Edexcel A Level Biology |83 Questions| With Correct Answers.

Nodes of Ranvier {Ans: These are gaps in the myelin sheath where depolarisation can occur.}Neural plasticity {Ans: The ability for neurones to change in structure and function.}Chorionic villus sampling {Ans: }Habitat {Ans: The natural environment in which a species lives.}Midbrain {Ans: This relays information (including visual information from the eyes and auditory from the ears) to the cerebral hemispheres.}Homeostasis {Ans: Maintenance of internal body conditions within an appropriate range.}T helper cells {Ans: }Pituitary gland {Ans: Gland that controls other glands and regulates growth rate, reproduction, and metabolism}Molecular phylogeny {Ans: It compares the structure of a particular molecule from different organisms to discover their degree of evolutionary relation.}Hypothalamus {Ans: This is below the thalamus and contains the thermoregulatory centre. It is responsible for homeostasis of body temperature, water in the body, sleep, thirst and hunger. It is also directly connected to the pituitary gland.}Basal Ganglia {Ans: A collection of neurones deep in each hemisphere which select and initiate stored programs for movement.}Rhodopsin {Ans: The purplish pigment in the rod cells which absorbs light and chemically changes. It is stored in the flattened vesicles on the outer segments of the