Last minute Biology Unit 5 revision 0.0 / 5 ? BiologyDNA, genetics and evolutionA2/A-levelAQA Created by: LZ95Created on: 19-06-14 21:16 When a person is being genetically screened for a disease, how would you tell they have the disease? The X-ray film used to distinguish fragments will be exposed as the radioactive probe is complementary to section of DNA of the patient 1 of 29 What do introns contain? Repetitive sequences of DNA called core sequences 2 of 29 What has a unique pattern to each individual? Number and length of core sequences 3 of 29 What are the 5 stages of genetic fingerprinting? Extraction, digestion, separation, hybridisation and development 4 of 29 What happens in extraction? DNA extracted from animal tissue e.g. hair root and is increased in quantity by PCR 5 of 29 What happens during digestion? DNA is cut into fragments using restriction endonucleases 6 of 29 What happens in separation? Fragments separated using gel electrophoresis and transferred from gel to nylon membrane by southern blotting 7 of 29 What happens during hybridisation? DNA probes bind with core sequences 8 of 29 What happens during development? X-ray film put under nylon membrane and radiation from probes exposes the film, revealing a series of bands 9 of 29 How is this interpreted to see if it is from the same person? Machine calculates length of fragments from bands and odds calculated of someone else having an identical fingerprint 10 of 29 Name 3 features of the structure of RNA Pentose sugar ribose, an organic base and a phosphate group 11 of 29 Describe mRNA Single helix, template for proteins, easily broken down, has codons 12 of 29 Describe tRNA Quite small, clover leaf structure, amino acid attached, contains anticodon 13 of 29 How does transcription start DNA helicase acts on specific region of DNA to break down hydrogen bonds 14 of 29 When does transcription stop When a stop codon is reached 15 of 29 What happens in splicing Introns are removed from pre-mRNA 16 of 29 What happens in gene replacement Defective gene replaced with healthy gene 17 of 29 What happens in gene supplementation One or more healthy genes added next to defective gene, dominant so masks effects 18 of 29 What happens in gene line therapy Defective gene is replaced/supplemented in fertilised egg 19 of 29 What happens in somatic cell gene therapy Affected tissues are targeted 20 of 29 How are adenoviruses made harmless A gene is interfered with in their replication 21 of 29 How are the adenoviruses with the CFTR gene inserted into patients Through the nose as a nasal spray 22 of 29 How else can the CFTR gene be inserted into patients By wrapping it in lipid molecules and spraying it into the nostril 23 of 29 What can a DNA probe be used for Locating where a particular gene is 24 of 29 What does the autonomic nervous system control? The involuntary (subconscious) activities of internal muscles and glands 25 of 29 What does the sympathetic nervous system do Stimulate effectors to speed up activity 26 of 29 What does the parasympathetic nervous system do Inhibits effectors to slow down activity 27 of 29 What are changes to heart rate controlled by? Medulla oblongata 28 of 29 Where are chemoreceptors located? Wall of the carotid arteries and the aorta 29 of 29
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