Deck 5: Raw Material: Heritable Variation Among Individuals

Question 1

What is a nucleotide?

A) the structural unit of proteins
B) the structural unit of DNA and RNA
C) one of four nitrogen-containing molecules
D) a double-stranded, helical molecule

Answer 1

B

Question 2

Which type of mutation has the highest rate of occurrence in humans?

A) insertions
B) deletions
C) duplications
D) point mutations

Answer 2

D

Question 3

Mutations can affect an organism's phenotype without altering the protein-coding sequence by influencing

A) when a protein is made.
B) where a protein is made.
C) the amount of protein made.
D) a and b
E) a, b, and c

Answer 3

E

Question 4

Which of these statements about the effect of environment on gene expression is false?

A) Signal molecules produced by one cell can affect gene expression in other cells.
B) The environment that can affect a gene only refers to conditions immediately surrounding the cell.
C) Genes in one part of an organism can be exposed to different environments than other parts.
D) Some phenotypic traits are relatively unaffected by differences in environmental conditions.

Question 5

Which of the following statements is/are correct?

A) MicroRNAs bind DNA and block transcription.
B) MicroRNAs bind mRNA and block translation.
C) MicroRNAs bind ribosomal RNA and block translation.
D) all of the above

Question 6

A mature RNA transcript differs from a primary RNA transcript in that

A) exons are spliced out of the mature transcript.
B) introns are spliced out of the mature transcript.
C) exons are added to the mature transcript.
D) introns are added to the mature transcript.

Question 7

Cis-acting elements often code for

A) proteins.
B) microRNA.
C) binding sites.
D) transcription factor.

Question 8

Which of the following are examples of mobile genetic elements?

A) transposons
B) plasmids
C) pseudogenes
D) a and b
E) a, b, and c

Question 9

Which of the following statements best describes how genetic information stored in DNA is transformed into a product?

A) Genes are translated into mRNA, which is then transcribed into proteins.
B) Genes are transcribed into mRNA, which is then translated into proteins.
C) Genes are translated into proteins, which are then transformed into mRNA.
D) RNA polymerase is transcribed into mRNA, which is then translated into proteins.

Question 10

Craig Venter and colleagues found how many instances where the corresponding nucleotides in homologous chromosomes didn't match each other?

A) 453
B) 13,000
C) 870,000
D) 3,200,000

Question 11

Weight, because it can vary among individuals over a range of values, is an example of a

A) recessive trait.
B) dominant trait.
C) quantitative trait.
D) polyphenic trait.

Question 12

You are studying crickets and notice that individuals have one of two distinctive wing phenotypes (short-winged or long-winged). From this, you can confidently conclude that

A) long- and short-winged crickets have different alleles at a locus controlling wing size.
B) only one genetic locus must contribute to the wing phenotype.
C) the trait must be polyphenic.
D) all of the above
E) none of the above

Question 13

Genetic recombination occurs during meiosis when

A) genetic material is duplicated.
B) chromosomes are paired.
C) sister chromatids are segregated.
D) haploid gametes are formed.

Question 14

Organisms vary considerably in genome size. Which of the following explains most of this variation?

A) differences in the number of protein-coding genes
B) differences in the number of ribosomal RNA genes
C) differences in the number of pseudogenes
D) differences in the number of mobile genetic elements

Question 15

Which of the following statements is correct?

A) All cells have the same genes.
B) All cells express the same genes.
C) All cells have the same proteins.
D) all of the above

Question 16

Which of the following is/are sources of genetic variation between gametes?

A) the exchange of genetic material between chromosomes
B) the nonidentical, paired chromosomes of parents
C) the random mixing of parental copies of chromosomes
D) a and b
E) a, b, and c

Question 17

Duplication is a type of mutation that alters DNA by copying a segment a second time. Which of the following segments of DNA can be duplicated?

A) a region of a gene
B) a whole gene
C) an entire genome
D) all of the above

Question 18

Which of the following examples illustrates phenotypic plasticity?

A) Humans are almost always born with two eyes regardless of how much food was available to the mother.
B) Individuals with two copies of the HMGA2 allele grow taller than individuals with only one copy.
C) Paired chromosomes exchange genetic material, leading to gametes with unique combinations of DNA.
D) Children with access to adequate nutrition can grow taller than children who are malnourished.

Question 19

Meiosis is a form of cell division that

A) occurs only in eukaryotes.
B) cuts the number of chromosomes in half.
C) produces two identical daughter cells.
D) a and b
E) a and c

Question 20

Horizontal gene transfer

A) can occur via the transfer of plasmids.
B) can be beneficial to the organism.
C) is more common in eukaryotes than in prokaryotes.
D) a and b
E) a, b, and c

Question 21

What is/are the mechanism(s) by which stress can influence gene expression?

A) producing hormones that bind to regulatory regions of genes
B) triggering changes in the coiling of DNA around histones
C) causing mutations that change the DNA sequence in a gene
D) a and b
E) a, b, and c

Question 22

Which of the following is involved in pre-transcriptional gene regulation?

A) histones
B) microRNA
C) DNA methylation
D) alternative splicing

Question 23

Organisms benefit from having homologous pairs of chromosomes because

A) if a mutation occurs, only the functional copy will be passed on to offspring.
B) a deleterious allele can be masked by the presence of a functional copy.
C) possessing two copies of chromosomes enables cells to more easily divide.
D) genetic variation is introduced into gametes through independent assortment.

Question 24

The presence of a mRNA transcript of a gene in a cell means that

A) translation of the gene has occurred.
B) transcription of the gene has occurred.
C) a and b
D) none of the above

Question 25

DNA methylation

A) is a form of transcriptional regulation of gene expression.
B) is a form of post-translational regulation of gene expression.
C) is a form of post-transcriptional regulation of gene expression.
D) none of the above

Question 26

The number of possible combinations of paternal and maternal chromosomes is

A) 2.
B) 23.
C) 2²³.
D) 2 × 23.

Question 27

Which of the following statements about genome size is false?

A) The complexity and size of genomes vary widely between taxa.
B) The genome includes all coding and noncoding regions of an organism's DNA.
C) There is a correlation between genome size and gene number across species.
D) Protein-coding genes make up a tiny portion of the genome in many eukaryotes.

Question 28

Which of the following could be considered part of the environment that could influence gene expression?

A) signals from other cells
B) contact with neighboring cells
C) products from other genes
D) a and b
E) a, b, and c

Question 29

How do bacteria and archaea pass on genetic information to the next generation?

A) copying their chromosome and then dividing
B) dividing their chromosome into four daughter cells
C) going through the process of mitosis
D) passing plasmids to other bacteria via conjugation

Question 30

A genetic polymorphism is

A) multiple discrete phenotypes arising from a genotype, depending on the environment.
B) the simultaneous occurrence of two or more discrete phenotypes within a population.
C) a measurable phenotype that varies among individuals over a given range of values.
D) a change in the phenotype produced by a single genotype in different environments.

Question 31

Changes to the structure of a protein can affect the protein's ability to

A) catalyze chemical reactions.
B) respond to signal molecules.
C) carry information from one cell to another.
D) a and b
E) a, b, and c

Question 32

The genome of an organism does not contain which of the following elements?

A) proteins
B) pseudogenes
C) protein-coding genes
D) mobile genetic elements

Question 33

Trans-acting regulatory elements

A) are typically adjacent to genes they regulate.
B) are typically far away from genes they regulate.
C) include transcription factors.
D) a and c
E) b and c

Question 34

Which of the following type of mutation cannot be inherited by animals?

A) somatic mutation
B) germline mutation
C) point mutation
D) frameshift mutation

Question 35

Traits that are more sensitive to environmental stimuli would have

A) more phenotypic plasticity.
B) a higher chance of mutation.
C) more genetic polymorphisms.
D) fewer loci that control them.

Question 36

You are studying snails and find that individuals have shells that coil either to the right or to the left. Which of the following is/are the most plausible explanation(s) for this variation?

A) Different alleles at a single locus produce the different phenotypes.
B) Individuals are genetically identical, but certain environmental conditions trigger the production of each coil type.
C) This is a quantitative trait, meaning that many loci contribute to the phenotypic differences.
D) a and b
E) a, b, and c

Question 37

Which of the following could not be described as a phenotype?

A) a sequence of nucleotides
B) a molecule produced by a gene
C) a developmental process
D) a morphological structure

Question 38

Which of the following could result in a polyphenism?

A) A mutation creates a deleterious version of an allele that is then passed on to an organism's offspring.
B) A change in an environmental cue switches the production of one phenotype to an alternate phenotype.
C) The cumulative action of multiple genes produces variation among individuals over a given range.
D) A combination of alleles on a single gene produces two or more discrete phenotypes in a population.

Question 39

The human genome consists of

A) more than 50% protein-coding segments.
B) more protein-coding genes than other organisms.
C) the same amount of mobile genetic elements and pseudogenes.
D) approximately the same amount of pseudogenes as protein-coding genes.

Question 40

Why are mutations crucial for evolution?

A) Mutations in germline cells that affect large parts of the genome are very common.
B) Mutations are not necessarily harmful and may be beneficial.
C) Mutations are the ultimate source of genetic variation in populations.
D) Mutations can change the DNA sequence without affecting the protein it codes for.

Question 41

Please critique the following statement: a single gene codes for a single protein.

Question 42

Transcription factors and hormones can both influence gene expression. Describe how they differ.

Question 43

How could the presence or absence of a transcription factor in a gene's environment affect the expression of that gene?

Question 44

Most chemical reactions in a cell are performed by

A) DNA.
B) RNA.
C) proteins.
D) amino acids.

Question 45

Each of us is genetically unique. Describe two processes that ensure that your future full sibling is going to be genetically different from you, even though you have the same parents.

Question 46

Height is a quantitative trait, meaning that genes at several loci contribute to the phenotype. Does this mean that any two individuals in a population that differ in height also differ in the alleles they carry?

Question 47

Compare and contrast how genetic variation is created in eukaryotes versus bacteria and archaea.

Question 48

Describe one reason histone proteins are important in cells.

Question 49

Discuss the importance of somatic and germline mutations for evolution.

Question 50

Michael Lynch and his colleagues demonstrated in yeast that mutations occur rarely-in fact, a single yeast cell may not experience a single point mutation in its genome. How can we reconcile the low rate of mutation with the fact that mutation is the engine that drives evolution?

Question 51

Polyphenic traits are an example of

A) phenotypic plasticity.
B) quantitative trait loci.
C) simple genetic polymorphism.
D) dominant traits.