Chapter 38 test

The protein coat of a virus encloses

• DNA only.

• RNA only.

• DNA or RNA.

• DNA and RNA.

The following events occur when a virus infects a host cell.

(1) synthesis of protein coat

(2) lysis of host cell

(3) penetration into host cell

(4) synthesis of viral genetic material

(5) taking over the metabolism of host cell

Which of the following shows the correct sequence of events?

• (3) → (5) → (4) → (1) → (2)

• (3) → (4) → (5) → (1) → (2)

• (3) → (5) → (1) → (2) → (4)

• (4) → (1) → (5) → (3) → (2)

Which of the following statements about bacteria is incorrect?

• All bacteria are prokaryotes.

• Bacteria may have more than one plasmid.

• The chromosomes of bacteria are located inside the nucleus.

• Bacteria can be autotrophic.

Which of the following factors affect the growth of microorganisms?

(1) availability of carbon

(2) availability of nitrogen

(3) availability of water

• (1) and (2) only

• (1) and (3) only

• (2) and (3) only

• (1), (2) and (3)

A student decided to carry out an experiment to find out if a species of bacterium produces protease or not. Which of the following is a suitable culturing method?

• incubating the bacteria in a nutrient broth with milk

• incubating the bacteria in a nutrient broth with essential amino acids

• incubating the bacteria on an agar plate with milk

• incubating the bacteria on an agar plate with an antibiotic

Which of the following is not one of the safety precautions that must be taken when handling microorganisms in laboratory?

• Open all the windows and doors of the laboratory during experiment.

• Disinfect the working area after the experiment.

• Wear a laboratory coat and disposable gloves.

• Use sterilized and autoclaved apparatus.

The graph shows the growth curve of a yeast population in a nutrient broth.

During which phase do some of the nutrients in the broth start to run out?

• I

• II

• III

• Iv

In an investigation, a scientist tested the effect of four antibiotics, A, B, C and D, towards a type of bacterium by adding them into a bacterial culture respectively. The graphs show the results. Which antibiotic is the most effective towards this type of bacterium?

• A

• B

• C

• D

Which of the following correctly compares the various measurement methods of microbial growth?

(1) Cell counts measure the number of microorganisms per unit area while biomass method measures the mass of microorganisms per unit volume.

(2) Both total cell count and optical method count living and dead microorganisms.

(3) Biomass method involves separating microorganisms from the liquid culture while optical method does not.

• (1) and (2) only

• (1) and (3) only

• (2) and (3) only

• (1), (2) and (3)

An experiment began with two bacterial cells and ended up with 512 cells. How many generations did the bacterial species go through in the experiment?

• 256

• 160

• 9

• 8