Question

Cystic fibrosis is a disease in which people have a mutation in an ion channel called CFTR. This type of channel is found in multiple tissues throughout the body, and a simple mutation in this channel may be expressed in a multitude of ways (sweating disorder, digestive system malfunction, respiratory difficulties, etc…). This type of situation when a genetic mutation expresses itself in a multitude of phenotypes is called

Select one:

a. Polygenic inheritance

b. Codominance

c. Epistasis

d. Pleiotropy

e. Incomplete dominance

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DNA nucleotides have a hydroxyl group at the 2’ position on the ribose

Select one:

a. False

b. True

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DNA polymerases can only work on the lagging strand of the replication fork once they are finished with the leading strand

Select one:

a. False

b. True

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DNA polymerases read the DNA

Select one:

a. In the 3’ to 5’ direction

b. In the 5’ to 3’ direction

c. In either 3’ to 5’ or 5’ to 3’ direction – depending on the situation

Answer 1

1)d.pleiotropy

Pleiotropy is a condition in which a gene influence more than one unrelated trait.

Polygenic inheritance is a condition where a trait is controlled by more than one gene.

Codominance is the condition where the recessive allele also expresses its own trait and its expression is not dominated by dominant allele and produce a phenotype with expression of both alleles in heterozygous individuals.

Epistasis is a condition where one gene mask the expression of another gene.

Incomplete dominance is a condition where heterozygous individuals produce a trait intermediate between the homozygotes(dominant and recessive).

2)a.false

DNA molecules have no hydroxyl group at 2' position of ribose.instead have hydrogen so an oxygen is missing and so it is called 2' deoxyribose. In RNA hydroxyl group is present at 2' of ribose.

3)a.false

DNA replication is simultaneous on both strands but synthesis on lagging strand is discontinuous.

4)a.in the 3' to 5' direction.

DNA polymerase requires hydroxyl group at 3' for initiation of DNA synthesis, so template strand is read in 3'-5' direction and new strand is formed in 5'-3' direction.