Bio - Cells - Y12

activation energy

minimum amount of energy required to trigger a chemical reaction

active site

the site on an enzyme that attaches to a substrate

active transport

movement of molecules through protein channels in the membrane from low to high concentration requiring energy (ATP)

ADP

(Adenosine Diphosphate) The compound that remains when a phosphate group is removed from ATP, releasing energy

aerobic

Containing oxygen; referring to an organism, environment, or cellular process that requires oxygen.

anaerobic

process that does not require oxygen

ATP

(adenosine triphosphate) main energy source that cells use for most of their work

Catalyst

(chemistry) a substance that initiates or accelerates a chemical reaction without itself being affected

Cell membrane

thin, flexible barrier around a cell; regulates what enters and leaves the cell

cell wall

a rigid structure that surrounds the cell membrane and provides support to the cell

cellular respiration

process that releases energy by breaking down glucose and other food molecules in the presence of oxygen

cellulose

hard, nonliving material that makes up the cell wall of a plant cell

centriole

organize the spindle fibers to separate chromosomes during animal cell mitosis

chloroplast

organelle found in cells of plants and some other organisms that captures the energy from sunlight and converts it into chemical energy

co-enzyme

a small molecule (not a protein but sometimes a vitamin) essential for the activity of some enzymes

concentration gradient

a difference in the concentration of a substance across a distance

cristae

Infoldings of the inner membrane of a mitochondrion that houses the electon transport chain and the enzyme catalyzing the synthesis of ATP.

cytoplasm

A jellylike fluid inside the cell that holds the organelles.

denatured

destroyed by high temps that change their pH and can no longer function properly

endoplasmic reticulum

a cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another

enzyme

protein that acts as a biological catalyst

flaccid

lacking firmness or stiffness

glycolysis

a metabolic process that breaks down carbohydrates and sugars through a series of reactions to either pyruvic acid or lactic acid and release energy for the body in the form of ATP

golgi apparatus

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

grana

a stack of thylakoids within a chloroplast

induced fit model

change in the shape of an enzyme's active site that enhances the fit between the active site and its substrate(s)

lock and key theory

This theory says that the enzymes active site is exactly complementary to the structure of the substrate.

lysosome

membrane-bound sac containing digestive enzymes that can break down proteins, nucleic acids, and polysaccharides

mitochondria

Powerhouse of the cell, organelle that is the site of ATP (energy) production

nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

osmoregulation

the control of the gain and loss of water and dissolved solutes in an organism

osmosis

diffusion of molecules through a semipermeable membrane from a place of higher concentration to a place of lower concentration until the concentration on both sides is equal

passive transport

transport of a substance across a cell membrane by diffusion

phagocytosis

process in which phagocytes engulf and digest microorganisms and cellular debris

pinocytosis

process by which certain cells can engulf and incorporate droplets of fluid

plasmolysis

when a cell is in a hypertonic environment, the cell will lose water to its surroundings, shrink, and its plasma membrane will pull away from the wall

ribosome

site of protein synthesis

semipermeable membrane

a membrane (as a cell membrane) that allows some molecule to pass through but not others

stroma

watery substance where light independent reactions take place, location of enzymes needed for calvin cycle

substrate

The reactant on which an enzyme works.

turgor

a cell's swelling against its cell wall caused by the pressure of the cell's contents

vacuole

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

vesicle

small membrane-bound sac that functions in moving products into, out of, and within a cell

pyruvate

Three-carbon compound that forms as an end product of glycolysis.

Krebs Cycle

a series of biochemical reactions that convert pyruvic acid into carbon dioxide and water; it is the major pathway of oxidation in animal, bacterial, and plant cells, and it releases energy

enzyme inhibitor

any substance or molecule that slows down the rate of an enzyme-controlled reaction by affecting the enzyme molecule in some way

Photosynthesis

6CO2 + 6H2O --> C6H12O6 + 6O2

Respiration

C6H12O6 + 6O2 --> 6CO2 + 6H2O

Glucose

C6H12O6

Thylakoid

Found in chloroplasts and contains chlorophyll. It is where the light dependant reactions take place.

Grana

A stack of thylakoids within a chloroplast. Singular form is granum.

Light dependent reaction

Reaction in thylakoids in which light and water are used to produce oxygen, ATP, and reduced NADP

Light independent reaction

Uses products from the light dependent reaction to convert carbon dioxide to an organic molecule (usually sugar)

Limiting factors

A feature that reduces the rate of photosynthesis