Topic 3 - Inter-relationships

Question 1

Describe a depressant

Answer 1

They decrease the activity of the Brain and slow down responses of the nervous system causing slow reactions and poor judgement of speed and distances.

Question 2

Describe a stimulant

Answer 2

They increase the activity of the brain by increasing the amount of neurotransmitters at some neurone synapses which increases the speed of reactions and makes you feel more alert and awake

Question 3

Describe painkillers

Answer 3

They decrease the feeling of pain. Work in different ways

Question 4

Describe how morphine works as a pain killer

Answer 4

It blocks the nerve impulses in the brain

Question 5

Reaction time is

Answer 5

How quickly you repairs to a stimulus

Question 6

Why is smoking Tobacco harmful?

Answer 6

• contains carbon monoxide which combines with Haemoglobin in the red blood cells and means the blood can carry less oxygen
• contains carcinogens which are chemicals that can lead to cancer
• it’s addictive

Question 7

How can alcohol affect you in the short term?

Answer 7

• slows down your reactions (depressant)

- being drunk leads to blurred vision and can also lower inhibitions

Question 8

How can alcohol affect you in the long term?

Answer 8

• it’s poisonous, drinking too much causes the death of liver cells which forms scar tissue echo h can start to block blood flow through the liver (cirrhosis) The liver is responsible for cleaning the blood
• too much drinking can lead to brain damage

Question 9

What are pathogens?

Answer 9

Microbes that cause disease

Question 10

What are the different ways pathogens can be spread?

Answer 10

• water (bathing in or drinking dirty water)
• food (eating contaminated food)
• air (airborne pathogens are carried in the air in droplets produced when you cough or sneeze)
• contact (touching contaminated surfaces)
• body fluids (blood, breast milk, semen)
• animal vectors (vectors are animals that spread diseases eg mosquitos)

Question 11

What physical barriers stop pathogens entering the body?

Answer 11

• the skin (if it gets damaged blood clots seal cuts and keep micro organisms out)
• the respiratory system (the respiratory tract is lined with mucus which catches dust and bacteria before it enters the lungs and cilia which push the mucus away from the lungs)

Question 12

What chemical barriers stop pathogens from entering the body ?

Answer 12

• the eyes (produce lysozyme which kills bacteria on the surface of the eye)
• the stomach (hydrochloride acid kills bacteria)

Question 13

When plants are attacked by pathogens they

Answer 13

Can produce chemicals to defend themselves

Question 14

Antiseptics are:

Answer 14

• used outside the body
• clean wounds and surfaces
• used in household products
• used in hospitals

Question 15

Antibiotics are:

Answer 15

• used inside the body
• used to treat patents infected with bacteria or fungi
• don’t destroy viruses

Question 16

What are the two different types of antibiotics and how do they work?

Answer 16

Antibacterial
- used to treat bacterial infections 
- kill bacteria or stop them from growing
- bacteria can evolve resistance
Antifungals
- used to treat fungal infections
- kill fungi or stop them from growing

Question 17

How can bacteria become resistant to antibiotics ?

Answer 17

• bacteria can mutate to be resistant to antibiotics
• this means when treating an infection only the non-resistant bacteria will be killed- the resistant bacteria will survive and reproduce and the population of resistant bacteria will increase

Question 18

Why is some energy lost in the food chain?

Answer 18

Energy is used up at each stage in things like respiration or lost to surrounding as heat
It’s also lost as droppings

Question 19

Pyramids of biomass show

Answer 19

Weight -shows how much the creatures of a food chain would weigh if you put them together

Question 20

Parasites :

Answer 20

Live in or on a host and take what they need to survive without giving anything back

Question 21

What are some examples of parasites?

Answer 21

Fleas, head lice, tapeworms, mistletoe

Question 22

A mutualistic relationship is where:

Answer 22

Both organisms benefit

Question 23

What are some examples of a mutualistic relationship?

Answer 23

Oxpeckers (live on the backs of buffalo and eat pests and also alert animal to any predators near)
Cleaner fish (eat dead skin and parasites of larger fish, get food and don't get eaten by the big fish)
Nitrogen Fixing bacteria in legumes (bacteria get constant supply of sugar and plant gets essential nitrates)
Chemosynthetic bacteria in deep sea vents (live in tube worms, get given chemicals from host that they ten into food for themselves and the host)

Question 24

Why is the population increasing so quickly?

Answer 24

• modern medicine

- modern farming methods

Question 25

What are potential problems of the quickly growing population?

Answer 25

- raw materials are being rapidly used up - more waste is being produced - more pollutants are being produced

Question 26

Describe eutrophication

Answer 26

- excess nitrate washed into river which causes rapid growth of algae - plants start dying due to competition for light - microbe numbers increase as they feed on the dead material - microbes use up all the oxygen and fish and other aquatic animals suffocate

Question 27

What are some examples of recyclable materials?

Answer 27

- metals - paper - plastics

Question 28

What are some problems with recycling ?

Answer 28

- it still uses energy - some materials can be difficult and time consuming to sort out - the equipment need can be expensive - sometimes the quality of recycled products isn't as good as new materials - some materials can only be recycled a limited number of times

Question 29

What are indicator species for water pollution ?

Answer 29

- if raw sewage containing nitrates are released into a river the bacterial population increases and uses up the oxygen - stonefly large and freshwater shrimp are sensitive to the concentration of oxygen (if they're present it indicated the water is clean) - blood worms and sludge worms have adapted to live in polluted condition (if they're present it indicates a very high level of water pollution)

Question 30

What is a indicator species ?

Answer 30

Organisms that are very sensitive to changes in their environment and can be studied to see the effect of human activities

Question 31

What are indicator species of air pollution?

Answer 31

- lichen are very sensitive to the concentration of sulfur dioxide, the number and type of lichen inidicates how clean the air is (clean air = lots of lichens) - black spot fungus (present indicates clean air)

Question 32

Describe the carbon cycle

Answer 32

- the only thing that removed co2 from the atmosphere is photosynthesis - eating passed the carbon compounds in the plant along to animals in a food chain or web - respiration puts co2 back into the atmosphere - plants and animals eventually die and decay - when they decay they're broken down by bacteria or fungi which release co2 back into the air by respiration - fossil fuels made by decayed plants and animal matter are burned which released co2 back into the air

Question 33

Describe the nitrogen cycle

Answer 33

- nitrate is very Unreactive and can't be used directly by plants or animals - nitrogen is needed to make proteins for growing - nitrogen from the air has to be turned into nitrogen compounds (plants absorb nitrates from the soil, animals have to eat it) - decomposers in the soil break down dead plants and animals, decomposed bacteria turn proteins and urea into ammonia - nitrifying bacteria convert ammonia into nitrates - nitrogen fixation is the process of turning nitrogen into nitrogen compounds in the soil which plants can use, the two main ways of this are by lightening (so much energy that it's enough to make nitrogen react with oxygen in the air to give nitrates) and nitrogen fixing banter in roots and soil

Question 34

What are the four different types of bacteria involved in the nitrogen cycle ?

Answer 34

- decomposers bacteria (decompress proteins and urea and turn them into ammonia) - nitrifying bacteria (turn ammonia in decaying matter into nitrates) - nitrogen fixing bacteria (turn atmospheric nitrogen into nitrogen compounds that plants can use) - denitrifying bacteria (turn nitrates back into nitrogen gas, no benefit to living organisms)

Question 35

Describe the first phase of the earths atmosphere

Answer 35

- the earths surface was originally molten, it was so hot that any atmosphere just boiled away into space - eventually it cooled and a thin crust formed but volcanoes kept erupting - the volcanoes have out lots of gas including carbon dioxide and water vapour which is thought to be how the oceans and atmosphere were formed - according to this theory the early atmosphere was mostly co2 (similar to Mars and Venus today) - the oceans formed when the water vapour condensed

Question 36

Describe phase 3 of the earths atmosphere

Answer 36

- the build up of oxygen killed off some early organisms that couldn't tolerate it but allowed more complex organisms to evolve - the oxygen created the ozone layer which blocked harmful rays from the sun and enabled more complex organisms to evolve - there is very little co2 left now

Question 37

Drugs are chemical substances that

Answer 37

Affect the central nervous system