2.4 - Metabolism

Question 1

What is metabolism?

Answer 1

Refers to the range of biological processes that occur in a living organism.
Consists the processes of anabolism (substance synthesis) and catabolism (substance breakdown).

Question 2

What is a metabolic pathway?

Answer 2

Refers to the reactions that occur in a series of small steps, which each step is catalysed by a specific enzyme.

Question 3

Why are small regulated steps used in metabolism?

Answer 3

Makes reactions easier to control.

Question 4

What is lost after every small step in metabolism?

Answer 4

Some heat

Question 5

What do mitochondria and chloroplasts have in common?

Answer 5

Thin inner membranes

• Cristae (Mitochondria)
• Lamellae (Chloroplasts)

Question 6

What is the name of the thin inner membrane of mitochondria?

Answer 6

Cristae

Question 7

What is the name of the thin inner membrane of chloroplasts?

Answer 7

Lamellae

Question 8

What is the purpose of cristae and lamellae?

Answer 8

They are highly convoluted (intricate), allowing for efficient exchange of materials in biochemical processes.

Question 9

The mitochondria is the site of what processes?

Answer 9

Glycolysis
The Krebs Cycle
Oxidative Phosphorylation

Question 10

The chloroplasts are the site of what processes?

Answer 10

Light and dark reactions

The Calvin Cycle

Question 11

How can chemicals interfere with cell metabolism?

Answer 11

By binding to proteins and enzymes involved in metabolic pathways.

Question 12

What is an example of chemical interfering with cell metabolism?

Answer 12

Cyanide which binds non-competitively to cytochrome oxidase and alters the shape of its active site. Consequently, electrons cannot be released to oxygen and the electron transport chain shuts down.

Question 13

What are some chemical groups used by humans which have both positive and negative effects?

Answer 13

Medical Drugs: antibiotics

Non-medical drugs: legal (caffeine, alcohol, nicotine) and illegal (cocaine, heroin)

Fossil Fuels: Produce carbon monoxide gas, combines with haemoglobin and cellular respiration enzymes

Fertilisers: Soluble in water, increases minerals in waterways leading to algal blooms in rivers

Industrial Chemicals: Can act as enzyme inhibitors such as tobacco = lung cancer

Insecticides: Can accumulate in the soil and may not break down quickly (DDT)

CFCs: Destroy ozone, allowing more UV light to reach living things which can cause DNA mutations and cancer.

Nuclear Reactions: Produce harmful, cancer-causing radiation