B1 Revision cards

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  • Created by: HKL
  • Created on: 04-06-14 17:15
What does DNA stand for?
deoxyribonucleic acid
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What is a gene?
A section of DNA which describes how to make proteins
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Give an example of a structural protein
collagen in skin
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Give an example of a functional protein
the enzyme amylase which breaks down starch
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What is a chromosome made of?
DNA molecules
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What is a double helix made of?
The two strands of a DNA molecule
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Define the term genotype
The genetic makeup of an organism
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Define the term phenotype
The observeable characteristics an organism has
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What are alleles?
Different versions of the same gene
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What is a dominant allele?
One that controls the development of a characteristic even if it is present on only one chromosome in a pair
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What is a recessive allele?
One that only controls the development of a characteristic if the dominant allele is not present
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How many alleles does each body cell have?
Two for each gene
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What does homozygous mean?
The two alleles are the same
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What does heterozygous mean?
The two alleles are different
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Where are eggs produced?
The ovaries
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Where is sperm produced?
The testes
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Why do we have variation?
Becasue the pairing up of the chromosomes during fertilisation is random, so the new offspring will differ from its parents and any brothers and sisters. Some characteristics will come from the mother and some from the father.
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What does a punnet square diagram show?
All the possible pairings of alleles from sperm and egg at fertilisation
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Which is shorter, the Y or the X chromosome?
Y
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What type of allele is Huntington's caused by?
A faulty dominant allele on chromosome 4
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What type of allele is cystic fibrosis caused by?
A faulty recessive allele
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What is the sex of an embryo determined by?
The SRY gene (the sex-determining region of the Y chromosome)
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What happens if the SRY gene is not present?
The embryo develops into a female and ovaries grow
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What are the symptoms of Huntington's disease?
A tremor, clumsiness, memory loss, an inability to concentrate and mood changes
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What does Cystic fibrosis cause?
A think mucus produced in the lungs, gut and pancreas leading to difficulty breathing, an increased number of chest infections and difficulty digesting food
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What is predictive testing for genetic diseases?
Testing sdults children or embryos for a faulty allele if there is a family history of a genetic disorder so that they can decide whether or not to have children . Also used for prescibing drugs to some people
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What is pre-implantation genetic diagnosis(PGD)?
Testing a single cell from each embryo at the eight cell stage to see if it carries the alleles for a specific disease. Then the ones without the disease are implanted into the mother's uterus.
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What are the risks of PGD?
The results could be inacurate and it may decrease the chance of the embryo surviving when it has been implanted.
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What is amniocentesis testing?
A needle is inserted into the uterus between 14-16 weeks and a sample of amniotic fluid, which carries cells from the fetus, is extracted. There is a 0.5% chance of the test causing a miscarriage.
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What is chorionic villus testing?
A special catheter is inserted through the ****** and cervix until it reaches the placenta. Samples of finger-like protrusions in the placenta called chorionic villi are removed for testing. The chance of miscarriage is 2%
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How do strawberry plants reproduce?
By growing runners, which eventually break off and become new plants.
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What happens when a bulb grows?
It produces a plant which is genetically identical to the parent plant
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How can clones be made artificially?
By taking the nucleus out of an adult body cell and transferring it into an empty, unfertilised egg cell.
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How do cells become specialised?
Certain genes are switched on and off so the cell only produces the proteins that are specific to its type.
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What can stem cells treat?
Serious burns by growing new skin and blindness which is due to cornea damage.
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Other cards in this set

Card 2

Front

What is a gene?

Back

A section of DNA which describes how to make proteins

Card 3

Front

Give an example of a structural protein

Back

Preview of the front of card 3

Card 4

Front

Give an example of a functional protein

Back

Preview of the front of card 4

Card 5

Front

What is a chromosome made of?

Back

Preview of the front of card 5
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