BIO 156 Exam 2 Practice Questions (Book & RioLearn)

T/F: All traits are inherited in a Mendelian pattern.

False

In a diagram, how can we tell the cell is in anaphase I, not anaphase II?

Sister chromatids are still attached

A duplicated chromosome has how many chromatids?

Two

How many sex chromosomes are in an egg or a sperm? a. one b. two c. 23 d. 46 e. It varies from individual to individual

a.

Dogs have a diploid chromosome number of 78. How many chromosomes do their gametes have? a. 39 b. 78 c. 156 d. 234

a. 39

Refer to question 74. Assuming complete dominance, the F2 generation will show a phenotypic ratio of ___. a. 3:1 b. 9:1 c. 1:2:1 d. 9:3:3:1

a. 3:1

What is a testcross? a. A mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest. A mating between an individual of unknown genotype and an individual homozygous dominant for the trait of interest. c. A mating between an individual of unknown genotype and an individual heterozygous for the trait of interest. d. A mating between two individuals heterozygous for the trait of interest. e. None of these choices are correct.

a. A mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest.

Choose the statement that is incorrect. a. A son can inherit a recessive allele on an X chromosome from either parent b. An individual may inherit three or more of each type of chromosome characteristic of the species, a condition called polyploidy c. A female child inherits one X chromosome from her mother and one from her father d. Pedigree analysis can be used to determine a future child's chance of being born with achondroplasia

a. A son can inherit a recessive allele on an X chromosome from either parent

The creation of offspring carrying genetic information from just a single parent is called which of the following? a. Asexual reproduction b. A life cycle c. Sexual reproduction d. Regeneration e. None of these choices are correct

a. Asexual reproduction

In a Mendelian monohybrid cross, which generation is always completely heterozygous? a. F1 generation b. F2 generation c. F3 generation d. P generation e. All of the above

a. F1 generation

___ are all the characteristics of cancer. a. Malignant cells b. Neoplasms c. Tumors

a. Malignant cells

During which stage of meiosis does crossing-over occur? a. Prophase I b. Anaphase I c. Telophase I d. Prophase II e. Anaphase II

a. Prophase I

Let T represent a tall plant and t represent a small plant. Let Y represent the allele for yellow seed color and y represent the allele for green seed color. If an individual is heterozygous for both traits, then what are the possible gametes of this individual? a. TY, Ty, tY, ty b. TtYy, TtYy, TtYy, TtYy c. Tt, TY, Ty, yy d. T, t, Y, y

a. TY, Ty, tY, ty

Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! Then you realize, this is a cell that is which of the following? a. Undergoing cytokinesis. b. In the G1 phase of interphase. c. About to undergo mitosis. d. In the S phase of interphase. e. In the G2 phase of interphase.

a. Undergoing cytokinesis.

Homologous chromosomes ___. a. are inherited from two parents b. are sister chromatids c. are different in size and length

a. are inherited from two parents

A person who has type AB blood illustrates the principle of: a. co-dominance b. incomplete dominance c. blending inheritance d. polygenic inheritance e. regressive absorption

a. co-dominance

Mendel's law of independent assortment states: a. during meiosis, two alleles at one gene locus tend to be sorted into gametes independently of alleles at other loci. b. during meiosis, two alleles at one gene locus are not sorted into gametes independently of alleles at other loci. c. Two alleles at any locus separate during gamete production. d. Two alleles at any locus do not separate during gamete production. e. None of the choices are correct.

a. during meiosis, two alleles at one gene locus tend to be sorted into gametes independently of alleles at other loci.

In intervals of interphase, G stands for ___. a. gap b. growth c. Gey d. gene

a. gap

In which kind of cross would you expect to find a ratio of 3:1 among the F2 offspring. a. monohybrid cross b. dihybrid cross c. test cross d. hybrid cross e. crossing-over

a. monohybrid cross

An organisms's observable traits constitute its ___. a. phenotype b. variation c. genotype d. pedigree

a. phenotype

Crossing over happens during which phase of meiosis? a. prophase I b. prophase II c. anaphase I d. anaphase II

a. prophase I

A recognized set of symptoms that characterize a genetic disorder is a(n) ___. a. syndrome b. disease c. abnormality d. inheritance pattern

a. syndrome

In multicellular organisms, mitosis is ___. a. the means of tissue growth and repair b. a way of generating new kinds of mutant or recombinant organisms c. the means of sexual reproduction d. not useful in stem cell lines that constantly replace skin, etc. e. able to occur in only a few cells of specialized tissues

a. the means of tissue growth and repair

After mitosis, the chromosome number of a descendant cell is ___ the parent cell's. a. the same as b. one-half of c. rearranged compared to d. double that of

a. the same as

A recessive disorder is a genetic disorder ___. a. with two functioning alleles b. that will express itself in the presence of two defective alleles c. that involves changes in chromosomal number c. that will express itself in the presence of one functioning allele e. that is the result of a change in chromosome structure

b.

The expression of both alleles for a trait in a heterozygous individual illustrates: a. incomplete dominance b. co-dominance c. pleiotropy d. polygenic inheritance e. blending inheritance

b.

If a parental cell has 14 chromosomes prior to mitosis, how many chromosomes will each daughter cell have? a. 28 because each chromatid is a chromosome b. 14 because the chromatids separate c. only 7 after mitosis is finished d. any number between 7 and 28 e. 7 in any nucleus and 7 in the cytoplasm, for a total of 14

b. 14 because the chromatids separate

A duplicated chromosome has ___ chromatid(s). a. 1 b. 2 c. 3 d. 4 e. 46

b. 2

In an individual with a dominant phenotype is crossed with an individual with a recessive phenotype, 4 of their 9 offspring show the recessive phenotype. What is the genotype of the first parent using B for the dominant allele and b for the recessive allele? a. BB b. Bb c. bb d. brown eyes e. blue eyes

b. Bb

Tay-Sachs disease is caused by recessive alleles on an autosome. In which case(s) could two parents with a normal phenotype have a child with Tay-Sachs? a. Both parents are homozygous for a Tay-Sachs allele b. Both parents are heterozygous for a Tay-Sachs allele c. One parent is homozygous for a Tay-Sachs allele, and the other is heterozygous

b. Both parents are heterozygous for a Tay-Sachs allele. A person who is homozygous for a Tay-Sachs allele does not live long enough to reach reproductive age.

Which occurs in metaphase? a. Centrioles move to opposite poles b. Chromosomes line up along the equator of the dividing cell. c. Chromosomes move to opposite poles. d. The nuclear envelope disappears. e. The nuclear envelope forms.

b. Chromosomes line up along the equator of the dividing cell.

Which of the following is one of the very important differences between mitosis and meiosis? a. Chromosomes align midway between spindle poles only in meiosis. b. Homologous chromosomes separate only in meiosis. c. DNA is replicated before mitosis only. d. Sister chromatids separate only in meiosis. e. Interphase occurs only in mitosis.

b. Homologous chromosomes separate only in meiosis.

What is the importance of crossing-over? a. It provides extra genetic material for the daughter cells. b. It increases the likelihood that daughter cells contain different genetic material. c. It produces the proteins that are associated with DNA in chromosomes. d. It increases chromosomes condensation. e. It separates the homologous chromosomes.

b. It increases the likelihood that daughter cells contain different genetic material.

During which phase of mitosis do the chromosomes line up on the plane located equidistant from the two spindle poles? a. Interphase b. Metaphase c. Telophase d. Prophase e. Anaphase

b. Metaphase

Independent orientation of chromosomes at metaphase I results in an increase in the number of which of the following? a. Gametes b. Possible combinations of characteristics c. Points of crossing over d. Homologous chromosomes e. Sex chromosomes

b. Possible combinations of characteristics

Crossing over mixes up ___. a. chromosomes b. alleles c. zygotes d. gametes

b. alleles

Independent assortment means ___. a. alleles at one locus assort into different gametes b. alleles at different loci assort into gametes independently of each other c. the assortment of genes on homologous chromosomes varies independently

b. alleles at different loci assort into gametes independently of each other

Nondisjunction in meiosis can result in ___. a. base-pair substitutions b. aneuploidy c. crossing over d. pleiotropy

b. aneuploidy

The phenotype of individuals heterozygous for ___ alleles comprises both homozygous phenotypes. a. epistatic b. codominant c. pleiotropic d. hybrid

b. codominant

Mitosis and cytoplasmic division function in ___. a. asexual reproduction of single-celled prokaryotes. b. development and tissue repair in multicelled species. c. sexual reproduction in plants and animals.

b. development and tissue repair in multicelled species.

The nuclear division that changes the chromosome number from the ___ number to the ___ number is known as meiosis. a. haploid; triploid b. diploid; haploid c. triploid; diploid d. diploid; diploid e. haploid; diploid

b. diploid; haploid

A ___ allele masks the effect of a ___ allele when it is paired with it in a ___ individual. a. dominant; recessive; homozygous b. dominant; recessive; heterozygous c. dominant; dominant; heterozygous d. recessive; dominant; homozygous e. recessive; dominant; heterozygous

b. dominant; recessive; heterozygous

A testcross is a way to determine ___. a. phenotype b. genotype c. dominance

b. genotype

Meiosis ___ the parental chromosome number. a. doubles b. halves c. maintains d. mixes up

b. halves

One evolutionary advantage of sexual over asexual reproduction is that it produces ___. a. more offspring per individual b. more variation among offspring c. healthier offspring

b. more variation among offspring

Pedigree analysis is necessary when studying human inheritance patterns because ___. a. humans have more than 20,000 genes b. of ethical problems with experimenting on humans c. inheritance in humans is more complicated than it is in other organisms d. genetic disorders occur only in humans

b. of ethical problems with experimenting on humans

Constructing a pedigree is particularly useful when studying inheritance patterns in organisms that ___. a. produce many offspring per generation b. produce few offspring per generation c. have a very large chromosome number d. have a fast life cycle

b. produce few offspring per generation

Meiosis is a necessary part of sexual reproduction because it ___. a. divides two nuclei into four new nuclei b. reduces the chromosome number for gametes c. gives rise to nw alleles

b. reduces the chromosome number for gametes

A heterozygous individual has ___ for a trait being studied. a. the same allele on both homologous chromosomes b. two different alleles of a gene c. a haploid condition, in genetic terms

b. two different alleles of a gene

Dr. Smith's parents have normal hearing. However, Dr. Smith has an inherited form of deafness. Deafness is a recessive trait that is associated with the abnormal allele d. The normal allele at this locus, associated with normal hearing, is D. Dr. Smith's parents could have which of the following genotypes? a. DD and dd b. dd and dd c. Dd and Dd d. DD and DD e. None of the choices are correct

c.

If both parents in a dihybrid cross are heterozygous for both traits, the expected phenotypic ratio in the offspring would be: a. 1:1 b. 2:1 c. 9:3:3:1 d. 1:2:1 e. The results vary from individual to individual

c. 9:3:3:1

The phenotypic ratio resulting from a dihybrid cross showing independent assortment is expected to be which of the following? a. 1:2:1 b. 9:1:1:3 c. 9:3:3:1 d. 3:1 e. 3:9:9:1

c. 9:3:3:1

The F2 offspring of a monohybrid cross would show the genotype(s) ___. a. AA and Aa b. Aa and aa c. AA, Aa, and aa d. AA only e. Aa only

c. AA, Aa, and aa

At what stage of meiosis is each chromosome composed of a single chromatid? a. Prophase I b. Metaphase II c. Anaphase II d. Prophase II e. Metaphase II

c. Anaphase II

Which of the following is false? a. Cell division can reproduce an entire organism. b. Cell division ensures the continuity of life from generation to generation. c. Cell division is common in eukaryotes but rare in prokaryotes. d. Cell division is necessary for development to occur. e. Cell division is the basis of both sexual and asexual reproduction.

c. Cell division is common in eukaryotes but rare in prokaryotes.

Which occurs in anaphase? a. Centrioles move to opposite poles b. Chromosomes line up along the equator of the dividing cell c. Chromosomes move to opposite poles d. The nuclear envelope disappears e. The nuclear envelope forms

c. Chromosomes move to opposite poles

Which of the following does not directly contribute to variation in traits among the offspring of sexual reproducers? a. Crossing over during meiosis b. The union of gametes at fertilization c. Equal distribution of chromosomes into gametes d. Alleles on homologous chromosomes e. Mutation

c. Equal distribution of chromosomes into gametes

The second-generation offspring of a cross between individuals who are homozygous for different alleles of a gene are called the ___. a. F1 generation b. hybrid generation c. F2 generation d. daughters

c. F2 generation

During which stage of meiosis do synapsis and the formation of tetrads occur? a. Interphase I b. Interphase II c. Prophase I d. Prophase II e. None of these choices are correct

c. Prophase I

Alleles of a gene are found at which chromosomes? a. The same locus on homologous mitochondrial b. Different loci on homologous c. The same locus on homologous d. the same locus on heterologous e. Different loci on heterologous

c. The same locus on homologous

Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as which of the following? a. Hybrids b. Monohybrid crosses c. True-breeding d. The F2 generation e. Independent crosses

c. True-breeding

A monohybrid cross is: a. the second generation of a self-fertilization plant. b. a breeding experiment in which the parental varieties have only one trait in common. c. a breeding experiment in which the parental varieties differ only in one trait. d. a triploid plant that results from breeding two very different plants. e. None of the choices are correct

c. a breeding experiment in which the parental varieties differ only in one trait.

Interphase is the stage when ___. a. a cell ceases to function b. a germ cell forms its spindle apparatus c. a cell grows and duplicates its DNA d. mitosis takes place e. the nucleoli disappear

c. a cell grows and duplicates its DNA

Interphase is the part of the cell cycle when ___. a. a cell ceases to function b. a cell forms its spindle apparatus c. a cell grows and replicates its DNA d. mitosis proceeds

c. a cell grows and replicates its DNA

The offspring of the cross AA x aa are ___. a. all AA b. all aa c. all Aa d. half are AA and half are aa

c. all Aa

Which phase of meiosis reduces the chromosome number? a. prophase I b. prophase II c. anaphase I d. anaphase II

c. anaphase I

Different alleles of the same gene are found: a. at the same place on mitochondrial chromosomes. b. at different places on homologous chromosomes. c. at the same place on homologous chromosomes. d. throughout the chromosomes at different places. e. in different individuals on different chromosomes.

c. at the same place on homologous chromosomes.

The spindle attaches to chromosomes at the ___. a. centriole b. contractile ring c. centromere d. centrosome

c. centromere

Which of the following cells can undergo meiosis? a. the diploid body cells of an animal b. haploid gametes c. germ cells

c. germ cells

Meiosis ___. a. occurs only in animals b. supports growth and tissue repair in multicelled species c. gives rise to genetic diversity among offspring d. is part of the life cycle of all cells

c. gives rise to genetic diversity among offspring

A pair of chromosomes that are similar in length, shape, and the traits they govern are called ___. a. diploid chromosomes b. mitotic chromosomes c. homologous chromosomes d. germ chromosomes e. homozygous chromosomes

c. homologous chromosomes

The probability of a crossover occurring between two genes on the same chromosome ___. a. is unrelated to the distance between them b. decreases with increasing distance between them c. increases with the distance between them

c. increases with the distance between them

Which is not a stage of mitosis? a. prophase b. metaphase c. interphase d. anaphase

c. interphase

Klinefelter syndrome (XXY) can most be easily diagnosed by ___. a. pedigree analysis b. aneuploidy c. karyotyping d. phenotypic treatment

c. karyotyping

Crossing-over occurs between ___. a. sister chromatids of the same chromosome b. two different kinds of chromosomes c. nonsister chromatids of chromosomes d. two daughter nuclei e. two different tetrads

c. nonsister chromatids of chromosomes

One gene that affects three traits is an example of ___. a. dominance b. codominance c. pleiotropy d. epistasis

c. pleiotropy

Which sequence of stages in mitosis is correct? a. prophase, anaphase, metaphase, telophase b. prophase, telophase, anaphase, metaphase c. prophase, metaphase, anaphase, telophase d. telophase, anaphase, prophase, metaphase e. anaphase, metaphase, prophase, telophase

c. prophase, metaphase, anaphase, telophase

Two parents are both carriers for an autosomal recessive disease. What is the probability that they will have a child that is also a carrier? a. 0% b. 25% c. 33% d. 50% e. 75%

d.

When you trace the occurrence of a specific characteristic through your past ancestry, you are constructing a family ___. a. genetic probability chart b. incidence of occurrence c. genotype reference d. pedigree e. meiotic history

d.

Which of the following terms refers to the situation where a single phenotypic characteristic is determined by the additive effects of two or more genes? a. incomplete dominance c. co-dominance c. pleiotrophy d. polygenic inheritance e. blending inheritance

d.

Solve this monohybrid genetics problem: Black hair is governed by the dominant gene (B) and blond hair is determined by the recessive gene (b). In this monohybrid cross, if both parents are heterozygous, what percentage of the offspring would be expected to have blond hair? a. 75% b. 50% c. 100% d. 25% e. 33.3%

d. 25%

If a parental cell has 12 chromosomes, then each of the daughter cells following meiosis will have ___. a. 48 chromosomes b. 24 chromosomes c. 12 chromosomes d. 6 chromosomes e. 4 chromosomes

d. 6 chromosomes

Assuming complete dominance, a cross between dihybrid F1 pea plants produces F2 phenotype ratios of ___. a. 1:2:1 b. 3:1 c. 1:1:1:1 d. 9:3:3:1

d. 9:3:3:1

___ in a trait is indicated by a bell curve. a. An epigenetic effect b. Pleiotropy c. Incomplete dominance d. Continuous variation

d. Continuous variation

Which of the following genotypes would be homozygous dominant for both alleles? a. Ddee b. DDEe c. ddee d. DDEE e. DdEe

d. DDEE

A trait that is present in a male child but not in either of his parents is characteristic of ___ inheritance. a. autosomal dominant b. autosomal recessive c. X-linked recessive d. It is impossible to answer this question without more information

d. It is impossible to answer this question without more information. the trait could be an outcome of both parents carrying a recessive allele on an autosome, or the mom carrying a recessive allele on an X chromosome.

The phase of mitosis during which of the nuclear envelope fragments and the nucleoli disappear is called which of the following? a. Interphase b. Metaphase c. Telophase d. Prophase e. Anaphase

d. Prophase

Sister chromatids are which of the following? a. Found right after a cell divides. b. Formed when chromatids separate during cell division. c. Unique to prokaryotes. d. Tightly linked together at a centromere. e. Made only of DNA

d. Tightly linked together at a centromere.

Color blindness is inherited in a(n) ___ pattern. a. autosomal dominant b. autosomal recessive c. X-linked dominant d. X-linked recessive

d. X-linked recessive

Sexual reproduction in animals requires ___. a. meiosis b. fertilization c. gametes d. all of the above

d. all of the above

The BRCA1 gene ___. a. is a checkpoint gene b. is a proto-oncogene c. encodes a tumor suppressor d. all of the above

d. all of the above

Cytoplasm of a plant cell divides by the process of ___. a. telekinesis b. nuclear division c. fission d. cytokinesis

d. cytokinesis

If a pea plant shows the recessive trait for the stem length phenotype, ___. a. it can either TT or Tt b. it can either Tt or tt c. it can be only TT d. it can be only tt e. it can be TT, Tt, or tt

d. it can be only tt

Nondisjunction occurs when: a. a portion of a chromosome breaks off and is lost b. chromosomes replicate too many times c. two chromosomes fuse into one d. members of a chromosome pair fail to separate e. an entire pair of chromosomes is lost during meiosis I.

d. members of a chromosome pair fail to separate

Mendel was fortunate to work out the laws of segregation and independent assortment because he used an organism that reproduced quickly and in which the traits were discrete (easy to observe). Mendel's organism of choice was the: a. elephant b. dog c. other monks at the Abby d. pea plant e. common garden toad

d. pea plant

Which of the following is false? a. The genetic makeup of an organism constitutes its genotype b. Alleles are alternate forms of a gene c. The expressed physical traits of an organism are called its phenotype d. An organism with two different alleles for a single trait is said to be heterozygous e. An allele that is fully expressed is referred to as recessive.

e. An allele that is fully expressed is referred to as recessive.

Which cross would result in a 1:1 phenotypic ratio for the trait of pea seed shape where R = round and r = wrinkled? a. Rr x Rr b. rr x rr c. RR x rr d. RR x Rr e. Rr x rr

e. Rr x rr

Which of the following is false? a. The offspring of two different varieties are called hybrids. b. The parental plants of a cross are the P generation c. The hybrid offspring of an F1 cross are the F2 generation d. Hybridization are also called a cross. e. The hybrid offspring of a cross are the P1 generation

e. The hybrid offspring of a cross are the P1 generation

If you had an individual who showed a dominant phenotype and you wanted to find out if the individual was homozygous or heterozygous, you could do a test cross. You would cross the unknown with a known: a. homozygous dominant b. heterozygous c. homozygous dominant or heterozygous individual d. individual that looks just like itself e. homozygous recessive

e. homozygous recessive

Most healthy body cells spend the majority of their lives in ___. a. prophase b. metaphase c. anaphase d. telophase e. interphase f. senescence

e. interphase