AQA Biology Unit 5 3.5 / 5 based on 3 ratings ? BiologyOverall revisionA2/A-levelAQA Created by: Claire AshworthCreated on: 10-04-15 12:02 What is meant by homeostasis? Maintaining a constant internal environment 1 of 26 How does insulin affect blood glucose levels? Lowers blood glucose levels 2 of 26 Where are the receptors that detect a rise in temperature? Hypothalamus 3 of 26 Why is a gene longer than the resulting mRNA? mRNA contains only exons 4 of 26 What bond is between amino acids Peptide bond 5 of 26 Name the enzyme used to convert mRNA into cDNA Reverse Transcriptase 6 of 26 Name the enzyme used to cut a gene Restriction Endonuclase 7 of 26 What is a Codon? Three unpaired bases on mRNA that code for an amino acid 8 of 26 Define degenerate An amino acid can be coded for by more than one triplet 9 of 26 What is the role of RNA polymerase in transcription? Join RNA nucleotides together to form a strand with phosphodiester bonds 10 of 26 Where are adult stem cells found? Bone marrow 11 of 26 Which is a difference between mRNA and tRNA? tRNA as hydrogen bonds, mRNA doesnt 12 of 26 What is recombinant DNA? Sections of DNA from two species 13 of 26 What is meant by refractory period? No new action potentials produced in this time 14 of 26 Describe how hormones and local chemical mediators reach the cells they affect Hormones in the blood, L.C.M spread by diffusion. 15 of 26 How do impulses move along a mylinated neauron Impulses jump between gaps in the axon known as node of ranvier 16 of 26 Why do cone cells have a higher level of visual acuity? Each cone cell is conneted to an individual neurone 17 of 26 How is resting potential established in an axon? Active transport of sodium ions out of an axon 18 of 26 How does mRNA move out of the nucleus? Through a nuclear pore 19 of 26 What is the role of troponin? To bind to Calcuim ions causing tropmyosin to move, exposing actin binding sites 20 of 26 When the sarcomeres contract what happens to the length of the I band? It decreases 21 of 26 What is an antigen? A protein on the cell surface membrane triggering an immune response 22 of 26 How does panting lead to heat loss? Evaporation of water from the lining of the mouth, heat transferred from blood 23 of 26 Define Taxis A movement that bares some relationship to the location of the stimulus 24 of 26 Define Tropism A growth movement of part of a plant in response to a directional stimulus 25 of 26 Define Kinesis A non-directional response to a stimulus 26 of 26
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