1. Aqa Gcse Biology: Cell Biology Study Guide Rated A+

Nanometre {Ans: nm, billionth of a metre, 10^-9m}What do plants require mineral ions for? {Ans: Healthy growth}Interphase {Ans: Longest part of cell cycle; cell grows, develops and functions in parts of our body. Almost at the end of interphase, genetic material is doubled}How are the lungs in mammals adapted for exchanging materials? {Ans: Alveoli have an enormous surface area and rich blood supply}Why must the Petri dishes and culture be sterilised before use? {Ans: To ensure no microbes are present before the experiement}Active transport {Ans: Move substances from a more dilute solution to a more concentrated solution (against a concentration gradient). This requires energy from respiration.}During the cell cycle, the genetic material... {Ans: ...is doubled and then divided into two identical cells}How are gills in fish adapted for exchanging materials? (3) {Ans: 1. Many gill filaments increase surface area 2. Gills have a rich blood supply - lots of capillaries 3. Pump water needed to maintain concentration gradient over gills with a flap called the operculum}What 3 factors affect the rate of diffusion? {Ans: 1. Temperature 2. Surface area of membrane 3. Steepness of concentration gradient (difference in concentrations)}Most animal cells