Biological Resources

Question 1

Describe how glasshouses and polytunnels can be used to increase the yield of certain crops

Answer 1

Glass provides greenhouse effect (traps heat); paraffin heaters provide heat and CO2 for increased photosynthesis; artificial lights mean crops can grow into the night and out of season; pests can be controlled easily; can easily control nutrition of crops being grown; protection from disease; control how much water is supplied to plants

Question 2

Describe the role of fertiliser in increasing crop yields

Answer 2

Can control exactly what mineral ions, e.g. magnesium and nitrates, the plants are getting; constant, effective growth

Question 3

State a danger of fertilizer use on fields of crops

Answer 3

Can leach into water ways and cause eutrophication

Question 4

Why might we want to use chemical pesticides?

Answer 4

Kill pests and increase crop yields

Question 5

Give three advantages of biological control over pesticides

Answer 5

No bioaccumulation (building up of toxic chemicals in food chain); specific to certain pests (exploits natural predator-prey relationships); no need to reapply (lowers cost compared to pesticides); no resistance forms; longer lasting

Question 6

State two commercial products that yeast can be used to make industrially

Answer 6

Bread, beer

Question 7

What species of bacteria can be used to make yoghurt? How does this work?

Answer 7

Lactobacillus; respires anaerobically and ferment lactose in milk to produce lactic acid; lactate coagulates milk proteins and causes milk to thicken

Question 8

Write a word equation for the anaerobic respiration of yeast

Answer 8

Glucose –> Ethanol + carbon dioxide

Question 9

Suggest two products that could be produced on a large scale using a fermenter

Answer 9

Insulin, penicillin (antibiotic)

Question 10

Why must conditions in a fermenter remain aseptic?

Answer 10

To prevent infection, disease or contamination of product

Question 11

Why might sterile air be pumped into a fermenter

Answer 11

To allow the bacteria to respire aerobically, providing energy for growth; sterility of air means less chance of contamination

Question 12

Why are there paddles in a fermenter?

Answer 12

To agitate the fluid, evenly distributing oxygen and nutrients

Question 13

Why might a fermenter be surrounded with a water jacket?

Answer 13

To cool the tank and ensure optimum temperature is achieved for enzymes

Question 14

What chemical could be used to test whether yeast are respiring anaerobically?

Answer 14

Bubble gas produced into limewater; turns cloudy

Question 15

Fish are a good source of which major nutrient?

Answer 15

Protein (fish diet can be carefully controlled in a fish farm)

Question 16

Why must water quality be monitored and maintained in fish farms?

Answer 16

Ensures pH, temperature and oxygen levels are appropriate; water can be removed and filtered to remove waste and faeces avoiding pollution

Question 17

How is intraspecific predation controlled in fish farms?

Answer 17

Younger fish are kept separate from bigger fish so that the big fish do not eat the little ones

Question 18

How is interspecific predation controlled in fish farms?

Answer 18

Fish are kept in cages in the sea to protect them from being eaten by other species (nets can be used too)

Question 19

How is disease prevented in fish farms?

Answer 19

Antibiotics can be used; biological control agents can be used to avoid parasites

Question 20

How might selective breeding be important in a fish farm?

Answer 20

Produces fish that are larger, higher quality and less aggressive

Question 21

Why might we use selective breeding be used to develop plants and animals with desired characteristics?

Answer 21

Can ensure maximum yield of meat, milk grain etc.; can breed plants resistant to frost, drought or disease; can breed animals with good temperaments, fertility etc.; can breed plants with nice smell, wheat with large seeds etc.

Question 22

Describe the basic process involved in selective breeding?

Answer 22

From existing stock, select organisms with best characteristics; breed them with each other; select best offspring and breed those together; continue over many generations until the trait (allele frequency) gets stronger and stronger

Question 23

How are restriction enzymes used in genetic engineering?

Answer 23

Used to cut DNA at specific sites and remove required gene; same restriction enzyme used to cut open plasmid so sticky ends are complementary

Question 24

How is DNA ligase used in genetic engineering?

Answer 24

Used to join pieces of DNA together, i.e. to stick the required gene into a plasmid

Question 25

What word is used to describe a bacterial plasmid?

Answer 25

Vector

Question 26

A plasmid with another gene inserted is known as a…

Answer 26

Recombinant plasmid

Question 27

Name one other type of vector, other than a bacterial plasmid

Answer 27

A virus (bacteriophage)

Question 28

Name a human protein that can be produced in large quantities using genetically modified bacteria grown in a fermenter

Answer 28

Insulin

Question 29

Why might genetically modifying plants be useful?

Answer 29

Can be used to improve food production

Question 30

What is meant by the term transgenic?

Answer 30

The transfer of genetic material from one species to a different species

Question 31

Small pieces of plant cut from a parent plant (to be cloned) using a sterile scalpel are called what?

Answer 31

Explants

Question 32

What is meant by the term cloning?

Answer 32

Producing many genetically identical offspring with desired characteristics

Question 33

What is meant by the term ‘in vitro’?

Answer 33

Grown in a petri dish in the lab

Question 34

Why must explants be grown in nutrient agar jelly?

Answer 34

To ensure developing explants have required mineral ions, e.g. magnesium, nitrates, for growth

Question 35

What term describes the process whereby many genetically identical plants are produced?

Answer 35

micropropagation

Question 36

Why must explants be sterile before implanting them into the agar?

Answer 36

To kill any microorganisms

Question 37

Give an example of a mammal successfully cloned from a mature adult body cell

Answer 37

Dolly the sheep, Snuppy etc.

Question 38

What was the nucleus of sheep to be cloned implanted into?

Answer 38

An enucleated egg cell from a donor

Question 39

What word describes the chromosomes number of the hybrid cell?

Answer 39

Diploid

Question 40

How was this hybrid cell stimulated to start dividing by mitosis?

Answer 40

an electric shock

Question 41

Where was the embryo placed after several divisions took place?

Answer 41

In the uterus of a surrogate mother

Question 42

Give three examples of human proteins that may be produced using cloned transgenic animals

Answer 42

Human antibodies for arthritis, cancer and multiple sclerosis; transgenic chickens can produce human proteins in egg white; etc.

Question 43

Which type of cell division is involved in asexual reproduction?

Answer 43

Mitosis

Question 44

Describe the stages in cloning ie Dolly the Sheep

Answer 44

*A nucleus was removed from the udder cell (from the sheep being cloned)
* A nucleus was removed from an egg cell (from a donor sheep)
*Udder nucleus inserted into enucleated egg cell
*electric shock to promote fusion of nucleus into egg cell and hence cell division by mitosis
*developing embryo implanted into surrogate mother and after some time, Dolly was produced