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Biology for engineers and other non β biologists Assignment 3 answer key The correct option is highlighted. 1. The proteins that help in the packaging of the DNA are? a) b) c) d) Enzymes Albumin Immunoglobulins Histones 2. A five year old boy is filling a 2.5 L bottle with water using a 100 ml cup. He manages to pour three full cups of water into the bottle every minute. The bottle is however punctured and leaking water at the rate of 10 ml/minute. How long would it take him to fill the bottle this way? Choose the option closest to your answer. (a) 25.2 minutes (b) 8.6 minutes (c) 16 minutes (d) 2.3 minutes. Solution: The net rate at which the bottle is being filled with water = rate at which the boy fills the bottle β rate at which the bottle leaks = (3 x 100 ml/min) β 10 ml/min Therefore, the total time required to fill a 2.5 L bottle = 2500 ππ ππ πππ 290 = 8.62 minutes 3. Which of the following statements about eukaryotic cell division is true? a) At the end of mitosis, there will be 2 daughter cells, each with double the number of chromosomes as the parent cell. b) At the end of meiosis, there will be 2 daughter cells, each with equal number of chromosomes as the parent cell. c) At the end of meiosis, there will be 4 daughter cells, each with half the number of chromosomes as the parent cell. d) At the end of mitosis, there will be 2 daughter cells, each with half the number of chromosomes as the parent cell. 4. A bioreactor with a working volume of 100 L is inoculated with an organism at a cell concentration of 1 gL-1. The organism does not exhibit a lag phase and has a specific growth rate of 0.25 h-1. How long should the culture proceed for, to finally harvest 1 kg of the organism? (a) 10.6 hours (b) 4.3 hours (c) 9.2 hours (d) 20 hours Solution: One kilogram of biomass is to be harvested from 100 L media. Therefore, the cell concentration at this point of time would be = 1000 g/100 L = 10 g/L The time taken to achieve this biomass concentration must be calculated here. Recall from the course that, in batch growth, time t required to obtain a particular cell concentration xt when inoculated with a cell concentration x0 (at time t = 0) is given by: 1 π₯ π‘ = π‘0 + π ln(π₯ π‘ ) , where to is the lag phase period. 0 πΊππ£ππ π‘βππ‘ π‘0 = π§πππ π₯0 = 1 π/πΏ µ = 0.25 h-1 π₯π‘ = 10 π/πΏ Substituting all the values in the above equation, π‘ =0+ 1 10 ln( ) 0.25 1 π = π. ππ πππππ 5. Which of the following diseases occurs due to the loss of control over cell cycle? a) b) c) d) Diabetes Cancer AIDS Typhoid 6. A healthy mother (XX) and a father (XY) suffering from G6PD deficiency have children. Which of the following can be expected in terms of the disease? (a) (b) (c) (d) All boys are healthy All girls are carriers Both (a) and (b) None of the above Solution: Recall from the course that, G6PD is an X linked βrecessiveβ disorder XX (healthy mother) Carrier girls (XXG ) x or XGY (father with disorder) healthy boys (XY) β¦β¦β¦. (possible outcomes) 7. If the somatic cell of an organism has 20 pairs of chromosomes, what is the number of chromosomes in its sperm cell? a) b) c) d) 20 pairs 40 20 40 pairs 8. The G2 check point of cell cycle occurs at which of the following stages? a) b) c) d) Between G2 and mitotic phases After mitotic phase Before S phase Between G2 and S phase 9. Choose the correct option (a) Downβs syndrome: Extra pair of chromosome 21 (b) Thalassemia : Abnormal hemoglobin production (c) G6PD deficiency: Deficiency of glucose - 6 - phosphatase enzyme (d) All of the above 10. The specific growth rate is zero in which phase of batch growth (a) Stationary phase (b) Logarithmic phase (c) Exponential phase (d) Both (b) and (c)