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Which of the following events occur during the stationary phase of bacterial growth?<br>P. Rise in cell number stops.<br>Q. Spore formation in some Gram-positive bacteria such as Bacillus subtilis.<br>R. Cell size increases in some Gram-negative bacteria such as Escherichia coli.<br>S. Growth rate of bacterial cells nearly equals their death rate.<br>T. Decrease in peptidoglycan cross-linking.
A
P, Q and S only
B
P, S and T only
C
Q, R and S only
D
P, R and T only
Correct Answer:
P, Q and S only
S
1
: Different countries show different pattern of growth.
P: Many others have a high birth rate with a low death rate.
Q: Some have a high birth rate and still have a high death rate.
R: The developing countries show the most rapid growth rate.
S: Some others like the European nations, have a low birth rate and a low death rate.
S
6
: Compared to this in Europe the growth rate is low.
The Proper sequence should be:
A
PQSR
B
QSPR
C
RSQP
D
SPQR
Which of the following statement(s) is/are CORRECT for antigen activated effector T cells?
P. CD4+ cells make contact with macrophages and stimulate their microbicidal activity.
Q. CD4+ cells make contact with B cells and stimulate them to differentiate into plasma cells.
R. CD8+ cells make contact with B cells and stimulate them to differentiate into plasma cells.
S. CD8+ cells make contact with virus infected cells and kill them.
A
Q only
B
Q and S only
C
P, Q and S only
D
P, Q, R and S
A continuous process is set up for treatment of wastewater. Each day, 103 kg cellulose and 105 kg bacteria enter in the feed stream, while 102 kg cellulose and 1.5 x 102 kg bacteria leave in the effluent. The rate of cellulose digestion by the bacteria is 8 x 102 kg d-1. The rate of bacterial growth is 4x 102 kg d-l; the rate of cell death by lysis is 6 x 102 kg d-1. Write balances for cellulose and bacteria in the system.
A
1× 103 kg, 9 × 103 kg
B
1× 102 kg, 9.965 × 104 kg
C
1× 103 kg, 9.964 × 104 kg
D
1× 102 kg, 9 × 103 kg
In balanced growth phase of a cell,
P. All components of a cell grow at the same rate.
Q. Specific growth determined by cell number or cell mass would be the same.
R. The growth rate is independent of substrate concentration.
S. The growth rate decreases with decreasing substrate concentration.
A
P, Q and S only
B
Q, R and S only
C
P, Q and R only
D
P only
Structured William's model
P. Can describe the changes in intracellular components of the cell during growth.
Q. Cannot describe the death phase of the cells.
R. Can describe the variation of size of cells in the different phases of growth.
S. Cannot describe the lag period of growth.
Which one of the following is correct?
A
P, Q and S only
B
P, Q and R only
C
Q, R and S only
D
P, R and S only
A solid-oxide fuel cell is fed with carbon monoxide and reacts with air to produce CO2. This reaction will produce 2 electrons which are used to power an electric circuit external to the fuel cell. The reaction equation is shown below: 2CO(g) + O2(g) -> 2CO2(g) ΔHr° = -565.96 kJ/mol This reaction does not occur for other types of fuel cells which use a catalyst, such as polymerelectrolyte membrane or phosphoric-acid fuel cells. The presence of carbon monoxide on the anode side of these types of fuel cells will cause catalyst poisoning, reducing the efficiency and voltage of the fuel cell. Determine the rate of enthalpy change for a carbon dioxide production rate of 208 mol/hr. The extent of the reaction occurring in the fuel cell can be obtained by the following equation: where:
A
-16.35 kW
B
-15.35 kW
C
-16.45 kW
D
-15.45 kW
Which of the following constitutes patentable subject matter?
1. A toxin-where such toxin is found on the skin of a previously unknown tree frog of the Amazon basin, which, when administered to patients with a certain cell cancer, causes a substantial reduction in the number of cancerous cells.
2. An idea-where such idea is that there is a mathematical relation among (i) the exposure time of a tumor to a specified alpha-radiation emitting source, (ii) the size of the tumor in cubic centimeters, and (iii) the success rate of the procedure as determined by survival rate at five years
3. Kidney cells-where such cells are found in a certain variety of wild pigs
4. A new laparoscopic surgical technique-where such technique bears improved results in patient cure
Select the correct answer:
A
1, 2 and 3
B
2, 3 and 4
C
All of the above
D
None of the above
A bacteria gives birth to two new bacteria in each second and the life span of each bacteria is 5 seconds. The process of the reproduction is continuous until the death of the bacteria. initially there is one newly born bacteria at time t = 0, the find the total number of live bacteria just after 10 seconds :
A
$$\frac{{{3^{10}}}}{2}$$
B
3<sup>10</sup> - 2<sup>10</sup>
C
243 × (3<sup>5</sup> -1)
D
3<sup>10</sup> - 2<sup>5</sup>
E
None of these
Which of the following statements are true/false?
1. A minimum rate of wages for the time spent by employees for the production of output is minimum time rate.
2. Minimum piece rate is the rate based on the quantity of the output employees have produced.
3. The guaranteed time rate is a minimum rate of remuneration to apply in the case of employees employed on piece work for the purpose of securing to such employees a minimum rate of wages on a time work basis.
4. A minimum rate of remuneration to apply in the case of employees employed on piece work for the purpose of securing to such employees a minimum rate of wages on a time work basis is overtime rate.
A
1, 2, 3 and 4 are true
B
1, 3 are true and 2, 4 are false
C
2, 4 are true and 1, 3 are false
D
3, 4 are true and 2, 1 are false
Which of the following statements are correct regarding common differences between plant and animal cells?
1. Plant cells have cellulose cell wall, while animal cells lack it.
2. Plant cells lack plasma membrane, while animal cells have it.
3. Mature plant cell have a large vacuole, while animal cells have numerous small vacuoles.
A
1 and 2
B
2 and 3
C
1 and 3
D
1, 2 and 3