CH 22 - CLONING AND BIOTECHNOLOGY

Question 1

Immobilised enzymes can be produced by which of the following methods?
A. binding enzyme to a soluble matrix
B. intermolecular hydrogen bonding of enzymes
C. absorbing enzymes onto the surface of a gel
D. enclosing enzymes within a partially permeable membrane

Question 2

The last giant Galapagos tortoise died in 2012. Scientists froze some of the tortoise’s cells.
The following statements describe processes involved in potential cloning of the giant Galapagos tortoise using the cells. They are not in the correct order.
1 A donor egg is enucleated.
2 The embryo develops into a mature egg, which is incubated.
3 A somatic cell from the tortoise is defrosted and the nucleus is removed.
4 Electrofusion of the host cell and new nucleus.
5 The somatic cell nucleus is inserted into the enucleated oocyte.
6 The transformed egg divides in vitro.
Which option states the correct order for producing a clone of the giant Galapagos tortoise?
A. 1,3,4,5,6,2 B. 3,5,1,4,2,6 C. 1,6,3,5,4,2 D. 3,1,5,4,6,2

Question 3

A student investigated the effect of different sugars on the growth of bacteria.
The student found that the bacteria grew well when provided with glucose, sucrose and fructose, but did not
grow well when provided with lactose.
Which statement, A to D, provides the best explanation for these results?
A. lactose was too large to be absorbed
B. the bacteria could respire only monosaccharides
C. the bacteria did not possess the enzyme to digest lactose
D. the bacteria were inhibited by lactose

Question 4

Bacteria are used in many areas of biotechnology.
In which of the following processes, A to D, do bacteria not play an active role?
A bioinformatics
B bioremediation
C cheese-making
D manufacturing human insulin

Question 5

Mycoprotein is a food produced using the fungus Fusarium venenatum. Which statement about mycoprotein is correct?
A production of protein is slower than in animals and plants
B production is dependent on seasons
C waste products can be used as a substrate
D there are no ethical issues associated with production

Question 6

Corals are a group of animals that usually live on the sea bed close to the surface of the water. Many corals can reproduce both sexually and asexually.
Which of the following statements about asexually-produced coral offspring is not true?
A All offspring produced from an individual organism will be genetically identical.
B If a change in the environment harms one of the offspring produced from an individual organism it will probably harm them all.
C Meiosis occurred in order to produce the offspring.
D The offspring will tend to thrive if conditions are similar to those present when the parent organism reproduced.

Question 7

Plants have the ability to propagate themselves naturally by cloning. This ability is used by humans commercially when carrying out tissue culture.
Strawberry plants produce clones using runners. This is an example of natural cloning. State one other method of natural cloning in plants.

Name the type of plant tissue from which natural clones are produced.

Question 8

Scientists are able to clone desirable plants that show a high rate of photosynthesis. The following passage describes how plants are cloned.
Complete the passage using the most appropriate words or phrases.
Cells are removed from the meristem tissue in axial buds or ……………………………….. tips. The tissue sample that
is removed is called the ……………………………….. . Ethanol can be used to ……………………………….. the plant
tissue. Hormones are used to stimulate mitosis, which produces a mass of cells called a ……………………………… .

Question 9

State how a clone of potatoes could be produced for this investigation and explain why it is important to carry out this procedure under aseptic conditions.

Question 10

The clones were planted in adjacent fields in order to control variables such as temperature, wind speed and rainfall.
Suggest two other abiotic variables that this precaution was intended to control.

Question 11

Many plants can produce natural clones of themselves. Gardeners and farmers take advantage of this natural process by taking cuttings.
When a genetically modified plant is created, it may be cloned into many plantlets in the process called micropropagation.
Compare the equipment and techniques of taking cuttings with those used for micropropagation.

Question 12

Plant cloning is often used by farmers to produce new plants. Cloning plants is also known as vegetative propagation.
Identify three advantages of vegetative propagation in agriculture.

Question 13

A farmer had two fertiliser solutions, solution A and solution B, and wanted to investigate which one to use on lavender plants. In order to ensure the investigation would be valid, two cuttings were needed from the same parent plant.
i. Describe how to clone a plant by taking a cutting.

Question 14

Tissue culture greatly increases the number of cloned plants that can be produced from a single
parent plant.
Outline how it is possible to produce many clones from a single original parent plant.

Question 14

Mice are often used in laboratory studies to research treatments for heart conditions. These mice are often clones.
Suggest one reason why clones are used in these studies.

Question 15

The passage below describes some uses of microorganisms in biotechnology. Complete the passage by writing the most appropriate words in the blank spaces.
Microorganisms have many characteristics that make them useful in biotechnology. These characteristics include …………………………. life cycles and low energy requirements.
Species such as Pseudomonas putida and Dechloromonas aromatica can be used for bioremediation to remove …………………………. from water. Other species of bacteria
are used to manufacture drugs, such as insulin. Antibiotics, which are secondary …………………………. , are produced by fungi and are used to kill pathogenic bacteria.

Question 16

• Using examples, describe and explain some other advantages of using microorganisms to produce food for human consumption.

Question 17

Laboratory techniques are used by workers in various professions, and by scientists.
A patient has been coughing blood, and it is suspected that bacteria will be found in the blood.
A medical technician cultures the blood on an agar plate. What measures should the technician take to keep the agar plate culture sterile?

Question 18

After incubation for 24 hours, the student studied the agar plate. The plate was completely
covered by a film of bacteria and it was not possible to count colonies.
Describe a modification to the procedure that would enable the student to estimate the population size.

Question 19

Scientists wanted to estimate the number of yeast cells in a 25 cm3 solution of S. cerevisiae. They carried out the following two dilutions:
* 1 cm3 of the original solution was mixed with 9 cm3 of nutrient solution to make solution 2.
* 1 cm3 of solution 2 was mixed with 9 cm3 of nutrient solution to make solution 3. The scientists transferred 0.1 cm3 of solution 3 onto an agar plate. 15 separate colonies
grew on the plate.
Calculate the number of yeast cells in the original 25 cm3 solution.
Express your answer in standard form to three significant figures. Show your working.

Question 20

Two students investigated the growth of bacteria at different temperatures.
Three flasks containing identical solutions of nutrient broth were used.
iii. Scientists wanted to estimate the number of yeast cells in a 25 cm3 solution of S. cerevisiae. They carried out the following two dilutions:
1 cm3 of the original solution was mixed with 9 cm3 of nutrient solution to make solution 2.

Flask 1: inoculated with 1 cm3 of broth containing the bacterium Bacillus subtilis and incubated at 20 °C.
Flask 2: inoculated with 1 cm3 of broth containing B. subtilis and incubated at 30 °C.

Flask 3: inoculated with 1 cm3 of broth containing no bacteria and incubated at 30 °C.
Aseptic techniques were used throughout.
At set times over the next 3 days the students removed samples from each flask and measured the number of viable bacteria present.
State one further variable the students should have controlled in their investigation in order to produce valid results.

Question 21

A student was asked to measure the population density of bacteria in a broth. The student was supplied with a broth culture of the bacterium Bacillus subtilis. The teacher suggested that the student should measure the population by transferring a sample of the broth to an agar plate then incubating the plate for 24 hours. The bacterial colonies could then be counted.
* Once the student had mastered the procedure to estimate population size, they decided to investigate the effect of temperature change on the rate of population growth.
The student used the following procedure:
* A broth culture was incubated at 20°C.
* Every four hours a pipette was used to transfer a sample of the culture to agar growth
medium in a petri dish.
* The sample was spread over the surface of the agar by tilting and swirling the dish.
* The petri dish was incubated at 30°C for 24 hours.
* After 24 hours the petri dish was labelled and stored in a refrigerator until all results were
complete.
* The procedure was repeated with broth cultures incubated at 10°C, 30°C and 40°C.
* Once all the agar plates had been collected the student removed them from the
refrigerator and estimated population size by counting the visible colonies.
* Finally the student converted the data into a growth rate.
Describe and explain modifications that the student should make to improve the investigation and ensure the data collected are valid. (You may assume that full aseptic technique was used.)

Question 22

Describe a laboratory procedure that the scientists might have used to estimate the bacterial
population.

Question 23

Some humans are lactose intolerant. Milk can be treated with lactase to reduce the concentration
of lactose present. Fresh milk is passed over lactase molecules immobilised on a suitable matrix. Give two economic advantages of immobilising enzymes for large-scale production.

Question 24

Enzymes used in food production can be free in solution or immobilised.
Immobilised enzymes are often active over a greater pH and temperature range than free
enzymes.
Using immobilised enzymes can be cheaper than using free enzymes.
i.
Suggest two reasons why using immobilised enzymes in industrial processes could be cheaper than using free enzymes.

Question 25

Tannase is an enzyme produced by some microorganisms. Tannase is useful in many
industrial applications including food production.
The tannase used in food production can be free in solution or immobilised. State one method by which tannase could be immobilised.

Question 26

State one disadvantage of using immobilised enzymes in industrial processes.