A good diet keeps you healthy – what should it consist of?
Fats (warmth and energy)
Vitamins and minerals (health)
Protein (building cells)
Fibre (passing material)
What is metabolic rate and what type of people would have different metabolic rates?
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
What things can make you unhealthy?
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
Name 2 examples of micro-organisms (pathogens) and say how they reproduce and make you feel ill
Bacteria – copy themselves damaging cells and releasing toxins
Viruses – reproduce inside your cells and damage them
How does the immune system kill pathogens?
White blood cells ingest pathogens, make antibodies and make antitoxins
What is a vaccine and how does it work?
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
What is MMR vaccine and what does it protect against?
What are antibiotics used for and what do they not help with?
Antibiotics kill bacteria
Antibiotics do not work against a virus
How can bacteria become resistant (like those resistant to antibiotics such as MRSA)
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
Semmelweis was a doctor who suggested people do what in hospitals?
Doctors (and visitors) to wash hands before seeing patients
This reduces bacteria spreading
What are the five sense organs which detect stimuli
*Containing different receptors
How does the central nervous system work?
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)
What are reflexes and how do they work?
Reflexes are automatic responses (you don’t need to think about them)
What do the synapses do?
Synapses join neurons together (chemicals take the impulse across the gap)
What are hormones?
Hormones are chemicals sent in the blood which affect specific target cells
What are the 3 hormones needed to control the menstrual cycle and what do they do?
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
How does ‘the pill’ stop a woman from getting pregnant?
The pill stops FSH being released so no eggs mature (the pill contains oestrogen)
How can hormones help a woman get pregnant?
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
What is an auxin and how does it work in light?
An auxin is a plant growth hormone – shoots grow towards light
What is an auxin and how does it work in gravity?
An auxin is a plant growth hormone – roots grow down towards the soil
What 4 things does your body need to keep constant (homeostasis)
How does the body keep ions constant?
Ions are absorbed through food and lost through sweat and urine
How does the body keep water constant?
Water is taken in as drink / food and lost as sweat, breath and urine (hot days lots of sweat, cold days less sweat)
How does the body keep temperature constant?
Enzymes need to work at body temperature (37oC) so the body sweats / shivers
How does the body keep blood sugar constant?
Cells need energy constantly so the body keeps sugar content constant in the blood (via a hormone called insulin)
What is a drug?
A drug changes the body chemistry
What is a statin?
A statin lowers the risk of a heart attack
What are steroids?
Steroids increase muscle mass (though are often illegal for sports due to unfair completion / side effects)
What are the 3 stages of drug testing?
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)
What is a placebo?
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)
What is thalidomide and what was the problem with it (and how is it used now)?
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
What are the issues with cannabis?
Some drugs are illegal as they can cause health problems
Cannabis has associations with memory loss and mental illness
What does it mean for an organism to be adapted to its environment (e.g. in the desert)?
The organism has features which help it survive there
How are a polar bear / cactus adapted to their environments?
What is an extremophile?
An organism which can survive in really tough environments (hot places / deep places etc…)
What do animals and plants need to survive?
How can environmental changes be measured?
Living indicators (such as plants and indicators only living where it is clean)
Non-living indicators (such as temperature, pH, oxygen meter etc…)
What does a food chain show and what does the arrow indicate?
A food chain shows what is eaten by what (the arrow shows the energy being passed on)
What does biomass mean?
The amount of biological matter (how much all the organisms weigh (- the water content)
What does a pyramid of biomass show?
The quantity of biomass at each stage in the food chain
How are materials put back into the environment?
Decay – waste and dead organisms are broken down by microorganisms
What is the carbon cycle?
Carbon is taken in from the atmosphere via photosynthesis
Carbon is released back into the atmosphere via respiration, combustion and decay
Draw out the carbon cycle
What are genes?
Genes control features (e.g. eye colour)
What is the difference between characteristics caused by genes and the environment?
Characteristics caused by genes are inherited whilst the environment can cause organisms to change
What is the difference between sexual and asexual reproduction?
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)
How can plants be cloned?
Cuttings and tissue culture can clone a plant
How can animals be cloned using embryo transplants?
How can animals can be cloned using fusion cell cloning?
Fusion cell cloning
What are the advantages and disadvantages of cloning?
Advantages: lots of copies
Disadvantages: clones have the same genes so a disease which affects one affects them all
What is genetic engineering?
Genes from one organism (maybe of another species) are taken and put into another
What are the advantages and disadvantages of genetic engineering?
Advantages: higher crop yields / healthier foods
Disadvantages: maybe not safe to eat / playing ‘God’
What is evolution?
Evolution is the change of organisms over time…
What is natural selection and how does it drive evolution?
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
How can genes change?
Genes can change because of mutations
What was the difference between Darwin and Lamarck’s ideas for evolution?
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)
What problems did Darwin face with his theory of evolution via natural selection?
The idea went against that of the church and there was not much evidence at the time
Now his theory is accepted