRNA molecules that were originally transcribed from DNA in the nucleus. This process of translating genetic information into functional proteins is a fundamental aspect of the central dogma of molecular biology.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Steps of Translation: Peptide Bond Formation

The translation process involves several key steps, with peptide bond formation being a critical part of elongation. During this stage:

  1. The amino acid in the P (peptidyl) site of the ribosome forms a peptide bond with the amino acid in the A (aminoacyl) site.
  2. This bond formation is catalyzed by the peptidyl transferase activity of the large ribosomal subunit.
  3. The process occurs after codon recognition and before translocation.

Example: Imagine the ribosome as a molecular assembly line. The P site holds the growing protein chain, while the A site brings in the next amino acid. When these two amino acids are correctly positioned, they are joined together like linking two train cars.

Vocabulary: Peptide bond - A chemical bond formed between the carboxyl group of one amino acid and the amino group of another, creating the backbone of proteins.

This step-by-step process of peptide bond formation is crucial for the accurate synthesis of proteins based on the genetic information encoded in mRNA.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Transcription Initiation Complex in Eukaryotes

The transcription initiation complex in eukaryotes is a sophisticated assembly of proteins that forms at the promoter region of a gene. This complex includes:

  1. RNA polymerase II: The main enzyme responsible for transcribing protein-coding genes.
  2. General transcription factors: Proteins that assist RNA polymerase II in recognizing the promoter and initiating transcription.
  3. TATA box: A specific DNA sequence in the promoter that serves as a binding site for transcription factors.

The formation of this complex occurs in a step-wise manner:

  1. Transcription factors bind to the TATA box and other promoter elements.
  2. RNA polymerase II is recruited to the promoter.
  3. Additional factors assemble, creating the complete initiation complex.

Vocabulary: General transcription factors are a group of proteins required for the initiation of transcription in eukaryotes. They include TFIIA, TFIIB, TFIID, TFIIE, TFIIF, and TFIIH.

Highlight: The assembly of the transcription initiation complex is a highly regulated process that ensures genes are expressed at the right time and in the right amount.

This intricate process of complex formation is crucial for the precise control of gene expression in eukaryotic cells, allowing for the fine-tuning of cellular responses to various stimuli and developmental cues.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

DNA vs. RNA: Structural Differences

DNA (Deoxyribonucleic Acid) and RNA (Ribonucleic Acid) are both nucleic acids, but they have several key structural differences:

  1. Sugar component:

    • DNA contains deoxyribose
    • RNA contains ribose (has an extra OH group)
  2. Nucleobases:

    • DNA: Adenine (A), Guanine (G), Cytosine (C), Thymine (T)
    • RNA: Adenine (A), Guanine (G), Cytosine (C), Uracil (U) instead of Thymine
  3. Structure:

    • DNA is typically double-stranded
    • RNA is usually single-stranded
  4. Stability:

    • DNA is more stable due to its double-stranded nature
    • RNA is less stable and more prone to hydrolysis

Vocabulary: Nucleobases are the nitrogen-containing biological compounds that form the building blocks of nucleic acids (DNA and RNA).

Highlight: The structural differences between DNA and RNA reflect their distinct roles in the cell. DNA serves as the stable storage of genetic information, while RNA acts as a more versatile molecule involved in gene expression and regulation.

These structural differences are crucial for the distinct functions of DNA and RNA in cellular processes, including genetic storage, transcription, and translation.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Ribosome Structure and Function

Ribosomes are complex molecular machines essential for protein synthesis. The large subunit of the ribosome contains three crucial binding sites:

  1. A site (Aminoacyl-tRNA binding site): This is where new aminoacyl-tRNAs enter the ribosome.
  2. P site (Peptidyl-tRNA binding site): This site holds the growing polypeptide chain attached to a tRNA.
  3. E site (Exit site): This is where deacylated tRNAs leave the ribosome after delivering their amino acids.

The process of translation involves the coordinated use of these sites:

  1. The first tRNA binds directly to the P site.
  2. Subsequent aminoacyl-tRNAs enter through the A site.
  3. Peptide bonds form between amino acids in the P and A sites.
  4. Deacylated tRNAs exit through the E site.

Definition: Aminoacyl-tRNA is a tRNA molecule that has been charged with its specific amino acid, ready to deliver it to the growing polypeptide chain during translation.

Highlight: The precise arrangement of these binding sites in the ribosome allows for the accurate and efficient translation of mRNA into proteins, a fundamental process in all living cells.

This intricate structure of the ribosome enables the complex process of protein synthesis, ensuring the correct sequence of amino acids is assembled based on the genetic code.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Ribonucleic Acid (RNA): Structure and Function

RNA is a crucial molecule in cellular processes, particularly in gene expression. Key features of RNA include:

  1. Structure: Single-stranded molecule that can form various shapes and lengths
  2. Location: Found in both the nucleus and cytoplasm, depending on the type of RNA
  3. Composition: Made up of nucleotides, each consisting of:
    • Sugar (Ribose)
    • Phosphate group
    • Nitrogenous base (Adenine, Guanine, Cytosine, or Uracil)

RNA plays diverse roles in the cell:

  • Messenger RNA (mRNA): Carries genetic information from DNA to ribosomes
  • Transfer RNA (tRNA): Brings amino acids to ribosomes during protein synthesis
  • Ribosomal RNA (rRNA): Forms part of the ribosome structure

Vocabulary: Nucleotide - The basic structural unit of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base.

Highlight: The versatility of RNA in terms of structure and function makes it a key player in various cellular processes, from gene regulation to protein synthesis.

The unique properties of RNA, including its ability to form complex secondary structures, enable it to perform a wide range of functions in the cell, making it essential for life as we know it.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

mRNA Processing: Intron Removal and Exon Splicing

Before pre-mRNA leaves the nucleus, it undergoes crucial processing steps:

  1. Intron Removal: Non-coding sections (introns) are removed from the pre-mRNA.
  2. Exon Splicing: Coding sections (exons) are joined together to form the mature mRNA.

This process, known as RNA splicing, is a critical step in gene expression in eukaryotes. Key points include:

  • Introns are often referred to as "junk" DNA, although they may have regulatory functions.
  • Exons contain the actual genetic information for protein synthesis.
  • Alternative splicing can occur, where exons are combined in different ways to produce various protein isoforms from a single gene.

Definition: Alternative splicing is a process by which different combinations of exons are included in the mature mRNA, allowing a single gene to code for multiple protein variants.

Highlight: RNA splicing significantly increases the complexity of the eukaryotic proteome, allowing for greater diversity of proteins from a limited number of genes.

This sophisticated process of mRNA processing enables eukaryotic cells to fine-tune gene expression and increase protein diversity, contributing to the complexity of higher organisms.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Protein Synthesis Overview

Protein synthesis is a fundamental cellular process that translates genetic information from nucleic acids into functional proteins. This process involves two main stages:

  1. Transcription: The synthesis of mRNA from a DNA template in the nucleus.
  2. Translation: The synthesis of proteins from mRNA using ribosomes in the cytoplasm.

Key components involved in protein synthesis include:

  • DNA: The genetic blueprint containing instructions for protein synthesis
  • RNA polymerase: Enzyme responsible for transcribing DNA into RNA
  • mRNA: Carries genetic information from DNA to ribosomes
  • tRNA: Brings amino acids to the ribosome during translation
  • Ribosomes: Cellular structures where protein synthesis occurs

Highlight: Protein synthesis is a highly regulated process that ensures the correct proteins are produced at the right time and in the right amounts, crucial for proper cellular function and organism development.

Understanding the intricacies of protein synthesis is essential for comprehending how genetic information is expressed and how cells respond to their environment and developmental cues.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Transcription Elongation: RNA Polymerase II in Action

During the elongation phase of transcription, RNA polymerase II plays a crucial role in synthesizing the RNA transcript. The process involves several key steps:

  1. DNA Unwinding: RNA polymerase II unwinds the DNA double helix, breaking the hydrogen bonds between base pairs.

  2. Strand Separation: The enzyme separates the DNA strands, exposing the template strand.

  3. Base Pairing: Incoming RNA nucleotides pair with complementary DNA nucleotides on the template strand.

  4. RNA Synthesis: RNA polymerase II catalyzes the formation of phosphodiester bonds between nucleotides, elongating the RNA chain in a 5' to 3' direction.

Highlight: RNA polymerase II moves along the DNA template strand in a 3' to 5' direction, synthesizing the complementary RNA strand in a 5' to 3' direction.

Example: If the DNA template strand reads 3'-TACGTA-5', the corresponding RNA sequence will be 5'-AUGCAU-3'.

This process continues until RNA polymerase II reaches a termination sequence, resulting in the production of a complete RNA transcript that is complementary to the DNA template strand.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Understanding Genes: The Blueprint for Proteins

A gene is a fundamental unit of heredity, defined as a section of DNA that codes for a specific protein. Key points about genes include:

  1. One Gene, One Protein: Generally, each gene contains the information to produce one specific protein.

  2. Gene Structure: Genes consist of coding regions (exons) interspersed with non-coding regions (introns).

  3. Protein Coding: The genetic code within a gene determines the sequence of amino acids in the protein it encodes.

  4. Human Genome: Humans have approximately 30,000 protein-coding genes.

Highlight: While the "one gene, one protein" concept is a useful simplification, modern understanding recognizes that alternative splicing and other mechanisms can allow a single gene to produce multiple protein variants.

Example: A gene for eye color contains the instructions for producing melanin, the pigment that determines eye color. Different versions (alleles) of this gene can result in various eye colors.

Understanding the structure and function of genes is crucial for comprehending how genetic information is stored, transmitted, and expressed in living organisms.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Translation Initiation: The First Step in Protein Synthesis

The initiation phase of translation is a crucial step in protein synthesis, involving several key components and processes:

  1. Ribosomal Assembly: The small and large ribosomal subunits come together at the 5' end of the mRNA.

  2. Start Codon Recognition: The ribosome scans the mRNA in a 5' to 3' direction to locate the start codon (AUG).

  3. Initiator tRNA: The first tRNA, carrying methionine, attaches directly to the P site of the ribosome, unlike subsequent tRNAs which enter through the A site.

  4. First Amino Acid: Methionine is always the first amino acid in the newly synthesized protein, though it may be removed later in some cases.

Vocabulary: The start codon (AUG) is a specific sequence of nucleotides that signals the beginning of a protein-coding sequence on the mRNA.

Highlight: The precise positioning of the ribosome at the start codon is crucial for ensuring that the correct reading frame is established for accurate protein synthesis.

This intricate process of translation initiation sets the stage for the subsequent elongation phase, where the protein will be assembled one amino acid at a time based on the mRNA sequence.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Understanding Codons in Protein Synthesis

Codons are fundamental units of genetic code that play a crucial role in translating mRNA into proteins. Key points about codons include:

  1. Definition: A codon is a sequence of three nucleotides on the mRNA that specifies a particular amino acid or a stop signal.

  2. Codon Diversity: There are 64 different possible codons in the genetic code.

  3. Amino Acid Coding: Of the 64 codons, 61 code for amino acids, while 3 are stop codons that signal the end of protein synthesis.

  4. Redundancy: Multiple codons can code for the same amino acid, a feature known as the degeneracy of the genetic code.

Example: The codon AUG codes for methionine and also serves as the start codon, initiating protein synthesis.

Highlight: The genetic code is nearly universal across all living organisms, with only minor variations in some species, highlighting its fundamental importance in biology.

Understanding codons is essential for comprehending how genetic information is translated into the amino acid sequences that form proteins, a process central to the expression of genetic traits and the functioning of all living cells.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Transcription Termination: Ending the RNA Synthesis

The termination phase of transcription is a crucial step that signals the end of RNA synthesis by RNA polymerase II. This process involves several key elements:

  1. Termination Sequence: RNA polymerase II continues transcription until it encounters a specific termination sequence in the DNA.

  2. Hairpin Loop Formation: The termination sequence often leads to the formation of a hairpin loop structure in the newly synthesized RNA.

  3. Intrinsic Mechanism: In many cases, termination occurs through an intrinsic mechanism where the hairpin loop causes the RNA polymerase to pause and eventually release the RNA transcript.

  4. RNA Release: The completed RNA molecule is released from the DNA template and the RNA polymerase.

Vocabulary: A hairpin loop is a secondary structure in single-stranded nucleic acids where the strand folds back on itself to form a loop, resembling a hairpin.

Highlight: Proper transcription termination is essential for producing functional RNA molecules of the correct length and preventing interference with downstream genes.

This termination process ensures that each gene is transcribed accurately and independently, contributing to the precise control of gene expression in eukaryotic cells.

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Initiation
RNA Polymerase II attaches to the promoter (start signal region) of
a gene
Transcription factors mediate the binding of RNA polym

Sign up

Sign up to get unlimited access to thousands of study materials. It's free!

Access to all documents

Join milions of students

Improve your grades

By signing up you accept Terms of Service and Privacy Policy

Can't find what you're looking for? Explore other subjects.

Knowunity is the # 1 ranked education app in five European countries

Knowunity was a featured story by Apple and has consistently topped the app store charts within the education category in Germany, Italy, Poland, Switzerland and United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the # 1 ranked education app in five European countries

4.9+

Average App Rating

13 M

Students use Knowunity

#1

In Education App Charts in 11 Countries

950 K+

Students uploaded study notes

Still not sure? Look at what your fellow peers are saying...

iOS User

I love this app so much [...] I recommend Knowunity to everyone!!! I went from a C to an A with it :D

Stefan S, iOS User

The application is very simple and well designed. So far I have found what I was looking for :D

SuSSan, iOS User

Love this App ❤️, I use it basically all the time whenever I'm studying