Term
| What are your characteristics affected by? |
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Definition
Inherited variation: You inherit a different combination of alleles from your parents. Alleles are different versions of the same gene and genes are contained in chromosones.
Environmental factor, e.g. a man's genes may give him a high risk of heart disease, but if he has a healthy lifestyle he reduces his chance of getting ill. |
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Term
| Chromosomes and genes come in pairs. Where do pairs of chromosones come from? |
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Definition
Chromosomes pair up and genes for the same feature align next to each other.
There are 23 pairs of chromosones. One chromosone in each pair came from the mother's egg and the other from the father's sperm. |
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Term
Put in correct order, largest 1st
Chromosome, gene, cell, nucleus |
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Definition
| Cell, nucleus, chromosone, gene. |
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Term
| Different versions of the same gene are called: |
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Definition
| Different versions of the same gene are called ALLELES, e.g. eye colour (brown and blue alleles, but gene for the same feature). |
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Term
| Genes can be strong or weak. The correct terms are |
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Definition
One allele is always dominant and means this feature shows up. The other allele is recessive.
e.g. The allele that gives you straight thumbs is dominant. The allele that gives you curved thumbs is recessive. |
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Term
| How do genes actually work? |
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Definition
| Instructions for how to make proteins. |
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Term
| What sex chromsome would you find in a male and female body cells? |
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Definition
male is xy
female is xx
Sex cells - sperm and eggs contain only 23 chromosones.
At fertilisation, a sperm nucleus fuses with an egg nucleus:
. if a Y sperm fertilises an egg, the embryo develops male sex organs.
. If an X sperm fertilises the egg, the embryo develops female sex organs. |
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Term
| Why are brothers and sisters not identical? |
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Definition
| Because they have a different combination (mixture) of alleles. They have received alleles from both parents and they have different lifestyles. |
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Term
| What are the symptoms of Cystic fibrosis and what causes it? |
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Definition
Causes cells to produce sticky mucus, blocks the lungs and air passages, making breathig difficult.
prevents enzymes getting to the gut, making digestion difficult.
encourages bacteria to grow which causes infection to grow.
Results in lengthy physio and higher infections rates.
Caused by recessive allele,e.g. a baby who has two faulty alleles one from each parent - has cystic fibrois. A baby with one faulty allele is a carrier.
(Mainly people are carriers, carriers do not have the disease but can pass it on to their children.) |
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Term
| What are the symptoms of Huntington's disease and what causes it? |
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Definition
It attacks the nervous system and leads to loss of control over movements (muscle control)
memory loss and mental deterioration.
A person can inherit the disease from just one parent (a dominant allele). |
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Term
| Why can you be a carrier of Cystic fibrosis and not Huntingtons? |
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Definition
| The allele for Huntingtons disease is dominant, therefore only needs one. Cystic fibrosis is recessive therefore needs two. If you have one dominant allele, it overpowers the gene, therefore it can only be Huntington's disease. |
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Term
| How can doctor's test the genes of babies before they are born? |
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Definition
Amniocentesis is a test on an unborn baby to detect if it has cystic fibrosis.
THE RIGHT DECISION: It is not 100% reliable with a 0.5% miscarriage risk, small chance of infection, and results only between 15-18 weeks.
ETHICAL DECISION: Information could be used to decide on a termination (abortion). This is an ethical decision based on genetic testing. |
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Term
| What is PGD and why is it used? |
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Definition
Pre-Implantation Genetic Diagnosis.
When one or both members of a couple are carriers of a genetic disease and want a baby. Doctors test one cell from each eight-cell embryo for the disease-causing allele. |
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Term
| What is in vitro fertilisation (IVF)? |
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Definition
| Doctors use the father's sperm to fertilize eggs outside the mother's body. (Test tude). Embryos develop. |
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Term
| What is embryo selection? |
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Definition
Embryo selection (a form of IVF);
Gametes fertilised in labs, and then the embryo’s tested for genetic disease/s (checking the alleles). Healthy ones used for mothers womb. What about the others??Doctors choose an embryo without the faulty allele to implant into the mother's uterus. |
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Term
| What are stem cells and why are they important? |
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Definition
| Embryos contain stem cells. These are unspecialised cells and can develop into any type of cell. Under new British laws scientist will get the right to stem cell research using hybrids which may transform the leives of millions and eventually stamp out some diseases such as Alzheimers's and Parkinson's. |
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Term
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Definition
| Human Fertilisation and Embroyology Authority. This monitors and licences scientific research into IVF and Donor insemination (DI). They also regulate the storage of eggs, sperms and embroys. Without this Authority, scientists would be free to perform "Frankenstein experiments". |
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Term
| Scientists want to clone using cloned embryos. What are points for and against considering an ethical issue? |
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Definition
In favour;
Scientific progress, Organ transplants,
They could be a relation/friend who needs help.
Against:
Human rights
Lowers value of life
‘Murder’ of embryos |
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Term
| What is gene therapy and what conditions has it been used on? |
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Definition
Curing an inherited disease by putting correctly (healthy) working alleles into a person.
Had limited success. Currently illegal for sex cells. People worried it could lead to control features like eye colour, etc. |
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Term
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Definition
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Term
| What is asexual reproduction and what are the offspring like? |
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Definition
Reproduction with one parent. e.g. plants reproduce asexually.
Offspring are Identical clones to the original plant. |
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Term
| How are animal clones made? |
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Definition
| The first animal clone was called dolly the sheep. Scientists remove the nucleus egg. they took another nucleus from and adult body cell and transferred the 'empty' egg cell. They grew an embryo for a few days and then implanted it into a uterus. |
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Term
| Why would Insurance companys will want to know about genes |
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Definition
| Life insurance etc will be harder to come by if you have a certain disease. |
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Term
| What is therapeutic cloning? |
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Definition
| When you clone certain cells for certain alleles. |
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Term
B2. HOW DO OUR BODIES RESIST INFECTION?
What are the four natural barriers which our bodies have to resist microoranisms entering? |
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Definition
1. Skin
2. Chemicals in sweat, tears and stomach acid.
3. clotting. If we cut ourselves platelets seal the wound.
4. Mucus. The breathing organs produce mucus to cover the lining of these organs and trap the microbes
5. Cilia
6. White blood cells. |
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Term
| Why can microorganisms reproduce rapidly in the body? |
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Definition
| Because it is WARM and they enough FOOD and WATER |
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Term
| What are symptoms of a disease caused by microorganisms? |
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Definition
| Damaged cells or make poisons that damage cells. |
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Term
| What does our immune system do? |
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Definition
If harmful microorganism (antigens) get into the body,the IMMUNE SYSTEM defends against invaders. It tries to destroy them before they cause illness:
1. The white blood cells "detects" the foreign markers, these markers are called ANTIGENS.
2. White blood cells make antibodies to "fit the foreign markers(antigens)".
3. The antibodies fit/stick onto the antigens and cause them to "clump".
4. The antigens are "eaten" by the white blood cells. |
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Term
| Describe ways white blood cells fight infection. |
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Definition
If microbes enter our body they need to be neutralised or killed. This is done by White Blood Cells.
1. They eat the microbe.
2. They produce antibodies to neutralise the microbe.
3. They produce antitoxins to neutralise the poisons produced by microbes. |
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Term
| Why is a different antibody needed for each type of microorganism and how do we get protection from microorganisms? |
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Definition
| Your body makes a different antibody to recognise every type of microorganism that enters it. Some of the white blood cells that make each antibody stay in our blood. So if a microorganism invades your body a second time, you quickly make the correct antibody. Your body is protected against that microorganism? |
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Term
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Definition
| Vaccines prevent you getting disease and make you immune. |
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Term
| How do vaccinations work? |
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Definition
| After a vaccine is injected into your body, your white blood cells make antibodies against the microorganism (MO). If the dangerous Mo enters your body at a later date it quickly makes antibodies against the microorganism. You are then IMMUNE. |
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Term
| What is in a vaccination? |
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Definition
A vaccine contains dead or inactive parts of the disease-causing microorganism (MO).
again your body quickly makes the correct antibody. |
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Term
| Why are vaccines never competely safe? |
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Definition
| Vaccines can have side effects. |
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Term
How can we prevent an epidemic?
What must be considered in vaccination policy? |
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Definition
| A high percentage of the population need to be vaccinated to prevent epidemics and infections. Whether it vaccination has the greater effect for the larger population of people against an allergic reaction from the antibodies for a few people, e.g. whooping cough, the no. of cases reduced rapidly after vaccination by approx 51%. |
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Term
| How are new drugs developed and tested? |
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Definition
A new drug is tested for safety and effectiveness on lab-grown human cells and animals.
HUMAN TRIALS:
Healthy voluntees to test for safety.
People with the illness to test for effectiveness and safety.
In most human trials on ill people, one group of patients takes the new drug. Another group of patients are controls. The controls take either the existing treatment for the illness or a placebo. |
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Term
| Why does the flu vaccine not last for a long time? |
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Definition
| The flue virus changes quickly and there are many different strains of the disease, so new vaccines are needed every year - costly. |
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Term
| Why is it difficult to develope a vaccine for some diseases such as HIV? |
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Definition
| The HIV Virus changes quickly in the body - it MUTATES. It damages the immune system. So there is no effect vaccine. |
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Term
| B2.3. Why does the heart need its own blood supply? |
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Definition
| Your heart pumps blood around the body, so heart muscle cells need a continuous supply of energy. This energy comes from respiration. Respiration is a chemical reaction in cells. The reaction uses glucose and oxygen. Energy is released. Blood brings glucose and oxygen to the heart so that the heart needs its own blood supply. Coronary arteries supply blood to the heart. |
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Term
| 2. How are arteries and veins specialised for their function? |
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Definition
ARTERY: thick, elastic muscular wall.
Thin space for blood to flow through.
VEIN: thin outer wall.
Wider space for blood to flow through. |
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Term
| 3. What can fatty deposits lead to? |
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Definition
Coronary arteries carry oxygenated blood to the heart. Fat builds up in the coronary artery walls.
A blood clot may form on this fat.
The clot can block the artery
The blockage stops oxygen getting to the heart muscle.
Heart cells die and the heart is permanently damaged.
Heart Attack. |
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Term
| 5. List some lifestyle factors. |
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Definition
| Poor diet, smoking, lack of exercise, stress, excess alcohol. |
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Term
| 6. Where is heart disease more common? |
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Definition
| In the UK than in less industrialised countrie. |
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Term
| What is the procedure for developing and testing drugs? |
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Definition
A new drug is tested for safety and effectiveness on lab grown human cells and animals.
The drug is tested on healthy volunteers to test for safety.
3. The drug is tested with the illness to test for effectiveness and safety. |
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Term
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Definition
One group of ill people takes the new drug.
One group of people takes the existing treatment for the illness.
Placebox look like the treatment but have no drug in them. They are not used in human trials.
Some trials are double blind - no one knows who takes what.
Some trials as blind - doctors know but patients don't. |
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Term
What do antibiotics do?
Why must you take the full course? |
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Definition
Antibiotics can destroy invading bacteria or fungi.
There are problems with antibiotics - over time, some bacteria and fungi become resistent to antibiotics.
Antibiotics are expensive.
Don't use antibiotics unnecessarily and finish all the course of tablets, even if you feel better to stop antibiotic resistance. |
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Term
Why do you need exercise for the heart? |
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Definition
The heart pumps blood around the body so it needs a continuous supply of energy. I get my energy from respiration. Respiration uses oxygen and glucose. I need blood to supply these. The coronary arteries supply blood to the heart. |
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Term
B3 LIFE ON EARTH
When did life on Earth begin? |
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Definition
| about 3500 million years ago. |
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Term
How did life on earth begin -
What did all species of living and extinct things on Earth evolve from? |
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Definition
| Simple organisms developed from molecules that cold copy themselves. |
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Term
| Biologists disagreed about the origin of these molecules, what were the disagreements? |
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Definition
1. Some Biologists believed that molecules were produced by environment conditions on Earth at that time.
2. Other Biologists believed that they were produced by environmental conditions on Earth at that time.
3. Others believed the origin of the molecules came from elsewhere in the Solar System. |
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Term
| How do we know that all living things came from simple organisms? |
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Definition
| Fossils and DNA analysis provide evidence for evolution. |
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Term
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Definition
Evolution happens by NATURAL SELECTION.
Individuals of species are not identical - their charateristics vary.
- the environment changes.
- resources become scarce.
Competition - Individuals with certain characteris have a better chance of surviving, long enough to reproduce. They pass on their genes to their offspring.
Next generation - More individuals have these useful characteristics.
IF THE ENVIRONMENT stays the same - then
Next generation - even more individuals have these useful characteristics. |
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Term
| What is Selective Breeding? |
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Definition
| Humans choose characteristics they want individuals to have. |
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Term
| What is Variation between individuals of a species is caused by? |
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Definition
Environment and genes.
Only genetic variation can be passed from one genetic variation can be passed from one generation to the next, so without genetic variation there would beno natural selection. |
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Term
| What are the 3 things that make genes change or mutate? |
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Definition
1. Mistakes when copying chromosomes.
2. ionizing radiation.
3. some chemicals. |
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Term
| IF sex genes mutuate, what are the 3 things that may happen? |
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Definition
1. The mutation may have no effect.
2. The fertilized egg may not develop.
3. The offspring may have a better chance of surving and reproducing.
Then the mutated gene passes on to the next generation and becomes more common. |
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Term
How over many years and generations
NEW SPECIES have evolved? |
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Definition
| This is a result of the effects of mutations, environmental change, and natural selection. |
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Term
HOW DID HUMANS EVOLVE?
What are Hominids? |
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Definition
| Hominids are animals that are more like humans than apes. Many different hominid species evolved from a common ancestor. Those with BIGGER BRAINS and WHO WALKED UPRIGHT had a better change of surviving. Gradually all HOMINID species, except for moder humans (Homo sapiens), became extinct. |
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Term
| How are human communication systems organised? |
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Definition
| In living things with many cells - MULTICELLULAR ORGANISMS - cells are specialised for different jobs. Multicellur organisms evolved with two communication systems. |
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Term
| What are the two human communication systems? |
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Definition
1. The NERVOUS SYSTEM - this uses electrical impulses to transmit messages and respond to them QUICKLY.
e.g. You cough if you breathe in smoke and you blink if a fly gets in your eye.
2. HORMONES. Hormones are CHEMICALS that travel in the blood. They carry information all over the body and bring about long lasting reponses. Hormones transmit messages more SLOWLY than nerves. |
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Term
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Definition
| Testosterone is a hormone. At puberty, it causes many changes in boys. The testes start to make sperm, the voice deepens, and pubic hair grows. |
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Term
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Definition
| Insulin is another hormone. After a high-carbohydrate meal, the pancreas detects a high concentration of glucose in the blood. The pancreas makes insulin. Insulin causes the liver to remove glucose from the blood. |
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Term
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Definition
Both the nervous and hormonal communication systems help to keep a constant internal environment in organisms. This is HOMEOSTASIS.
e.g. If you are too hot, the brain detects that the temperature of the blood flowing through it is too high. It sends an electrical impulse through the nervous system to your sweat glands. You start to sweat more. |
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Term
| What is INTERDEPENDENCE OF ORGANISMS? |
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Definition
| Living organisms depend on OTHER SPECIES and the ENVIRONMENT for their needs, including nutrition and shelter. Within one habitat, species compete for resources. e.g. in gardens, weeds compete with vegetables for light, water, nutrients and space. |
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Term
| What does a FOOD WEB show? |
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Definition
It shows how animals that live in a particular habitat meet their nutritional needs. It shows what eats what.
Changes to one part of the food web affect other species in the same food web. e.g. many foxes may get ill and die. The fox population decreases. The populations of foxes' prey species - mice, slugs, beetles, and frogs then increase. At the same time, the badger population increases because there are few foxes to compete (COMPETITION) with for food. |
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Term
| WHY DO SOME SPECIES BECOME EXTINCT? |
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Definition
Some species are extinct, or are in danger of become extinct. These changes may lead to a species becoming extinct.
- Sudden changes in the environmental conditions.
- Other species in the FOOD WEB becoming extinct.
- New species arriving that compete with, eat or cause disease of the species. |
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Term
| DOES HUMAN ACTIVING ALSO CAUSE SPECIES TO BECOME EXTINCT? |
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Definition
Yes, DIRECTLY by HUNTING:
- passenger pigeons were hunted for sport and meat in North America.
- Tasmanian tigers were killed by farmes whose sheep they ate.
INDIRECTLY by Pollution or Destroying Habitats:
- a cow medicine has poisoned and killed most vultures in India.
- Pandas are endangered because their habitat is scarce. |
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Term
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Definition
There is enormous variety in living organisms. This is called BIODIVERSITY it is important for many reasons:
- We may develop new medicines from species that we do not yet use.
- For new food sources, e.g. breeding cultivated rice with wild species may produce rice that is resistant to disease. |
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Term
| WHY IS BIODIVERSITY IMPORTANT? |
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Definition
| Biodiversity is an important part of SUSTAINABLE DEVELOPMENT: using the environment to meet the needs of people today without damaging Earth for the people of the future. |
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Term
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Definition
| A placebo looks like the new treatment, but has no drugs in it. Placebos are not often usd in human trials because people who take them miss out on the benefits of both new and existing treatments. |
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Term
Human drug trials are BLIND or
DOUBLE-BLIND, what is meant by this? |
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Definition
BLIND - Doctors know who is in which group, but patients do not.
DOUBLE-BLIND trials - neither patient nor doctors know who is in which group. |
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Term
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Definition
Every living organism is made from CELLS. Most cells have a nucleus. Inside the nucleus are chromosones. Chromosomes are made from a chemical called DNA.
Chromosomes contain thousands of genes. Genes carry information that controls what an organism is like. Each gene determines one characteris. The information in a gene is a set of instructions for make proteins, including:
. structural proteins to build the body.
. enzymes to speed up chemical reactions. |
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