AP Biology Test 2

What are the three parts of cell theory?

1. All living things are made of cells
2. All cells come from other cells.
3. The cell is the basic unit of structure and function.

Schleiden

said that all PLANTS are made of cells

Schwann

said that all ANIMALS are made of cells

Virchow

said that all cells come from other cells

Why are cells limited in their size? (3)

If they are too large...
they will not be able to remove waste fast enough
they will not be able to get in nutrients fast enough
DNA would be unable to control it

Why is the organization of the cell and the size of the cell critical to maintaining homeostasis?

The organization of organelles is important, which carry out specific functions. Plasma membrane helps the cell maintain internal conditions, even if they're different from external conditions. Also, the plasma membrane regulates the exchange of materials

How do prokaryotic and eukaryotic cells differ? (3)

Prokaryotic cells lack a nucleus, have no membrane-bound organelles, and are generally smaller

nucleus

large, centralized organelle that stores DNA, double membrane, transcribes information from DNA during RNA synthesis

nuclear membrane/envelope

regulates movement in and out of nucleus

Plasma/Cell Membrane

selectively permeable, regulates movement in and out of the cell, main component is phospholipids

chromatin

DNA in a relaxed form

chromosomes

DNA during division

ribosomes

are either attached to the ER or floating free, build proteins, ball-shaped

Smooth Endoplasmic Reticulum

no ribosomes, produces lipids, detoxification site (liver)

Rough Endoplasmic Reticulum

studded with ribosomes, produces and transports proteins

Golgi Complex

stack of membrane sacs (looks like pancakes); processes, sorts, and modifies proteins

mitochondria

double membrane, converts energy from a stored form to a usable form, cellular respiration, apoptosis

apoptosis

programmed cell death, webbing between human fingers and toes

Chloroplast

double membrane, green, photosynthesis converts light energy into stored energy

lysosomes

fluid-filled sacs, contains digestive enzymes, breakdowns substances within the cell, only in animals

vacuole

large membrane sacs, stores things (waste, food, etc)

peroxisome

create hydrogen peroxide

plastids

produce and store food, mostly in plants (chloroplast is an example)

vesicle

anything membrane-bound

cytoskeleton

provides shape and allows movement; microtubules and microfilaments

flagella and cilia

used for movement in cells

phospholipids

form bilayer in water, two hydrophobic tails, hydrophillic head, amphipathic

amphipathic molecule

molecule with both hydrophobic and hydrophillic regions

fluid mosaic model

current model of cell membrane structure, bilayer with embedded phospholipids and proteins

Why is a fluid mosaic model important?

allows proteins to move where they are needed

components of a membrane (3)

phospholipids, cholesterol, proteins

integral protein

protein stuck into the membrane

transmembrane protein

protein stretched across the entire membrane =0==0==0=

peripheral protein

protein located on hydrophillic heads

What are membrane proteins used for? (5)

enzymes, transport, anchoring, cell communication, cell identification

examples of passive transport (3)

diffusion, osmosis, carrier-mediated transport

diffusion

movement or particles from areas of high concentration to low concentration

What changes the rate of diffusion? (5)

concentration gradient, temperature, particle size, electrical charges, molecular movement

osmosis

diffusion of water across a selectively permeable membrane

osmotic pressure

tendency of water to move into a solution

hypertonic

concentration of water is lower outside of cell

hypotonic

concentration of water is higher outside cell

isotonic

concentration of water is equal inside and outside cell

turgor pressure

internal water pressure in plants, keeps plants up right

carrier-mediated transport

requires special integral molecule, no energy required, carriers are molecule specific

What is an example of carrier-mediated transport?

facilitated diffusion

Active Transport

moving against concentration gradient (low to high), protein pump fueled by ATP

What is an example of Active Transport?

Sodium-Potassium Pump

Bulk Transport

moving large molecules in and out of the cell

exocytosis

moving large particles out of the cell; ex: waste removal, secreting products

endocytosis

moving large particles into the cell

What are the three types of endocytosis?

phagocytosis, pinocytosis, and receptor-mediated endocytosis

phagocytosis

moving solid particles out of the cell

pinocytosis

moving liquid in large groups out of the cell

recepter-mediated endocytosis

bonding of particle to receptor before entering the cell

What are the six steps of cell signaling?

1. Synthesis and release of signal molecule
2. Transport molecule to target
3. Reception of info by target
4. Signal transduction
5. Response by cell
6. Termination of signal

What are three examples of cell communication?

1. Neutrons/Neurotransmitters
2. Hormones
3. Organism to Organism

cell signaling

mechanism by which cells communicate

What are the two types of cell signaling?

1. Physically close (combination of cells)
2. Chemical communication (at a distance)

Why do cells communicate? (3)

1. Share info about the environment
2. Coordinate response
3. Growth and development

What is an example of plants using cell communication?

trees releasing chemicals into the air to communicate to others to heighten their defenses; apples releasing Etheline when damaged to ripen faster

prostaglandins

convince smooth muscle to contract or relax (used in blood vessels)

What are three types of local regulators?

1. prostaglandins
2. nitric oxide
3. neurons

receptors

large proteins or glycoproteins that receive and process cell signals, bind ligands, highly selective, regulate rate of reception

What are the four types of surface receptors?

ion channel-linked receptors, G-Protein linked receptors, intracellular receptor and enzyme-linked receptors

ion channel-linked receptor

Generally, gates are closed until ligand binds to them, opening the channel. This allows ions to move in and out.

G-Protein Linked Receptor

In normal conditions, G-proteins are inactive and in three pieces. When activated, pieces join together and trigger the release of a secondary messenger inside the cell.

Enzyme-Linked Receptor

function directly, (de)activate enzyme, regulate enzyme

Intracellular Receptor

ligand binds to DNA, producing RNA