key terms - cells Flashcards
Active transport
Movement of materials across membranes by using energy.
endocytosis vs exocytosis
Endocytosis:
The process of a cell’s membrane stretching out around a large particle in order to engulf it.
Exocytosis:
The process of a cell ‘spitting out’ a large particle by fusing a vesicle with the cell membrane.
What are the ‘pumps’ in active transport?
= ‘machinery’ that pumps a substance from an area of low concentration to an area of high concentration, against its concentration gradient.
Cell
The basic building block of every living thing.
DNA Replication
The process of creating a copy of every chromosome in the nucleus in preparation for mitosis.
Double helix
The spiral shape of DNA
Nucleotide
A group of a sugar, phosphate and a base.
Complimentary base pairing
A pairs with T
C pairs with G
Enzymes
Biological catalysts, which speed up the reactions inside cells.
Active site
The ‘pocket’ in the surface of an enzyme where the substrate binds
Substrate
The reactant catalysed by the enzyme
Mitosis
The process of splitting one cell into two identical cells (cloning)
Rate Limiting Factor
The reactant that is present in the smallest amount and therefore stops the rate of the reaction from increasing beyond a certain point.
Organelles
The ‘machinery’ inside cells which enables them to carry out their life processes.
Cell membrane
A phospholipid bilayer that surrounds a cell and determines what can get in and out of the cell
Cell wall
A rigid structure that wraps around the outside of the cell membrane to give plant cells a rigid shape and structure.
Chloroplasts
The organelle where photosynthesis is carried out (in plants).
Chlorophyll
A pigment that traps sunlight.
Grana
Stacks of thylakoids inside the stroma.
Stroma
The liquid-filled space inside the inner membrane of chloroplasts.
Thylakoids
Sacs covered with chlorophyll.
Mitochondria
The organelle where respiration is carried out.
Cytoplasm
The jelly-like, nutrient-rich substance that fills up cells.
Cristae
The wiggly inner membrane of mitochondria (the wiggles increase surface area).
Intermembrane space
The space between the inner and outer membranes in mitochondria.
Matrix
The liquid-filled space inside the inner membrane of mitochondria.
Nucleus
The ‘control centre’ of the cell, containing the cell’s DNA.
Passive transport
Movement of materials across cell membranes without the use of energy.
Diffusion
The movement of a substance from an area of high concentration toan area of low concentration, down its concentration gradient.
Osmosis
The movement of water from an area of low solute concentration to an area of high solute concentration.
Facilitated Diffusion
Diffusion of larger or charged molecules through channels inserted in the membranes of cells.
Solute
A substance that is dissolved in water.
Photosynthesis
The process of using light energy (from sunlight) to convert water and carbon dioxide into glucose for the plant to use as fuel to carry out its life processes.