Lecture 7: DNA, Chromatin and the Nucleus

Question 1

What is satelite DNA ?

Answer 1

main component of functional centromers and form the main structural constituen of heterochromatin

Question 2

What are minisatelites ?

Answer 2

Prominent in centromers and telomers of chromosomes ranging in length from 10-60 base pairs

Question 3

What are microsatelite DNA ?

Answer 3

Segments of repeated DNA with a short repeat length usually two to six nucleotides

Question 4

What are short interspersed nuclear elements ?

Answer 4

Non-autonomous, non-coding transposable elements that are 100-700 base pairs in length. Class of retrotransposons

Question 5

What are retrotransposons ?

Answer 5

DNA elements that amplify themselves throughout eukaryotic genomes often through RNA intermediates

Question 6

What are long terminal repeats ?

Answer 6

DNA that repeat hundreds or thousands of times found at either end of retrotransposons

Question 7

What are short interspersed nuclear elements ?

Answer 7

Retrotransposons that are widespread in the genome of many eukaryotes

Question 8

What are DNA transposons ?

Answer 8

Jumping genes, that can move an integrate to different locations within the genome

Question 9

What is DNA packaged in >

Answer 9

Chromosomes: 22 autosomal and 1 sex pair

Question 10

What do nucleat lamins form ?

Answer 10

The scaffold of the nuclear membrane

Question 11

What are histones ?

Answer 11

Proteins that are closely associated with DNA molecules

Question 12

What are the five type of histones ?

Answer 12

1. H1
2. H2A
3. H2B
4. H3
5. H4

Question 13

What are H1 nad H5 involved in ?

Answer 13

Higher order structures of chromatin

Question 14

What do the other histones do ?

Answer 14

Associate with DNA to form nucleosomes

Question 15

What do chromosomes have ?

Answer 15

Protein scaffolds

Question 16

What holds sister chromatids together after replication ?

Answer 16

Cohesin

Question 17

What does cohesin associate with ?

Answer 17

DNA late in G1 of cell cycle

Question 18

How are chromosomes separated ?

Answer 18

Kinetochores

Question 19

What are kinetochores ?

Answer 19

Microtubules initiated at the centrosomes become attached to chromosomes at kinetochores

Question 20

What are centromeric chromatin ?

Answer 20

The specialised chromatin at the centromere region that is the foundation of the kinetochore

Question 21

What are telomere ends maintained by ?

Answer 21

Telomerase enzyme

Question 22

What are telomere ends characterised by ?

Answer 22

T-loop, D-loop and G-quadruplex structures

Question 23

What are G-quadruplex structures ?

Answer 23

Secondary structures formed in nucleic acids by sequences rich in guanine. They are helical in shape and contain guanine tetrads that can form from one, two or four strands

Question 24

What can digest chromatin ?

Answer 24

Micrococcal nuclease enzyme

Question 25

What part of histones can be chemically modified ?

Answer 25

Long tails

Question 26

Where can histones move ?

Answer 26

Embryonic and undifferentiated stem cell

Question 27

Where do histones exchange ?

Answer 27

Active genes

Question 28

What controls gene transcription ?

Answer 28

DNA methylation

Question 29

What controld chromatin structure and gene transcription ?

Answer 29

Histone modification and DNA methylation

Question 30

What are activator proteins ?

Answer 30

Regulatory proteins that bind to DNA at distant enhancer sites

Question 31

What are enhancer sites ?

Answer 31

Regulatory sites on DAN distant from gene