Chapter 1

Question 1

genotype

Answer 1

your DNA sequence, both nuclear and mitochondrial

Question 2

phenotype

Answer 2

collection of your observable traits other than your DNA sequence

phenotype = genotype + environment + life history + epigenetics

Question 3

epigenetic factors

Answer 3

inheritable and acquired gene regulation patterns that alter gene function (phenotype) without changing gene structure (genotype)

Question 4

Most of your cells have the same DNA sequence except for …

Answer 4

• egg and sperm cells
• erythrocytes (red blood cells)
• cells of the immune system

Question 5

CRISPR-Associated (Cas) system

Answer 5

powerful technique for genome editing

Question 6

The most general classification of cells according to their structure and molecular biology is …

Answer 6

• prokaryotes (cells without a nucleus)
• eukaryotes (cells with a nuclei)

Question 7

What are the two problems cells face when structuring their DNA?

Answer 7

• packaging to fit (eukaryotes have an even harder challenge because they also have a nucleus to account for)
• what to do during cell division, after DNA replication, to ensure each daughter cell gets one copy of the DNA

Question 8

proteins

Answer 8

polymers of amino acids (20 amino acids which proteins are constructed from)

Question 9

ORF

Answer 9

• Open Reading Frame
• found in protein-coding regions of a DNA sequence
• starts with a start codon and ends with a stop codon

Question 10

exons and introns

Answer 10

• found in eukaryotes only
• exons are the coding region
• introns are the non-coding region that needs to be removed to form mRNA

Question 11

Why do genes for tRNA have a cloverleaf pattern?

Answer 11

some regions are expressed as non-protein-coding RNA which may show regions of local self-complementarity corresponding to hairpin loops

Question 12

What are the two basic approaches to identifying genes in genomes?

Answer 12

• priori method: which seeks to recognize sequence patterns within expressed genes
• ‘been there seen that’ method: which recognizes regions corresponding to previously known genes
• combined approaches are also possible

Question 13

metagenomic data

Answer 13

sequences determined from environmental samples without isolating individual organisms

Question 14

How much does any two person’s genomic sequence differ from one another?

Answer 14

0.1% (except for identical siblings)

Question 15

Which changes in a DNA sequence count as a mutation?

Answer 15

Any change including substitutions, insertions, translocations, and deletions

Question 16

Many of the differences between individuals take which form?

Answer 16

• single-nucleotide polymorphisms (SNPs)
• short deletions
• variations in number of replicates of repetitive sequences

Question 17

Mutations in different DNA molecules of diploid chromosomes become separated by … while mutations in the same DNA molecules become separated by …

Answer 17

• assortment
• recombination (except for most of the Y chromosome and mitochondrial DNA)

Question 18

What effect does “loss of function” mutations being recessive have?

Answer 18

homozygosity for the mutant allele generally has more more severe consequences than heterozygosity

Question 19

Many diseases are associated with the formation of insoluble aggregates which are usually what?

Answer 19

misfolded proteins

Question 20

How will mutations in the same DNA molecule in diploid chromosomes become unlinked?

Answer 20

recombination events that occur between their loci (the greater the separation distance, the more recombination)

Question 21

The MHC region contains over 120 expressed genes, coding for proteins that do what?

Answer 21

• provide the mechanism by which the immune system distinguishes “self molecules from “non-self” molecules
• determine individual profiles for competence for resistance to diseases
• useful markers for determining relationships (among humans and animals)

Question 22

What are two basic approaches to reversing extinction?

Answer 22

• selective breeding
• using CRISPR/Cas system to modify the genome of a living relative to approach that of the extinct species

Question 23

Gene Drive

Answer 23

applies CRISPR/Cas technology to accelerate the dispersal of a chosen gene throughout a population (much faster than selective breeding)

Question 24

De novo sequencing

Answer 24

sequencing a novel genome where there is no reference sequence available for alignment and sequence reads are assembled as contigs

Question 25

Resequencing

Answer 25

once a reference genome is available, fragment sequences are mapped on the reference genome

Question 26

What is exome sequencing used for?

Answer 26

• most inherited diseases result from the loss of activity of particular proteins which frequently arises from a specific mutation in the sequence coding for the protein (exon)
• to identify such a mutation we only need to sequence the exons

Question 27

Central Dogma

Answer 27

DNA makes RNA makes Protein

Question 28

proteome

Answer 28

amino acid sequences of the proteins expressed

Question 29

Which RNAs are involved in the control of gene expression?

Answer 29

most non-coding RNAs except for RNAs involved in the machinery of protein synthesis, such as tRNAs an the ribosome

Question 30

pseudogenes

Answer 30

degenerate genes that have mutated so far from their original sequences that the polypeptide sequence they encode will not be functional

Question 31

Variable Splicing

Answer 31

possibility of omitting one or more exon