thanks chat gpt Flashcards
(37 cards)
What direction does diffusion occur?
Down a concentration gradient.
How does active transport work?
Against a concentration gradient using ATP.
What type of molecules pass through the membrane?
Small, non-polar molecules diffuse through the phospholipid bilayer.
How does water move in osmosis?
From a region of high to low water potential.
What base pairs form in DNA?
Complementary base pairing: A with T, C with G.
What bonds hold base pairs together?
Hydrogen bonds.
What is meant by ‘degenerate code’?
More than one codon codes for the same amino acid.
What happens in transcription?
RNA polymerase joins RNA nucleotides to form pre-mRNA.
How do enzymes catalyse reactions?
By forming enzyme-substrate complexes.
What model explains enzyme specificity?
Induced fit model — active site changes shape to fit substrate.
What causes enzyme denaturation?
Bonds in the tertiary structure break, changing the active site shape.
What is an antigen?
A foreign protein that triggers an immune response.
Role of T-helper cells?
Activate B cells and stimulate phagocytes.
What do B cells do?
Clone into plasma cells which secrete specific antibodies.
How does a vaccine work?
Stimulates production of memory cells.
What happens to water in the light-dependent reaction?
Photolysis — splits into protons, electrons, and oxygen.
What enzyme fixes carbon in the Calvin cycle?
RuBisCO.
Final electron acceptor in respiration?
Oxygen.
Purpose of anaerobic respiration?
Regenerates NAD for glycolysis to continue.
What is a recessive allele?
Only expressed when homozygous.
How does meiosis cause variation?
Crossing over and independent assortment.
What test compares observed vs expected ratios?
Chi-squared test.
What do restriction enzymes do?
Cut DNA at specific recognition sites.
What joins DNA fragments?
DNA ligase.
