AP Bio Unit 2: Cell Structure and Function Vocabulary

Ribosomes

site of protein synthesis

Nucleus

A part of the cell containing DNA and RNA and responsible for growth and reproduction

Chloroplast

An organelle found in plant and algae cells where photosynthesis occurs

Lysosomes

cell organelle filled with enzymes needed to break down certain materials in the cell

Vacuoles

Cell organelle that stores materials such as water, salts, proteins, and carbohydrates

Mitochondria

An organelle found in large numbers in most cells, in which the biochemical processes of respiration and energy production occur.

Rough Endoplasmic Reticulum

An endomembrane system covered with ribosomes where many proteins for transport are assembled.

Smooth Endoplasmic Reticulum

An endomembrane system where lipids are synthesized, calcium levels are regulated, and toxic substances are broken down.

Golgi apparatus

A system of membranes that modifies and packages proteins for export by the cell

plasma membrane (cell membrane)

Flexible, selectively permeable (having pores or openings) boundary that helps control what enters and leave the cell.

main component of cell membrane

phospholipids

Cholesterol

A lipid that forms an essential component of animal cell membranes and regulates the rigidity of the cell membrane

protein channels

a protein that allows the transport of specific substances across a cell membrane

carbohydrates in cell membrane

Generally attached to proteins on extracellular surface

Can act as signaling and recognition molecules

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

active transport

Energy-requiring process that moves material across a cell membrane against a concentration difference

facilitated diffusion

process of diffusion in which molecules pass across the membrane through cell membrane channels

Osmosis

Diffusion of water through a selectively permeable membrane

isotonic solution

when the concentration of two solutions is the same

hypotonic solution

Solute concentration is less than that inside the cell; cell gains water

hypertonic solution

Solute concentration is greater than that inside the cell; cell loses water

Organelles

Structures specialized to perform distinct processes within a cell.

Peroxisomes

Break down fatty acids and produce hydrogen peroxide

detoxifies harmful substances

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

Eukaryote

A cell that contains a nucleus and membrane bound organelles

Nucleolus

produces ribosomes

Autophagy

A process in which lysosomes decompose damaged organelles to reuse their organic monomers

Chromosomes

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells

amphipathic

having both a hydrophilic region and a hydrophobic region

Glycolipids

Membrane carbohydrates that are covalently bonded to lipids.

Glycoproteins

Membrane carbohydrates that are covalently bonded to proteins.

integral proteins

penetrate the hydrophobic interior of the lipid bilayer

peripheral proteins

bound to the surface of the membrane

Hydrophilic

Attracted to water

Hydrophobic

Water fearing

selective permeability

A property of a plasma membrane that allows some substances to cross more easily than others.

fluid mosaic model

model that describes the arrangement and movement of the molecules that make up a cell membrane

polar

Molecule with partial charges. Mixes with water.

nonpolar

Molecule with no partial charges. Do not mix with water.

Ion

An atom or group of atoms that has a positive or negative charge.

passive transport

the movement of substances across a cell membrane without the use of energy by the cell

Exocytosis

Process by which a cell releases large amounts of material

Pinocytosis

process by which a cell takes in liquid from the surrounding environment

Endocytosis

process by which a cell takes material into the cell by infolding of the cell membrane

concentration gradient

difference in the concentration of a substance from one location to another

carrier proteins

bind to molecules and change shape to shuttle them across the membrane

Aquaporins

water channel proteins

Tonicity

The ability of a solution surrounding a cell to cause that cell to gain or lose water.

Osmoregulation

the control of solute concentrations and water balance

turgid

swollen as from a fluid; bloated

Plasmolysis

This happens when a cell shrinks inside its cell wall while the cell wall remains intact.

cotransport

The coupling of the "downhill" diffusion of one substance to the "uphill" transport of another against its own concentration gradient.

Vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

electrogenic pumps

membrane proteins that generate voltage across a membrane by the active transport of ions

water potential

the physical property that predicts the direction in which water will flow

Osmolarity

measure of total concentration of solute particles