Put DNA, nucleus, chromosomes, gene, double helix in order (starting with largest).
Nucleus, double helix, chromosomes, DNA, gene
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What are genes?
Genes are sections of DNA that describe how to make a protein. It could be structural or functional.
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Variation is due to which two factors?
Genes and environmental factors.
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What is the difference between genotype and phenotype?
Phenotype - dominant or recessive (physical appearance). Genotype - combination of alleles e.g. Bb, BB, bb For example, Bb means the phenotype is brown eyes but the genotype is different.
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When two alleles are the same they are? Give examples.
homozygous - AA or aa
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When two alleles are different they are? Give an example.
heterzygous - Aa
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How many pairs of chromosomes do we have in our body?
23 pairs - 46 in total.
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True or false - Female sex chromosomes are ** and male sex chromosomes are XY
true.
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Draw a genetic family tree and add a key.
Look online for an example or in revision book.
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How do you calculate the ratio of genotypes and phenotypes on genetic diagrams?
Look online or in revision book.
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What is androgen and how does that help sex determination?
6 weeks after fertilisation, the undifferentiated gonads (a sex gland where gametes are produced), start producing a hormone called androgen. Specialised receptors in the developing embryo detect the androgen. If it's not detected, you get girl bits
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What is Huntington's disease caused by?
It affects the CNS and is caused by a faulty dominant allele on chromosome 4.
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What are the main symptoms of Huntington's disease?
they develop in adulthood- Late onset, a tremor, clumsiness, memory loss, inability to focus and mood changes.
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What is cystic fibrosis caused by?
It affects the cell membranes, causing a thick mucus to be produced in the lungs, gut and pancreas. It is caused by a faulty recessive allele.
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What are the symptoms of cystic fibrosis?
Difficulty in breathing, increased number of chest infections, and difficulty digesting food.
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What is 'predictive testing for genetic diseases'?
If an adult gets checked if their family history has a faulty allele, then they will have to decide whether to have children or not.
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What is IVF and what does it stand for?
in vitro fertilisation - sperm and egg and fused in a tube then implanted in the mother's body.
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What is PGD and what does it stand for?
pre-implantation genetic diagnosis - check for disease and cure the embryo.
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What is amniocentesis testing?
During 14-16 weeks of pregnancy, needle is inserted into the uterus and a small sample of amniotic fluid is extracted. there's a 0.5% chance (1 in 200) the test will result in miscarriage.
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What is chorionic villus testing?
during 8-10 weeks, a special catheter is inserted through the vagina and cervix until it reaches the placenta. Chorionic villi are removed for testing. "% (1 in 50) chance the test will result in miscarriage.
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If a test comes out False Positive, does the subject have the disorder or not?
Does NOT have disorder!!!
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What does it mean by ethical considerations?
What should be done vs what can be done. rights vs wrong
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What is asexual reproduction?
When a cell grows and divides into two = reproduction. Does not involve sex
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Give an example of an organism that reproduces asexually.
Bacteria, plants and some animals.
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What is a clone?
mother cell divides into two daughter cells and they are identical.
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What are runners?
Plants such as strawberries produce shoots called runners. these break off and become new strawberry plants, which is a clone. Other plants grow bulbs.
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What is so special about Dolly the sheep? draw a diagram.
search online.
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What are stem cells? name two types?
unspecialised cells that develop into a specialised cell. Adult stem cells - develop into red blood cells, white blood cells.embryonic - any cell.
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When does an embryo's cells become specialised (some)?
After the zygote divides four times to reach 16 cell stage. Certain genes are switched on and off.
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Other cards in this set
Card 2
Front
What are genes?
Back
Genes are sections of DNA that describe how to make a protein. It could be structural or functional.
Card 3
Front
Variation is due to which two factors?
Back
Card 4
Front
What is the difference between genotype and phenotype?
Back
Card 5
Front
When two alleles are the same they are? Give examples.
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