Inter-relationships

Question 0

Describe the harmful effects of the following chemicals in cigarette smoke
a) nicotine b) tar c) carbon monoxide

Answer 0

Nicotine is an addictive chemical and makes smoking addictive
Tar is a chemical that can lead to cancer
Carbon monoxide combines irreversibly with haemoglobin, this means red blood cells can carry less oxygen

Question 1

How does a stimulant drug work. Give examples

Answer 1

A stimulant increased brain activity by increasing the amount of neurotransmitters at synapses

Nicotine and caffeine

Question 2

State two long term affects of drinking too much alcohol

Answer 2

Liver failure

Brain damage

Question 3

What is a pathogen

Answer 3

A pathogen is a harmful microorganism that cause disease

Question 4

What is a vector

Answer 4

Vectors are animals that spread disease

Mosquitoes, house fly

Question 5

State four ways that pathogens can be spread, give examples

Answer 5

In body fluids eg HIV
In water eg cholera
Skin contact eg athletes foot
In food eg salmonella

Question 6

Name one chemical and one physical barriers against pathogens

Answer 6

The skin - effective Barrier

The stomach - HCl kills all pathogens

Question 7

What do plants produce to defend themselves from bacteria

Answer 7

Produced chemical

Question 8

What are antiseptics

Answer 8

Antiseptics are used outside the body to destroy or stop bacteria growing

Question 9

Name two types of antibiotics

Answer 9

Antibacterials - stop bacteria

Antifungals - stop fungi

Question 10

Name one type of bacteria that has developed resistance

Answer 10

MRSA is resistant to methicillin

Question 11

Why shouldn’t your doctor give antibiotics for a mild infection

Answer 11

Giving antibiotics when not needed has increased the rate of developing resistance

Question 12

Where does the energy in a food chain originate. What happens to the energy

Answer 12

The sun. The energy is lost in waste or passed on to the next organism

Question 13

Why are pyramids of biomass always pyramid shaped

Answer 13

Because as you work up through the chain the mass goes down

Question 14

What is the difference between a parasitic and mutualistic relationship

Answer 14

Parasitic- only one organisms benefits

Mutualistic - both organisms in the relationship benefit

Question 15

Give an example of a parasitic relationship

Answer 15

Mistletoe

Grows on trees and uses all of the water and nutrients

Question 16

Give an example of a mutualistic relationship

Answer 16

Cleaner fish
Eat dead skin and parasites off of larger fish
Get a food source and protection in exchange

Question 17

Explain what eutrophication is

Answer 17

Eutrophication is when too much fertiliser is placed on a field
The fertiliser runs into lakes and rivers
This causes Algae to begin growing on the surface of the lake
Plants at the bottom of the lake can no longer get light to grow and begin to die
Microbes increase as they feed on the dead plants and use up all the oxygen
Fish die as there is no oxygen left for them

Question 18

What does it mean if you find stone fly larvae in a river

Answer 18

The river is clean

Question 19

Explain how lichen can be used as an indicator of air pollution

Answer 19

Lichen are sensitive to concentration of sulphur dioxide

If there are lots of lichen it means that the air is clean

Question 20

Describe the carbon cycle

Answer 20

CO2 in the air is taken in by plants to photosynthesis, plants give carbon out by then respiring or dead plants decaying
Animals then eat these plants and so transfer some of the carbon into them, they then respire it back into the air or give it out when they decay
CO2 is released from decay
It’s also released when fossil fuels are burnt

Question 21

Why is nitrogen needed by plants and animals

Answer 21

Nitrogen js needed for making proteins for growth

Question 22

What do decomposers do

Answer 22

Break down dead plants and animals

Turn proteins into ammonia

Question 23

Describe the nitrogen cycle

Answer 23

Lightning makes nitrogen react with oxygen to make nitrates
Nitrogen fixing bacteria turn N2 into nitrogen compounds
Decomposer bacteria turn proteins into ammonia
Nitrifying bacteria turn ammonia into nitrates
Denitrifying bacteria turn nitrates into nitrogen gas

Nitrates are in the soil by nitrogen fixing bacteria, plants absorb the nitrates, animals then eat the plants and get nitrates too.
Plants and animals decompose and decomposer bacteria turn nitrogen into ammonia
This ammonia is taken by nitrifying bacteria and turned back into nitrates