Eukaryotic Chromosome Structure and Function

Question 1

Which dye binds to chromosomes?

Answer 1

DAPI

Question 2

When are chromosomes visible?

Answer 2

During cell division

Question 3

Proteins contained in the nucleus are involved in what?

Answer 3

Packaging and unfolding of DNA within the nuclues
Controlling DNA replication, DNA repair and genetic recombination
Maintainging chromosome integrity by preventing loss of end sequences
Governing segregation
Regulating gene expression

Question 4

Which organelles contain some DNA?

Answer 4

Mitochondria and chloroplasts

Question 5

What is a karyotype?

Answer 5

The organised representation of all the chromosomes in a eukaryotic cell at metaphase
The chromosomes are painted a different colour each

Question 6

Where is transcriptionally inactive DNA located in the interphase nuclues?

Answer 6

On the periphery

Question 7

Trasncriptional activation of a gene is accomponied by what movement?

Answer 7

The genes move from the periphary to the centre of the nuclues
They move out of their chromosome territory to centre of the nucleus

Question 8

How thick is condensed isolated chromatin?

Answer 8

30nm thick

Question 9

What are the protein subunits of the nueclosomes called?

Answer 9

Core histones

Question 10

How many subunits make up a core histone?

Answer 10

8

Question 11

How do histones regulate chromatin structure and function?

Answer 11

They have 8 tails which can interact with other other proteins

Question 12

What is a telomere?

Answer 12

DNA sequences at the ends of linear chromosomes that maintain chromosomal integrity

Question 13

What is a replication origin?

Answer 13

DNA sequences where DNA replication is initiated

Question 14

What is a centromere?

Answer 14

DNA sequences on which kinetochores assemble and mediate chromosome segregation at mitosis and meiosis

Question 15

What is a kinetochore?

Answer 15

Protein complex that binds microtubules in the mitotic spindle

Question 16

What is the sequence of a telomere?

Answer 16

Repeats of TTAGGG

Question 17

Which enzyme replicates telomeres?

Answer 17

Telomerase

Question 18

Where are alpha satellite sequences located?

Answer 18

In condensed heterochromatin

Question 19

What do kinetochore inner plates bind to?

Answer 19

Alpha satellite DNA

Question 20

What do kinetochore outer plates bind to?

Answer 20

Components of the mitotic spindle in microtubules

Question 21

Describe the kinetochore in yeast

Answer 21

Basket that links a single nucleosome of centromic chromatin to a single microtubule

Question 22

How many microtubules can human kinetochores capture?

Answer 22

20

Question 23

How much of the human genome codes for the proteins?

Answer 23

1.5%

Question 24

50% of what makes up the human genome?

Answer 24

repeated DNA sequence elements

Question 25

Retrotransposons are also known as what?

Answer 25

Parasitic DNA

Question 26

What is the role of transcriptional regulatory information?

Answer 26

Determines where and when in the body adjacent coding genes are expressed

Question 27

Increasing biological complexity depends on what?

Answer 27

1) Increasing numbers of protein coding
2) Increasing amounts of non protein coding cis-regulatory DNA for regulating and organising access to protein coding genes

Question 28

What are the three types of transposons?

Answer 28

DNA transposons
Retroviral transposons
Non-retroviral polyA retrotransposons

Question 29

What are transposons?

Answer 29

Mobile genetic elements that jump around the genome

Question 30

How can transposons move?

Answer 30

Move by cut and paste mechanisms without self duplication requiring the transposon encoded enzyme transposase

Question 31

List three examples of transposons

Answer 31

P element in drosophila
Ac - Ds (maize)
TN3 / TN10 (E.coli)

Question 32

Who discovered transposons (Ac-Ds) of maize?

Answer 32

Barbara McClintock in 1952

Question 33

List three examples of retroviral retrotransposons

Answer 33

Ty1-copia
Ty3-gypsy
EAV elements

Question 34

Where are PolyA retrotransposons found?

Answer 34

Abundant in vertebrate genomes

Question 35

How do PolyA retrotransposons replicate?

Answer 35

Via an intermediate using its own retrotransposon encoded reverse transcriptase ie by copy an paste

Question 36

List three examples of PolyA retrotransposons

Answer 36

Human Ll elements
Human Alu elements
Mouse B1 elements

Question 37

Give an example of a disease which is caused by a gene due to Ll insertion

Answer 37

Haemophilia