Problem 1. Which of the following is(are) TRUE of a single human liver cell? a.
ID: 165522 • Letter: P
Question
Problem 1. Which of the following is(are) TRUE of a single human liver cell?
a. There are 46 chromosomes present.
b. There are two alleles for each gene.
c. There is one allele on each chromosome.
d. a and b
e. a, b, and c
Problem 2. What is the genotype of a person with cystic fibrosis?
a. The genotype includes two mutant CFTR genes, one each on the homologous chromosomes for chromosome 7.
b. The genotype includes one mutant CFTR gene and one normal gene, one each on the homologous chromosomes for chromosome 7
c. The genotype includes two mutant CFTR genes, both on a single homologous chromosome 7; the other homologous chromosome 7 is normal.
d. The genotype includes only one homologous chromosome 7; the second chromosome 7 is missing.
e. The genotype includes 2 additional chromosomes with the mutant CFTR gene, making a total of 25 chromosomes.
Problem 3. Why is it possible for two healthy parents to give birth to a child with a genetic defect such as cystic fibrosis?
a. CF is normally caused by a mutation that occurs only in the sperm and eggs of the parents, so their bodies are not affected.
b. CF is normally caused by a mutation that occurs in the fetus during pregnancy, and does not affect the mother.
c. CF is only evident in individuals with two mutant alleles; a healthy parent could carry both a defective allele and a normal copy and be healthy.
d. CF is not passed to children from their parents; it comes from their grandparents.
e. CF is caused by the inheritance of too many "normal" genes; the parents would be unaffected.
Problem 4. A woman is heterozygous for the CF-associated gene (the alleles are represented here by the letters A and a). Assuming that meiosis occurs normally, which of the following represent eggs that she can produce?
a. A
b. a
c. Aa
d. a and b
e. a, b, and c
Problem 5. Meiosis differs from mitosis in the __________.
a. way in which sister chromatids separate
b. number of cells produced immediately after the starting cells divide
c. number of chromosomes in the starting cells
d. number of sister chromatids in the starting cells
e. number of chromosomes in each ending cell
Problem 6. Besides recombination, what other event in meiosis increases the genetic diversity of the gametes?
a. the way in which chromosomes are replicated in meiosis II
b. the random line-up and separation of maternal and paternal chromosomes
c. the random exchange of DNA segments between paternal chromosomes
d. the random exchange of DNA segments between maternal chromosomes
e. the random way in which gametes fuse together to make uniquely different sperm and eggs
Problem 7. An alien has 82 total chromosomes in each of its body cells. The chromosomes are paired, making 41 pairs. If the alien's gametes undergo meiosis, what are the number and arrangement (paired or not) of chromosomes in one of its gametes?
a. 41 paired chromosomes
b. 41 unpaired chromosomes
c. 82 unpaired chromosomes
d. 82 paired chromosomes
e. 164 paired chromosomes
Problem 8. Children often have many of the phenotypes of their parents because __________.
a. they have the exact same genotypes as their parents
b. they inherit half of their genetic material from each parent
c. they carry the same combinations of alleles that their parents have
d. they inherit mutations that make their bodies appear identical to one or both parents
e. the cells of embryos divide by meiosis, a process that yields genetic duplicates
Problem 9. In order for a child to develop cystic fibrosis,
a. a sperm carrying a CF allele must fertilize an egg that also has that allele.
b. genetic recombination must occur in the father but not the mother.
c. genetic recombination must occur in the mother but not the father.
d. more than one sperm in the father must carry the CF allele.
e. more than one egg in the mother must carry the CF allele.
Problem 10. Use the following information for this question:
Phenylketonuria is considered to be an inborn error of metabolism. It is a recessive genetic condition in which the enzyme that breaks down the amino acid phenylalanine is defective or missing. Testing of all newborns allows this condition to be detected at birth. A special diet that severely minimizes phenylalanine (e.g., by avoiding diet sodas and most usual sources of protein) can treat the condition.
In this scenario, two carriers of both cystic fibrosis and phenylketonuria have a child.
What is the probability that the child will have both cystic fibrosis and phenylketonuria?
a. 6.25%
b. 12.5%
c. 18.75%
d. 56.25%
e. 0%
Explanation / Answer
1. e) true -the human liver cells contain diploid number of chromosomes i.e. 46. That means there are two copies of a chromosome in these cells. The human reproductive cells are the only cells that have haploid number of chromosomes i.e. 23. In a single human cell one gene has two alleles. A single allele is present on a single chromosome. Hence in a diploid cell a gene will have an allele on both chromosomes.
2) a - true . Cystic fibrosis is an autosomal recessive disease. Hence for a person to present the disease he has to have two copies of the mutant gene on homologous chromosomes.
3) c- true.Cystic fibrosis is an autosomal recessive disorder. Hence, an individual can carry a single mutant allele of the gene and one normal allele for the gene and not present the disease. These individuals are called carriers. For an individual to present the disease, both mutant alleles i.e. mutant genes on both chromosomes are essential. Therefore when a child born to normal parents, presents cystic fibrosis disease, it indicates that the parents are carriers (heterozygous) for the disease.
4) d- true . The woman is heterozygous for the gene hence her genotype is represented as Aa. Egg of this woman will have haploid number of chromosomes and hence will contain only one of the alleles. Hence, the egg produced can either have A or a allele (either one of the alleles).
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