MUTATIONS
Which type of point mutation results in a single amino acid change in the resulting polypeptide chain?
missense mutation
1.In a heterozygous individual, which allele is expressed in the phenotype assuming complete dominance?
only the dominant allele.
1.What are the three components that make up a standard DNA nucleotide?
A nitrogenous base, a deoxyribose sugar, and a phosphate group.
1.At the end of telophase II and cytokinesis in meiosis, how many daughter cells are produced and what is their genetic makeup?
four genetically unique haploid cells
1.A true-breeding red snapdragon is crossed with a true-breeding white snapdragon, and all F1 offspring are pink. If these pink F1 plants are self-pollinated, what phenotypic ratio is expected in the F2 generation?
1 red:2 pink:1white
2.Why does the insertion or deletion of a single nucleotide (that is not a multiple of three) usually have a more severe effect on a protein than a single nucleotide substitution?
it shifts the reading frame altering evert downstream amino acid ad often introducing a premature stop codon.
2.Which of the following genotypes represents a heterozygous individual?
Aa
2.If a double-stranded DNA molecule is found to contain 20% adenine (A) bases, what percentage of cytosine (C) bases would you expect to find?
30%
2.If a human skin cell (which is diploid, 2n = 46) undergoes mitosis, what will be the chromosome number of each resulting daughter cell?
46 chromosomes (haploid)
2.Which of the following statements best describes codominance?
both allekes in a heterozygote are fully and simultaneously expressed without bleding.
3.A chromosomal mutation where a segment of one chromosome breaks off and attaches to a nonhomologous chromosome is known as:
translocation.
3.When two heterozygous individuals (Cc × Cc) are crossed in a monohybrid cross, what is the expected genotypic ratio of the offspring?
1:2:1(CC:Cc:cc)
3.Which type of chemical bond holds the complementary nitrogenous bases together across the center of the double helix?
hydrogen bonds
3.During which specific phase of meiosis does crossing over (homologous recombination) occur?
porphase l
3.The human ABO blood group system is governed by multiple alleles (Ia,Ib,i). How many distinct alleles for this gene exist in the human population as a whole, and how many can any normal diploid individual inherit?
3 alleles in the population 2 alleles inherited
4.Exposure to ultraviolet (UV) radiation commonly causes DNA damage by forming?
thymine dimers that distort the DNA double helix.
4.In pea plants, tall (T) is dominant over short (t). If you cross a homozygous tall plant (TT) with a short plant (tt), what is the expected phenotypic ratio of the offspring?
All tall (100% tall)
4.What does it mean to say that the two strands of a DNA double helix are "antiparallel"?
the strands run in opposite 5 to 3 and 3 to 5 directions.
4.What primary event distinguishes Anaphase I of meiosis from Anaphase of mitosis?
homologous chromosomes separate while sister chromatids remain attached at their centromeres.
4.Human traits such as height and skin color typically exhibit a continuous, bell-shaped distribution of phenotypes across a population. This pattern is best explained by:
the additive effects of two or more independent genes on a single phenotypic character.
5.What is the direct consequence of a nonsense mutation occurring near the 5' end of a protein-coding gene?
translation will terminate permaturely, resulting in a shoetened (truncated) protein.
5.If two guinea pigs with black fur that are heterozygous (Bb) have offspring, what percentage of the offspring are expected to have white fur, assuming white fur (b) is recessive?
25%
5.A phosphodiester bond links which two parts of adjacent nucleotides within a single DNA strand?
the 3 cardbon of one sugar and the 5 carbon of the next sugar through a phosphae group.
5.Which of the following best describes the primary biological purpose of mitosis in multicellular organisms?
growth, tissue repair, and asexual reproduction
5.Red-green color blindness is an X-linked recessive trait. If a colorblind woman marries a man with normal vision, what percentage of their sons are expected to be colorblind?
100%