AP biology unit 2

active transport

the movement of molecules or ions across a cell membrane; requires ATP; lower concentration to higher concentration, against the concentration gradient

amphipathic

having both hydrophobic and hydrophillic parts

apoptosis

the process of programmed cell death

aquaporin

type of integral membrane (channel) protein that facilitates the transport of water across cell membranes

channel protein

integral membrane protein that creates holes/pores that penetrate the membrane, enabling molecules or ions to flow through without interacting with the protein

carrier protein

integral membrane protein that binds to molecules on one side of the membrane and release them on the other

ATP (adenosine triphosphate)

the source of energy for use and storage at the cellular level

cell (plasma) membrane

a biological membrane that separates and protects the interior of a cell from the outside environment

cell wall

a rigid layer of polysaccharides lying outside the plasma membrane of plant, fungi and bacteria cells

centrioles

in animal cells (not plant cells); cylinder shape made of 9 microtubules; their function is to organize microtubules in the cytoplasm

chloroplast

an organelle (in plants) where photosynthesis takes place

cholesterol

structural component of cell membrane; serves as a building block for synthesizing various steroid hormones

common ancestry

ancestral organism shared by two or more descendant lineages (homology)

homology

similarity of structure, physiology, or development based upon descent from a common evolutionary ancestor

compartmentalization

compartments (membrane-bound organelles and internal membranes) in eukaryotic cells

concentration gradient

the difference in the concentration of solute and solvent between sides of a membrane

cytoplasm

includes everything inside of the cell, except the nucleus

cytoskeleton

the structure that maintains the shape and organization of the cell and provides the cell’s mechanical support

cytosol

the fluid where organelles reside in a cell

diffusion

the movement of molecules from an area of high concentration of the molecules to an area with a lower concentration

double membrane

structure that consists of two layers of phospholipids surrounding a cellular organelle (inner and outer membrane; intermembrane space between the two membranes)

endocytosis

process by which cells take in substances (nutrients or pathogens) from outside of the cell by engulfing them in a vesicle (if the cell is immune to the entering pathogen it will destroy it)

endoplasmic reticulum

transportation organelle made of the smooth ER and the rough ER; only found in eukaryotes; it’s functions include protein folding and protein and lipid molecule synthesis

endosymbiosis

two organisms living together with one inside the other

endosymbiotic theory

proposes that some of the organelles in eukaryotic cells were once prokaryotic microbes

eukaryotic cells

cells containing organized nucleus and organelles which are enveloped by membrane-bound organelles

exocytosis

process by which large molecules move out of the cell to the cell exterior

extracellular

situated or occurring outside of a cell(s)

facilitated diffusion

the diffusion of solutes through transport proteins in the plasma membrane; type of passive transport because the solute is moving down the concentration gradient

flagella

microscopic hair-like structure involved in the locomotion of a cell

fluid mosaic model

describes the fluid and flexible nature of the cell membrane and also the components its made from

glycolipid

lipid with a carbohydrate attached by a glycosidic (covalent) bond

glycoprotein

molecule that consists of a carbohydrate plus a protein

golgi complex

a stack of small flat sacs formed by membranes inside the cell’s cytosol; prepares protein and lipid molecules for use in other places in or outside of the cell

heat exchange

the process of energy exchange between systems through their interconnected boundaries