Science A (Core): Biology (I) - The Basics

Question 1

A good diet keeps you healthy – what should it consist of?

Answer 1

Fats (warmth and energy)

Carbohydrates (energy)

Vitamins and minerals (health)

Protein (building cells)

Fibre (passing material)

Water

Question 2

What is metabolic rate and what type of people would have different metabolic rates?

Answer 2

Metabolic rate is the speed of all the chemical reactions in your body

People with lots of muscle / people who do lots of exercise will have fast metabolic rates

Question 3

What things can make you unhealthy?

Answer 3

An unbalanced diet (can make you overweight / underweight)

Not getting enough exercise

Genes play a role – some people are born with a slow metabolic rate / might have too much cholesterol which is bad for the heart

Question 4

Name 2 examples of micro-organisms (pathogens) and say how they reproduce and make you feel ill

Answer 4

Bacteria – copy themselves damaging cells and releasing toxins

Viruses – reproduce inside your cells and damage them

Question 5

How does the immune system kill pathogens?

Answer 5

White blood cells ingest pathogens, make antibodies and make antitoxins

Question 6

What is a vaccine and how does it work?

Answer 6

An injection of a dead / inactive pathogen

White blood cells make antibodies to kill the ‘harmless’ pathogen which then makes you immune (you won’t get sick)

If you then do come across the real pathogen your white blood cells can make the antibodies much more quickly before you can become ill

Question 7

What is MMR vaccine and what does it protect against?

Answer 7

Measles

Mumps

Rubella

Question 8

What are antibiotics used for and what do they not help with?

Answer 8

Antibiotics kill bacteria

Antibiotics do not work against a virus

Question 9

How can bacteria become resistant (like those resistant to antibiotics such as MRSA)

Answer 9

Bacteria can mutate and become resistant to the drug

Antibiotics need to be controlled (e.g. not given out for a cold) to prevent resistance

Question 10

Semmelweis was a doctor who suggested people do what in hospitals?

Answer 10

Doctors (and visitors) to wash hands before seeing patients

This reduces bacteria spreading

Question 11

What are the five sense organs which detect stimuli

*Containing different receptors

Answer 11

Eyes (light)

Ears (sound)

Nose (smell)

Tongue (taste)

Skin (touch)

Question 12

How does the central nervous system work?

Answer 12

The central nervous system is made up of the brain and spinal cord – neurons carry messages…

*Sensory neurons carry impulses from receptors to the brain

**Motor neurons carry impulses from the brain to the effectors (muscles / glands)

Question 13

What are reflexes and how do they work?

Answer 13

Reflexes are automatic responses (you don’t need to think about them)

Question 14

What do the synapses do?

Answer 14

Synapses join neurons together (chemicals take the impulse across the gap)

Question 15

What are hormones?

Answer 15

Hormones are chemicals sent in the blood which affect specific target cells

Question 16

What are the 3 hormones needed to control the menstrual cycle and what do they do?

Answer 16

FSH – makes the egg grow and mature

Oestrogen – stops FSH being released (for 1 egg at a time)

LH – makes the ovary release the egg

Question 17

How does ‘the pill’ stop a woman from getting pregnant?

Answer 17

The pill stops FSH being released so no eggs mature (the pill contains oestrogen)

Question 18

How can hormones help a woman get pregnant?

Answer 18

FSH and LH are given to stimulate egg maturation and release

IVF can join an egg and sperm ‘in a test tube’ which is put back into the woman to develop

Question 19

What is an auxin and how does it work in light?

Answer 19

An auxin is a plant growth hormone – shoots grow towards light

Question 20

What is an auxin and how does it work in gravity?

Answer 20

An auxin is a plant growth hormone – roots grow down towards the soil

Question 21

What 4 things does your body need to keep constant (homeostasis)

Answer 21

Ions

Water

Temperature

Blood sugar

Question 22

How does the body keep ions constant?

Answer 22

Ions are absorbed through food and lost through sweat and urine

Question 23

How does the body keep water constant?

Answer 23

Water is taken in as drink / food and lost as sweat, breath and urine (hot days lots of sweat, cold days less sweat)

Question 24

How does the body keep temperature constant?

Answer 24

Enzymes need to work at body temperature (37^oC) so the body sweats / shivers

Question 25

How does the body keep blood sugar constant?

Answer 25

Cells need energy constantly so the body keeps sugar content constant in the blood (via a hormone called insulin)

Question 26

What is a drug?

Answer 26

A drug changes the body chemistry

Question 27

What is a statin?

Answer 27

A statin lowers the risk of a heart attack

Question 28

What are steroids?

Answer 28

Steroids increase muscle mass (though are often illegal for sports due to unfair completion / side effects)

Question 29

What are the 3 stages of drug testing?

Answer 29

Laboratory testing on human cells / animals (is the drug effective / how harmful is it / best dose) Testing on healthy volunteers (safety check) Testing on ill volunteers (identify what drugs work best)

Question 30

What is a placebo?

Answer 30

A ‘fake’ medicine which has now drug in it which checks the drug is working (some people ‘feel better’ by simply being told it’ll help them which is not helpful when trying to identify if a drug does work)

Question 31

What is thalidomide and what was the problem with it (and how is it used now)?

Answer 31

Thalidomide is a drug that wasn’t tested properly which caused the babies of pregnant women to have deformities It is now banned for pregnant women but is used to treat leprosy

Question 32

What are the issues with cannabis?

Answer 32

Some drugs are illegal as they can cause health problems Cannabis has associations with memory loss and mental illness

Question 33

What does it mean for an organism to be adapted to its environment (e.g. in the desert)?

Answer 33

The organism has features which help it survive there

Question 34

How are a polar bear / cactus adapted to their environments?

Answer 34

Question 35

What is an extremophile?

Answer 35

An organism which can survive in really tough environments (hot places / deep places etc…)

Question 36

What do animals and plants need to survive?

Answer 36

Question 37

How can environmental changes be measured?

Answer 37

Living indicators (such as plants and indicators only living where it is clean) Non-living indicators (such as temperature, pH, oxygen meter etc…)

Question 38

What does a food chain show and what does the arrow indicate?

Answer 38

A food chain shows what is eaten by what (the arrow shows the energy being passed on)

Question 39

What does biomass mean?

Answer 39

The amount of biological matter (how much all the organisms weigh (- the water content)

Question 40

What does a pyramid of biomass show?

Answer 40

The quantity of biomass at each stage in the food chain

Question 41

How are materials put back into the environment?

Answer 41

Decay – waste and dead organisms are broken down by microorganisms

Question 42

What is the carbon cycle?

Answer 42

Carbon is taken in from the atmosphere via photosynthesis Carbon is released back into the atmosphere via respiration, combustion and decay

Question 43

Draw out the carbon cycle

Answer 43

Question 44

What are genes?

Answer 44

Genes control features (e.g. eye colour)

Question 45

What is the difference between characteristics caused by genes and the environment?

Answer 45

Characteristics caused by genes are inherited whilst the environment can cause organisms to change

Question 46

What is the difference between sexual and asexual reproduction?

Answer 46

Sexual reproduction requires the meeting of a sperm and egg and causes variation (differences in offspring) Asexual reproduction is where one cell splits into two (only one parent is needed and there is no variation – a clone has been produced)

Question 47

How can plants be cloned?

Answer 47

Cuttings and tissue culture can clone a plant

Question 48

How can animals be cloned using embryo transplants?

Answer 48

Embryo transplant

Question 49

How can animals can be cloned using fusion cell cloning?

Answer 49

Fusion cell cloning

Question 50

What are the advantages and disadvantages of cloning?

Answer 50

Advantages: lots of copies Disadvantages: clones have the same genes so a disease which affects one affects them all

Question 51

What is genetic engineering?

Answer 51

Genes from one organism (maybe of another species) are taken and put into another

Question 52

What are the advantages and disadvantages of genetic engineering?

Answer 52

Advantages: higher crop yields / healthier foods Disadvantages: maybe not safe to eat / playing ‘God’

Question 53

What is evolution?

Answer 53

Evolution is the change of organisms over time…

Question 54

What is natural selection and how does it drive evolution?

Answer 54

Living things are varied Some have characteristics which make them more likely to survive and breed Only these characteristics are passed on meaning they become more common

Question 55

How can genes change?

Answer 55

Genes can change because of mutations

Question 56

What was the difference between Darwin and Lamarck’s ideas for evolution?

Answer 56

Darwin came up with the idea of evolution by natural selection Lamarck thought if a characteristic was used a lot it would become more developed (this idea was incorrect)

Question 57

What problems did Darwin face with his theory of evolution via natural selection?

Answer 57

The idea went against that of the church and there was not much evidence at the time Now his theory is accepted