Download Assignment 3 answer key

Biology for engineers and other non – 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 – rate at which the bottle leaks
= (3 x 100 ml/min) – 10 ml/min
Therefore, the total time required to fill a 2.5 L bottle =
2500 𝑚𝑙
𝑚𝑙
𝑚𝑖𝑛
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
𝑥
𝑡 = 𝑡0 + 𝜇 ln(𝑥 𝑡 ) , where to is the lag phase period.
0
𝐺𝑖𝑣𝑒𝑛 𝑡ℎ𝑎𝑡 𝑡0 = 𝑧𝑒𝑟𝑜
𝑥0 = 1 𝑔/𝐿
µ = 0.25 h-1
𝑥𝑡 = 10 𝑔/𝐿
Substituting all the values in the above equation,
𝑡 =0+
1
10
ln( )
0.25
1
𝒕 = 𝟗. 𝟐𝟏 𝒉𝒐𝒖𝒓𝒔
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 ‘recessive’ disorder
XX (healthy mother)
Carrier girls (XXG )
x
or
XGY (father with disorder)
healthy boys (XY) ………. (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) Down’s 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)