Dna Mutations

Question 1

Explain the difference between necrosis and apoptosis

Answer 1

Necrosis could be cell injury. The well would burst and the conformational shape of the cell changed.
Apoptosis is cell suicide and can be reversed and organised. Tails, fingers, cell proliferation, Cell differentiation

Question 2

What is spontaneous DNA damage

Answer 2

dna damage that would occur due to the instability and chemical changes

Question 3

What is spontaneous base loss

Answer 3

When the covalent bond in the base and the sugar would break, due to the weakness in the covalent bonds. This would then damage the dna and would lead to mutations

Question 4

What is spontaneous deamination

Answer 4

When the cytosine base in dna is converted to uracil. This is bad as this is not a dna a base. Would change the sequence and effect proteins or cause cancer.
THIS IS CAUSED BY A CHEMICAL MUTAGEN NITROUS ACID

Question 5

What does smoking tobacco do to the dna

Answer 5

Would have a covalent adduct. The benzo[a]pyrene in the DNA would be lost. Old lead to cancer

Question 6

What does UV light do to the DNA

Answer 6

Cross links would form between the groups on the DNA stand. There can be one or two cross links formed

Question 7

Where do the radicals come from in the body and what would they do to the DNA

Answer 7

Radical come from the mitocondtia due to the processing of Oxygen.
Could add the O, OH or HOOH groups, this would then cause the double strand in DNA to break leading to mutations, cancer and ageing

Question 8

What does ionising radiation do to the DNA strand

Answer 8

Double strand breaks
Damage of the bases
Damage in many areas
Cross links would form

Question 9

What genetic effects can cause DNA damage

Answer 9

DNA replication
Recombination of the DNA between the homologous chromosomes

Question 10

What is photo-reactivation

Answer 10

Repairs the DNA.
Would use the photolyase enzyme that would absorb the photon from the sun and would fix the cross link formed in the DNA

Question 11

What is Excision repair

Answer 11

Enzyme would move across the DNA strand and would detect the damage
Signals a protein that would locate the damage
Protein would cut out the damaged part of the DNA
Polymerase and nucleotides to fix

Question 12

What is non-homologous repair of the DNA

Answer 12

DNA placed into a complex.
Would force the dna strands together for them to be fixed.
Would cause more damage
Happens in the non-coding areas, so this would be a compromise

Question 13

What is homologous repair of dna

Answer 13

Repair that would fix the back bone of the dna
This would need the homologous series And therefore would occur after the s-phase of the cell cycle

Question 14

What causes radiation sickness

Answer 14

The damage of the organs and the cells

Question 15

What happens to the body in the high and the low dose of radiation exposure

Answer 15

High doses: immediate and serious damage that would cause the damage to the cells and cause the cell death. This would then cause the damage to the organs and give radiation sickness

Low doses: delayed but serious effects

Question 16

What occurs in the recombinant repair of DNA.

Answer 16

The dna would be fixed using a different pathway

Question 17

What are the ways in which the mutations can abolish or damage the DNA

Answer 17

Frameshift
Insertions
Duplications of parts of the chromosome
Stops transcription from occurring
Decrease the mRNA stability

Question 18

What is the difference between transition and transversion of the dna

Answer 18

Transition would be when the individual base changes, e.g. A to T (point mutation)
Transversion would be when the purine would be converted to the pyramidine or visa versa.

Question 19

Describe what occurs in phenylketonuria

Answer 19

Point mutation where the phenylalanine would be converted to the tyrosine
Would then cause the neurological issues and would not be able to eat: milk, dairy, meat and fish

Question 20

What causes sickle cell anemia

Answer 20

A point mutation that would cause a nucleotide to change which would then cause the amino acid. A to T

Question 21

What mutation would cause common Down syndrome

Answer 21

A transitional mutation that would change glycine to arginine. Would then cause a change in the FRGR3 chromosome.
The change from glycine to arginine would enhance the FRGR3 and would then allow lower amounts of proliferation. Would not allow bone growth

Question 22

What mutation would cause cystic fibrosis

Answer 22

CFTR gene
Deletion in the phenylalanine amino acid
F508del

Question 23

What are the treatments for cystic fibrosis

Answer 23

Aerosols, that would contain lipids would treat the symptoms
Digesting enzymes
Drainage of the lungs from when it gets full of liquid

Question 24

What are the biological effects caused by ionising radiation

Answer 24

Necrosis of the cells
Increased chance of leukaemia
Eye irritation
Erythema (skin redness)

Question 25

What are the direct and the indirect effects radiation has on bio molecules

Answer 25

Directs: through the direct interaction with the radiation and the bio molecules
Indirect caused through ionising water or even the radioactive radicals that would then go onto interact with the bio-molecules

Question 26

What are the advantages of using a physical map to map gene defects

Answer 26

Allows a more precise location to be viewed
Allows identification of new defects

Question 27

What is the mutation of the HD gene (Huntington’s disease)

Answer 27

A triplet repeat of CAG

Question 28

What are the conditions for an X-linked dominant disorder

Answer 28

Both men an women effected
If have an effected man would have all daughters effected but none of the sons would be effected
Fragile X syndrome (large head, large ears long face)

Question 29

What are the conditions for an X linked recessive disorder

Answer 29

Only males would be effected
No male to male transmission
Haemophilia A, duchennes muscular distrophy, red and green colour blindness

Question 30

What conditions would be autosomal dominant

Answer 30

Huntingtons
Common Down syndrome (Achondroplasia mutation in the FGFR3 gene)

Question 31

What conditions would be autosomal recessive

Answer 31

Cystic fibrosis (CFTR gene mutation)
Phenylketonuria (the defective phenylalanine hydroxylase that would normally convert phenylalanine to tyrosine)

Question 32

What causes phenylketonuria

Answer 32

The defective phenylalanine hydroxylase (PAH) that would allow the phenylalanine to be converted to tyrosine
There would also be a g to a point mutation that would lead to a premature stop codon (so a nonsense mutation)

Question 33

What can you use to treat phenylketonuria

Answer 33

The polyribsomes
Since enzyme deficiency would wand to synthesis the PAH from an RNA.
Shear the ribosome and isolate the complex using an enzyme that would be complementary to the PAH
Make a cDNA.

Question 34

What mutation causes sickle cell anemia

Answer 34

A mutation in the persons HBB gene (haemoglobin gene)
A GAG to GTG mutation

Question 35

What chromosome would be effected by Huntington’s disease

Answer 35

Chromosome 4
The triplet CAG CAG CAG (when have the disease would have the increased length of the CAG so would allow this triplet to form)

Question 36

What would it mean if a cell is mis-repaired

Answer 36

Mutation would occur

Question 37

What can cause free radical damage

Answer 37

Ionising radiation or UV

Question 38

Translocation of what chromosomes would lead to myeloid leukaemia

Answer 38

9 and 22