Biology Topic 2

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what happens to the surface area to volume ratio as an orgnaism gets bigger?
It decreases meaning diffusion is less effective.
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What is ficks law?
(difference in conc mutiplied by surface area)/thickness of diffusion pathway
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What is the affect of sticky mucus in the lungs?
Blocks alveoli so reduces surface area, allows air in but not out so leads to overinflation, traps pathogens but can't move them out of the lungs leading to infection.
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What are the different bonds in a tertiary structure?
Hydrophilic/hydrophobic, disulfide bridges, hydrogen bonding, ionic bonds.
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What two bonds in a tertiary strucutre are sensitive to pH?
Disulfide. ionic
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What is the term when a polypeptide chain has another gorup associated with it?
Conjugated protein. e.g. haemoglobin
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What does degenerate mean?
Mutiple triplets code for the same amino acid.
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Why are insertion and deletion mutations particularly bad?
They cause a frameshift which means that more than one of the triplets will be changed.
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Describe the process of DNA replication.
Double helix unravels, free nucleotides line up next to the DNA strand and DNA polymerase joins them together. The is semi conservative replication.
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What are the three possible ways for DNA to replicate?
conservative replication (new DNA molecule formed), semi conservative (one new strand for each old one), fragmentary (all DNA stands are a mixture of old and new).
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What happened when the DNA was centrifuged?
After one cycle only one band was formed so it couldnt have been conservative replication,after 2 cycles two bands were formed so it couldnt have been fragmentary replication as that would mean only one band getting lighter and lighter.
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What is sickle cell anemia?
Mutation in a gene that codes for a polypeptide in haemoglobin. The change means haemoglobin is less soluble and so means the red blood cells become moon shaped and carry less oxygen.
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What is the locus?
The specific location of a gene on a chromosome.
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Is cystic fibrosis dominant or recessive?
Recessive
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Why has natural selection not removed the allele for cystic fibrosis?
Because if a person is heterozygous they have protection against the disease typhoid.
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What is monohybrid inheritance?
Where the characteristic is controlled by only one gene.
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Methods for prenatal genetic testing
Amniocentesis (collect fetal cells that have fallen off the placenta and fetus), Chrionic villus sampling (small sample of placenta tissue is removed), non invasive prenatal diagnosis (analysing DNA fragments in the blood plasma of the mother)
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Card 2

Front

What is ficks law?

Back

(difference in conc mutiplied by surface area)/thickness of diffusion pathway

Card 3

Front

What is the affect of sticky mucus in the lungs?

Back

Preview of the front of card 3

Card 4

Front

What are the different bonds in a tertiary structure?

Back

Preview of the front of card 4

Card 5

Front

What two bonds in a tertiary strucutre are sensitive to pH?

Back

Preview of the front of card 5
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