The Basocs/fundamentals + mutations

Question 1

How does the allele for sickling and normal globin allele relate to malaria resistance?

Answer 1

If heterozygote you are malaria resistant

So allele for sickling is is dominant with respect to malaria resistance

Question 2

How does the allele for sickling and normal globin allele

relate to bete globin isoform production?

Answer 2

They are codominant with reepct to beta globin production .

As both the beta subunit and sickling allele create both normal and abs normal isoforms

Question 3

How does the allele for sickling and normal globin allele

relate to Red blood cell (RBC) count at high altitudes?

Answer 3

Homozygote for beta subunit mutation you get normal RBC at high altitude
Homozygote for sickling yo get v. Low RBC at high altitude
Heterozygote you get reduced RBC at high altitude

So the alleles are INCOMPLETELY DOMINANT to each other wit respect to RBC at high altitude

Question 4

Which blood type is the universal donor
A type O
B type AB
C type A
D type B

Answer 4

Blood type O (which is recessive to A and B

Why…..

Question 5

In a pedigree, a trait that appear in both sexes and doesn't skip generations describes
A autosomal dominant
B autosomal recessive 
C seX linked dominant 
D seX linked recessive

Answer 5

Option A please

E.. G huntingdon disease where at least one aren’t is affected

Question 6

In a pedigree, a trait that appear in more in females  and doesn't skip generations describes
A autosomal dominant
B autosomal recessive 
C seX linked dominant 
D seX linked recessive

Answer 6

Option C
Father’s do not transmit to sons (as they give the unaffected Y) but can pass o trait to daughter
E. G. Familial vitamin D rickets

Question 7

The appearance of a third intermediate phenotype describes
A codomiance
B over dominance
C incomplete dominance
D under dominance

Answer 7

Option C
E. G having medium sized dots when you stated out with small and large dots

under and over dominance realte to the fitness of the heterozygote (advantage or disadvantage)

Question 8

What is meant by a multiple allele

Answer 8

These alleles have polymorphic loci so there are multiple alles for a trait at Population level
E. G hair, eye skin colour

Question 9

What is penetrance?

Answer 9

The propertion of individuals that display the expected phenotype in a population (with a specific genotype)
> usually alleles have 100% penetrance

Question 10

A mutation is
A Any change is the DNA sequence
B Any change in the amino acid sequence
C Any heritable change in the DNA sequence
D Any heritable change in the amino acid sequence

Answer 10

OPTION C
IT IS inherited!
> random but mutagens can increase frequency

Question 11

Which of these does a single base pair mutation not cause? (single polymorphism SP
A Silent mutation
B Missense mutation
C Frame shift mutation
D Nonsense mutation

Answer 11

OPTION C - caused by Insertion/deletion (INDEL)

Question 12

what is the difference between transversion and transistion mutaiton

Answer 12

transistion is purine for purine (A-G)

tranversion is purine for pyrmadine (A -T)

Question 13

…’ how many porgency are the parent type (non-recombinatn type)?

Answer 13

add up both the parent geotypes together
> bigger number

porgency = offspring

Question 14

normal chromosome : A B C D E F G H
mutant chromosome: A B E F D C G H
A insertion
B deletion
C duplication
D inversion
E chromosomal fusion

Answer 14

OPTION D
‘’ C D E F’’ inverted!

> chromosomal fusion would mean an extra bit would be added (e.g. I J K )

Question 15

What does the ABO locus encode?
A glycosyltransferase
B glycocalyx
C transferrin
D glycophorin a
E glycosylamine

Answer 15

glycosyltransferase modifies the oligosaccharides on cell surface glycoproteins to form ABO blood groups.

Question 16

Which of the following mutations is a transverse mutation?
ATTGAC -> GTTGAC

ATTGAC -> AGTGAC

ATTGAC -> ATTCGAC

ATTGAC -> ATCGAC

ATTGAC -> ATGAC

Answer 16

OPTION B

A - transition mutation (purine A substituted for purine G)
CORRECT B - transverse mutation (pyrimidine T substituted for purine G)
C- insertion mutation
D- transition mutation (pyrimidine T substituted for pyrimidine C)
E - deletion mutation

Question 17

Sometimes damaged bases are excised and replaced with a template strand. This is used to remove pyramidine dimers formed by UV radiation. What repair mechanism is this?
A homologous recombination
B mis-match repair
C Nucleotide excision repair
D non homologus recombination
E base excision repair

Answer 17

Nucleotide excision repair
> the whole nucleotide is removed
> look at that lovely poster

Question 18

What condition would prevent independent assortment from occurring?
A Probability of inheriting one specific allele has not impact on effecting the heritably of another allele for a different trait
B There are at least two alleles for each of the traits of interest
C The organism you are using must have its full genome mapped
D The probability of inheriting one allele for one trait affects the probability of inheriting the other allele for another specific trait

Answer 18

OPTION D - epistasis? as that is NOT INDEPENDENT

A and B must be true for independent assortment to occur, C has no relation to independent assortment

Question 19

disease causing allele has variable penetrance. what mean?
A allele is dominant
B severity of disease differs between individuals with different genotype
C allele is reccesive
D severity of diease varies between individuals with same genotype
E allele affects another allele

Answer 19

OPTION D

only for those with the SAME genotype

Question 20

'' changes codeon for a specific aa to a codon for a different aa'' describes
A silent mutation
B mis-sense mutation
C non-sense mutation
D frame shift mutation

Answer 20

this is mis-sense

> nonsense is when the a stopcodon is made = trunchated protein

Question 21

phildelphi chromosme is an exmaple of
inversion
mutation
variable expressivity
translocation
genes and environment

Answer 21

translocation event

> between chromosome 9 and 22 creating a protien fusion product contributing to chronic myelogenus leukemia

Question 22

what do ‘intercalating agents’ do?

Answer 22

squeeze between basepairs and recognised by DNA as a extra base so get INSERTED during dna replication
> frame shift mutation depending on how many are added (INDEL)