AQA A LEVEL BIOLOGY QUESTIONS AND ANSWERS 100% PASS

AQA A LEVEL BIOLOGY QUESTIONS AND ANSWERS 100% PASS the krebs cycle takes place in the _______ of the ___________ matrix mitochondria epistasis arises when the allele of one gene affects or masks the expression of another in the phenotype autosome a chromosome that is not a sex chromosome biodiversity the range and variety of genes, species and habitats within a particular region biomass the total mass of living material, normally measured in a specific area over a given period of time intraspecific competition competition between organisms of the same species interspecific competition competition between organisms of different species krebs cycle series of aerobic biochemical reactions in the matrix of the mitochondria of most eukaryotic cells by which energy is obtained through the oxidation of acetylcoenzyme A produced from the breakdown of glucose meiosis the type of nuclear division in which the number of chromosomes is halved mutation a sudden change in the amount or the arrangement of the genetic material in the cell NADP a molecule that carries electrons produced in the light dependent reaction of photosynthesis selection process that results in the best-adapted individuals in a population surviving to breed and so pass their favourable alleles to the next generation selection pressure the environmental force altering the frequency of alleles in a population stroma matrix of a chloroplast where the light-independent reaction of photosynthesis occurs substrate-level phosphorylation the formation of ATP by the direct transfer of a phosphate group from a reactive intermediate to ADP stabilising selection preserves the average phenotypes (ones around the mean) of a population by favouring average individuals. in other words, selection against the extreme phenotypes