Biology Terms Flashcards
Organelles
are tiny structures that are present in a cell’s cytoplasm as discrete units normally surrounded by a membrane and responsible for a specialised function (such as photosynthesis)
Ultra structure
The ultrastructure of a cell is its fine structure as revealed at high magnification.
Cell Membrane
The cell membrane controls the movement of molecules into and out of the cell. It is described as selectively permeable.The cell membrane is made up of two types of molecule: proteins and phospholipid.
Passive Transport
Passive transport is the movement of molecules down a concentration gradient from a high concentration to a lower concentration, and does not require energy for it to take place.
Diffusion
The movement of a molecule down a concentration gradient from a high concentration to a lower concentration.
Osmosis -
Osmosis is a special case of diffusion that specifically involves water.
Active Transport -
The movement of molecules and ions against a concentration gradient, from a region of low concentration to a region of high concentration.
Mitosis
Normal cell division and provides new cells for growth and repair of damaged cells and maintains the diploid
chromosome complement
Complementary base pairing
Holds DNA strands together.
A-T
G-C
Base sequence codes
The order of bases (C-G-T-A) on a DNA/mRNA strand. The base sequence determines the amino acid sequence in a protein
mRNA
MRNA carries a complementary copy of the code from the DNA, in the nucleus, to a ribosome
Ribosomes
The site of protein synthesis - The protein is assembled from amino acids
Amino acids
coded from the sequence of base pairs. IT makes up proteins.
Biological catalysts
Speed up biochemical reactions in cells and remain unchanged in the process
Active site
Area on an enzyme’s surface that binds with a specific substance
Substrate
The reactant(s) in a reaction, and is specific to an enzyme
Optimum conditions
Are the temperature and pH which the enzymes work best at
Denatured
When the active site permanently changes shape and affects the rate of the enzyme reaction
Genetic engineering
Transferring genetic information (DNA) from one cell into another
Light reactions
Stage one of respiration that breaks one molecule of glucose down into 2 molecules of pyruvate and releases enough energy to make 2 ATP molecules
Carbon fixation
Stage 2 with oxygen (aerobic respiration) breaks pyruvate down into carbon dioxide and water and yields 36 ATP molecules
Respiration
A series of enzyme-controlled reactions which release the chemical energy stored in glucose
ATP
Adenosine triphosphate
Molecule that is the main energy carrier molecule in cells
Aerobic respiration
Type of respiration requiring oxygen in which substrates such as glucose are completely broken down to water and carbon dioxide to release large amounts of energy
Anaerobic respiration
Respiration where oxygen isn’t present
Fermentation
Stage 2 of respiration without oxygen is called