AP Biology Unit 2

ribosomes

universal cell component; synthesize proteins from mRNA sequences; consist of rRNA and proteins

endoplasmic reticulum

network of membrane tubes in cytoplasm of eukaryotic cells

rough endoplasmic reticulum

has ribosomes on the membrane; packages newly-synthesized proteins for potential export

smooth endoplasmic reticulum

detoxifies and synthesizes lipids

Golgi apparatus

series of flattened membrane-bound sacs; involved in protein folding and chemical modification of synthesized proteins and protein packaging

mitochondria

functions in the production of ATP for cell work; double membrane to increase surface area

lysosomes

membrane-enclosed sacs containing hydrolytic enzymes used to digest materials (damaged cell parts, macromolecules)

vacuoles

membrane-bound sacs that vary in function between plant and animal cells; store macromolecules, release waste and help maintain turgor pressure in plant cells.

chloroplasts

have a double outer membrane; specialized for photosynthesis to produce sugar for the organism

thylakoids

folded membrane compartments organized in stacks called grana; site of the light-dependent reactions of photosynthesis.

chlorophyll

pigments that comprise photosystems and are essential for capturing light energy during photosynthesis.

stroma

fluid between the inner chloroplast membrane and outside thylakoids; place of carbon fixation reactions

Krebs cycle

citric acid cycle occurring in the matrix of the mitochondria

turgor pressure

internal cellular force, typically from water pushing against the plasma membrane and cell wall

apoptosis

self-initiated cell death

stomata

structures on plants that aid in exchange of materials with the surrounding environment

cell membrane

create a boundary between the cell interior and outside environment; control transport of materials in/out of the cell

phospholipids

form a bilayer in aqueous environments; composed of a phosphate head and a fatty acid tail

peripheral proteins

embedded protein bound loosely to the surface of the membrane; hydrophilic, charged/polar side groups

integral proteins

embedded protein spanning the membrane; amphipathic

embedded protein functions

transport; cell-cell recognition; enzymatic activity; signal transduction; intercellular joining; extracellular matrix/cytoskeleton attachment

the fluid mosaic model

the bilayer of the cell membrane is a dynamic structure with a interspersed proteins in a fluid bilayer; most lipids and some proteins can shift/flow along the membrane

cholesterol

randomly distributed/wedged between phospholipids; maintains bilayer fluidity when extracellular conditions change

amphipathic

simultaneously hydrophobic and hydrophilic

carbohydrates

in cell membrane: function as markers

channel protein

tunnel that spans membrane, allows target molecules to pass through

carrier proteins

span membrane, change shape to allow target molecules to move through

chitin

polysaccharide that forms cell walls of fungi

peptidoglycan

sugar/amino acid polymer that forms cell walls of prokaryotes

concentration gradient

when a solute is more concentrated in one area than another

passive transport

net movement of molecules from high to low concentration without input of metabolic energy

diffusion

small molecules move through the lipid bilayer

facilitated diffusion

large nonpolar molecules and ions through specific or non-specific transport proteins

active transport

net movement of molecules from low concentration to high concentration with the input of metabolic energy (ex. ATP)

endocytosis

when the cell takes in macromolecules and particulate matter using energy to form new vesicles

phagocytosis

endocytosis of large particles

pinocytosis

endocytosis of extracellular fluid containing dissolved substances

receptor-mediated endocytosis

receptor proteins on cell membrane capture target molecules

exocytosis

internal vesicles use energy to fuse with the plasma membrane and secrete large macromolecules out of the cell (ex. proteins, hormones, waste)

electrochemical gradient

concentration gradient concerning electrical potential difference across a membrane

osmosis

diffusion of free water across a semi-permeable membrane (through aquaporins in large quantities)

osmolarity

the total solute concentration in a solution

tonicity

the measurement of the relative concentrations of solute inside and outside the cell

hypertonic

more solute inside

hypotonic

less solute inside

isotonic

equal concentrations inside and out

plasmolysis

water leaving the cell; occurs when a cell is in a hypertonic environment

turgid

the optimal state for plant cells; when a cell is in a hypotonic environment and is filled with water

water potential

measures the tendency of water to move by osmosis; more negative values = more likely movement of water to the negative

requirements for active transport

metabolic energy; membrane proteins; sodium/potassium pump maintaining gradient

nucleoid region

where genetic material is located in prokaryotic cells

endosymbiotic theory

the theory that mitochondria and chloroplasts originated from free-living prokaryotes that were taken up by ancestral eukaryotic cells. supported by the mitochondria and chloroplasts possessing their own DNA, ribosomes, and double membranes

nucleus function

houses genetic material and controls cellular activities by regulating gene expression.

nucleolus function

is involved in ribosomal RNA synthesis and assembly of ribosomal subunits.

ribosome function

involved in protein synthesis, translating mRNA into polypeptide chains.

rough ER function

synthesizes and processes proteins destined for the membrane or export.

smooth ER function

involved in lipid synthesis and detoxification processes in cells.

Golgi apparatus function

modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.

lysosome function

functions to break down waste materials and cellular debris, containing digestive enzymes.

peroxisome function

involved in the breakdown of fatty acids and detoxification of hydrogen peroxide.

vacuole function

storage of substances, maintaining cellular turgor and homeostasis.

cytoskeleton function

provides structural support, helps in cell movement, and aids in intracellular transport.

microfilaments

are the thin, thread-like components of the cytoskeleton that play a key role in muscle contraction, cell division, and maintaining cell shape.

microtubules

are the thick, hollow tubes of the cytoskeleton that provide structural support, facilitate cell division, and serve as tracks for intracellular transport of organelles.

centrosome function

is the organization of microtubules and serves as a major microtubule organizing center in the cell, playing a critical role in cell division.

mitochondrion function

is to generate adenosine triphosphate (ATP) through aerobic respiration, providing energy for various cellular processes.

glycolipid function

is to provide structural support to the cell membrane and facilitate cell recognition and signaling by serving as a component of the lipid bilayer.

glycoprotein function

is to aid in cell recognition, signaling, and adhesion by serving as a component of cell membranes and interacting with other molecules.