Point mutations affect a large region of the DNA.
Which of the following can cause DNA Mutations?
Chemicals
Radiation
Medication
Errors in DNA Repair Mechanisms
In eukaryotes, DNA Mutations that occur in the non-coding regions may still have an affect on the organism.
Most mutations occur in the DNA of germ-line cells.
A new mutation is only of consequence to the next generation if it occurs in germ line cells.
Which of the following is a direct consequence of somatic cell DNA mutation?
Cancer
Diabetes
Cushing's Syndrome
Fatty Liver
Ageing may be, in part, a consequence of an accumulation of somatic cell mutations.
Evolution depends on mutations.
How are gene mutations removed from population?
Individuals choose not to mate with another individual carrying mutations.
Individuals with mutations choose not to mate with healthy individuals.
Mutations that have detrimental effects lower the chance of survival of that individual, a lower chance of reproduction means the genes are not inherited.
The DNA splices out mutations when the foetus is developing.
A point mutation occurring in non-coding DNA can still be lethal.
Which of the following is NOT a type of DNA mutation?
Insertion or Deletion
Base Substitution
Base Transportation
Large Deletions
Point Mutations
Roughly what percentage of DNA is non-coding?
99%
95%
22%
57%
Base Transversions involve a purine being replaced by a pyrimidine or vice versa.
How do base transversions affect the DNA?
If a pyramidine is replaced with a purine, the DNA will fall apart.
If a purine is added, the DNA will stick to the edge of the nucleolus.
The DNA double helix shape will have either a bulge of dip in it.
The DNA double helix will not form at all, so these are fatal mutations.
Base Transitions can include example such as: G replacing A or T replacing C.
Normal base pairing involves Adenine ( a keto type ) binding with Thymine (also a keto type) with 2 hydrogen bonds.
Normal base pairing involves Cytosine (an amino type) binding to Guanine ( a keto type) with 3 hydrogen bonds.
What are Tautomeric forms of the DNA bases?
Tau protein becomes embedded in the histone proteins.
Keto types are transformed into Enol groups and vice versa.
They are unable to bind to anything, so the DNA cannot form.
Low concentrations of Guanine(enol) exist, so one rare abnormal base pairing is: G(enol) with T(keto).
Spontaneous mutations can be caused by tautomeric forms of DNA bases. These abnormal bases exist in low concentrations, in equilibrium in the cell. In vitro studies show that what percentage of DNA bases are in the rare abnormal form?
0.003%
0.1%
1%
0.013%
Which of the following statements concerning DNA/RNA proofreading is correct?
DNA Polymerase proofreads DNA and RNA in all organisms.
There is no proofreading mechanism available for RNA.
Viruses, such as influence and HIV, mutate regularly because they contain DNA polymerase, a mutagen for RNA.
One common repair mechanism is that of Alkylation - DNA polymerase alkyl groups, removes and replaces them.
DNA Glycosylase removes and replaces the alkylated base.
What feature of the Genetic Code minimises the chance of disadvantageous and fatal mutations?
We have so much non-coding DNA that we can use that are a repair template.
The Degeneracy of the Genetic Code.
DNA cannot become mutated once you are born, all mutations occur when you are growing.
The mutation causing sickle cell anaemia has not been removed from certain populations because is confers some resistance to...
HIV/AIDS in Caucasian individuals.
Malaria in Afro-Carribean individuals.
AIDS in children.
Lung cancer in Afro-Carribean smokers.
Nonsense mutations may lead to a truncated protein. How may this be detrimental?
The protein may become shaped like a elephant's trunk and will adhere to ribosomes.
The resulting protein may be missing active sites.
The protein might be so small that it can become 'lost' in the cytoplasm, because it can exit the nucleus through the nuclear pores.
Transposase is an enzyme which that promtes the jumping of short DNA sequences from one DNA molecule to another.
Chromosomal translocation in the Philadelphia chromosome leads to...
Chronic Myeloid Leukaemia
Acute Lymphoblastic Leukaemia
A predisposition to Pancreatic Cancer.
Chronic Anaemia
