AP BIO CELL TEST

flagella

whip like tails found in one-celled organisms to aid in movement; cellular locomotion

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

eukaryote

A cell that contains a nucleus and membrane bound organelles and chromosomes; evolved from prokaryotes

unified cell theory

all living things are composed of one or more cells; new cells arise from existing cells

electron microscope

use a beam of electrons instead of light to produce a magnified image

3 domains of life

Bacteria, Archaea, Eukarya

plasma membrane

separates cell from environment, semipermeable phospholipid bilayer with embeded proteins; controls passage of organic molecules, ions, water, and oxygen in and out of the cell

phospholipid

lipid molecule with 2 fatty acid chains and phosphate group

cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended; provided turgor pressure to plant cells as fluid inside the central vacuole; site of metabolic reactions

cystol

gel-like stuff in cytoplasm; semi-solid consistency due to proteins; contains proteins, amino acids, fatty acids, nucleic acids, and ions

ribosomes

important for synthesis of proteins; small and large subunits; receives orders for protein synthesis from nucleus, where DNA is transcribed to mRNA

Amino Acid

a building block of proteins that are added to the protein chain within a ribosome based upon the information encoded in the mRNA base sequence

Doexyribonucleic acid (DNA)

store and transmit hereditary information

cell wall

A rigid layer of nonliving material that surrounds the cells of plants and some other organisms; made mostly of cellulose

nucleoid

DNA exists as single circular chromosome in the center of the cell; contains single celled organisms

polysaccharide capsule

enables the cell to attach to surfaces in its environment

pili

Appendages that allow bacteria to attach to each other and to transfer DNA

Fimbriae

help prokaryotes stick to each other and to surfaces; attach to host cell

cilia

cellular locomotion, movement of particles along extracellular surface of plasma membrane; filtration

extracellular matrix

the material, primarily collagen, glycoproteins, and proteoglycans, secreted from animal cells that provides mechanical protection and anchoring for the cells in the tissue; allows cells within tissue to communicate with each other

surface area to volume ratio

Ratio of a cell's outside area to its internal volume; as cell size increases, ration decreases

cell efficiency

the larger the cell, the less efficient it is, because diffusion and movement of materials takes longer (go farther); increase area makes a cell more efficient

cell shape

squamous, cuboidal, columnar; allows for a shorter distance of travel for nutrient exchange

microvilli

finger-like projections of folded plasma membrane of absorption cells; lines the intestines

nucleus

houses cell's DNA and directs the synthesis of ribosomes and proteins

nuclear envelope

double-membrane structure that constitutes outermost portion of nucleus (phospholipid bilayer); punctuated with pores that allow molecules to pass

chromosomes

structures within the nucleus that are made up of DNA; every species has specific number in the nucleus; can only be seen when cells are about to divide

chromatin

unwound protein-chromosome complex; material that makes up chromosomes

nucleolus

darkly staining body within nucleus that is responsible for assembling ribosomal subunits

mitochondria

powerhouse of cell; responsible for making ATP, cells main energy molecule, abundant in muscle cells; have their own ribosomes and DNA

Adenosine Triphosphate (ATP)

short-term stored energy of a cell; used to power majority of energy requiring reactions; made of 5 carbon sugar, adenine nucleotide, and 3 phosphate groups; has potential to break bonds and release energy

mitochondrial matrix

area surrounding folded cristae of mitochondria

peroxisomes

small, round organelles enclosed by single membranes; carry out oxidation reactions, break down fatty and amino acids

vesicles and vacuoles

membrane bound sacs that function in storage and transport; can fuse with other membranes (only vesicles)

centrosomes

microtubule-organization center found near nuclei of animal cells; eplicate before cell divides

centrioles

cylinder of 9 triplets of microtubules; pull chromosomes to poles during anaphase

lysosomes

cell's "garbage disposal;" aid breakdown of proteins, lipids and old organelles; more acidic that cytoplasm and allows for acidic reactions that couldn't happen in cytoplasm

chloroplasts

plant cell organelles that carry out photosynthesis; contain their own DNA and ribosomes; contain interconnected fluid-filled sacs called thylakoids

photosynthesis

uses carbon dioxide, water, and light to make glucose and oxygen and energy for plants

autotrophs

make own food; plants

heterotrophs

must eat something for food (animals/humans)

Chlorophyll

A green pigment found in the chloroplasts of plants, algae, and some bacteria; captures the light energy that drives photosynthesis

central vacuole

regulates cell's concentration of water in changing environmental conditions; supports expansion of cells

endoplasmic reticulum (ER)

a series of interconnected membranous sacs and tubules that collectively modifies proteins and synthesizes lipids; membrane is continuous with nuclear envelope membrane

rough ER

ribosomes attached to its cytoplasmic surface give studded appearance; accepts newly synthesized proteins and modifies them

transport vesicles

bud off ER membrane holding proteins or phospholipids to transport out to the rest of the cell

smooth ER

continuous with rough ER, but has few to no ribosomes on surface; synthesis of carbs, lipids, hormones; detoxify medications and poisons; storage of calcium ions

Golgi apparatus

series of flattened membranes that sort, tag, pack, and distribute lipids and proteins; modified by adding sugar that tag it and direct it to the destination

secretory vesicles

packaged proteins that bud of trans face of golgi apparatus; deposit contents to other parts of cell, fuse with plasma membrane and release contents out of cell

phagocytosis

section of plasma membrane folds in and engulfs a pathogen, pinches off, and becomes vesicles that fuse with lysosomes and kill the pathogen

cytoskeleton

protein fiber network, helps maintain the shape of the cell, secure some organelles in specific positions, allow cytoplasm and vesicles to move within the cell and enable cells within multicellular organisms to move

microfilaments

narrowest; function in cellular movement; made of 2 intertwined strands of a globular protein - actin

filiments

serve as a track for movement of myosin, a motor protein

intermediate filaments

made of several strands of fibrous proteins wound together, middle size, function is purely structural; bear tension and maintain shape of cell and anchor nucleus in place

microtubules

small hollow tubes, widest components of cytoskeleton, made of polarized dimers of a-tubulin and B-tubulin; help cells resist compression, provide a track along which vesicles move through the cell, and pull replicated chromosomes to opposite ends of dividing cells

gap junctions

in animal cells; channel between adjacent cells that allow for the transport of ions, nutrients, and other substances that enable cells to communicate

integral proteins

span the membrane, transport materials in or out of cells, hydrophobic or hydrophilic; may or may not penetrate through both layers

peripheral proteins

found on exterior and interior surface of membrane are enzymes, part of cytoskeleton structure and part of cell's recognition sites

cell specific prteins

part of plasma membrane, transmit signals by means of integral proteins; receiver of input and activator of intercellular processes

Singer and Nicolson

fluid mosaic model, still used today

fluid mosaic model

a mosaic of components, including phospholipids, cholesterol, proteins, and carbs, that give the membrane a fluid character

Hydrophobic lipid tails

fatty acid part of phospholipids, no charge, water fearing, facing inside of membrane

hydrophilic lipid head

phosphate containing part of phospholipid, polar, negative change, can form hydrogen bonds, heads facing outward

carbs in plasma membrane

forms specialized sites on cell surface to allow cells to recognize each other; allows body to distinguish between "self" and "non-self" cells

fluidity of membrane

loosely connected, made of unsaturated fatty acids, so the kinks due to double bonds allow the tails some extra room to move more freely

osmosis

diffusion of free water molecules across plasma membrane; moved through aquaporins according to the concentration gradient

tonicity

how the extracellular concentration of solutes can change volume of cell by effecting osmosis

hypertonic

extracellular fluid has a lower osmolarity than inside the cell; water enters cell

isotonic

concentration of solutes are equal on both sides of membrane; no net water movement

Hypotonic

Having a lower concentration of solute than another solution

selectively permeable membrane

allow some substances to pass through, but not others; some use ATP to gain necessary molecules and materials

passive transport

a naturally occurring phenomenon and does not require the cell to exert any of its energy to accomplish movement; moves from high concentration to low concentration

diffusion

passive transport; move from high to low concentration, until reached equilibrium in and out; needs no energy

dynamic equilibrium

movement of molecules after concentration gradient has been removed (no net movement)

factors that effect rate if diffusion

1) extent of concentration gradient (greater difference = more rapid diffusion)

2) mass of molecules diffusion (heavier molecules move slower)

3) temp (high temp = high energy = increase rate of diffusion)

4) solvent density (density increase, rate of diffusion decreases)

5) solubility (nonpolar and lipid molecules pass through membrane more easily)

6) surface area and thickness of membrane (high surface area = high rate of diffusion)

7) distance traveled (greater distance = slower rate if diffusion)

filtration

material moves according to its concentration gradient through a membrane; pressure can increase the rate of diffusionand siltrations

facilitated transport

materials diffuse across the plasma membrane with the help of membrane proteins

facilitated transport proteins

shield materials from the repulsive force of the membrane, allowing molecules into the membrane

transport proteins

integral prtiens involved in facilitated transport; function as either channels for material or carriers

channel proteins

have hydrophilic domains exposed to the intracellular and extracellular fluids; have a hydrophilic channel through their core that provides a hydrated opening though the membrane layers; much quicker than carrier proteins

aquaporins

channel proteins that allow water to pass through the membrane at very high rates

carrier proteins

binds a substance and trigger a change of its own shape, moving the bound molecules from the outside of the cell to interior; specific for each substance

osmolarity

total solute concentration of the solution (measures number of particles); high = fewer water molecules with respect to solute particles

hypotonic solutions

extracellular fluid has lower osmolarity than the fluid inside the cell, water enters cell

hypertonic solution

extracellular fluid having a higher osmolarity than the cell's cytoplasm, water moves out and leaves the cell

osmoregulation

regulation of solute concentrations and water balance by a cell or organism; controlling effects of osmosis

plasmolysis

plant is hypertonic, membrane detaches from the cell wall and constricts the cytoplasm; loses turgor pressure and wilts

active transport

mechanisms require the use of the cell's energy (ATP); moves against the gradient - concentration inside cell is greater than outside the cell

electrochemical gradient

combined gradient of concentration and electrical charge that affects an ion; interior has negative charge

pumps

work agains the electrochemical gradient, using ATP

primary active transport

moves ions across a membrane and creates a difference in charge, which is directly dependent on ATP

secondary active transport

movement of material that is sue to the electrochemical gradient, does not directly require ATP; uses kinetic energy of ions to create compounds

transporters

specific carrier proteins or pumps to facilitate membrane movement

uniporter

carries one specific ion or molecule