b1 Flashcards
what is the metabolic rate
it is the fat to muscle ratio in your body, men usually have a higher metabolic rate than women. exercise can change the proportion
is the metabolic rate genetic?
yes mate
why do people who are very thin suffer from deficiency desieses?
because they don’t get enough mineral ions
what effects your cholesterol levels
your cholesterol levels are affected by exercise, regular exercise lowers your blood cholesterol levels. it helps balance out your different types of cholesterol.
how many types of cholesterol are there?
2 one is produces by eating fatty foods and not excersising and one by excersising
how is am infectious disease caused?
it is caused by microorganisms entering and attacking your body. the microorganisms that can cause disease are called pathogens, common pathogens are bacteria and viruses
what is the difference between bacteria and viruses
a bacteria is a single living organism that is much smaller than an animal or plant cell, although some cause disease most are harmless and some are really useful to us. we use them to make food like yoghurt and cheese, treat sewage and make medicine
viruses are even smaller than bacteria they usually have regular shapes they cause disease in every type of living organism from people to bacteria
how do pathogens cause disease
once bacteria and viruses are in your body they reproduce rapidly, this is how they make you ill, bacteria simply split in 2, they often produce toxins (poisons) which affect your body sometimes they directly damage your cells. viruses take over your body as they reproduce damaging and destroying the cells they very rarely produce toxins
what will happen if you don’t get s balanced diet?
you will become malnourished and if you don’t have enough minerals you will suffer deficiency diseases
what is a balanced diet?
A balled diet has the right balance of food types.
Why do people need different amounts of food
Because the metabolic rate changes from person to person
if the energy (food) taken is less than the energy used…
the person will lose mass
what is the metabolic rate
The speed of chemical reactions in cells, excersising increases it
what happens if you eat more food
your mass will increase
name 2 factors that affect metabolic rate
your parents genes and your exercise
describe the 2 types of cholesterol
The bad cholesterol can lead to heart disease, and you need good cholesterol for your cell membranes and to make vital substances
what are pathogens?
pathogens are microorganisms that cause infectious diseases
what do pathogens do inside the body?
reproduce rapidly and may produce toxins
what do viruses do
reproduce inside cells and damage them
what is a mutation and why is it. a problem
when a pathogen of virus changes to a new firm and not many people are immune to it so it spreads rapidly
how do vaccines work
they contain dead or inactive pathogens and encourage your white blood cells to produce antibiotics that destroy the pathogens
what is the nervous system
the nervous system allows humans to react to their surroundings and coordinates behaviour, receptors detect external stimuli, electrical impulses pass to the brain along neurons and the brain coordinates responses
what are reflex actions
reflex actions are rapid automatic responses to a stimulus, they protect us from damage
what is FSH?
It is made by the pituitary gland and causes the eggs to mature and oestrogen to be produced.
What is oestrogen
It is produced in the overs and inhibits (stops) the further production of FSH. It stimulates the production of LH and also stimulates the womb lining to develop to recieve the fertilised egg
what is LH
Luteinsisting hormone is made by the pituitary gland and stimulates the mature egg to be released from the ovary
How do white blood cells defend the body?
They can ingest pathogens. This means they digest and destroy them. They produce antibodies, to help destroy particular pathogens. They produce antitoxins to counteract the toxins (poisons) that pathogens produce.
how are most. pathogens prevented from getting in
the skin, mucus and stomach acid
Why are antibiotics only able to kill bacteria?
they can only kill bacteria because viruses reproduce inside the body’s cells, so any treatment could also damage the bodies cells
How do you make sure that unwanted microorganisms do not contaminate a pure culture of bacteria?
Kill the bacteria on the equipment by passing metal loops through a flame, boil solutions and agar. Prevent microorganisms from the air getting into the solution
Why do some pathogens spread rapidly?
because very few people are immune to them so it will transfer faster than other pathogens
How does natural selection cause resistant populations of bacteria to develop?
Mutations of pathogens produce new strains. some. are resistant to antibiotics. Antibiotics kill individual pathogens of the non-resistant strain. The resistant. bacteria survive and reproduce and a whole population of a resistant strain developed. This is natural selection. Antibiotics should not be used for mild infections in order to slow down the rate of development of resistant strains.
What is meant by vaccination
A wide range of vaccines are given to immunise people against
disease. Vaccines contain dead or inactive pathogens. Vaccines can protect against both bacterial and viral pathogens. Vaccines encourage the white blood. cells to produce antibodies that destroy the pathogens.
What are the advantages and disadvantages of vaccinations?
They protect vast amounts of people from diseases but some vaccines cause may cause side effects that could be mild or serious.
Why is it necessary to develop new medicines
Overdose of antibiotics can lead to the development of new strains of bacteria. Doctors do not prescribe antibiotics for mild infections such as minor sore throats. The new strains become resistant to the old antibiotics so new ones are needed
What are the sense organs?
Eyes, ears, tongue, nose and skin. These detect external stimuli and electrical impulses pass to. the brain along neurons, the brain then coordinates responses
What is the cns and how do impulses pass from the receptors to the cns?
The brain and spinal cord form the cns central nervous system. Nerves contain neurons, sensory neurons carry impulses from receptor to the cns, motor neurons carry impulses from the cns to effector organs which may be. muscles or glands. The muscles respond by contracting. the glands respond by. secreting. (releasing) chemicals
What are the main steps involved in a reflex action?
A receptor detects a stimulus eg sharp pain
A sensory neuron transmits the impulse to. the cns,
A relay neuron passes the impulse on,
A motor neuron is stimulated
The impulse passes to an effector (muscle or gland)
Action is taken (the response)
What do contraceptive pills contain and do?
It may contain oestrogen and progesterone, some pills are progesterone-only pills and have fewer side effects. The contraceptive pill prevents the production of FSH so no eggs mature.
How does the body control its internal conditions
Water and ions leave the body through sweat, urine. We must keep out internal climate constant otherwise the enzymes in our body will not work properly, or may not work at all. Sugar in the blood is the energy source for cells. The levels of sugar in the blood is controlled by the pancreas
Why do plant shoots grow towards light?
it is a response to phototropism
What are the advantages. and disadvantages of using hormones to control fertility
Many women use the contraceptive pill to prevent pregnancies. Other women use hormones to help them become pregnant. Sometimes hormone treatment is used to to help older women to have babies. This may. involve using an egg donor who is given hormones to produce extra eggs.
How do farmers use hormones?
They use hormones eg weed killer to kill unwanted plants on lawns. when cuttings are taken from plants, hormones are used to encourage roots to grow before the cutting is planted. some hormones are used to encourage fruits to ripen. If plant hormones are used incorrectly they can cause damage to the environment, eg. weedkillers may harm other more useful plants
Why is it important to test new drugs?
It is important to make sure that it is safe and that the drug doesn’t have any negative effects on people
Why do doctors provide statins?
heart disease and stroke rates have gone down by 40% because stating lower the cholesterol levels
why are some drugs addictive?
because if taken away they cause withdrawal symptoms, they cause changes in the brain and nervous system
why do some canna it users go to use heroin
because a lot of dealers that sell canna it also sell heroin
Why do some athletes take drugs to improve their performances?
Because they can help to do many things eg build up muscle mass, prizes for sports are rising a lot and so taking drugs can give. the edge to winning. and getting all the money
What is meant by an adaptation?
A change in the body to fit an environment
Why do large animals find it difficult to cool down?
because bigger animals have smaller surface areas compared to their volume
give 3 ways a plant can conserve water
- They can lose water vapour through holes in the leaf called. stomata
- water can be collected has an extensive root system
- water can be conserved is the plant has very small or waxy leaves, a plant might have a swollen stem to store the water
- in dry conditions eg the desert, plants such as cacti have become very well adapted to collecting water using extensive root systems
Why do animals need a territory?
Animals are in competition with each other for water, food, space, mates and breeding sites. An animals territory is large enough to find water, food and have space for breeding.
Why do plants try to spread their seeds as far as possible
They spread their seeds as far as possible so that they are not in competition with themselves for water and light
Name 3 non living environmental factors
Temperature, rainfall, and light
Why do some birds fly further north to find nesting sites?
They fly further north because it is too warm in the south.
Give and example of a detritus feeder
These are organisms that start the process of decay by eating dead animals or plants and producing waste materials. Decay organisms then break down the waste of dead plants and animals
What is a decomposer?
They are decay organisms and microorganisms. Decay is faster if it is warm and wet, many of them need oxygen
Which process removes Co2 from the air?
Photosynthesis removes Co2 from the atmosphere
Why do gardeners add works to compost?
Because it speeds up the process of composting
Where are genes found?
In the chromosome threads
What do the genes control?
different genes control the development of different characteristics of the offspring
Explain which type of reproduction produces genetically identical offspring?
asexual reproduction does not involve the fusion of gametes. All of the genetic information comes from one parent. All of the offspring are genetically identical to the parent so there is little variety
Explain which type of reproduction leads to variation inthe offspring?
Sexual reproduction involves the fusion of sex cells (gametes), there is a mixing of genetic information so the offspring show variation.
What are the two factors which control some of our characteristics
Genes and environment
Name a quick way of cloning plants
taking cuttings
Why is it more difficult to clone animals than plants
because cloning animals requires transporting embryos to a host animal
name the 2 cells needed in animal cell cloning
An adult cell, eg skin cell. and a mature egg cell
What is used to cut genes out of chromosomes?
An enzyme
Why do farmers grow go crops
Some GM crops are immune to herbicides and insects
Briefly explain natural selection
This theory states that when life started on earth about 3 billion years ago, there were only simple life forms in which small changes took place over a very long time, all organisms varied and therefore some are more likely to survive, those that are adapted Bremen and pass on their characteristics.
Which birds did Darwin observe to find evidence for evolution?
Darwin uses Finches on the Galápagos Islands could change over time if they lived under different environmental conditions.
Why do organisms show a wide range of variation
Organisms show a wide range of variations because of differences in their genes
Why are mutated genes sometimes an advantage?
Mutated genes are sometimes an advantage because some disease may wipe out most. of the rabbit population but some rabbits with a mutation that makes them immune to the disease will stay alive
What are the main kingdoms
The plant kingdom
the animal kingdom
the kingdom which contains the microorganisms
