Question 1

Humans have chromosomes in the gametes.&#10;A)2&#10;B)12&#10;C)24&#10;D)48

Accepted Answer

Humans have 23 pairs of chromosomes, totaling 46 in somatic cells, but gametes (sperm and egg cells) contain half, which is 23 chromosomes.

Question 2

In the following genetic cross,Pp x Pp,what percentage of the offspring will have a recessive phenotype?&#10;A)0%&#10;B)25%&#10;C)50%&#10;D)75%

Accepted Answer

In a cross between Pp x Pp, where P stands for dominant allele and p stands for recessive allele, the genotypes of the offspring will be PP, Pp, and pp in a 1:2:1 ratio. Out of these, only pp genotype will have a recessive phenotype. Therefore, the percentage of offspring with a recessive phenotype will be 25%.

Question 3

Sex-linked genes only affect male carriers.

Accepted Answer

Sex-linked genes are located on the sex chromosomes (X and Y) and can be inherited differently depending on whether the carrier is male (XY) or female (XX). However, both male and female carriers can be affected by sex-linked genes, although the presentation and severity of the phenotype may differ.

Question 4

Homologous chromosomes contain the same genes for the same traits at the same loci.

Accepted Answer

Homologous chromosomes are two chromosomes that pair up during meiosis and contain genes for the same traits at the same loci. They may have different alleles for those genes, but they carry the same basic genetic information.

Question 5

Sex-linked genes are found on .&#10;A)the X chromosome only&#10;B)the Y chromosome only&#10;C)either the X or the Y chromosome&#10;D)the autosomes

Accepted Answer

Sex-linked genes can be located on either the X chromosome or the Y chromosome, affecting the traits linked to gender.

Question 6

Sister chromatids occur following .&#10;A)gamete fusion&#10;B)cell division&#10;C)transcription&#10;D)replication

Accepted Answer

Sister chromatids occur following replication of the DNA in the S phase of the cell cycle, where each chromosome is duplicated to form two identical sister chromatids attached at the centromere region.

Question 7

Gametes are and somatic cells are .&#10;A)diploid;haploid&#10;B)haploid;diploid&#10;C)haploid;haploid&#10;D)diploid;diploid

Accepted Answer

Gametes are haploid cells, meaning they have one set of chromosomes, while somatic cells are diploid cells, meaning they have two sets of chromosomes.

Question 8

A triploid organism would have copies of all genes.&#10;A)0&#10;B)1&#10;C)2&#10;D)3

Accepted Answer

Triploid organisms have three copies of all genes, as indicated by the prefix "tri-" which means three.

Question 9

Which statement is false?&#10;A)Individuals who are heterozygous for a defective gene are carriers of the defective allele.&#10;B)Heterozygous individuals have the genetic disorder.&#10;C)Heterozygotes have two different alleles for the same trait.&#10;D)All of the above are false.

Accepted Answer

Heterozygous individuals do not have the genetic disorder since they have one functional allele and can produce the necessary protein/enzyme. It is individuals who are homozygous for the defective allele who have the genetic disorder.

Question 10

A allele determines the phenotype even when only one copy is present.&#10;A)dominant&#10;B)recessive&#10;C)codominant&#10;D)homozygous

Accepted Answer

A dominant allele will always determine the phenotype, even in the presence of only one copy. In contrast, a recessive allele will only determine the phenotype when two copies are present (homozygous recessive). Codominant alleles will both contribute to the phenotype when present together. Homozygous refers to having two copies of the same allele.

Deck 2: Basic Genetics