Biology Exam 4 Clicker Questions/Launchpad

As part of their normal function, many proteins bind to DNA briefly and then release it again. Which types of bonds might be involved in these transient protein-DNA interactions? (Select all that apply.) A. van der Waals forces B. ionic C. covalent D. hydrogen

A, B and D

A woman who is color blind has a child with a man who is not color blind. What is the likely chance that they will have a color blind daughter? A. 0% B. 25% C. 50% D. 100%

A. 0%

Over the past several decades, populations of Staphylococcus aureus (a type of bacteria that infects wounds) have become resistant to penicillin. You run an experiment on a population of S. aureus of 10 million cells that has been exposed to penicillin for many generations. You select three samples (A-C) of 100,000 cells each and expose each sample to a new antibiotic called Antibiotic X. None of the cells had previously even been exposed to Antibiotic X, which has a different mechanism of action than penicillin. You measure the percent of the population that survives exposure to Antibiotic X and plot your data. The following graph shows your results. What is the probable origin of Antibiotic X resistance in these cells? A. A small percentage of the cells had preexisting mutations that confer resistance to Antibiotic X. These cells survived exposure to the drug. B. Either of the other answer options could be correct because both happen often in nature, but more information is needed to answer the question. C. The cells probably developed resistance to Antibiotic X by undergoing mutation when exposed to the drug, and thus survived the exposure.

A. A small percentage of the cells had preexisting mutations that confer resistance to Antibiotic X. These cells survived exposure to the drug.

Which genotype would be the best to have in a malaria-free environment? A. AA B. CC C. SS D. AS E. CS

A. AA is "normal"

In a muscle cell, myosin binds to actin to cause muscle contraction. Researchers have found that rabbit muscle myosin binds to actin from an amoeba. How can this be? A. All of these choices are correct. B. Proteins whose functions are important to many types of organisms are more likely to be conserved. C. The myosin from amoeba and rabbits is similar due to a distant common ancestor. D. The myosin from amoeba and rabbits is similar due to a distant common ancestor, and the differences between them do not affect the actin binding site. E. The differences in myosin between amoeba and rabbits do not affect the actin-binding site of myosin.

A. All of these choices are correct.

The MOST common syndrome resulting from nondisjunction is: A. Down syndrome. B. Klinefelter syndrome. C. None of the answer options is correct. D. Turner syndrome. E. emphysema.

A. Down syndrome.

What is a likely consequence of high rates of mutation in a virus, such as HIV? A. High rates of mutation meant that drugs targeting HIV may lose effectiveness B. HIV will likely inactivate itself in the next 20 years and will no longer be a problem C. High rates of mutation mean that each person has a completely different phenotype after infection

A. High rates of mutation meant that drugs targeting HIV may lose effectiveness

You decide to sequence the genome of your resistant S. aureus cells and compare it to the sequence for nonresistant S. aureus cells. What type of genetic difference probably causes this difference in antibiotic resistance in the two cell types? A. It may involve a single base pair or many base pairs; genetic changes on both scales are mutations. B. It must involve many base pairs because of the huge selective advantage the mutation confers. C. It must be a difference in a single base pair of a single gene because the definition of a mutation is a change to a single base pair.

A. It may involve a single base pair or many base pairs; genetic changes on both scales are mutations.

Which of the following is TRUE of blending inheritance? A. None of the answer options is correct. B. Blending inheritance leads to an increase in variation over time. C. Blending inheritance explains the disappearance of a trait several generations after it appeared. D. Blending inheritance allows for rare variants of traits to increase in frequency.

A. None of the answer options is correct.

Which of the following statements is TRUE regarding pyruvate and glucose? A. None of the other answer options is correct. B. Pyruvate is typically "trapped" in the intermembrane space of mitochondria, where it is oxidized to form acetyl-CoA. C. Glucose easily passes in and out of mitochondria, and can often be found in the mitochondrial matrix. D. Both glucose and pyruvate can feed directly into the citric acid cycle, although acetyl-CoA is the preferred reactant for this process. E. Glucose and pyruvate are remarkably similar in structure, with both molecules possessing a ring shape.

A. None of the other answer options is correct.

Mendel's famous experiments were done using which plants? A. Pea plants B. Corn (maize) C. Artichokes D. Tomato plants

A. Pea plants

At what stage is meiosis arrested in prepubescent female humans? A. Prophase 1 B. Metaphase 1 C. Prophase 2 D. Metaphase 2

A. Prophase 1 (be careful about D which happens only post puberty)

Replication of DNA in a eukaryote occurs during which phase of the cell cycle? A. S phase B. G2 phase C. M phase D. G1 phase

A. S phase

Which if the following mutations does not change the function of a protein? A. Silent (synonymous) B. Missense (non-synonymous) C. Nonsense D. Frameshift

A. Silent (synonymous)

The principle of independent assortment states that: A. alleles of a gene pair assort independently of other gene pairs. B. one set of alleles of a gene pair always assorts with the alleles of another gene pair. C. when gametes are formed, the two members of a gene pair assort together in gametes. D. when gametes are formed, the two members of a gene pair will separate equally into gametes.

A. alleles of a gene pair assort independently of other gene pairs.

Which of the following is a critical region of a tRNA molecule? A. amino acid attachment site and anticodon loop B. amino acid attachment site and start codon C. stop codon and Shine-Dalgarno sequence D. ribosome binding site and 5′ cap E. anticodon loop and ribosome binding site

A. amino acid attachment site and anticodon loop

In a homozygous genotype: A. both alleles for a given trait are the same. B. the two alleles for a given trait are different. C. the individual will be phenotypically dominant. D. the individual will be phenotypically recessive. E. both alleles for a given trait are the same, and the individual will be phenotypically dominant.

A. both alleles for a given trait are the same.

A recessive trait is expressed when the genotype is: A. homozygous recessive only B. heterozygous only C. homozygous dominant only D. homozygous recessive or heterozygous E. homozygou dominant or heterozygous

A. homozygous recessive only

What is an allele? A. one of several different forms of a gene B. a group of unrelated genes seen in true-breeding stock C. a spontaneous mutation D. a circular strand of DNA capable of self-replication E. the external appearance of an organism

A. one of several different forms of a gene

In E. coli, an isomer of lactose binds with the lactose operon: A. repressor, preventing it from binding to the operator. This allows the lacZ and lacY genes to be transcribed. B. operator, preventing it from binding to the repressor. This allows the lacZ and lacY genes to be transcribed. C. repressor, helping it bind to the operator. This prevents the lacZ and lacY genes from being transcribed. D. operator, preventing RNA polymerase from being recruited. This prevents the lacZ and lacY genes from being transcribed. E. operator, recruiting RNA polymerase. This allows the lacZ and lacY genes to be transcribed.

A. repressor, preventing it from binding to the operator. This allows the lacZ and lacY genes to be transcribed.

Mismatch repair, base excision repair, and nucleotide excision repair are similar in that each: (Select all that apply.) A. uses an undamaged segment of DNA as the template to repair a damaged segment of DNA. B. repairs a short strand of mismatched nucleotides. C. repairs multiple mismatched or damaged bases across a region. D. None of the answer options is correct. E. repairs a single mismatched base.

A. uses an undamaged segment of DNA as the template to repair a damaged segment of DNA.

In which of the following regions of the cell can protein synthesis occur in eukaryotes? (Select all that apply.) A. nucleus B. cytoplasm C. rough endoplasmic reticulum D. Golgi apparatus E. lysosomes

B and C

How many human chromosomes could fit into a single bacterial cell? A. 92 B. 0 C. 1 D. 46 D. 23

B. 0

Which of the following represents the expected genotypes of an F1 generation consisting of 16 individuals from a cross of a true-breeding black (BB) rabbit and a true-breeding white (bb) rabbit? A. 8 BB, 8 bb, 0 Bb B. 0 BB, 0 bb, 16 Bb C. 4 BB, 4 bb, 8 Bb D. 16 BB, 0 bb, 0 Bb

B. 0 BB, 0 bb, 16 Bb

Diploid somatic cells of elephants have 56 chromosomes. If nondisjunction of one of an elephant's chromosomes occurs in meiosis 1, the resulting sperm are expected to have the chromosome complement: A. 28, 28, 28, 28. B. 29, 29, 27, 27. C. 29, 29, 28, 28. D. 28, 28, 29, 27. E. 56, 56, 57, 55

B. 29, 29, 27, 27.

When the DNA sequence of the gene that codes for the peptide hormone insulin is compared in two mammals, most of the sequence differences are synonymous mutations. these far outnumber sequence differences that result in amino acid substitutions. Why might this be? A. Mutations are random with respect to an organism's needs B. Amino acid substitutions often result in proteins that have lost or compromised function and, therefore, are selected against C. A DNA sequence is more likely to mutate if the change does not alter the amino acid sequence D. Most amino acid substitutions result in a beneficial phenotype that improves fitness and results in a greater number of offspering E. Synonymous mutations occur in noncoding DNA sequences

B. Amino acid substitutions often result in proteins that have lost or compromised function and, therefore, are selected against

_____________ suggests that traits in offspring resemble the average of the parents. A. Eugenic inheritance B. Blending inheritance C. Mendelian inheritance D. Natural selection

B. Blending inheritance

Imagine that you and your colleagues are working in a lab to develop a protein synthesis system for a new type of synthetic cell. During your brainstorming sessions, you propose that polycistronic mRNA would be much more useful than mRNA that is only translated into one protein. This would allow for multiple proteins necessary for a particular function to be translated together. One of your colleagues says that is a good idea, but if you decide to go with polycistronic mRNA, you'd better make sure to use a prokaryotic translation system. Why might it be problematic to use a eukaryotic translation system with polycistronic mRNA? A. Introns would always prevent translation of the mRNA. B. Eukaryotic ribosomes initiate translation by binding to the 5′-cap, which is only at the end of the mRNA. C. Prokaryotic ribosomes do not detach from mRNA when they reach a stop codon. D. Eukaryotic start and stop codons are different from prokaryotic start and stop codons.

B. Eukaryotic ribosomes initiate translation by binding to the 5′-cap, which is only at the end of the mRNA.

The "human genome" refers to the exact nucleotide sequence that is common to all humans. A. True B. False

B. False: b/c each of us has a unique genome. the human genome is actually a mix of genomes human genome sequence in 2003.

Two slides ago we said XXX is a "normal" female because the extra copy of X(along with the normal 2nd X) is inactivated in each cell. So, why does the XO genotype lead to a phenotype? A. In an XO person, the single X chromosome is inactivated in some cells so there are no X-linked genes active in those cells B. In order to be a phenotypically "normal" female you need expression of certain genes from both X chromosomes C. You cannot survuve without at least 2 sex chromosomes D. I have no idea

B. In order to be a phenotypically "normal" female you need expression of certain genes from both X chromosomes - some x-inactivated genes are actually active

Where do you think you got your mitochondria? A. Papa B. Mumsy C. Equally from mom and dad D. a space alien

B. Mumsy

Does the number of genes in a genome tell you anything about organism complexity? A. Yes B. No

B. No

Does the size of a genome tell you anything about organism complexity? A. Yes B. No

B. No

Which of the following statements is TRUE about Klinefelter syndrome (47, XXY)? A. The risk increases with the father's age B. Nondisjunction is the usual cause C. Affected males can reproduce normally D. Most affected fetuses undergo spontaneous abortion E. None of the other answer options is correct

B. Nondisjunction is the usual cause

What kind of mutation is represented by the hemoglobin alleles? A. Frameshift B. Nonsynonymous C. Synonymous D. Nonsense mutation

B. Nonsynonymous

ABL is a receptor kinase which promotes the cell cycle. The BCR-ABL fusion protein is not able to be regulated by cyclins; this makes BCR-ABL constantly active, resulting in chronic myelogenous leukemia. How would we classify ABL? A. Oncogene B. Proto-oncogene C. Tumor Suppressor D. Cyclin

B. Proto-oncogene

The human X chromosome carries approximately 1000 genes. The Y chromosome contains only about 50 genes. How can males survive with only these 50 genes in the Y chromosome?7 A. The genes in the X chromosome are not required for survival. B. The Y is paired with a functional X chromosome, which has all the genes. C. Most of the 1000 genes in the X chromosome are only required for females. D. In males, the missing genes are found in autosomal chromosomes.

B. The Y is paired with a functional X chromosome, which has all the genes.

Matt was sick with strep throat. He was given antibiotics and felt a little bit better, so he stopped taking the recommended course. Three days later, he got sick again but the antibiotics were no longer working. Why? A. Antibiotics that Matt took led to antibiotic resistant bacteria B. The original population already had a small number of bacteria that was resistant to antibiotics. This small number grew, resulting in a large population of antibiotic resistant bacteria C. By chance, new mutations that lead to antibiotic resistance arose after antibiotics were used

B. The original population already had a small number of bacteria that was resistant to antibiotics. This small number grew, resulting in a large population of antibiotic resistant bacteria

Which of the following structures are responsible for the shape of a cell? A. microvilli B. cytoskeleton C. cell junctions D. organelles

B. cytoskeleton

The mitochondrial DNA sequence of a woman should match all of the following people except: A. her mother B. her father C. her sons D. her daughters E. her siblings from the same parents

B. her father

You identify a mutation affecting the lac operon and find the following: lacZ is expressed whether lactose is present or not. lacI is expressed normally. What could be WRONG in this mutant? A. lacP is deleted. B. lacO is deleted. C. lacZ is deleted. D. lacI is deleted.

B. lacO is deleted.

When Mendel crossed true-breeding yellow-seed plants with true-breeding green-seed plants, the offspring were genotypically: A. a mixture of yellow and green seed. B. made up of a combination of yellow and green alleles. C. yellow seed. D. green seed.

B. made up of a combination of yellow and green alleles.

In eukaryotes, genetic material is packaged in the nucleus. Which one of the following MOST accurately lists the components in order of increasing size? A. nucleotide, DNA duplex, chromatin, nucleosome, chromosome B. nucleotide, DNA duplex, nucleosome, chromatin, chromosome C. chromosome, chromatin, nucleosome, DNA duplex, nucleotide D. nucleotide, nucleosome, DNA duplex, chromatin, chromosome E. chromosome, nucleosome, chromatin, DNA duplex, nucleotide

B. nucleotide, DNA duplex, nucleosome, chromatin, chromosome

In what ways do human X and Y chromosomes differ from one another? (Select all that apply.) A. The X and Y chromosomes have no regions in common and do not pair during meiosis. B. The X chromosome is found only in females, while the Y chromosome is found only in males. C. The X chromosome has about 1000 genes and the Y chromosome only about 50. D. The X chromosome is larger than the Y chromosome.

C and D

Which of the following statements provides evidence that organelles (e.g., mitochondria and chloroplasts) originated billions of years ago as a result of primitive eukaryotic cells engulfing free-living bacterial cells? (Select all that apply.) A. Organelles have an inordinate amount of noncoding DNA. B. Organelles do not synthesize proteins. C. Organelle DNA is usually circular. D. Organelle DNA is not associated with nucleosomes.

C and D

If 8 alleles exist in a population, what is the maximum number of copies a normal individual is expected to have? A. 8 B. 5 C. 2 D. 3 E. 4

C. 2

Which one of the following can contribute to a protein's tertiary structure? A. hydrogen bonding B. ionic bonding C. All of the other answer options are correct. D. van der Waal's forces E. covalent bonding

C. All of the other answer options are correct.

A patient comes into a clinic with a tumor caused by a nucleotide insertion/deletion in the p53 gene. You want to identify the mutation that was made so you use PCR followed by SANGER sequencing on DNA from the patient. Unfortunately, there was a problem with the PCR so that the accuracy was off during the reaction. As a result, when you get the sequence back and compared it to the normal p53 gene sequence you are given multiple options for the mutation. Which possibility is most likely to have caused the tumor? A. Insertion of 15 nucleotides B. Insertion of 19 nucleotides C. Deletion of 5 nucleotides D. Deletion of 3 nucleotides

C. Deletion of 5 nucleotides

Which of the following events occur during anaphase I of meiosis? A. The chromosome number is doubled during this phase of meiosis. B. In females, the two X chromosomes remain together. C. In males, the X chromosome is segregated from the Y chromosome. D. The centromeres of the chromosomes divide. E. Homologous chromosomes move as one unit.

C. In males, the X chromosome is segregated from the Y chromosome.

Which of the following statements about the strands of a newly replicated DNA molecule is CORRECT? A. Both strands contain some nucleotides from the original molecule. B. The base pairs are conserved and new sugar-phosphate backbones are built up on them. C. One strand is new and the other is from the original molecule. D. The sugar-phosphate chains are conserved and new bases are inserted between them. E. Both strands are made up of newly assembled nucleotides.

C. One strand is new and the other is from the original molecule.

Which of the following is NOT part of the general response of cells during cellular communication? A. An activated cell-surface receptor transfers the signal to the interior of the cell. B. Receptors on the outside of the cell bind to specific signal molecules. C. The cell does not return to its normal activities after the signal has exerted its effect. D. The signal is transmitted inside the cell and amplified as a series of proteins are activated in sequence, affecting cellular activities according to the type of signal involved. E. A cell-surface receptor molecule becomes activated by binding to a molecular signal.

C. The cell does not return to its normal activities after the signal has exerted its effect.

How would the phenotypes of progeny differ if a trait was produced from the influence of many genes, compared to a trait caused by a single gene with two alleles and incomplete dominance? A. They would not differ, and progeny in both would have an array of phenotypes that vary continuously across a range. B. The progeny from the single gene cross would all be identical, while the many gene cross would vary continuously across a spectrum C. The progeny from the single gene cross would have three phenotypes, while the progeny of the trait caused by many genes would vary continuously across a spectrum

C. The progeny from the single gene cross would have three phenotypes, while the progeny of the trait caused by many genes would vary continuously across a spectrum

In a different set of experiments, you identify two kinds of mutations in S. aureus. The first type of mutation makes the bacteria more susceptible to Antibiotic X; the second type of mutation makes it more resistant to Antibiotic X. Which type of mutation is more likely to occur in the population? A. the first type (more susceptible0 B. It depends if the cell population has been exposed to Antibiotic X. C. There is no difference in likelihood because the mutation is a random event D. the second type (more resistant) E. It depends if either of mutation confers additional survival benefits to S. aureus

C. There is no difference in likelihood because the mutation is a random event

Some common domesticated fruit plants, including seedless watermelon and banana, are triploids. The seeds are small because most are genetically abnormal and do not undergo complete development. Why are most of the seeds genetically abnormal? (Hint: In normal meiosis, the chromosomes form pairs.) A. Their DNA replication is disrupted B. They have excessive numbers of mitochondria C. They have extra and/or missing chromosomes D. They have broken chromosomes because of crossing over

C. They have extra and/or missing chromosomes

Pairing of homologous chromosomes at metaphase of meiosis I appears to be critical for proper alignment, crossing over, and subsequent separation. This pairing is facilitated by sharing of sequence homology. If X and Y chromosomes are so different, how can they achieve the necessary pairing? A. They do not need to pair because they are not a homologous pair. B. A special function of the spindle apparatus forces X and Y together. C. They share short homologies at their respective tips. D. They use a unique sex-linked mechanism not present in other pairs.

C. They share short homologies at their respective tips.

If blending inheritance was an accurate model of transmission genetics, which of the following would be TRUE? A. Variation in natural populations would remain the same over time. B. Variation in natural populations would increase over time. C. Variation in natural populations would decrease over time. D. Variation would increase in some populations, decrease in some populations, and remain the same in some populations. E. Mutation would not contribute to variation in natural populations.

C. Variation in natural populations would decrease over time.

The principle of independent assortment states that: A. when gametes are formed, the two members of a gene pair assort together in gametes B. one set of alleles of a gene pair always assorts with the alleles of another gene pair C. alleles of a gene pair assort independently of other gene pairs D. when gametes are formed, the two members of a gene pair will separate equally into gametes

C. alleles of a gene pair assort independently of other gene pairs

In a pedigree: A. males are squares and females are triangles. B. females are circles and males are triangles. C. females are circles and males are squares. D. females are squares and males are triangles. E. males are circles and females are triangles. F. males are circles and females are squares.

C. females are circles and males are squares.

According to the principle of segregation, a heterozygous plant with alleles Aa will produce: A. gametes with only the A allele. B. gametes with only the a allele. C. gametes in the ratio of 1 A allele:1 a allele. D. gametes in the ratio of 3 A alleles:1 a allele. E. some gametes with the A allele and some with the a allele, but in no predictable ratio.

C. gametes in the ratio of 1 A allele:1 a allele.

The lethality of most monosomies and trisomies in humans shows the: A. rarity of gene copy-number variation in the genome. B. deleterious effects of variable number tandem repeat sequences. C. importance of gene dosage. D. advantage of sexual reproduction.

C. importance of gene dosage.

How is incomplete dominance different from blending inheritance? A. incomplete dominance describes the averaging of parental traits in offspring B. blending inheritance allows for the F2 generation to have multiple phenotypes C. incomplete dominance allows for the reemergence of the parental phenotypes D. They are the same

C. incomplete dominance allows for the reemergence of the parental phenotypes

In prokaryotes, inducers are small molecules that bind to _____ and _____ transcription. A. activators; promote B. activators; inhibit C. repressors; promote D. repressors; inhibit E. None of the answer options is correct.

C. repressors; promote

Mendel's principle of segregation corresponds to what part of meiosis? A. condensation of chromosomes in prophase I B. alignment of homologs in metaphase I C. separation of homologs in anaphase I D. alignment of chromosomes in metaphase II E. separation of daughter chromatids in anaphase II

C. separation of homologs in anaphase I

Solve the following cross using a Punnet Square. A true breeding, round pea plant is crossed to a heterozygous wrinkled pea plant. What are the phenotypic ratios of the offspring? A. 3(round):1(wrinkled) B. 3(round):2 (wrinkled) C. 3(wrinkled):1(round) D. 1(round):1(wrinkled)

D. 1(round):1(wrinkled) BB x Bb = BB, BB, Bb, Bb

A woman who is color blind has a child with a man who is not color blind. What is the likely chance they will have a daughter who is a carrier for the color blind allele? A. 0% B. 25% C. 50% D. 100%

D. 100%

Think about the stage of female meiosis where there is a prolonged arrest and then answer the following question: What molecular process(es) is possibly compromised and contributes to non-disjunction during female meiosis? A. Homologous chromosomes disassociate before metaphase 1 B. Chromosomes fail to replicate normally C. Chromosomes fail to form bivalents in prophase 1 D. During anaphase 1, homologous chromosomes fail to seperate

D. Anaphase 1. One of the homologous chromosomes separates so 3 pieces of chromosome 21 fo to one of the daughter cells

Which of the following statements MOST accurately describes the benefits of the proofreading function of DNA polymerase? A. All DNA mutations can be detected and repaired during DNA replication. B. DNA polymerase is always present in the nucleus and can repair all mutations when they occur. C. DNA polymerase can be recruited to recently mutated sites to repair mutations. D. DNA polymerase can repair most mutations as they occur during DNA replication.

D. DNA polymerase can repair most mutations as they occur during DNA replication.

In humans, ability to roll the tongue (R) is dominant to being unable to roll (r). Having freckles (F) is dominant to having no freckles (f). A freckled tongue-roller could have which of the following genotypes? A. RRFF B. RrFf C. rrFF D. RRFF and RrFf only E. All of these choices are correct.

D. RRFF and RrFf only

Which of the following statements best describes the effect of having the S allele, which codes for sickle-cell anemia? A. The effect depends on the environment (i.e., whether malaria present). B. Having the allele is always beneficial C. Having the allele is always harmful D. The effect depends on whether the allele occurs in its homozygous or heterzygous form, and the environment (i.e., whether malaria is present). E. The effect depends on whether the allele occurs in its homozygous or heterozygous form.

D. The effect depends on whether the allele occurs in its homozygous or heterzygous form, and the environment (i.e., whether malaria is present).

Which one of the following statements is true with regard to non-disjunction rates in humans? A. None of these options is true. B. XX females have higher DNA mutations in their eggs compared to XY males C. XY males have higher non-disjunction rates than human females D. XX females have higher non-disjunction rates than human males

D. XX females have higher non-disjunction rates than human males

In 1891, August Weismann reported an experiment in which he cut the tails off 10 mice in each of 19 consecutive generations. The expected result is: A. after the first generation of amputation, the progeny are born with no tails. B. offspring are born with progressively shorter tails in each generation. C. offspring are born with tails that are the same length as their parents for a few generations, but subsequent generations of offspring have shorter tails. D. all generations of offspring have tails of approximately the same length.

D. all generations of offspring have tails of approximately the same length.

Mismatch repair, base excision repair, and nucleotide excision repair are similar in that: A. each repairs a single mismatch base B. each repairs a short strand of mismatched nucleotides C. each repairs multiple mismatched or damaged bases across a region D. each uses an undamaged segment of DNA as the template to repair a damaged segment of DNA E. None of the answer options is correct

D. each uses an undamaged segment of DNA as the template to repair a damaged segment of DNA

The failure of a pair of chromosomes to separate during anaphase is referred to as: A. trisomy B. inversion C. disjunction D. nondisjunction E. translocation

D. nondisjunction

Why was it important for Mendel to remove the anthers from pea plants in his experiments when crossing two different true-breeding pea plants? A. to stimulate the pea plants to ovulate B. to protect the pea plants from environmental pollen C. to make sure self-fertilization would occur D. to prevent self-fertilization

D. to prevent self-fertilization

When the DNA sequence of the gene that codes for the peptide hormone insulin is compared in two mammals (e.g., humans and rats), most of the sequence differences are synonymous mutations. These far outnumber sequence differences that result in amino acid substitutions. Why might this be? A. A DNA sequence is more likely to mutate if the change does not alter the amino acid sequence. B. Synonymous mutations occur in noncoding DNA sequences. C. Most amino acid substitutions result in a beneficial phenotype that improves fitness and results in a greater number of offspring. D. Mutations are random with respect to an organism's needs. E. Amino acid substitutions often result in proteins that have lost or compromised function and, therefore, are selected against.

E. Amino acid substitutions often result in proteins that have lost or compromised function and, therefore, are selected against.

Situation: You have a Tall (T) plant and a dwarf (t) plant. What is the Tall plant's genotype? A. TT B. Tt C. tT D. tt E. Cannot be determined with info given

E. Cannot be determined with info given

Complex organisms can be characterized as having a: A. large genome with few protein-coding genes. B. small genome with few protein-coding genes. C. small genome with many protein-coding genes. D. large genome with many protein-coding genes. E. None of the other answer options is correct.

E. None of the other answer options is correct.

A baby is born with the XYY genotype. Which if the following explains how this could have happened? A. During the first phase of mitosis in the fertilized egg, the Y chromosome was duplicated but the cell did not divide B. There was a non-disjunction event during meiosis 1 of the mother C. There was a non-disjunction event during meiosis 2 of the mother D. There was a non-disjunction event during meiosis 1 of the father E. There was a non-disjunction event during meiosis 2 of the father

E. There was a non-disjunction event during meiosis 2 of the father

During the formation of female gametes, nondisjunction of X chromosomes may occur during meiosis I, resulting in two types of eggs with different compositions of sex chromosomes. If normal sperm fertilize these two types of egg, which of the following are possible sex chromosome complements in the resulting fertilized egg? A. XXX and XYY B. XX and XY C. XYY and XO D. XYY and YO E. XXY and XO

E. XXY and XO

The relatively large number of new mutations that occur in the human genome in each generation is tolerable because: A. we have excellent DNA repair mechanisms. B. most of the mutations occur in somatic cells, not germ cells. C. compared to other organisms, changes in our proteins have relatively little effect on our cells' structures and functions. D. we have excellent protein repair mechanisms. E. most of our genome is noncoding DNA, so few mutations affect our proteins.

E. most of our genome is noncoding DNA, so few mutations affect our proteins.

Which of the following are true regarding meiosis in human females versus males? A. Meiosis is arrested in one sex but not the other B. Over the course of a lifetime, a XY male will produce many more gametes than a XX female C. Meiosis starts during embryonic development in XX females D. Mutation rates during DNA replication before meiosis increase with age in XY males E. Meiosis begins at puberty in XY males F. All of these options are true

F. All of these options are true

A mutant DNA has the sequence 5' CCT-GAG-GAC 3' while the regular DNA sequence has the sequence 5' CCT-GAG-GAG 3'. Using the codon chart from a few slides back, determine the type of mutation and if there is a change, what the new amino acid is. A. Synonymous - no change B. Non-synonymous - no change C. Synonymous - glutamic acid D. Non-synonymous - glutamic acid E. Synonymous - aspartic acid F. Non-synonymous - aspartic acid G. Missense - stop codon

F. Non-synonymous - aspartic acid

Situation: You have a Tall(T) plant and a dwarf(t) plant. You do a test cross between these plants and get some Tall and some dwarf offspring. What are the possible genotypes of the offspring? A. All TT B. All Tt C. All tt D. Some TT some Tt E. Some TT some tt F. Some Tt some tt

F. Some Tt some tt

T/F: Autosomal trisomies are associated with the X or Y chromosome.

False

A child is born with trisomy 18 to a mother that is 36 years old and a father that is 31 years old. At what stage of meiosis and in what parent could the non-disjunction have happened? A. Father or mother in meiosis II B. Father in meiosis I or II C. Father in meiosis I D. Mother in meiosis I E. Father or mother in meiosis I F. Mother in meiosis II G. Mother in meiosis I or II H. Father or mother in meiosis I or II

H. Father or mother in meiosis I or II

SEE SLIDE 61 OF CLICKER QUESTIONS FOR FINAL

SEE SLIDE 61 OF CLICKER QUESTIONS FOR FINAL

Homologous chromosomes usually have the same arrangement of genes along their length. True False

True