genomes nd variants

Question 1

compact bacterial chromosome

Answer 1

Nucleoid

Question 2

bacterial genomes occupy about a ________ of the volume of the cell and have many independent ________ domains

Answer 2

1/3, chromosomal

Question 3

Supercoil loop of DNA that is randomly distributed

Answer 3

chromosomal domains

Question 4

t/f Most bacterial chromosomes are circular, but some are linear.

Answer 4

T

Question 5

Select All That Apply: Bacterial chromosomes
Circular
Linear
Multiple 1-Mb chromosomes in Borrelia species
8-Mb chromosomes in Streptomyces species

Answer 5

Circular, Linear, Multiple chromosomes in Borrelia species, 8-Mb chromosomes in Streptomyces species

Question 6

Select All that Apply: Species that have unique bacterial chromosomes (either multiple or of larger size)?

Borrelia
Streptomyces
Escherichia coli
Clostridium

Answer 6

Borrelia
Streptomyces

Question 7

OOO: Nucleoid-associated proteins (NAPs) in bacteria

DNA bridging
DNA repair
DNA wrapping
DNA bending

Answer 7

DNA repair

Question 8

T/F Viral genomes can consist of either RNA or DNA.

Answer 8

T

Question 9

protein shell surrounding a viral genome

Answer 9

capsid

Question 10

Sequence: Phage Lamba Maturation
1. DNA packing begins
2. Headshell reaches full size
3. Prohead II is empty
4. Prohead I has protein core
5. Tail is attached
6. Headshell expands as DNA returns

Answer 10

4 - 3 - 1 - 6 - 2 - 5

Question 11

The human genome has approximately ________ nucleotide bases, with almost all people sharing ________% of these nucleotide bases

Answer 11

3 billion, 99.9%

Question 12

there are ______ number of genes, with ____% of discovered genes having unknown function

Answer 12

21,000; 50%

Question 13

T/F average human gene contains approximately 3000 nucleotide bases.

Answer 13

t

Question 14

largest known human gene with 2.4 million bases

Answer 14

Dystrophin

Question 15

Select All that Apply: Components involved in the DNA packaging to chromatin

Nucleosomes
Chromatosomes
H1 Histones
Ribosomal RNA

Answer 15

Nucleosomes, Chromatosomes, H1 Histones

Question 16

Sequence Question:Steps of DNA packaging

1 Nucleosome formation
2 30 nm fiber looping
3 Chromatosome formation
4 300 nm fiber compression
5 Tight coiling into chromatids

Answer 16

1 3 2 4 5

Question 17

T/F Chromatin at simplest level is single-stranded DNA

Answer 17

F - double stranded helical

Question 18

each nucleosome is composed of ______ histone proteins

Answer 18

eight

Question 19

T/F: DNA wraps around histone proteins approximately 1.65 times to form a nucleosome.

Answer 19

T

Question 20

The packaging of DNA and histone modification are critical for ________ and ________ to fit eukaryotic DNA into the nucleus.

Answer 20

DNA packaging; packing capacities

Question 21

term used to describe the eight histone proteins with DNA wrapped around them in a nucleosome

Answer 21

Core Histone Complex

Question 22

Select All That Apply: core histone variants involved in DNA repair, gene activation/silencing, or tumor suppression

H2A
H2A.Z
H2A.X
MacroH2A

Answer 22

H2A.Z, H2A.X, MacroH2A

Question 23

________ histone variants are replication-independent, while ________ histone variants are replication-dependent

Answer 23

H2A.X, H3.1

Question 24

T/F expression of H2A.X is reduced in cancer progression, particularly in p53 knockout mice.

Answer 24

T

Question 25

histone variant that when overexpressed, acts as an oncogene in multiple cancers?

Answer 25

H2A.Z

Question 26

________ histone variant, when reduced, functions as a tumor suppressor and is associated with cancers like melanoma.

Answer 26

MacroH2A

Question 27

bacterial genomes referred to when compactly organized inside the cell

Answer 27

Nucleoid

Question 28

Select All That Apply: Major features of the human genome - 21,000 genes - 99.9% identical nucleotide bases across individuals - 50% of genes have unknown functions - Circular chromosomes

Answer 28

21,000 genes, 99.9% identical nucleotide bases across individuals, 50% of genes have unknown functions

Question 29

unique chromosomes characterized by lateral loops extruding from chromomeres at specific positions

Answer 29

lampbrush chromosomes

Question 30

T/F Chromomeres appear during the prophase stage of meiosis when chromosomes resemble a series of beads on a string.

Answer 30

T

Question 31

Lampbrush chromosomes are typically found in the ________ of ________ amphibians during diplotene prophase

Answer 31

oocytes, urodele

Question 32

extruded segment of DNA from lampbrush chromosomes that is actively transcribed

Answer 32

loop

Question 33

unique chromosomes found in the interphase nuclei of some tissues in larvae of flies, and are useful for studying interphase chromosome organization

Answer 33

Polytene Chromosomes

Question 34

Odd One Out: Polytene chromosomes Found in larvae of flies Successive duplication of chromosomal elements Active participation in mitotic cell division Develop from diploid nuclei

Answer 34

active participation in mitotic cell division

Question 35

t/f cells with polytene chromosomes differ from mitotically dividing cells due to successive duplication of each chromatid.

Answer 35

t

Question 36

Sequence: Increasing minimum gene number required for their complexity: 1Free-living bacterium 2 Mammals 3 Unicellular eukaryote 4 Intracellular parasitic bacterium 5 Multicellular eukaryote

Answer 36

4 1 3 5 2

Question 37

The minimum gene number for mammals is about ________, whereas the minimum gene number for a unicellular eukaryote is about ________.

Answer 37

25,000; 5000

Question 38

T/F The genome of Homo sapiens is around 3,300 Mb, with approximately 25,000 genes.

Answer 38

T

Question 39

unique type of DNA sequences that only have one copy in a haploid genome, usually corresponding to protein-coding genes

Answer 39

Nonrepetitive DNA

Question 40

t/f length of nonrepetitive DNA increases with overall genome size

Answer 40

t

Question 41

In higher eukaryotes, the increase in genome size usually reflects an increase in the amount and proportion of ________ DNA

Answer 41

repetitive

Question 42

OOO: Nonrepetitive DNA Unique sequences Corresponds to protein-coding genes Often involved in genome size increase Found in multiple copies in a haploid genome

Answer 42

Found in multiple copies in a haploid genome

Question 43

What type of repetitive sequence involves DNA transposons and retrotransposons, including SINEs and LINEs, that can move within the genome?

Answer 43

Interspersed Elements: Repetitive Transposed Sequences

Question 44

T/F SINEs (Short Interspersed Elements) are repetitive transposed sequences that are usually less than 500 base pairs long.

Answer 44

T

Question 45

Select All That Apply: Characteristics of LINEs (Long Interspersed Elements) 1 Typically around 200–300 base pairs long 2 Can be present up to 850,000 times in the human genome 3 Are about 6kb in length 4 Considered retrotransposonss

Answer 45

Can be present up to 850,000 times in the human genome Are about 6kb in length Considered retrotransposon

Question 46

The Alu family is part of the SINEs, and each sequence is typically ________ to ________ base pairs long, uniformly dispersed throughout the genome.

Answer 46

200, 300

Question 47

type of tandem repeats that are microsatellites with di-, tri-, tetra-, and pentanucleotide sequences, dispersed throughout the genome and varying among individuals

Answer 47

Short Tandem Repeats (STRs)

Question 48

T/F Minisatellites are longer tandem repeats, typically around 15-bp in length, with an array size between 0.5–30 kb.

Answer 48

T

Question 49

Variable Number Tandem Repeats (VNTRs) are usually ________ to ________ base pairs long, and variation in the number of tandem copies forms the basis for ________.

Answer 49

15, 100, DNA fingerprinting

Question 50

OOO: Microsatellites 1 Composed of 2- to 5-bp repeats 2 Array size usually between 0.5–30 kb 3 Useful for genetic analysis due to variation in repeat numbers 4 Dispersed throughout the genome

Answer 50

2 Array size usually between 0.5–30 kb

Question 51

highly repetitive DNA sequences called that are often found in centromeric and subtelomeric regions, forming large arrays of short sequences

Answer 51

Satellite DNA (satDNA)

Question 52

T/F Satellite DNA sequences are highly repetitive, typically AT-rich, and are involved in posttranscriptional gene regulation via siRNAs.

Answer 52

T

Question 53

Select All That Apply: Characteristics of Satellite DNA (satDNA) 1 Located mostly in centromeric and subtelomeric regions 2 Composed of highly repetitive sequences 3 Contains long sequences repeated fewer than 100 times 4 Monomer length typically ranges from 150 to 400bp

Answer 53

1, 2, 4

Question 54

Satellite DNA likely plays a role in sequence-specific interactions and epigenetic processes, particularly in the formation and maintenance of ________.

Answer 54

Heterochromatin

Question 55

complex involved in gene silencing and associated with noncoding RNAs

Answer 55

RNA-induced silencing complex (RISC)

Question 56

T/F Noncoding RNAs do not play a significant role in neuronal functions.

Answer 56

F

Question 57

________ are considered dead genes that may evolve functions in regulating the expression of related genes

Answer 57

Pseudogenes

Question 58

OOO: Pseudogenes They are dead genes. They have active functions in regulating gene expression. They are evolutionary vestiges of duplicated genes. They undergo significant mutational alteration.

Answer 58

They have active functions in regulating gene expression.

Question 59

first step in genome evolution involving replication errors or DNA damage

Answer 59

intro of mutation

Question 60

t/f substitution mutations can be synonymous or nonsynonymous

Answer 60

t

Question 61

Select All That Apply: Nonsynonymous mutations Silent mutation Missense codon Nonsense codon Frameshift mutation

Answer 61

Missense codon, Nonsense codon

Question 62

_____ refers to random changes in the frequency of a mutational variant in a population

Answer 62

Genetic drift

Question 63

T/F A variant may either be lost from the population or become fixed, replacing all other variants.

Answer 63

T

Question 64

combination of the mutation rate and the rate of fixation

Answer 64

evolutionary rate

Question 65

because genetic drift overcomes selection more in __________ populations, slightly deleterious mutations are more likely to become fixed.

Answer 65

smaller

Question 66

Select All That Apply: Mechanisms of genome evolution - Gene duplication - De Novo Origination - Horizontal Gene Transfer - Genetic drift

Answer 66

Gene duplication, De Novo Origination, Horizontal Gene Transfer

Question 67

hypothesis explains that smaller genomes are favored by selection for cellular economization

Answer 67

Streamlining Hypothesis

Question 68

T/F: Natural selection directly favors genome reduction and low G+C content in free-living prokaryotes living in nutrient-rich environments

Answer 68

F - low nutrient

Question 69

In populations undergoing constant bottlenecks and no recombination, genome reduction occurs through the accumulation of slightly __________ mutations.

Answer 69

deleterious

Question 70

Select All That Apply: Modify genes coded in the reduced genome of endosymbionts to help cope with gene loss - Presence of complementary genes in the genomes of cosymbionts - Host-origin genes - Horizontally transferred genes from unrelated organisms - Genetic drift

Answer 70

Presence of complementary genes in the genomes of cosymbionts Host-origin genes Horizontally transferred genes from unrelated organisms

Question 71

The genes coded in the genome of the host can compensate for gene losses in the genome of the __________.

Answer 71

Endosymbiont

Question 72

number of nucleotide pairs in the mitochondrial genome

Answer 72

16,569 nucleotide pairs

Question 73

T/F The mitochondrial genome encodes 13 proteins.

Answer 73

T

Question 74

The human genome contains approximately ________ nucleotide base pairs packaged into ________ pairs of chromosomes.

Answer 74

3 x 10^9, 23

Question 75

T/F: 99.9% of nucleotide bases are different among all humans.

Answer 75

F - 99.99% same

Question 76

Select All That Apply: Basic concepts in genetic variation Locus Allele Genotype Polymorphism Mutation

Answer 76

Locus, Allele, Polymorphism, Mutation

Question 77

position or location of a gene in the genome

Answer 77

locus

Question 78

T/F an allele is an alternative version of a gene that is present at any given locus.

Answer 78

t

Question 79

somatic mutations occur in ________ tissues and are ________

Answer 79

nongermline, nonheritable

Question 80

Select All That Apply: Germline mutations Present in egg or sperm Are heritable Cause cancer family syndrome Nonheritable

Answer 80

Present in egg or sperm heritable Cause cancer family syndrome

Question 81

type of mutation occurs in nongermline tissues

Answer 81

somatic mutations

Question 82

T/F Germline mutations do not affect the offspring

Answer 82

F - affect

Question 83

The mutations that occur in egg or sperm can affect ________ in the offspring

Answer 83

all cells

Question 84

Select All That Apply: Types of genetic variations - Point mutations - Tandem repeats - Inversions - Copy number variations

Answer 84

tandem repeats

Question 85

Short sequences of DNA that has the ability to move to new locations in the genome

Answer 85

Transposons

Question 86

transposons are called Called _____ DNA or _____ DNA

Answer 86

selfish DNA or junk DNA