Biology Past Papers Aqa As 104 Correctly Answered Questions Latest Update

Suggest how the flow of some of the blood between the aorta and pulmonary artery could cause children to die in the first 12 months (3) {Ans: 1. Some oxygenated blood from aorta flows into pulmonary artery 2. Less O2 delivered to cells 3. So less O2 for AEROBIC respiration 4. Tissue won't develop properly causing death}Describe how change is chromosome number is Patau syndrome was produced (an extra chromosome on chromosome 13) (2) {Ans: 1. In meiosis 2. Sister chromatids do not seperate}describe the process involved in the transport of sugars in plant stems (5) {Ans: 1. (At source) sucrose is actively (transported) into the phloem/sieve element/tube; 2. By companion/transfer cells; 3. Lowers water potential in phloem/sieve element/tube and water enters by osmosis; 4. (Produces) high (hydrostatic) pressure; 5. Mass flow/transport towards sink/roots/storage tissue; 6. At sink/roots sugars are removed/unloaded;}Explain why all the cells of the body will have this mutation (2) {Ans: 1. All cells derived from a zygote by mitosis 2. Mitosis produces genetically identical cells}explain how the structure of DNA is related to its functions (6) {Ans: -sugar phosphate backbone- gives strength -helix- gives compact shape -large molecule- stores a lot