Question | Answer |
What are the two factors that affect someone's appearance? Give an example! | Inherited - eye colour, skin colour, etc. Environment - tattoos, scars, etc. Weight, height etc are all combinations! |
Put these in size order, largest to smallest: nucleus, chromosome, cell, gene | Cell Nucleus Chromosome Gene |
What are genes? | A gene is an instruction for making one specific protein. |
What is a structural protein? | A protein for building the body, eg collagen, the protein found in tendons. |
What is a functional protein? | A protein that takes part in the chemical reactions of the body, eg amylase is an enzyme. |
What are clones? Do they occur in Nature? | A clone is an organism genetically identical to another organism. Identical twins, strawberry plants and many others are clones. |
What is an inherited disorder? | A disorder passed down from parents to children through their genes. |
How many (non paired) chromosomes in a normal cell, a sex cell and a fertilised egg? | Normal - 46. Sex cell - 23 and 23. Fertilised - 46. |
What gene causes the male's testes to develop in a 6-week-old embryo? | The SRY gene. 'sex-determining region of the Y chromosome' |
What are hormones? | Hormones are chemicals that control many processes in the cells. Tiny amounts of hormones are made by different parts of the body. |
Chromosomes come in pairs. Do the chromosomes in each pair have the same sets of genes or not? | The same. The chromosomes may contain different versions of the same gene, but the two 'match', one from either parent. |
What are alleles? | Different versions of the same gene. |
What is your genotype and your phenotype? | Genotype - the inherited alleles Phenotype - your characteristics, eg eye colour |
The D allele is dominant. What does this mean? | You only need one copy of a dominant allele to have its feature. |
What is a Punnett square? | A genetic diagram that shows all the possibilities for one couple. |
The d allele is recessive. What does this mean? | You must have two copies of a recessive allele to have its feature, one from each parent. |
If you inherit both alleles exactly the same, what are you for that characteristic? | homozygous |
If you inherit different alleles, what are you for that characteristic? | heterozygous |
Some disorders are single gene disorders. What does this mean? | The feature is dominant - a H instead of an h. You only need to inherit it from one parent. |
What is cystic fibrosis? | A recessive genetic disorder that causes mucus to be much thicker than it should be. |
Jim has the alleles Ff. What does this make him when a disease is recessive? | A carrier of the disease. He won't experience any symptoms but if he has a child with another carrier, that child could be clean, a carrier too or a patient. |
There are two tests that can take place during a pregnancy to see whether a child has a genetic disorder. What are they, without descriptions? | The chorionic villus test. An amniocentesis test. |
Describe an amniocentesis test? Include miscarriage risk and when the results can be taken. | Amniotic fluid is withdrawn from the womb using a needle. 1% miscarriage risk with results at 15-18 weeks. |
Describe a chorionic villus test? Include miscarriage risk and when the results can be taken. | A suction tube inserted up the vagina removes cells from the placenta. 2% miscarriage risk with results at 10-12 weeks. |
What is an ethical question? | When a person has to make a decision on the right or wrong way to behave. |
Give an example of an ethical question (that relates to this subject). | Whether to terminate a pregnancy. Whether to use embryonic stem cells. |
Why might someone believe terminating a pregnancy is wrong? | All life is sacred. We shouldn't pick and choose our children. We have a duty to protect children. The way a child is, even if disabled, is God's will. |
Why might someone believe terminating a child is okay? | Up until 22 weeks, the baby is just a mass of cells. It's the parents choice. It's the woman's body. Having a baby that will suffer in life is wrong. Having an ill child is expensive to the NHS. |
What's a false negative and a false positive? | When a test comes back either positive or negative but the result is faulty. Fairly rare. |
What is genetic screening? | Testing a population for a particular allele, eg the Jewish community screened all those engaged for Tay-Sachs |
How can genetic testing be used to find the correct treatments? | Some people react very badly to some drugs, because of their genes. How responsive you are could be tested genetically. |
What are the 3 reasons someone may want to be genetically tested? | 1. So they can plan their life, if they will develop the disease. 2. If they're a carrier and are worried for future children they might have. 3. If they're at greater risk of heart disease etc they may alter their lifestyle. |
Why shouldn't insurance company's know the results of genetic tests? | After 2014 they could use them to charge higher premiums or not give life insurance to those who will probably die early. |
How do the police use genetic information? | DNA is collected from crime scenes and can be matched to criminals in a national database. |
What is PGD? | Pre-implantation genetic diagnosis, similar to IVF but at the 8-cell stage the embryo is tested for disorders. |
Why would people be against PGD? | It's considered 'playing God' with genes and they worry that it will lead to designer babies. 'Faulty' embryos are often destroyed. |
Why would people be pro PGD? | It insures no babies are born with genetic disorders and removes the need to terminate a pregnancy. |
What is asexual reproduction? | When an organism reproduces by dividing, causing children that are clones of the adult. |
What are stem cells? | Unspecialised cells that can grow into more cells. |
Why do some people want to clone human cells within embryos? | Embryonic stem cells can be rejected by the body as in a transplant, unless the DNA is the same as in the adult. |
Why are embryonic stem cells more useful than adult ones? | Embryonic stem cells can turn into any part of the body, but adult stem cells are very limited. |
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