Deck 2: Genetics

Question 1

Mitosis

A) results in half the number of chromosomes in the daughter cells.
B) results in either sperm or egg.
C) results in a daughter cell that has the exact copy of the chromosomes of its parent.
D) results in an egg only.

Answer 1

C

Question 2

Chromosomes are contained in

A) the gametes of prokaryotes.
B) the nuclei of eukaryotes.
C) the ribosomes.
D) the mitochondria.

Answer 2

B

Question 3

In mitosis

A) a haploid cell divides into two diploid cells.
B) a diploid cell divides into two haploid cells.
C) a haploid cell divides into two diploid cells.
D) a diploid cell divides into two diploid cells.

Answer 3

D

Question 4

In meiosis,

A) haploid cells are produced from a single diploid cell.
B) haploid cells are produced from two diploid cells.
C) diploid cells are produced from a single diploid cell.
D) diploid cells are produced from two haploid cells.

Question 5

Which of the following is true of mitosis?

A) Mitosis produces identical daughter cells.
B) Mitosis produces nonidentical daughter cells.
C) Mitosis produces cells with different chromosomes.
D) Mitosis produces haploid gametes.

Question 6

A cross between true-breeding plants bearing yellow seeds produces offspring bearing

A) all yellow seeds.
B) 1/2 yellow and 1/2 green seeds.
C) 3 yellow seeds and 1 green seed.
D) all green seeds.

Question 7

Which of the following is true of meiosis?

A) Daughter cells contain one chromosome from each homologous pair.
B) Daughter cells contain both chromosomes from each homologous pair.
C) Meiosis produces somatic cells.
D) Meiosis produced diploid cells.

Question 8

In diploid organisms

A) chromosomes occur in homologous pairs.
B) chromosomes occur in homologous triplets.
C) meiosis produces diploid gametes.
D) mitosis produces haploid cells.

Question 9

The possible genotype(s) of a pea plant with yellow seeds is

A) AA.
B) aa.
C) Aa.
D) both a and

Question 10

Mendel's second principle (of independent assortment) states that

A) eggs and sperm are formed independently of one another.
B) transmission includes both blending and particulate inheritance.
C) particles inherited from the mother and the father are equally likely to be transmitted to offspring.
D) particles inherited from the mother are more likely to be transmitted to female offspring and particles inherited from the father are more likely to be transmitted to male offspring.

Question 11

Gametes

A) contain both homologous chromosomes.
B) are responsible for normal body growth of organisms.
C) can be eggs or sperm.
D) are diploid.

Question 12

Gametes

A) are not involved in the transmission of genes.
B) are the sex cells, or eggs and sperm.
C) do not differ between male and female animals.
D) were discovered by Darwin.

Question 13

A pea plant with only green seeds is

A) homozygous recessive.
B) always tall.
C) an example of blending inheritance.
D) heterozygous.

Question 14

The genotype of an individual refers to

A) the alleles it carries.
B) its visible characteristics.
C) the number of chromosomes in its sex cells.
D) the number of chromosomes in its body cells.

Question 15

Cross-breeding the offspring of true-bred green and yellow peas led to ________ in the second generation.

A) only green individuals surviving the first days of life
B) a 3:1 ratio of yellow to green offspring
C) yellowish green individuals
D) half the offspring being green and the other half yellow

Question 16

Reduction of chromosome number occurs during

A) recombination.
B) meiosis.
C) somatic cell formation.
D) linked genes.

Question 17

Chromosomes are

A) composed of ribonucleic acid.
B) attached to organelles.
C) replicated during cell division.
D) made of proteins.

Question 18

If you have two parents with the genotype Aa, what is the chance that they will have an offspring with the genotype AA?

A) 1/8
B) 1/2
C) 1/4
D) 1/16

Question 19

Homologous chromosomes

A) come in pairs.
B) move together into the gametes during meiosis.
C) are found only in mammals.
D) have three codons.

Question 20

Mendel's first principle (of segregation) states that

A) characteristics from the parents blend together to produce intermediate offspring.
B) characteristics from the parents do not blend together in offspring.
C) only paternally derived characteristics segregate into gametes during meiosis.
D) only maternally derived characteristics segregate into gametes during meiosis.

Question 21

Under which circumstance does Mendel's principle of independent segregation hold?

A) Only when traits are tightly linked (close together) on the same chromosome
B) Only when traits are on different chromosomes
C) Only when there is crossing over
D) Only when the traits are not influenced by selection

Question 22

Imagine two loci on one chromosome. At one locus the genotype is Aa, and at the other locus the genotype is Bb. After meiosis, what are all of the possible genotypes of the gametes?

A) AB and ab gametes
B) All AB gametes
C) AB, ab, Ab, and aB gametes
D) Ab and aB gametes

Question 23

When Mendel crossed true-breeding plants bearing yellow seeds with true-breeding plants bearing green seeds, what was the phenotypic ratio among the offspring?

A) All aa individuals
B) All AA individuals
C) Half yellow and half green individuals
D) All yellow individuals

Question 24

When Mendel crossed true-breeding plants bearing yellow seeds with true-breeding plants bearing green seeds, what was the genotypic ratio among the offspring?

A) 100% aa individuals
B) 100% AA individuals
C) 100% Aa individuals
D) 3 to 1 yellow to green individuals

Question 25

When Mendel crossed heterozygote pea plants for two different traits, he recorded a phenotypic ratio of

A) 1:2:1.
B) 4:8:4.
C) 9:3:3:1.
D) 12:4.

Question 26

An individual with two identical alleles at a locus is

A) an independent phenotype.
B) a homozygote.
C) a heterozygote.
D) dominant.

Question 27

What genotype do true-breeding plants bearing yellow seeds have?

A) aa
B) aA
C) Aa
D) AA

Question 28

Recombination and crossing over are very important in the genetic process because they produce

A) variation.
B) a new somatic cell.
C) DNA.
D) linked chromosomes.

Question 29

Mendel crossed AABB with aabb individuals, where B = smooth, b = wrinkled, A = yellow, and a = green. What was the genotypic ratio of the F₁ generation?

A) All AAbb
B) 1/2 AAbb and 1/2 aaBB
C) All AaBb
D) All AABB

Question 30

What is the probability that an Aa individual will produce a gamete with an A allele?

A) 100%
B) 75%
C) 50%
D) 25%

Question 31

Mendel crossed true-breeding plants bearing yellow seeds with true-breeding plants bearing green seeds. He then crossed the offspring from that mating with each other (F₁ generation). What was the genotypic ratio among the offspring of the F₁ generation?

A) All Aa or aA
B) 25% aa, 50% Aa/aA, and 25% AA
C) All AA or aa
D) 33.3% aa, 33.3% Aa/aA, and 33.3% AA

Question 32

Consider a cross between tall and short plants in which all of the offspring are tall. This suggests that

A) the allele for tall is recessive.
B) the allele for tall is dominant.
C) the alleles for tall and short are codominant.
D) None of the above.

Question 33

Imagine a cross between AA and Aa individuals. What is the genotypic ratio among the offspring?

A) 1/2 AA and 1/2 aa
B) 1/2 Aa and 1/2 aa
C) 1/2 AA and 1/2 Aa
D) All AA

Question 34

Mendel crossed true-breeding plants bearing yellow seeds with true-breeding plants bearing green seeds. He then crossed the offspring from that mating with each other (F₁ generation). What was the phenotypic ratio among the offspring?

A) All yellow
B) 1/2 green and 1/2 yellow
C) 3/4 yellow and 1/4 green
D) 3/4 green and 1/4 yellow

Question 35

When a true-breeding plant bearing yellow seeds produces gametes, what alleles are represented among those gametes?

A) Only A alleles
B) Only a alleles
C) Both a and A alleles, in equal frequencies
D) Both a and A alleles, but mostly A alleles

Question 36

Which of the following is true of chromosomes?

A) Hereditary material is contained in the chromosomes.
B) Chromosomes come in tetrads.
C) Two chromosomes from each homologous pair are passed on to daughter cells during meiosis.
D) One chromosome from each homologous pair is passed on to daughter cells during mitosis.

Question 37

The phenotype of an individual refers to

A) its visible characteristics.
B) the number of homologous pairs of chromosomes.
C) the number of chromosomes in its body cells.
D) the number of chromosomes in its sex cells.

Question 38

A heterozygote is an individual with

A) the same paternal and maternal allele at a particular locus.
B) a different paternal and maternal allele at a particular locus.
C) a recessive allele.
D) a dominant allele.

Question 39

What genotype do true-breeding plants bearing green seeds have?

A) aa
B) aA
C) Aa
D) AA

Question 40

The law of independent segregation states that

A) the fact that a gamete has an A rather than an a allele does not influence the probability that it will have a B rather than a b allele.
B) alleles on different chromosomes do not influence each other as they assort into gametes.
C) dominant alleles act independently of recessive alleles.
D) both a and b are correct.

Question 41

Alternative splicing

A) allows the same DNA sequence to code for more than one protein.
B) allows prokaryote exons to be included in the genome of eukaryotes.
C) allows only certain sections of DNA to be copied.
D) allows a maximum of four exons to be attached to mRNA.

Question 42

Crossing over

A) can occur between loci on nonhomologous chromosomes.
B) can occur between alleles on the same chromosome.
C) increases genetic variation.
D) decreases genetic variation.

Question 43

Exact replication of DNA is possible because

A) the low number of possible nucleotides.
B) base-pair complementarity.
C) the sequence of nucleotides along the DNA, which is always the same.
D) both a and c are correct.

Question 44

Sickle-cell anemia

A) is on the decline.
B) is caused by the change in two amino acids that make up the hemoglobin molecule.
C) results when hemoglobin molecules do not fold correctly, reducing their ability to bind to oxygen.
D) increases an individual's susceptibility to malaria.

Question 45

As DNA codes for proteins, it can be interrupted by noncoding sequences called

A) organelles.
B) proteins.
C) introns.
D) synthetases.

Question 46

Which of the following statements is true?

A) DNA has a nonrepeating four-base structure.
B) DNA is contained in chromosomes.
C) DNA stands for determining nuclear acid.
D) DNA does not tell us why heredity leads to the patterns Mendel described in pea plants.

Question 47

Molecular genetics

A) links biology to geophysics.
B) has explained the way the solar system works.
C) has demonstrated that humans descended from chimpanzees.
D) provides data for reconstructing the evolutionary history of species.

Question 48

The organelles that splice the mRNA in eukaryotes after the introns have been snipped out are called

A) splitosomes.
B) ribosomes.
C) spliceosomes.
D) Golgi bodies.

Question 49

At least ________ of the genome is expressed as noncoding DNA.

A) 50%
B) 25%
C) 75%
D) 5%

Question 50

Which of the following is true of DNA transcription/translation?

A) A codon corresponds to an amino acid.
B) A DNA sequence codes for a protein.
C) A protein consists of a series of codons.
D) Both a and b are true.

Question 51

If the DNA codon for an amino acid is ACC, what are the mRNA and its tRNA anticodon, respectively?

A) TGG; UCC
B) GGT; CCA
C) GTG; CAC
D) UGG; ACC

Question 52

Analysis of DNA sequences tells us that

A) humans and chimpanzees share a more recent common ancestor than either shares with gorillas.
B) the last common ancestor of chimpanzees and humans were gorillas.
C) humans left Asia about 1 million years ago.
D) humans left Asia and went to Africa.

Question 53

________ binds to complementary mRNA molecules and regulates the translation of mRNA into proteins.

A) Transfer RNA
B) MicroRNA
C) Noncoding DNA
D) Mitochondrial RNA

Question 54

Some biologists hypothesize that introns are maintained in eukaryotes because their population sizes are much smaller than in prokaryotes. ________ is the random, nonadaptive evolutionary process that explains this phenomenon.

A) Genetic drift
B) Natural selection
C) Protein synthesis
D) Transcription

Question 55

When two loci are very close together on a chromosome,

A) they are linked.
B) a crossing-over event between them is less likely than when two loci are far apart.
C) they can blend into a single gene.
D) both a and b are correct.

Question 56

The structure of DNA is that

A) of a series of intertwining chromosomes.
B) of a double-stranded molecule, consisting of four bases.
C) of a series of bases: adenine, guanine, thymine, and cytosine.
D) both b and c are correct.

Question 57

Because there are 64 possible codons and only 20 amino acids,

A) many mutations have no effect on phenotype.
B) every mutation has some effect on phenotype.
C) each tRNA molecule contains two extra amino acids.
D) each tRNA molecule contains two extra codons.

Question 58

Unlike a eukaryote, a prokaryote

A) does not have DNA.
B) has many introns and exons.
C) has a large number of chromosomes.
D) does not have a nucleus.

Question 59

Which of the following sequences is accurate for transcription and translation?

A) DNA tRNA mRNA protein
B) DNA mRNA protein
C) Protein tRNA DNA
D) Protein tRNA DNA

Question 60

The presence of repressors and activators in regulatory genes means that there is ________ of gene expression.

A) translation
B) combinatorial control
C) a biochemical pathway
D) primary structure

Question 61

Describe the structure of DNA.

Question 62

How do the results of Mendel's experiments affect our understanding of how variation is preserved?

Question 63

How does a sequence of DNA produce a protein through transcription and translation?

Question 64

What is the role of regulatory genes? What is meant by the combinational control of gene expression? Illustrate your answer with an example.

Question 65

True-bred tall pea plants with violet flowers are crossed with short plants with white flowers. Assume the trait for tall plants (T) is dominant and short plants (t) is recessive. Also assume the trait for violet flowers (V) is dominant and white flowers (v) is recessiv
1. What are the genotypes of the F1 plants?
2. What are the genotypes of the gametes for the F1 plants?
3. What are the phenotypes and phenotypic ratios of the F2 generation and why?

Question 66

Consider a homologous pair of chromosomes with the genotype Aa at one locus and the genotype Bb at another locus. After undergoing meiosis, what are all of the possible genotypes of the gametes produced?

Question 67

Explain the life cycle of diploid organisms in terms of meiosis and mitosis.

Question 68

How does alternative splicing allow the same DNA sequence to code for more than one protein? Why is alternative splicing important in eukaryotes?

Question 69

Imagine a cross between two AaBb individuals, where A = yellow, a = green, B = smooth, and b = wrinkled. What is the genotypic and phenotypic ratio among the offspring?

Question 70

Compare and contrast mitosis and meiosis. Include in your discussion for each process (a) the number of daughter cells produced and (b) the number of chromosomes each new cell contains. What are recombination and crossing over, and why are they important in the study of evolution?