HSC Biology
What type of mutation occurs when a nucleotide substitution creates a premature stop codon?
Nonsence mutation
During meiosis, what process independently distributes homologous chromosomes into gametes?
Independent assortment
What enzyme adds complementary nucleotides to a growing DNA strand?
DNA polymerase
What type of immunity involves antibodies transferred across the placenta?
Natural Passive Immunity
What mutation changes a codon without changing the amino acid produced?
Silent Mutation
What process produces genetically unique gametes through homologous chromosome exchange?
Crossing Over
What immune cells destroy infected body cells?
Cytotoxic T cells
What evolutionary mechanism is particularly significant in small populations following a random reduction in population size?
Genetic Drift
What type of pathogen lacks its own cellular machinery for reproduction?
Virus
What genetic phenomenon occurs when one allele completely masks the expression of another allele?
Complete Dominance
During DNA replication, which strand is synthesised discontinuously?
Lagging Strand
What structure on tRNA pairs with a complementary sequence on mRNA.
Anti codon
What type of pathogen causes tuberculosis?
Bacteria
What small circular DNA molecule is commonly found in bacteria?
Plasmid
What mutation results when nucleotides are added or removed in numbers not divisible by three?
Frameshift mutation
What type of immunity develops following exposure to an antigen and production of memory cells?
Active Immunity
What DNA fragments are produced on the lagging strand?
Okazaki Fragments
What is the main evolutionary significance of meiosis?
Increase genetic variation
What type of anaemia results from abnormal haemoglobin caused by a genetic mutation?
Sickle Cell anemia
What meiotic error can produce an extra chromosome
Give 2 examples of positive feedback loop, breifly explain how they work.
Blood Clotting and Oxytocin Levels during pregnancy
A person has two copies of a recessive disease allele but shows no symptoms. What term describes this individual?
Unaffected carrier
Give 2 examples of negative feedback loop and briefly explain how they work
Insulin and Glucagon levels
Temperature (thermoregulation)
What are the 2 types of hearing loss.
Conductive - outer and middle ear problems
Sensrorineural - inner ear damage
What hormone increases water reabsorption in the kidney by making the collecting ducts more permeable to water?
ADH (antidiuretic hormone)