Quiz 3

Question 1

Chromosomes

Answer 1

Contain genetic information

Question 2

Viral and material chromosomes are composed of:

Answer 2

Almost completely of nucleic acid (DNA and RNA)

Question 3

Eukaryotic chromosomes are composed of:

Answer 3

DNA and protein (and RNA)

Question 4

Length of DNA in humans

Answer 4

In one cell: about three inches per strand, six feet in one cell
In one human: miles and miles

Question 5

Where in cells is DNA stored?

Answer 5

Prokaryotes: in nucleotides
Eukaryotes: in nucleus

Question 6

Organization of genetic material in viruses vs bacteria vs eukaryotes

Answer 6

Viruses: simple (not living)
Bacteria: fairly simple
Eukaryotes: more complex

Question 7

General structure and function of virus

Answer 7

Protein shell called capsid that contains genetic material; attaches to host cell and injects genetic material in order to replicate/produce more viruses (often destroying host)

Question 8

DNA binding proteins

Answer 8

Small, positively charged amino acids that are attracted to negatively charged DNA; don’t compact DNA in same way that eukaryotic counterparts do

Question 9

Linking number

Answer 9

Number of complete turns in a DNA helix

Question 10

Underwound

Answer 10

Energetically strained

Question 11

Negative supercoils

Answer 11

Because DNA is right handed, coils go opposite direction

Question 12

Hiw are supercoils generated

Answer 12

Topoisomerase I cuts a strand and unwinds (reduces number of supercoils), while topoisomerase II cuts two strands and winds (introduces negative supercoils)

Question 13

Chromatin

Answer 13

DNA and protein (and RNA)

Question 14

Histones

Answer 14

Positively charged proteins attached to negatively charged DNA

Question 15

Nucleosome

Answer 15

Spherical bead-like particle on linking DNA string

Question 16

Linker DNA

Answer 16

20-60bps that connects nucleosomes

Question 17

Core DNA

Answer 17

DNA in nucleosomes, 147bps

Question 18

Four levels of chromosome compaction

Answer 18

Nucleosomes packaged into solenoids, which side by side form 30nm fiber which is then looped into domains which are compacted to form chromatid

Question 19

Chromatin remodeling

Answer 19

Changing structure of chromatin to make DNA accessible so it can be expressed or vice versa

Question 20

Histone tails

Answer 20

Can be modified by chemicals such as acetyl groups that make tail less positive in order to lose DNA affinity so it is available for proteins involved in replication and/or translation

Question 21

Euchromatin

Answer 21

Expressed DNA

Question 22

Heterochromatin

Answer 22

DNA we don’t use; densely packed; either no or unexpressed genes

Ex: centromere and telomere

Question 23

Position effect

Answer 23

Piece of heterochromatin is translocation to another location in genome, meaning active DNA in that location is inactivated

Question 24

C-banding

Answer 24

Stains centromere region

Question 25

G-banding

Answer 25

Stains various regions to produce unique pattern; basis for nomenclature

Question 26

Repetitive DNA

Answer 26

Repeats in genome; some are and some aren't genes (most)

Question 27

Satellite DNA

Answer 27

Highly repetitive; heterochromatin such as centromeres

Question 28

Variable number tandem repeats

Answer 28

(Minisatellites) Moderately repetitive DNA that is 15-100bp long, found in between genes and varied by location/people

Question 29

Short tandem repeats

Answer 29

(Microsatellites) between 2 and six bps that are dispersed throughout genome and vary among individuals

Question 30

Multiple copy genes

Answer 30

Moderately repetitive; rRNA genes such as functional genes that are present tandemly

Question 31

Transposable element

Answer 31

Mobile; not tandemly repeated

Question 32

Short interspersed elements

Answer 32

(SINEs) less than 500bp, about one and a half million in human genome with uniform distraction of about 13% of human genome

Question 33

Long interspersed elements

Answer 33

About 6,000bp, about 850,000 or 2% of human genome Retrotransposons: RNA is transcribed into DNA instead of the other way around

Question 34

Retrotransposons

Answer 34

Ex: LINEs RNA is transcribed to make DNA instead of vice versa

Question 35

Highly and moderately repetitive DNA and pseudogenes

Answer 35

Do not code for genes

Question 36

Pattern of degeneracy

Answer 36

The first two nucleotides are often common to codons encoding same amino acids and last nucleotide is different