Biology 1 Flashcards

What are the 5 main food groups?

1) Carbohydrates: release energy. 2) Fats: warmth and energy. 3) Protein: growth and cell repair/replacement. 4) Fibre: prevents digestive problems. 5) Vitamins and minerals: skin, bones, blood etc healthy.

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What is metabolism?

Chemical reactions within the body.

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How does metabolic rate differ in people?

In general, men have a higher metabolic rate than women. However if someone is taller, exercises more and has a high muscle:fat ratio, their metabolic rate will be higher than someone who does not have/do these things.

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What is the definition of obesity?

Being 20% (or more) over maximum recommended body mass.

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Four factors that can lead to obesity.

1) Bad diet. 2) Overeating. 3) Lack of exercise. 4) Hormones.

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Five health problems associated with obesity.

1) Arthritis (inflammation of the joints). 2) Type 2 diabetes. 3) High blood pressure. 4) Heart disease. 5) Some kinds of cancer.

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Too much saturated fat in your diet can cause...

An increase in the blood cholesterol level.

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Too much salt in your diet can cause...

High blood pressure and heart problems.

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Four health problems that lack of food can cause.

1) Slow growth in children. 2) Fatigue. 3) Poor resistance to infection. 4) Irregular periods in women.

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What can a lack of vitamin C cause?

Scurvy - a deficiency disease that causes problems with the skin, joints and gums.

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Two inherited factors that can affect health.

1) Underactive thyroid gland - which can lower the metabolic rate. 2) Inherit factors that can affect their blood cholesterol level.

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Four things to consider when looking at slimming products' effectiveness.

1) Is the report a scientific study? 2) Written by a non-bias qualified person. 3) Was the sample of people large enough for reliable results? 4) Have other studies showed similar results?

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The best things to do to loose weight is...

Eat less fat or carbohydrates and do more exercise.

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Two main types of pathogens.

Bacteria and Viruses.

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What are bacteria?

Very small cells (about 1/100th of body cells) which reproduce rapidly inside the body.

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How do bacteria make people feel ill?

By damaging body cells and producing toxins.

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What are viruses?

Viruses are not cells, they're about 1/100th the size of a bacterium.

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How do viruses make people ill?

They replicate themselves by invading your cells and using the cells' machinery to produce many copies of themselves. The cell will usually then burst, releasing all the new viruses. The cell damage is what make you feel ill.

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Three ways white blood cells attack invading cells.

1) Consume them. 2) Produce antibodies. 3) Produce antitoxins.

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Describe how producing antibodies fights disease.

When your body comes across a foreign antigen (unique molecules on the surface) the white blood cells will start to produce proteins called antibodies that lock onto specific antigens and kill the invading cells.

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What is a vaccination and how are they effective?

Injecting small amounts of dead or inactive microorganisms. These carry antigens - causing your body to produce antibodies to attack them. So if live organisms of the same type appear after, the white cells can rapidly produce antibodies to attack.

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Two advantages of vaccination.

1) Vaccinations have helped control lots of infectious diseases that were once common in the UK. 2) Big outbreaks of disease (epidemics) can be prevented if a large percentage of the population is vaccinated.

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How does mass vaccination prevent epidemics?

People who aren't vaccinated are less likely to catch the disease because there are fewer people able to pass it on. But if a significant number of people aren't vaccinated, the disease spreads quickly & lots of people will be ill at the same time.

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Two disadvantages of vaccination.

1) Vaccines don't always work - sometimes they don't give you immunity. 2) You can have a bad reaction to vaccines (e.g. swelling, fever or seizures). However, this is rare.

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Two different types of drug.

1) Drugs that relieve symptoms. 2) Drugs that cure the problem.

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What makes bacteria resistant to antibiotics?

When the bacteria mutates it is unaffected by the antibiotics and reproduces - causing the new bacteria to also be resistant.

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What is MRSA?

Methicillin-resistant Staphylococcus aureus.

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What did Ignaz Semmelweis notice in the 1840's and what did he conclude?

Women were dying in huge numbers after childbirth from a disease called puerperal fever. He believed that doctors were spreading the disease on unwashed hands. So he made doctors wash their hands with antiseptic solution.

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Four main concerns regarding bacteria.

1) Bacteria can mutate to produce new strains. 2) New strains can be antibiotic resistant. 3) A new strain could be unencountered before so no one would be immune. 4) A new strain can easily cause an epidemic.

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Four main concerns regarding viruses.

1) Viruses mutate often - as their DNA changes, their antigens change so vaccines are hard to develop. 2) If a virus mutates to be highly infectious and deadly - a flu pandemic could possibly kill billions of people over the world.

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What is a epidemic and what is a pandemic.

Epidemic: disease/infection affecting a widespread area. Pandemic: disease/infection affecting multiple countries.

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What is a stimulus?

A change in the environment that you may need to react to.

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What are the five sense organs?

Eyes: sight. Ears: sound and balance. Nose: smell. Tongue: taste. Skin: touch, pressure, temperature and pain.

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What are receptors?

Groups of cells which are sensitive to a stimulus. They change stimulus energy (e.g. light energy) into electrical impulses.

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What are sensory neurones?

The nerve cells that carry signals as electrical impulses from the receptors in the sense organs to the central nervous system.

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What are relay neurones?

The nerve cells that carry signals from the sensory neurones to the motor neurones.

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What are motor neurones?

The nerve cells that carry signals from the central nervous system to the effector muscles or glands.

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What are effectors?

Muscles and glands. Muscles respond by contracting in response to a nervous impulse and glands secrete hormones.

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What is the central nervous system?

Where all the information from the sense organs is sent, and where reflexes and actions are coordinated. Consists of the brain and the spinal cord only.

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What are neurons?

Nerve cells that transmit the information (as electrical impulses) very quickly to and from the CNS.

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What is a synapse?

The connection between two neurones. The nerve signal is transferred by chemicals which diffuse across the gap.

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What are reflexes?

An automatic response to certain stimuli. The passage of information in a reflex is called a reflex arc.

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What are the seven steps of the reflex arc?

1) Stimulus. 2) Receptor. 3) Sensory neurone. 4) Relay neurone. 5) Motor neurone. 6) Effector. 7) Response.

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Why are reflexes effective when (for example) you touch something hot.

Because you don't have to think about the response to the stimuli - the response is quicker to normal responses.

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What are hormones?

"Chemical messages carried in the blood plasma to activate target cells". They are produced and secreted by various glands. They control things in organs and cells that need constant adjustment and have a relatively long lasting effect.

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Differences between nerves and hormones.

Nerves: very fast action, act for a very short amount of time, act on a very precise area. Hormones: slower action, act for a long time, act in a more general way.

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Stage one of the menstrual cycle.

Day one is when the bleeding starts. The uterus lining breaks down for about four days.

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Stage two of the mentrual cycle.

The lining of the uterus builds up again, from day 4 to 14, into a thick spongy layer full of blood vessels - ready to receive a fertilised egg.

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Stage three of the menstrual cycle.

An egg is released from the ovary at day 14.

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Stage four of the menstrual cycle.

The wall is then maintained for about 14 days - until day 28. If no fertilised egg has landed on the uterus wall by day 28, the spongy lining starts to break down again and the cycle restarts.

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What is FSH?

Follicle-Stimulating Hormone. Produced by the pituitary gland. Causes an egg to mature in one of the ovaries and stimulates the ovaries to produce oestrogen.

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What is oestrogen?

Produced in the ovaries. Causes the pituitary gland to produce LH and inhibits the further release of FSH.

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What is LH?

Luteinising Hormone. Produced by the pituitary gland and stimulates the release of an egg at around the middle of the menstrual cycle.

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How can oestrogen be used to help control fertility?

If oestrogen is taken every day - the level of it stays perminantly high and so the production of FSH is inhibited and after a while egg development and production (from the ovary) stop and stays stopped.

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How does progesterone control fertility?

It stimulates the production of thick cervical mucus which prevents any sperm getting through and reaching an egg.

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Advantages of the contraceptive pill.

The pill is over 99% effective. It reduces the risk of getting some types of cancer.

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Disadvantages of the contraceptive pill.

It isn't 100% effective. It can cause side effects like headaches, nausea, irregular menstrual bleeding and fluid retention. It doesn't protect against STD's.

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What hormones can be injected to increase fertility in a woman?

LH and FSH to stimulate egg release.

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How does IVF work?

The woman is given FSH and LH to stimulate egg production; they're collected from the ovaries and fertilised in a lab using the mans sperm. These are then grown into embryos (in vitro). One or two of the embryos are then transferred into the uterus.

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Disadvantages of IVF.

1) Some women have strong reactions to the hormones (pain, vomiting, dehydration). 2) Reports of an increased risk of cancer due to hormonal treatment. 3) Multiple births can happen if more than one embryo grows into a baby - higher risk birth.

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What is auxin?

A plant hormone that controls growth near the tips of shoots and roots in response to light (phototropism), gravity (gravitropism or geotropism) and moisture.

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Why do shoots grow towards sunlight?

When a shoot tip is exposed to light, more auxin accumulates on the side that's in the shade than the side that's in the light. This makes the cells grow (elongate) faster on the shaded side, so the shoot bends towards the light.

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Why do shoots grow away from gravity?

When a shoot is growing sideways, gravity produces and unequal distribution of auxin in the tip, with more ausin on the lower side. This causes the lower side to grow faster, bending the shoot upwards.

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Why do roots grow towards gravity?

A root growing sideways will have more auxin on its lower side. But in a root the extra auzin inhibits growth, This means the cells on top elongate faster and the root bends downwards.

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Why do roots grow towards moisture?

An uneven amount of moisture either side of a root produces more auxin on the side with more moisture. This inhibits growth on that side, causing the root to bend in that direction - towards the moisture.

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What do drugs do?

Change your body chemistry.

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What are two different types of performance enhancing drugs and what do they do?

1) Anabolic steroids - increase muscle size. 2) Stimulants - increase heart rate.

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Arguments against taking performance enhancing drugs.

1) Its unfair if people gain an advantage by taking drugs, not just through training. 2) Athletes may not be fully informed of the serious health risks of the drugs they take (e.g. high blood pressure).

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Arguments for taking performance enhancing drugs.

1) Athletes have the right to make their own decision about whether taking drugs is worth the risk or not. 2) Drug-free sport isn't really fair anyway - different athletes have access to different training facilities, coaches, equipment etc.

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What are statins?

Prescribed drugs used to lower the risk of heart and circulatory disease.

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The three main stages in drug testing.

1) The drugs are tested on human cells and tissues in the lab. 2) The drugs are testes on live animals. 3) The drug is tested on human volunteers in a clinical trial - firstly healthy humans, then humans with the illness the drug is targeting.

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Why are drugs tested on live animals?

To see whether the drug has the desired effect, to find out it's toxicity and the best dosage.

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What is the 'optimum dose'?

The quantity of the drug that is the most effective and has few side effects.

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Why are the clinical trial humans separated into two groups?

To see if the drug actually makes a difference. One group is given the new drug, and the other is given a placebo. Usually 'double-blind', so neither the patient or doctor knows who's been given the placebo so their not subconsciously influenced.

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What went wrong with thalidomide in the 1950's?

Intended as a sleeping pill and was tested for that use. It was found to be effective as relieving morning sickness. But because this purpose wasn't tested - it wasn't known that the drug was passed into the foetus, causing abnormal limb development.

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What are the two main classes illegal drugs are divided into?

Soft and hard. Hard drugs are usually thought of as being seriously addictive and generally more harmful.

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What are the three 'link' theories between cannabis and hard drug use?

1) Stepping stone: effects of cannabis create a desire to try harder drugs. 2) Gateway: cannabis use brings people into contact with drug dealers. 3) Genetics: certain people are more likely to take drugs - cannabis users will also take other drugs.

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Effects of smoking.

1) Causes disease of the heart, blood vessels and lungs. 2) Tobacco smoke also causes cancer. 3) Nicotine is the drug found in cigarettes - it's addictive so it'd hard to stop smoking.

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Effects of alcohol.

1) Alcohol effects the nervous system and slows down the body's reactions. 2) Too much alcohol leads to impaired judgement, poor coordination and unconsciousness. 3) Excessive drinking can cause liver disease & brain damage. 4) Alcohol is addictive.

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Desert animals: How does large surface area compared to volume help them survive?

Lets them lose more body heat - which prevents them from overheating.

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Desert animals: How are they more efficient with water?

Desert animals lose less water by producing small amounts of concentrated urine. They also make very little sweat.

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Desert animals: How are they adapted to withstand high temperatures?

Have very thin layers of body fat and a thin coat to help the lose body heat.

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Arctic animals: How does small surface area compared to volume help them survive?

Have a compact (rounded) shape to keep their surface area to a minimum and reduce heat loss.

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Arctic animals: How are they well insulated?

They have a thick layer of blubber for insulation - this also acts as an energy store when food is scarce. Thick hairy coats keep body heat in, and greasy fur sheds water - prevents cooling due to evaporation.

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How do desert plants prevent water loss?

No leaves - because water vapour is lost from leaves. Small surface area to their size.

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How do desert plants store water effectively?

Thick/lots of water storage tissues. Shallow but extensive roots to absorb water quickly over a large area. Others have deep roots to access underground water.

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How are some plants and animals adapted to deter predators?

Some plants and animals have 'amour' (e.g. roses: thorns, tortoises: shells). Some produce poisons (e.g. bees and poison ivy). Some have bright warning colours (e.g. wasps).

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What are extremophiles?

Microorganisms (e.g. bacteria) that are adapted to live in extreme conditions. E.g. hot volcanic vents, very salty lakes or at high pressures on the sea bed.

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What do plants compete for in order to survive?

Light, space, water and minerals (nutrients) from the soil.

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What do animals compete for in order to survive?

Space (territory), food, water and mates.

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Environmental changes caused by living factors.

1) A change in the occurrence of infectious diseases. 2) A change in the number of predators. 3) A change in the number of prey or the availability of food sources. 4) A change in the number or types of competitors.

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Environmental changed cause by non-living factors.

1) A change in average temperature. 2) A change in the average rainfall. 3) A change in the level of air or water pollution.

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Three ways environmental changes affect population.

1) Population size increases (e.g. if the number of prey increases - more food for predators). 2) Population size decreases. 3) Population distribution changes because of the changes in temperature.

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Why is there a decreasing amount of bees?

1) Some pesticides may be having a negative effect on bees. 2) Less food available. 3) There more disease.

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How can environmental changes be measured?

Using living indicators.

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How can air pollution be monitored?

Observing particular types of lichen that are very sensitive to the concentration of sulfur dioxide in the atmosphere (from car exhausts, power stations etc). The more lichen at a particular location - the cleaner the air.

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How can water pollution be monitored?

If raw sewage is released into a river, the bacterial population in the water increases and uses up the oxygen. Some invertebrate animals, like mayfly larvae, are very sensitive to the concentration of dissolved oxygen in the water.

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What do satellites measure?

The temperature of the sea surface and the amount of snow and ice cover - accurate, global coverage.

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What do automatic weather stations do?

Measure the atmospheric temperature at various locations - very accurate and precise.

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What happens when you move up a stage (trophic level) in a food chain?

There's less energy and less biomass - usually fewer organisms every time you move up a level too.

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What does each bar of a biomass pyramid represent?

The mass of living material at that stage of the food chain. How much all the organisms at each level would weigh if you put them all together.

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How is energy 'lost' at each stage of a food chain?

Plants: use and store energy for photosynthesis. Animals: energy is lost to the surroundings as heat. Both: some of the material is inedible (e.g. bone) so it doesn't pass to the next level of the food chain.

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What are the two types of variation?

Genetic variation and environmental variation.

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What causes genetic variation?

The combining of genes from two gametes.

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What is environmental variation?

Any difference that has been caused by the conditions something lives in.

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What is a gene?

A short length of a chromosome, and a long length of DNA.

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How many chromosomes does the human cell nucleus contain?

23 pairs of chromosomes.

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What is sexual reproduction?

When male and female gametes fuse together and their genetic information from is combined to produce offspring which are genetically different to either parent.

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What is asexual reproduction?

There is only one parent, so there is no genetic variation between parent and offspring. The offspring are genetically identical to the parent - clones.

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What is an embryo transplant?

When the sperm from a male is used to artificially fertilise eggs from the female. The cloned embryos can then be implanted into multiple surrogates to create identical offspring.

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What is adult cell cloning?

Taking an unfertilised egg cell and removing its genetic material (nucleus). A complete set of chromosomes from an adult body cell is inserted into the empty egg cell. The egg cell is then stimulated by an electric shock - it then divides.

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Advantages of cloning.

1) Studying animal clones could lead to greater understanding of the development of the embryo and of aging/age-related disorders. 2) Help preserve endangered species.

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Disadvantages of cloning.

1) Reduced gene pool - there are fewer different alleles in a population so if a new disease appears and there's no resistance in the population, they will all be wiped out. 2) Clones may not be very healthy. 3) Human cloning could be risky.

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Describe genetic engineering

A useful gene is 'cut' from one organisms chromosome using enzymes. Enzymes are then used to cut bacteria DNA and insert the useful gene so it multiplies rapidly (e.g. human insulin).

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Advantages of genetically modified crops.

1) Increase the yield of a crop - making more food. 2) GM crops can be engineered to contain nutrients that people in developing countries are lacking.

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Disadvantages of genetically modified crops.

1) Some people think it will reduce biodiversity. 2) Some people think they're not safe and increase the risk of allergies. 3) Herbicide resistance gene may be picked up by weeds creating a 'superweed'.

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What is the theory of evolution?

More than 3 billion years ago, life on earth began as simple organisms from which all the more complex organisms evolved.

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What is natural selection?

Species show variations because of their genes. Individuals with characteristics that make them better adapted to the environment have a better chance of survival and are more likely to breed successfully - so these successful genes passed on.

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What is mutation?

A change in an organisms DNA.

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Why was Darwin's theories not accepted immediately?

1) It went against common religious beliefs about how life on earth developed. 2) There was no knowledge of genes or mutations so Darwin couldn't give a good explanation to back up his findings. 3) Not many studies or evidence supported his theories.

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What was Lamarck's theory?

If a characteristic was used used a lot by an organism then it would be more developed during its lifetime. So these acquired characteristics would be passed onto the next generation.

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Biology 1 Flashcards

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