Chapter 7C - Biomass, Food and Biotechnology

Question 1

What are trophic levels?

Answer 1

Trophic levels are the different stages of a food chain.

Question 2

What is the apex predator?

Answer 2

This is the animal that is the highest in the food chain, and has no other animal eating it.

Question 3

What are pyramids of biomass?

Answer 3

These show the relative mass of each trophic level

Question 4

How is biomass transferred?

Answer 4

Biomass is transferred through a food chain in an ecosystem when organisms eat other organisms. However, not much biomass gets transferred from trophic level to another. Only about 10% gets transferred.

Question 5

How is biomass lost?

Answer 5

UNEATEN MATERIAL - organisms do not always eat every single part of the organism they are consuming. For example, bone is inedible.
WASTE PRODUCTS - organisms do not absorb all the contents in the food they eat, as it can be excreted. Biomass is lost as as some of the material is converted into substances that are lost as waste.

Question 6

What is the equation for Efficiency of Biomass Transfer?

Answer 6

Biomass transferred to next level // Biomass available at previous level

Question 7

What are the factors affecting food security?

Answer 7

1. Populations are increasing
2. HICs demand more food and better quality
3. Land is being used for biofuels
4. Farming can be affected by pests or pathogens
5. Farming is very expensive
6. Desertification

Question 8

How can overfishing be reduced?

Answer 8

FISHING QUOTAS - limits on the number and size of fish that can be caught to prevent certain species from being overfished.
NET SIZES - using a bigger mesh size means that younger fish can escape and have time to develop and breed

Question 9

How is Mycoprotein created?

Answer 9

Mycoprotein is used to make high protein meat substitutes for vegetarian meals.

1. Fusarium is the main source of Mycoprotein
2. It is grown in large vats on glucose syrup, which acts as food for the fungus
3. The Fusarium respires aerobically, so oxygen is supplied, together with nitrogen
4. The mixture is kept at the right temperature and pH
5. The fungal biomass is then harvested, purified and dried to make Mycoprotein

Question 10

How is human Insulin created?

Answer 10

1. A plasmid is removed from a bacterium
2. The Insulin gene is cut out of a human chromosome, using a restriction enzyme
3. Restriction enzymes recognise specific base sequences, and cut the DNA at these points. The cut leaves the strand of DNA with unpaired bases.
4. The plasmid is cut open, using the same restriction enzyme leaving the same ‘sticky ends’
5. Ligase joins the sticky ends together to produce recombinant DNA
6. This DNA is inserted into a bacterium, so the bacterium produce Insulin

Question 11

What are the pros to GM crops?

Answer 11

1. Some areas in the world have a deficiency is a certain nutrients, so crops can be genetically modified to contain those nutrients.
2. GM crops can be drought resistant, or resistant to pests

Question 12

What are the cons to GM crops?

Answer 12

1. GM crops may affect biodiversity, as it affects the number of wild flowers
2. Transplanted genes may get out into the natural environment, which may lead to the rise of ‘superweeds’, as they have the herbicide resistant gene.