biology - cells

active transport

movement of material against a concentration gradient. This method requires energy produced during respiration.

anaerobic respiration

respiration without oxygen

catalyst

substance which speeds up a chemical reaction without being used up itself

chloroplast

structure found in plants which is the site where photosynthesis occurs

cilia

tiny strands or threads around the outside of unicellular organisms which help the cilia move

cytoplasm

the semi-liquid material inside a cell in which all organelles float in

denatured

loss of an enzyme's normal shape so that it no longer functions; caused by a less than optimal pH and temperature

diffusion

the movement of material from high concentration to low concentration. This method does not require any energy.

endoplasmic reticulum (ER)

network of folded membranes with or without ribosomes, where many chemical reactions occur, or chemicals are transported

enzymes

proteins that acts as organic catalysts to speed up the rate of a chemical reaction

extracellular

outside the cell

flaccid

a cell that has lost water due to osmosis

flagella

long hair-like strands which whip back and forth to move a unicellular organism along

golgi bodies

organelle in the cytoplasm which modifies the packages secretions (proteins)

cell membrane

the lipid bilayer that surrounds the cytoplasm of a cell

mitochondria

organelles within the cell where respiration occurs

nucleus

the part of the cell which contains the cells genetic material and controls the cells processes

osmosis

the diffusion or movement of water through a semipermeable membrane from a high water concentration to low water concentration

phagocytosis

the process by which some cells may flow around particles and engulf them

photosynthesis

the process by which green plants manufacture glucose from carbon dioxide and water

plasmolysis

the process whereby cell lose water and cause the cytoplasm to shrink away from the cell wall

respiration

the process by which living cells break down large organic molecules to release energy in the form of ATP

semi-permanable membrane

a membrane which allows only small and uncharged molecules to pass through

specific enzyme

enzymes which control only one type of reaction

turgid

a cell that is full of water due to osmosis

unicellular

an organism made up of only one cell

vacuole

a large bubble filled with watery fluid inside a cell

ribosomes

site of protein synthesis

Proteins

enzymes, nails, hair etc are examples

christae

inner folds inside a mitochondrion which increase the surface area for the reactions during respiration

centriole

the small structures found in animal cells that are involved in cell division

grana

piles of disk like structures in a chloroplast where light is trapped and used to split the water molecule into oxygen and hydrogen

cellulose wall

the tough cellulose layer around plant cells which protects and supports the cell

lock and key model

the model by which substrates fit into the ridged active site of the enzyme

induced fit

the model by which substrates fit into the active site of the enzyme.

high surface area to volume ratio

small cells are better at diffusing things in and out due to their high surface area to volume ratio

contractile vacuole

the special organelle found in many freshwater unicellular organism to expel excess water. Form of active transport (ATP needed)

passive transport

the transport of small and uncharged molecules with the concentration gradient. No energy/ATP is needed.

active site

the place on an enzyme where the substrate fits

ATP

the main energy carrying molecule in an organism

organelle

the general name for the structures inside a cell

co-enzyme

a complex organic molecule which helps certain enzymes to function

concentration gradient

change in concentration between one area and another

cytoskeleton

a framework of microtubules inside the cytoplasm

electron transport chain

the series of reactions that produces ATP during respiration

fermentation

anaerobic respiration in plants

eye spot

a light sensing organelle which is often found in photosynthetic aquatic unicellular organisms

oral groove

opening which is often found in photosynthetic aquatic unicellular organisms which have to feed

glycolysis

the first stage of respiration where food is broken down into pyruvic acid

krebs cycle

middle stage of respiration which occurs inside the mitochondrial matrix space

lactic acid

toxic compound produced in animals during anaerobic respiration

light reaction

stage of photosynthesis where water is split by the sun's energy

liposomes

cell organelle which contains enzymes to breakdown unwanted cell components

nucleolus

dark stained region inside the nucleus where ribosomes are produced

osmoregulation

the maintenance of correct water level inside a cell/organism

phagocytes

cells which engulf and destroy solids (foreign) matter

pinocytosis

the process by which the cell membrane surrounds fluid to take it into the cell

rough ER

endoplasmic reticulum with ribosomes attached

smooth ER

endoplasmic reticulum with no ribosomes attached

stroma

'space' inside chloroplasts containing starch grains and enzymes

substrate

substance that an enzyme acts upon

activation energy

energy required so a reaction can start. enzymes and catalysts lower this