Deck 3: Genome Structure, Organization, and Variation

Question 1

In an evolutionary context, what is fitness?

A) The likelihood that an organism will survive and reproduce successfully in a given environment
B) The ability of an organism to pass on the propensity to produce more offspring
C) The genetic changes that increase the number of offspring produced by an organism
D) The speed at which an organism can produce offspring in a specific environment

Answer 1

The likelihood that an organism will survive and reproduce successfully in a given environment

Question 2

Which of the following statements regarding natural selection are true? Please select all that apply.

A) Genotypes increasing in frequency in a population are under positive selection.
B) Gene sequences must change for natural selection to occur.
C) Selection strength is not affected by the environment.
D) Phenotype must be affected for natural selection to act on genetic changes.

Answer 2

Genotypes increasing in frequency in a population are under positive selection.
Phenotype must be affected for natural selection to act on genetic changes.

Question 3

Which of the following phenomena results in the largest change of genome size?

A) Polyploidization
B) Gene loss
C) Horizontal gene transfer
D) Gene family expansion

Answer 3

Polyploidization

Question 4

Which of the following statements about bacteria are true? Please select all that apply.

A) Bacteria usually have nuclei
B) Bacterial chromosomes are usually larger than plasmids
C) Bacterial chromosomes are usually circular
D) Bacteria usually have multiple chromosomes

Question 5

Which genome features are generally found in eukaryotes but not in bacteria? Please select all that apply.

A) Telomeres
B) Plasmids
C) Chromosomes
D) Centromeres

Question 6

Which of the following features is characteristic of heterochromatin

A) Heterochromatin is densely packed
B) Heterochromatin appears pale on stained chromosomes
C) The majority of active genes are found in heterochromatic regions
D) Chromosomal proteins are not found in heterochromatin

Question 7

Which if the following features is not characteristic of histones

A) Histones have a negative charge
B) Histones form an octamer
C) A nucleosome consists of DNA plus a core histone particle
D) Histones are highly conserved

Question 8

Where can extrachromosomal DNA be found in eukaryotes? Please select all that apply.

A) Chloroplasts
B) Plasmids
C) Mitochondria
D) Ribosomes

Question 9

Genome size and chromosome number tend to increase with organism complexity.

Question 10

Which of the following statements about human chromosomes are true? Please select all that apply.

A) Humans have 46 pairs of chromosomes
B) The X chromosome is larger than the Y chromosome
C) Chromosome 7 is smaller than chromosome 15
D) The human diploid number is 23

Question 11

The two chromosomes in one pair are referred to as which of the following?

A) Homologous
B) Alleles
C) Centromeres
D) Sister chromatids

Question 12

Sequence differences between homologues are greater than between sister chromatids.

Question 13

Which of the following factors is not considered to be a fundamental property of a gene.

A) Genes are alleles
B) Genes consist of DNA sequences
C) Genes are inherited
D) Genes are expressed

Question 14

What is a genetic locus?

A) A place in a genome where a gene resides
B) A map of all gene positions in a genome
C) A distance between positions on a genome
D) A specific gene

Question 15

A random base change is less likely to affect phenotype in humans than in bacteria. Why? Please select all that apply.

A) Humans have two copies of a gene whereas bacteria have one copy.
B) A higher percentage of the human genome consists of genes than the bacterial genome.
C) Less of the human genome is functional than the bacterial genome.
D) A third base change is more likely to occur in bacteria than in humans.

Question 16

Which of the following are examples of biological redundancy? Please select all that apply.

A) There is more than one codon for most amino acids
B) Gene families have multiple genes with the same/similar functions
C) Multiple pathways exist to carry out a function
D) In humans, there are two alleles of most genes

Question 17

Match the missing words in the following phrase. Alternative splicing refers to the process where multiple [A] are produced from one [B]. This process is most common in [C], occurs less frequently in [D], and is rare in [E].

Question 18

Orthologs are different members of the same gene family within an organism, whereas paralogs are genes in different species that have shared ancestry, encode similar proteins, and have similar functions.

Question 19

What is copy number variation?

A) A substitution of a base for a different base
B) A sequence that is found in one species but is missing in another species
C) A difference in the amount of a specific DNA sequence found in different individuals or species
D) Duplication of a genome

Question 20

Which of the following characteristics is not true of gene families?

A) The number of paralogs usually varies widely between individuals in a species
B) Gene families arise through gene duplications
C) Functional divergence can arise in gene families because there is no loss of fitness when the function of one copy changes.
D) The original functions of a gene can be split between two paralogs in a gene family.

Question 21

Which of the following is the major contributing factor to phenotypic differences between individuals of the same species?

A) Variation in amino acid sequences
B) Variation in regulatory sequences
C) Variation in splicing
D) Variation in novel genes

Question 22

What is a pseudogene?

A) A non-functional gene
B) A paralogous gene
C) A member of a gene family
D) A protein domain

Question 23

Polyacrylamide gel electrophoresis (PAGE) separates proteins based on differences in which of the following? Please select all that apply.

A) Their size
B) Their pH
C) Their GC%
D) Their charge

Question 24

Match the DNA sequencing technology to its primary disadvantage

-Sanger dideoxy sequencing

A) Only single molecules can be sequenced at once.
B) High cost for the amount of sequence produced
C) Short sequence reads

Question 25

Match the DNA sequencing technology to its primary disadvantage

-Roche 454 sequencing

A) Only single molecules can be sequenced at once.
B) High cost for the amount of sequence produced
C) Short sequence reads

Question 26

Match the DNA sequencing technology to its primary disadvantage

-Illumina sequencing

A) Only single molecules can be sequenced at once.
B) High cost for the amount of sequence produced
C) Short sequence reads

Question 27

During which of the following processes can genes be duplicated?

A) Replication
B) Transcription
C) Translation
D) Splicing