Key Concepts in Biology Flashcards
Active site
A specific region on an enzyme where the substrate binds and the reaction takes place.
Active transport
The movement of substances from a low concentration to a higher
concentration (against the concentration gradient) across a membrane, with the use of
energy from respiration.
Cell membrane
A partially permeable barrier that surrounds the cell.
Cell wall
An outer layer made of cellulose that strengthens plant cells
Chloroplast
An organelle that is the site of photosynthesis.
Cilia
Hair-like structures found on ciliated epithelial cells which waft substances across the
surface of the tissue in one direction.
Concentration gradient
The difference in concentration between two areas.
Denatured
Upon exposure to high temperatures or extremes of pH, the permanent
change in the shape of an enzyme’s active site that prevents the binding of a substrate.
Diffusion
The net spreading out of particles from a high concentration to a lower
concentration (down their concentration gradient)
Diploid cell
A cell that contains two copies of each chromosome (i.e. a full set of
chromosomes).
Egg cell
A specialised female sex cell involved in reproduction.
Electron microscope
- A type of microscope that uses a beam of electrons, focused using
magnets, to produce an image of a specimen. It has a greater magnification and resolution
than a light microscope.
Enzyme
A biological catalyst that increases the rate of reactions in living organisms.
Eukaryotic cell
A type of cell found in plants and animals that contains a nucleus.
Flagella
A long hair-like structure found on bacterial cells that is used for cell movement.
Haploid cell
A cell that contains a single copy of each chromosome (i.e. half the number of
chromosomes).
Lipid
A large molecule that is synthesised from fatty acids and glycerol
Magnification
magnification = image size / object size
Mitochondria
An organelle that is the site of respiration.
Nucleus
An organelle found in most eukaryotic cells that contains the genetic material of
the cell and controls the activities of the cell.
Osmosis
The diffusion of water molecules from a region of high water concentration to a
region of lower water concentration across a partially permeable membrane.
Plasmid
Loops of DNA found in the cytoplasm of prokaryotic cells.
Prokaryotic cell
A type of cell found in bacteria that does not contain a nucleus.
Protein
A large molecule that is synthesised from amino acids.
