B1 T3

Question 1

What do depressants do?

Give an example

Answer 1

Decrease activity of brain slows down responses in central nervous system causing slow reaction times
Eg alcohol

Question 2

What do stimulants do

Answer 2

They increase activity of brain by increasing the amount of neurotransmitters at some Neuton synapses, this increase speed or reactions makes you feel more alert and awake
Eg nicotine and caffeine

Question 3

What do painkillers do

Answer 3

Decrease feeling of pain

Eg morphine works by blocking the nerve impulses in the brain

Question 4

What are hallucinogens

Give an example

Answer 4

They distort what’s seen and heard by altering the pathways nerve impulses normally travel along
Eg lsd

Question 5

How does smoking effect pregnant women

Answer 5

The carbon monoxide in the smoke combines with haemoglobin in red blood cells so the blood can carry less oxygen this deprives the foetus of oxygen leading to the bby being underweight

Question 6

Short-term effects of alcohol

Answer 6

Slows down reaction times as it’s a depressant

Blurred vision and lowers inhibitions

Question 7

What are the long-term affects of alcohol

Answer 7

Normally liver breaks down toxins in alcohol death of liver cells forming scar tissue that starts to block blood flow through the liver this is called Cirrhosis if the live account to its normal job of cleaning the blood dangerous substances start to build up and damage the rest of the body
Too much drinking can also lead to brain damage

Question 8

What is a pathogen

Answer 8

Microorganisms that causes infectious diseases

Question 9

What is a vector

Answer 9

An animal that spreads diseases

Question 10

How does mosquitos and house flys spread diseases

Answer 10

Mosquitos carries the protozoan that causes malaria (damage brain and kidneys) biting other organisms
House fly Carrie bacterium that causes dynestry, carrying bacteria only food

Question 11

State 4 diff ways pathogens can be spread and give examples for each

Answer 11

Water- drinking or bathing in contaminated water, bacteria cholera- diharea n dehydration
Body fluids- HIV virus causes aids (immune system)
Contact- athletes foot spread by touching contaminated surfaces of the person

Question 12

What are 2 physical and chemical barriers that protect us against pathogens

Answer 12

Physical
Skin, blood clots if it gets damages
Respiratory system- lined with mucus that catches dust n bacteria. Cilia push mucus with junk in away from lungs
Chemical
Eyes- lysozyme kills bacteria on surface of eye.
Hydrochloride acid in stomach kills any bacteria in food

Question 13

What do plants produce to defend themselves from bacteria

Answer 13

Chemicals that protect them from pathogens such as tea tree tree produces tea tree oil which has antibacterial effects

Question 14

What are antiseptics?

Answer 14

Chemicals that destroy bacteria or stop them from growing, used on outside of body to treat wounds.
Clean surfaces
Used in operations to prevent spread of bacteria

Question 15

Name the two types of antibiotics

Answer 15

Antibacterial antibiotics

Antifungals

Question 16

Name a bacteria that has become resistant to antibiotics

Answer 16

MRSA- caused serious wound infections and is resistant to the powerful antibiotic methicillin

Question 17

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

Answer 17

Bacteria becomes resistant if are over prescribed bacteria so the bit that is resistant reproduces and the population left will be resistant so you could be left with a serious disease that is untreatable

Question 18

What does energy in a food chain originate? What happens to the energy in a food chain?

Answer 18

The sun
Plans, energy lost through resperation, animal eats in energy lost through life processes and heat to the surroundings so energy levels go down as the foot chain goes on

Question 19

Give an example of a parasitic and a mutualistic relationship

Answer 19

Parasitic - tapeworms attach to intestine wall absorbing nutrients causing host malnutrition
Head lice suck blood for food making ppl itch
Mutalistic- oxpeckers eat pests off buffalo providing them with a source of food, make animals alert of predators by hissing
Bacteria in deep sea vents- live inside giant tube worms, supply chemicals to bacteria from sea water, bacteria turn it into food for themselves and the host worm

Question 20

Give three ways a greater human population has effects on the environment

Answer 20

Non renewable energy sources being rapidly used up
More waste being produced filling up landfill sites polluting area
Pollutants being produced from fossil fuels being burnt

Question 21

What’s eutrophication

Answer 21

Nitrates from fertilisers gets washed into the river causing rapid growth of algae
Some plants start dyin due to completion for light
Microbe numbers increase as they feed on dead material
Microbes use up all the oxygen so fish and other animals suffocate

Question 22

Give two advantages and two disadvantages of recycling

Answer 22

Advantages-conserves natural resources as don’t have to be extracted and doesn’t use as much energy
Doesn’t fill up landfill sites
Disadvantage- time consuming
Uses energy for collecting sorting cleaning n processing waste
Expensive

Question 23

3 materials that can be recycled

Answer 23

Metals-
Paper
Plastics - conserves crude oil
Plastic takes ages to decompose so takes up landfill sites if not recycled

Question 24

What does it mean if u find stonefly larvae in fe river and freshwater shrimps

Answer 24

Good indicators to water pollution very sensitive to dissolved oxygen in waters
If there’s a lot of these then the water is clean

Question 25

Explain how lichen can be used as an indicator or air pollution
Give another example

Answer 25

If there is a lot of lichen in an area it means that the air is not polluted as they are very sensitive to concentrations of surfer dioxide
Blackspot fungus

Question 26

Explain the carbon cycle

Answer 26

Plants take in co2 from atmosphere through photosynthesis, plants respire, animals eat plants. When animals die and decay. Broken down by fungi n bacteria, these decomposed release co2 through resperation, some decayed material is left and is burnt as a fossil fuel and releases co2