Prokaryotic Cells: Single-celled, oldest type of cell, no nucleus, no organelles, has a cell wall around the membrane and a flagella (bacteria, archaea)                               Eukaryotic Cells: Larger and more complex than Prokaryotic Cells, single or multicellular, has membrane bound organelles (animal, plant, fungi)                                            Both: Has DNA, ribosomes, cytoplasm, plasma membrane 

What’s the difference between Prokaryotic Cells and Eukaryotic Cells  

The “control center” of the cell, contains DNA and Chromatin (tangled form of DNA found in the nuclear membrane). When DNA is ready to split, it condenses into chromosomes. Contains a Nucleolus that produces Ribosomes

Ribosomes are non-membrane, enclosed organelles found in both prokaryotic and eukaryotic cells. Made up of rRNA and proteins, synthesizes proteins, according to mRNA sequences. 

A network of membrane tubes within the cytoplasm. Provides mechanical support to the cell, plays a role in intercellular transport. Rough ER has ribosomes attached to its membrane, compartmentalizes the cell, and is associated with packaging of the newly synthesized proteins made by those attached ribosomes for the possible shipment to the membrane or other parts of the cells. Smooth ER does not have ribosomes attached to it, detoxifies wastes or drugs in the cell, makes lipids for the cell

A series of flattened membrane- bound sacs found in Eukaryotic cells. Involved in folding and modifying newly made proteins and packaging them to be exported to other parts of the cell or out of the cell. 

Membrane containers that help move materials from one part of the cell to the next (transfers proteins from the ER to the GA) 

A double membrane (outer membrane is smooth while the inner membrane s highly convoluted, forming folds called cristae). Produces ATP that Eukaryotic cells need to perform vital cellular processes. Captures energy from macromolecules (primarily carbohydrates)

The Krebs Cycle reactions occur in the matrix while the electron transport and ATP synthesis occurs in the inner mitochondrial membrane. Folding of the inner membrane increases surface area, allowing more ATP to be made

Where and what happens in the Mitochondria?

Membrane-enclosed sacs that are found in some Eukaryotic cells. Contains hydrolytic enzymes that digest damaged cell parts or macromolecules. Allows cells to recycle organic materials and even program cell death (apoptosis). Once macromolecules are broken down into organic monomers, these monomers can be released by the lysosome and be used by the mitochondria as a source of energy for the cell

Membrane bound sacs found in Eukaryotic cells. Contain a variety of functions from storing water (plant cells) and other macromolecules to releasing waste from the cell. In plants, vacuoles aid in the retention of water through turgor pressure (an internal cellular force caused by water pushing up against the plasma membrane and cell wall), makes plants not wilted

Found in Eukaryotic, photosynthetic organisms. Has a double outer membrane where photosynthesis occurs. Contains two compartments. Thylakoid are highly folded membrane compartments that are organized in stacks called grana, contain chlorophyll pigments and electron transport proteins (where light-dependent reactions occur) folding of the membranes increases the efficiency of these reactions. Stroma is the fluid between the inner chloroplast membrane and thylakoid. Where carbon fixation occurs

Cells are typically small because moving nutrients and waste in and out of the cell is more difficult if the cell is larger. Cells need a sufficient amount of surface for exchanging materials with its surrounding environment

Larger the ratio between surface area and volume = the more efficient the cell will be. Smaller cells have a higher surface area to volume ratio and are more efficient in exchanging materials with the environment. These limitations can restrict cell size and shape

What is the ideal surface area to volume ratio?

As a cell gets larger, the demand for internal resources (taking in oxygen and nutrients as well as dissipating heat and ridding itself of waste and carbon dioxide) increases- more complex structures are needed to adequately exchange materials with the environment. Membrane folding can increase surface area (root hairs on plant roots used to be able to absorb more water and nutrients)

A mosaic of protein molecules in a fluid bilayer of phospholipids. Structure is not static and is held together primarily by hydrophobic interactions which are weaker than covalent bonds- allows most lipids and some proteins to flow along the surface of the membrane or across the bilayer. The cell membrane has a phospholipid bilayer as well as transmembrane proteins that create semipermeable chambers. Phospholipids in the membrane do not just stay in one spot, moved around by enzymes

Can: Small hydrophobic molecules, steroids, small uncharged polar molecules (glycerol urea, ethanol),                         Cannot: Polar molecules, ions, and large molecules, sugar, potassium, salt 

What can and cannot pass through the cell mebrane?

Things that enter the membrane: Food (carbohydrates, sugars, proteins, amino acids, lipids
salts, O2, H2O)
Things that exit the membrane: Waste (ammonia, salts, CO2, H2O, products)

What needs to go through and exit the membrane?

Peripheral proteins are loosely bound to surface of membrane (ex: cell surface identity marker (antigens)), hydrophilic with charged and polar side groups. Channel proteins are like a canal/tunnel (if it cannot pass through the phospholipid bilayer it can go through here). Carrier proteins (protein pump) change shape to allow molecule to pass (like a door, used in active transport)

What are the different types of membrane proteins?

Membrane carbohydrates play a key role in cell-cell recognition. Cell-cell recognition is the ability of a cell to distinguish one cell from another. Important in organ and tissue development, the basis for rejection of foreign cells by the immune system. Glycoproteins (one or more carbohydrates attached to a membrane protein) and Glycolipids (one or more carbohydrates attached to a lipid)

What is the role of membrane carbohydrates?

Membranes must be fluid & flexible (about as fluid as thick salad oil). The unsaturated fatty acids in phospholipids keep membrane less viscous. Cholesterol is a type of steroid that is randomly distributed and wedged between phospholipids in the cell membrane of eukaryotic cells. Regulated bilayer fluidity under different environmental conditions

Cell walls in plant cells are used to protect and maintain the shape of the cell, prevent cellular rupture, and help plants stand up against the force of gravity. Plasmodesmata are small holes between plant cells that allows the transfer of nutrients, waste, and ions (basically membrane proteins for plant cells). Found in plants, fungi, and prokaryotes

No cell energy required. Only from high to low concentration (Down the concentration gradient). Stops at equilibrium. Plays a primary role in the import of materials and the export of waste. Simple Diffusion, the diffusion of small, nonpolar molecules through the phospholipid bilayer, high to low concentration gradient. Facilitated diffusion, the diffusion of polar molecules and ions through the use of carrier or channel proteins, high to low concentration gradient

Diffusion against the concentration gradient requires energy (ATP) and carrier proteins (protein pumps). Establishes and maintains concentration gradients. Cotransport is a secondary active transport that uses energy from an electrochemical gradient to transport two different ions across the membrane through a protein. Symport is when two different ions are transported in the same direction. Antiport is when two different ions are transported in opposite directions

Endocytosis, cell uses energy to take in macromolecules and particulate matter by forming new vesicles derived from the plasma membrane (Phagocytosis (big solid) and Pinocytosis (droplets of fluid). Receptor-mediated endocytosis- Receptor proteins on the cell membrane are used to capture specific target molecules. Exocytosis, internal vesicles use energy to fuse with the plasma membrane and secrete large macromolecules out of the cell 

Examples of Active Transport for larger molecules?

Allows for nerve impulses and muscle movement. 3 sodium ions leave the cell while 2 potassium ions enter the cell. Creates a concentration gradient of electrical charge. Makes a “battery out of your cells to “run” the muscle and nerves. Requires a carrier protein (active transport)

Type of concentration gradient. Membranes may become polarized by the movement of ions. Membrane potential is the electrical potential difference (voltage) across the membrane

The movement of water from an area of low solute concentration (high concentration of water) to an area of high solute concentration (low concentration of water) across a semipermeable membrane. Does not require energy (passive transport), moves rapidly in and out of cells. Occurs when the a solute cannot diffuse (too big or has a charge and cannot pass the membrane). Osmoregulation - the control of water balance in animal cells

A water channel for bacteria (water cannot go through the membrane through the phospholipids because it is polar). Don’t need a living cell to function. The aquaporin in the kidney plays a role in short term and long-term regulation of water balance, mediating rapid water transport across the membrane and play a critical role in urine concentration in dilution.

If in a hypotonic solution, the water enters the cell and causes the plasma membrane to expand and press on the tough cell wall causing turgor pressure. Creates structural support, many plants depend on this to survive
If in a isotonic solution or turgor pressure is lost, plant becomes flaccid
If in a hypertonic solution, the plasma membrane pulls away from the cell wall, which is called plasmolysis (recoverable)

Hypertonic: Solution with a higher concentration of solute, lower amounts of water, cells shrivel up. Hypotonic: Solution with a lower concentration of solute, cells blow up and possibly explode (fixed through a contractile vacuole that pumps water out of cell (requires ATP)). Isotonic: Equal amounts of solutes/water, equilibrium is reached (still moves when equilibrium is reached, keeps moving equally).

What are the three types of water solutions? 

The measure of a water’s potential to do work or move. Highest WP is 0 (distilled water), lower the number lower water potential. Water potential = Solute potential (usually negative) + Pressure potential (usually positive). Ψ = Ψs + Ψp, units is bars. Moves from area of high water potential (low solute concentration) to low water potential (high solute concentration)

Ψ = -iCRT (formula for solute potential). i = Ionization constant (between 1 and 2, NaCl is 2, Sucrose is 1), C = molar concentration (moles/liter), R = Pressure constant (0.0831 bars) T = Temperature in Kelvin. Ψs + Ψp = Ψs + Ψp

What is the formula for solute potential?

The separation of the cell interior and distinct compartments with specific local conditions that allows the simultaneous occurrence of diverse metabolic reactions and processes. In eukaryotic cells, a system of internal membranes and organelles generate compartmentalization. 

Membranes in organelles minimize competing interactions (lysosomes), hydrolytic enzymes of the lysosome function at an acidic environment, needs to maintain this environment in order to perform efficient hydrolysis 

How does compartmentalization occur in lysosomes?

Membrane folding maximizes surface area for metabolic reactions to occur (mitochondria), maximizing the amount of atp the mitochondria can generate for the cell to do work 

How does compartmentalization occur in the mitochondria? 

Back in the day there was aerobic bacteria that performed cellular respiration (breaking down food in the presence of oxygen) and cyanobacteria that were performing photosynthesis- they were engulfed by another host cell and became mitochondria 

Unit 2: Cell Structure and Function

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Cell Division: The Process of Cell Reproduction

AP Bio Unit 1

AP Biology Unit 1 Overview

General Biology 1-Chapters 1-4 Exam Review