Lecture 14: Specialized Chromosome Structure Sequences

Question 1

Human telomere sequence is.. and how many repeats at birth

Answer 1

TTAGGG -2500

Question 2

Centromere is essential for

Answer 2

Chromosome separation

Question 3

T or F: G strand sequence is longer than C strand on telomere sequence

Answer 3

True - G strand is longer

Question 4

Which strand of the telomere folds over to from T loop

Answer 4

G rich strand

Question 5

Shortened telomere sequences are linked to

Answer 5

Shorter life span and increased disease. Specifically restricted cell proliferation/tissue degeneration - CARDIOVASCULAR DISEASE

Question 6

Lead and telomeres

Answer 6

Lead exposure leads to shortened telomeres

Question 7

Longer telomeres effect

Answer 7

Increase risk related to increased PROLIFERATVE growth, including major CANCERS

Question 8

Centriole

Answer 8

Small cylindrical organelle, located near nucleus, divides in perpendicular fashion during mitosis

Question 9

What is the primary sequence at human centromeres

Answer 9

Alpha satellite DNA in tandem head-tail fashion

Question 10

What is the predominate form of alpha satellite DNA

Answer 10

Complex high order sequences (HORs)

Question 11

What is crucial for centromere/kinetochore assembly/function during cell division

Answer 11

Transcription of Alpha satellite DNA

Question 12

What is at the core of the kinetochore/centromere and it is surrounded by what

Answer 12

Centromere-specific histone H3 variant CENP-A

Surrounded by heterochromatin

Question 13

What links together centromeric chromatin

Answer 13

Cohesin

Question 14

What happens if a chromosome break occurs near centromere and one fragment does not get a centromere

Answer 14

That piece of DNA is usually lost from the nucleus

Question 15

Histones are ___ charged

Answer 15

Positively

Question 16

Nucleosome core of histone is comprised of

Answer 16

Two H2A-H2B dimers

H3-H4 Tetramer

Question 17

Nucleosome

Answer 17

Basic unit of DNA packaging

Segment of DNA wound in sequence around 8 core histone proteins (DNA wraps around each 1.65 times)

Question 18

Chromatosome

Answer 18

A histone octamer, one molecule of linker histone, and 166BP of DNA.

Question 19

Linker DNA

Answer 19

Double stranded DNA b/w two nucleosome cores, that, in association with Histone H1, holds the cores together

Question 20

High order chromatin structure

Answer 20

30nm fiber
300nm loops
250nm wide fiber

Question 21

What is the fundamental repeating unit of chromatin

Answer 21

Nucleosome

Question 22

Polytene chromosome created by

Answer 22

Repeated rounds of DNA replication w/o cell division

Question 23

Chromosomal puffs

Answer 23

Regions of relaxed chromatin where active transcription is taking place

Question 24

Does chromatin structure change during the course of transcription? How would we know?

Answer 24

Yes it does. Shown but the fact that DNA’s sensitivity to be degraded by DNAse I is correlated with gene expression

Question 25

Epigenetics

Answer 25

A heritable alteration of phenotype because of altered chromatin structure (histone modification, acetylation)

Question 26

Unique sequence DNA

Answer 26

Similar but not identical copies of unique DNA sequences that arose through duplication of an existing gene

Question 27

Repetitive DNA

Answer 27

Stretches of DNA that repeat themselves throughout a genome, in tandem or interspersed along the genome.

Question 28

Alu element

Answer 28

Short interspersed elements: SINEs

Question 29

Moderately repetitive DNA length

Answer 29

150-300bp long

Question 30

Highly repetitive DNA length

Answer 30

Less than 10bp

Question 31

Microsatellite DNA

Answer 31

(Short Tandem Repeats) Tract of tandemly repeated (adjacent) DNA motifs thtat range in length from 2-5 nucleotides, and are typically repeated 5-50 times. TATATATA is an example of a dinucleotide microsatellite

Question 32

What can microsatellite DNA be used for

Answer 32

Mapping locations within the genome

Question 33

STR sequencing project

Answer 33

Initiated to facilitate the description of sequence based alleles at the STR loci