Section A All questions in this Section should be attempted.
10 The codon CAG codes for the amino acid lysine. The anticodon on the coresponding tRNA molecule will be: A B C D
GUA GUC CUG AUC
13 Biotechnologists in Antarctica have discovered a bacterium which grows only in a medium rich in salt and specific levels of chromium. What term could be used to describe this medium? A B C D
Complex and general purpose. Synthetic and selective. Synthetic and general purpose. Complex and selective.
14 Three different species of bacteria were exposed to antibiotic discs. The antibiotics tested were P, Q, R and S and the results obtained after incubation at 30C for 24 hours are shown here.
REVIEW QUESTIONS
1
Multiple Choice
What is the only conclusion that can be drawn from these results? A B C D
Antibiotic P is ineffective against all bacteria Antibiotic R is effective against all bacteria Bacterium Y is most susceptible to antibiotics Antibiotic S is effective against some bacteria.
REVIEW QUESTIONS
2
Multiple Choice
Use the following key to answer questions 17, 18 and 19. The key identifies some gramnegative rods on the basis of biochemical tests. gram-negative rods
lactose fermenter
citrate +
citrate -
Citrobacter intermedius NOTE:
lactose non-fermenter
citrate +
E. coli
citrate -
Salmonella typhimurium
Proteus mirabilis
+ = positive result - = negative result
15 Which two organisms are able to utilise citrate? A B C D
E. coli and Proteus mirabilis Citrobacter intermedius and Salmonella typhimurium E. coli and Salmonella typhimurium Citrobacter intermedius and Proteus mirabilis
16 Which organism cannot utilise citrate but can ferment lactose? A B C D
Citrobacter intermedius Salmonella typhimurium Proteus mirabilis E. coli
17 Which of the following statements is true for Salmonella typhimurium? A B C D
It does not ferment lactose and cannot grow on citrate It does not ferment lactose and can grow on citrate It ferments lactose and cannot grow on citrate It ferments lactose and can grow on citrate
REVIEW QUESTIONS
3
Multiple Choice
18 The following diagram represents a bacterial cell.
0.6m
The length of this organism in millimetres (mm) is A B C D
0.6 0.06 0.006 0.0006
19 F
G
Inhibitor absent Section of DNA molecule Inhibitor present
H
Repressor active
Repressor inactive
Enzyme formed
In the above diagram, the regulator is represented by A B C D
DNA segment F DNA segment G DNA segment G and H DNA segment H
REVIEW QUESTIONS
4
Multiple Choice
20 The graph below shows the effect of temperature on the growth of three different bacterial species (J, K and L).
Which of the following statements is true for all three species? A They are all killed at temperatures above 35oC B The optimum temperature for growth is 35oC C As temperature increases up to 35oC the time taken for the bacteria to reproduce increases D As temperature increases up to 35oC the time taken for the bacteria to reproduce decreases
21 In eukaryotic cells, areas of DNA with no known function, are called A B C D
codons introns exons operons
REVIEW QUESTIONS
5
Multiple Choice
22 A length of DNA can be cut into fragments by the restriction endonucleases BamHI and Hind III at the sites indicated
DNA
BamHI cuts at sites indicated by HindIII cuts at sites indicated by
If the DNA was cut with both the restriction endonucleases, the number of fragments would be A B C D
6 7 10 11
23 Which of the following processes uses micro-organisms for bioremediation? A B C D
Accumulation of contaminating chemicals in soil Sewage treatment Clean up of oil spills Processes named in A, B and C all use micro-organisms for bioremediation
REVIEW QUESTIONS
6
Multiple Choice
