A level Biology Paper 2 Revision questions and answers, Exams of Biology

Download A level Biology Paper 2 Revision questions and answers and more Exams Biology in PDF only on Docsity! A level Biology Paper 2 Revision questions and answers Role of producers in an ecosystem - Correct Answer Perform photosynthesis and produce sugar and oxygen It also regulates carbon Role of consumers in an ecosystem - Correct Answer animals, eat plants or other consumers Role of decomposers/saprobionts - Correct Answer - release enzyme onto dead plants/dead animals/animal Waste (organic matter) - breaking them down to obtain Biological molecules How do organisms get the energy they need? - Correct Answer by breaking down food molecules gradually and capturing their chemical energy Main Source = Glucose Stored as Starch in plants and Glycogen in animals How does energy move through an ecosystem? - Correct Answer Energy moves through an ecosystem when one organism eats another in the trophic level. EXAM QUESTION: PHOTOSYNTHESIS Heat stress decreases the light-dependent reaction of photosynthesis. Explain why this leads to a decrease in the light-independent reaction. - Correct Answer 1. No ATP; 2. No reduced NADP; A decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis. Explain why. - Correct Answer 1. Less carbon dioxide reacts with RuBP; 2. Less GP; Where precisely is rubisco found in a cell? - Correct Answer Stroma of a chloroplast EXAM QUESTION: PHOTOSYNTHESIS The scientists concluded that heat stress reduces the activity of rubisco in plant Leaves by affecting rubisco activase. Use all the information to evaluate their conclusion. - Correct Answer 1. Rubisco activity increases with temperature 2. (Rubisco) activase activity decreases at High temperatures 3. Graphs suggest activase does not affect activity of rubisco There are different types of gene mutation. Box Put an X in the box next to the statement which describes incorrectly the effect of the mutation in an exon of a gene. - Correct Answer An inversion will result in a change in the number of DNA bases. X Describe how alterations to tumor suppressor genes can lead to the development of Tumors. - Correct Answer 1. Increased methylation of tumor suppressor Genes 2. Mutation occurs 3. Tumor suppressor genes are not transcribed/expressed What is meant by a genome? - Correct Answer All the DNA in an organism Explain why the antibody binds to the transcription factor. - Correct Answer 1. Transcriptional factor has a specific shape 2. Complementary shape structure Explain what 'precipitated DNA' consists of - Correct Answer DNA, transcription factor and antibody The solution that a student used to produce the chloroplast suspension had the same water potential as the chloroplasts. Explain why it was important that these water potentials were the same - Correct Answer so that: Osmosis does not occur Chloroplast does not burst Explain why the student set up Tube 1. (No chloroplasts present in solution, only DCIPIP) - Correct Answer 1. To show light does not affect DCPIP; 2. To show chloroplasts are required; Explain the results in Tube 3. (Turned colorless) - Correct Answer 1. Reduction of DCPIP by electrons; 2. from light dependent reaction One hypothesis for LP in humans suggests that the selective pressure was related to Some human populations farming cattle as a source of milk. Describe how farming cattle as a source of milk could have led to an increase in LP - Correct Answer 1. Allele due to mutation 2. Milk provides named nutrient;