Practice Set 1 Flashcards
- A sample of normal double-stranded DNA was found to have a guanine content of
18%. What is the expected proportion of adenine?
32%
In one strand of DNA the nucleotide sequence is 5’-ATGC-3’. The complementary
sequence in the other strand must be
3’-TACG-5’.
How many different DNA molecules eight nucleotide pairs long are theoretically
possible?
65,536
Wild cats (Felis silvestris) and common mice (Mus musculus) are diploid. In wild cats
2n = 38, while in common mice 2n = 40. Based on this information, we can conclude
that wild cat cells have
fewer DNA molecules than common mouse cells.
Beside DNA, which of the following are major components of chromatin?
Proteins
A gene is transcribed into an mRNA and this mRNA is 110 nucleotides long. Which of
the following proteins could it encode?
A signalling protein that is 10 amino acids long
The nuclear genome of a mouse nerve cell is compared to that of a mouse skin cell.
What differences can we expect to see between these two cells’ nuclear genomes?
The two cells have the same genome; there will be no differences.
Arabidopsis thaliana is a diploid plant model organism with 2n = 10.
a) How many copies of each gene does each Arabidopsis thaliana cell have?
b) How many sets of chromosomes does the nucleus of an Arabidopsis thaliana leaf cell contain?
c) How many pairs of homologous chromosomes does the nucleus of an Arabidopsis thaliana leaf cell contain?
a) 2
b) 2
c) 5
Explain the difference between forward and reverse genetics in the genetic study of
traits and biological characteristics.
Forward genetics utilizes differences between wild type and mutant phenotypes.
Crosses are made (in model organisms) or pedigrees are studied (in humans) to understand the genes involved in the phenotypic expression.
Reverse genetics starts with the DNA information and tries to find out what phenotypic effects result if the DNA is changed.
A mutation occurs in a germ cell of a pure-breeding, wild-type male mouse prior to DNA replication. The mutation is not corrected, and the cell undergoes DNA replication and a normal meiosis producing four gametes.
How many of these gametes
will carry the mutation?
2
In pet rabbits, brown coat color is recessive to black coat color. A black female rabbit gives birth to four black-coated and three brown-coated baby rabbits.
What can be deduced about the genotype of the baby rabbits’ father?
He could be heterozygous black/brown or homozygous brown.
A very common type of red/green colorblindness in humans is caused by a mutation in
a gene located on the X chromosome. Knowing that the mutant allele is recessive to
the wild-type, what is the probability that the son of a woman whose father is
colorblind is going to also be colorblind?
50%
pedigree
pedigree
pedigree
