Biology 1201 EXAM 3 Moodle Quizzes

What is the proper order of the following events in the expression of a eukaryotic gene? 1. translation 2. RNA processing 3. transcription 4. modification of protein a. 4, 2, 3,1 b. 2 ,3, 4, 1 c. 1, 2, 3, 4 d. 1, 2, 4, 3 e. 3, 2, 1, 4

3

The centromere is a region in which _____. a. microtubules are fastened to the centrioles during anaphase b. chromosomes become aligned during metaphase c. the chromosomes are connected to the cell plate in metaphase d. sister chromatids are attached to one another in prophase e. the new cell plate forms in telophase

d

A cell entering the cell cycle with 32 chromosomes will produce two daughter cells, each with _____. a. 64 pairs of chromosomes b. 32 chromosomes c. 32 pairs of chromosomes d. 16 chromosomes e. none of these

b

All the offspring of a cross between a black-eyed MendAlien and an orange-eyed MendAlien have black eyes. This means that the allele for black eyes is ________ the allele for orange eyes. a. recessive to b. dominant to c. codominant to d. better than e. more aggressive than

b

In sexually reproducing species, the chromosome number remains stable over time because _____ and _____ always alternate. a. meiosis ... interphase b. meiosis ... fertilization c. meiosis ... mitosis d. meiosis I ... meiosis II e. mitosis ... fertilization

b

What is the probability that a male will inherit an X-linked recessive allele from his father? a. 100% b. 0% c. 25% d. 75% e. 50%

b

Which of the following is true of translation in both prokaryotes and eukaryotes? a. Ribosomes are affected by streptomycin. b. The codon UUU codes for phenylalanine c. Translation is coupled to transcription. d. The product of transcription is immediately ready for translation. e. The signal-recognition particle (SRP) binds to the first 20 amino acids of certain polypeptides.

b

A cell biologist carefully measured the quantity of DNA in grasshopper cells growing in cell culture. Cells examined during the G2 phase of the cell cycle contained 200 units of DNA. What would be the amount of DNA at G1 of the cell cycle in one of the grasshopper daughter cells? a. 400 units b. between 50 and 100 units c. 100 units d. 200 units e. 50 units

c

A cross between homozygous purple-flowered and homozygous white-flowered pea plants results in offspring with purple flowers. This demonstrates a. true-breeding. b. a dihybrid cross. c. dominance. d. the mistakes made by Mendel. e. the blending model of genetics.

c

Humans have 46 chromosomes. That number of (human) chromosomes will be found in _____. a. all the egg and sperm cells b. all the cells of the body c. liver cells d. all gamete-producing cells after meiosis I

c

If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughter cell at the completion of the cell cycle? a. 60 b. 120 c. 30 d. 15 e. 45

c

Pea plants were particularly well suited for use in Mendel's breeding experiments for all of the following reasons except that a. many of the observable characters that vary in pea plants are controlled by single genes. b. it is possible to obtain large numbers of progeny from any given cross. c. peas have an unusually long generation time. d. peas show easily observed variations in a number of characters, such as pea shape and flower color. e. it is possible to completely control matings between different pea plants.

c

What enzyme joins Okazaki fragments? a. primase b. DNA polymerase c. topoisomerase d. DNA ligase e. helicase

d

Which one of the following catalyzes the linkage between ribonucleotides to form RNA during gene expression? a. a ribozyme b. RNA ligase c. tRNA d. RNA polymerase e. reverse transcriptase

d

Which one of the following is the only known viable human monosomy? a. XY b. YO c. XXY d. XO e. XYY

d

Which one of the following occurs in meiosis, but not mitosis? . A spindle apparatus forms. b. The nuclear envelope disappears. c. The cells formed have the same combination of genes as found in the initial cell. d. Homologous chromosomes separate. e. Sister chromatids undergo disjunction.

d

Telomerase _____. a. speeds cell aging b. slows the rate of cancer cell growth c. is an enzyme made up of protein and RNA that lengthens telomeres d. prevents the loss of centromeric DNA e. splits telomeres

c

What is the function of meiosis? a. none of these b. to make exact copies of the parent cell c. to make cells with a haploid (half that of the parents) number of chromosomes d. to make four cells with the same chromosome number as the parent e. to make one cell with twice the number of chromosomes as the parent pairs

c

When a person has Down syndrome, he or she has an extra chromosome 21. Therefore, Down syndrome is a kind of _____ and results from _____. a. polyploidy ... occurrence of meiosis without cytokinesis b. replication error ... an extra cycle of DNA synthesis during the S phase c. aneuploidy ... nondisjunction of chromosome 21 during meiosis I d. none of these e. genomic imprint ... excessive methylation of either the paternal or maternal chromosome 21

c

Which of the following mutations would be most likely to have a harmful effect on an organism? a. a deletion of three bases near the middle of a gene b. a single nucleotide deletion in the middle of an intron c. a single nucleotide insertion downstream of, and close to, the start of the coding sequence d. a base-pair substitution e. a single nucleotide deletion near the end of the coding sequence

c

You would know a dividing cell was a plant cell rather than an animal cell if you saw that _____. a. it had formed a cleavage furrow b. it had microtubules c. it had formed a cell plate d. the nucleolus was visible during metaphase e. it had two pairs of centrioles during prophase

c

A human somatic cell contains _____. a. 22 autosomes and 1 sex chromosome b. 21 autosomes and 2 sex chromosomes c. 45 autosomes and 1 sex chromosome d. 44 autosomes and 2 sex chromosomes e. n chromosomes

d

A person with two X chromosomes and one Y chromosome would appear to be _____. a. female b. both male and female c. neither male nor female d. male e. any of these, depending on the number of other chromosomes

d

A point mutation in which a single base pair is inserted or deleted from DNA is called a _____. a. inversion mutation b. translocation mutation c. missense mutation d. frame-shift mutation e. nonsense mutation

d

At which point in the cell cycle do centrosomes begin to move apart to two poles of the cell in a dividing human skin cell? a. metaphase b. anaphase c. G2 phase d. prophase e. S phase

d

During Griffith's experiments with Streptococcus pneumoniae in mice, material from _____ bacteria transformed _____ bacteria. a. living nonvirulent ... heat-killed virulent b. living nonvirulent ... living virulent c. living virulent ... heat-killed nonvirulent d. heat-killed virulent ... living nonvirulent e. heat-killed nonvirulent ... living virulent

d

Hemophilia is a sex-linked disorder. The daughter of a father with hemophilia and a carrier mother has a _____ probability of having hemophilia. a. 100% b. 25% c. 0% d. 50% e. 33%

d

In a diploid cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing _____ chromosomes. Select one: a. 10 b. 20 c. 40 d. 5 e. 0

d

In transcription, _____. a. the RNA nucleotides used are produced by the cell b. none of these c. only one of the DNA strands is used as the template d. all of these e. the promoter region acts as an initial binding site for RNA polymerase

d

In werewolves, pointy ears (P) is dominant over round ears (p). The gene is on the X chromosome. (Sex determination in werewolves is the same as for "other" humans.) A certain female werewolf has pointy ears even though her father had round ears. What percentage of her sons will have round ears if she marries a werewolf with round ears? a. 25% b. 0% c. 100% d. 50% e. 75%

d

Mitosis results in the formation of _____; meiosis results in the formation of _____ a. four diploid cells ... four haploid cells b. four haploid cells ... two diploid cells c. two diploid cells ... two haploid cells d. two diploid cells ... four haploid cells e. two diploid cells ... two diploid cells

d

One difference between meiosis I and meiosis II is that _____. a. the two daughter cells produced at the end of meiosis I are different from each other, but the two cells produced in meiosis II are identical b. only meiosis I includes prophase, metaphase, anaphase, and telophase c. only meiosis I occurs in males, but both meiosis I and meiosis II occur in females d. crossing over occurs in meiosis I, but not in meiosis II e. chromosomes line up at the metaphase plate during meiosis I, but remain dispersed throughout the cell during meiosis II

d

A woman is red-green color-blind. What can we conclude, if anything, about her father? a. He is red-green color-blind. b. He has two Y chromosomes. c. We have too little information to tell. d. None of these e. There is a 50% probability that he has normal vision.

a

All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is ________ to the allele for white flowers. a. incompletely dominant b. codominant c. dominant d. recessive e. pleiotropic

a

Chargaff found that for DNA _____. a. the ratio of A to T is close to 1:1 and the ratio of G to C is close to 1:1 b. the ratio of A to G is close to 1:1 and the ratio of T to C is close to 1:1 c. A + T = 50% of the total bases d. the ratio of A to C is close to 1:1 and the ratio of G to T is close to 1:1 e. A + T = G + C

a

Hypophosphatemia (vitamin D-resistant rickets) is inherited as a X-linked dominant disorder. An unaffected woman mates with a male with hypophosphatemia. What is the expected phenotypic ratio of their offspring? a. 1 daughter with hypophosphatemia : 1 normal son b. 1 normal daughter: 1 daughter with hypophosphatemia c. 3 normal daughters : 1 son with hypophosphatemia d. 2 normal daughters : 1 normal son : 1 son with hypophosphatemia e. 1 normal daughter : 1 son with hypophosphatemia

a

In Klinefelter syndrome, individuals are phenotypically male, but they are tall and thin, have a female-like development of the hips and breasts, and have testes that remain in the abdomen instead of descending into the scrotum. The cells of Klinefelter individuals have two X chromosomes and one Y (they are XXY instead of XY). That is, Klinefelter syndrome is a _____. a. aneuploidy b. duplication c. monosomy d. polyploidy e. translocation

a

In an X-linked, or sex-linked, trait, it is the contribution of _____ that determines whether a son will display the trait. a. the mother b. the paternal grandfather c. the paternal grandmother d. none of these e. the father

a

In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (Rr) offspring of red (RR) and white (rr) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white? a. roan × roan b. red × white c. white × roan d. red × roan e. The answer cannot be determined from the information provided.

a

When RNA is being made, the RNA base _____ always pairs with the base _____ in DNA. a. U ... A b. T ... A c. A ... U d. U ... T e. T ... G

a

Which of the following is not true of a codon? a. It extends from one end of a tRNA molecule. b. It may code for the same amino acid as another codon does. c. It is the basic unit of the genetic code. d. It consists of three nucleotides. e. It never codes for more than one amino acid.

a

A biochemist measured the amount of DNA in cells growing in the laboratory and found that the quantity of DNA in the cells doubled _____. a. between the G2 phase and prophase b. between prophase and anaphase c. between anaphase and telophase d. during the M phase of the cell cycle e. between the G1 and G2 phases

e

A genetic defect in humans results in the absence of sweat glands in the skin. Some men have this defect all over their bodies, but in women it is usually expressed in a peculiar way: A woman with this defect typically has small patches of skin with sweat glands and other patches without sweat glands. In women, the pattern of sweat-gland distribution can best be explained by _____. a. an operon b. RNA splicing c. a homeobox d. a mutation e. X chromosome inactivation

e

A plant with purple flowers is allowed to self-pollinate. Generation after generation, it produces purple flowers. This is an example of a. incomplete dominance. b. polygenetics. c. hybridization. d. the law of segregation. e. true-breeding.

e

Avery and his colleagues' 1944 experiment showed that DNA _____. a. contains adenine, guanine, thymine, and cytosine b. has two strands held together with hydrogen bonds c. uses three bases to code for one amino acid d. consists of sugars, phosphate groups, and bases e. was the substance that transformed the bacteria in Griffith's experiment

e

Crossing over is _____. a. also referred to as the "independent assortment of chromosomes" b. the movement of genetic material from one chromosome to a nonhomologous chromosome c. a direct consequence of the separation of sister chromatids d. making an RNA copy of a DNA strand e. the exchange of homologous portions of nonsister chromatids

e

DNA polymerase adds nucleotides to the _____ of the leading strands, and to the _____ of the lagging strands (Okazaki fragments) . a. 3' end ... 5' end b. 5' end ... 3' end c. 5' end ... 5' end d. sugar group ... phosphate group e. 3' end ... 3' end

e

During anaphase of mitosis _____. a. identical chromatids move to opposite poles b. the centromeres divide c. a spindle made of microtubules is present d. the centrioles are at opposite poles e. all of these are correct

e

If a somatic human cell is just about to divide, it has _____ chromatids? a. 0 b. 23 c. 46 d. There is insufficient information to answer the question. e. 92

e

If there are 20 chromatids in a cell in G2, how many centromeres are there? Select one: a. 80 b. 40 c. 20 d. 30 e. 10

e

One strand of a DNA molecule has the base sequence 5'-ATAGGT-3'. The complementary base sequence on the other strand of DNA will be 3'-_______-5'. a. TGGATA b. TGGAUA c. ATAGGT d. UAUCCA e. TATCCA

e

Sister chromatids ____. a. are created when DNA is replicated b. are separated during mitosis c. have matching copies of the chromosome's DNA d. are attached at the centromere prior to division e. all of these

e

Telomeres _____. a. are found in both prokaryotic and eukaryotic cells b. are shorter for younger individuals c. get longer with continued cell division d. remain the same regardless of the frequency of cell division e. get shorter with continued cell division

e

The anticodon of a particular tRNA molecule is a. complementary to the corresponding triplet in rRNA. b. the part of tRNA that bonds to a specific amino acid. c. catalytic, making the tRNA a ribozyme. d. changeable, depending on the amino acid that attaches to the tRNA. e. complementary to the corresponding mRNA codon.

e

The role of DNA polymerases in DNA replication is to _____. a. separate the two strands of DNA b. link together short strands of DNA c. synthesize an RNA primer to initiate DNA strand synthesis d. all of these e. attach free nucleotides to the new strand

e

Ultraviolet (Uv) radiation is damaging to cells because it _____. a. deactivates the enzymes needed for DNA replication b. shreds the cytoskeleton c. pokes holes in the nuclear envelope d. blocks all translation e. causes mutations in the DNA

e

What is the expected phenotypic ratio of a cross between two orange-eyed MendAliens? a. 1 black-eyed:0 orange-eyed b. 1 black-eyed:1 orange-eyed c. 1 black-eyed:3 orange-eyed d. 3 black-eyed:1 orange-eyed e. 0 black-eyed:1 orange-eyed

e

Which of the following is (are) true for alleles? a. They can represent alternative forms of a gene. b. They can be identical or different for any given gene in a somatic cell. They can be dominant or recessive. c. They can be identical or different for any given gene in a somatic cell. d. They can be dominant or recessive. e. They can be identical or different for any given gene in a somatic cell. They can be dominant or recessive. They can represent alternative forms of a gene.

e

Which one of the following is not true about double-stranded DNA? a. It is helical. b. It contains phosphodiester linkages. c. The strands run antiparallel. d. The two strands are complementary. e. Adenine and uracil are present in equal amounts.

e

Which one of the following statements is true? a. Each DNA base codes for three amino acids. b. It takes three genes to code for one protein. c. Each triplet has many different meanings. d. Each gene codes for three proteins. e. Each amino acid in a protein is coded for by three bases in the DNA.

e