The Nucleus + DNA Packing

Question 1

The nuclear envelope consists of the following:

Answer 1

A double unit membrane

Perinucleur space

Question 2

Which of the following statements is true?

Answer 2

Eukaryotic cells have a nucleus

Question 3

What are the benefits of having a separate, membrane bound nucleus?

Answer 3

Enabled the evolution of SPLIT genes + alternative splicing

Rapid response to external environment

Separation of delicate DNA from cystoskeletal filaments

Question 4

The nucleus may have evolved from membrane INVAGINATIONS which can be seen in modern bacteria. True or false?

Answer 4

True

Question 5

What does DNA stand for?

Answer 5

deoxyribonucleic acid (DNA)

Question 6

Name the process these molecules go through:

DNA, mRNA, Protein

Answer 6

replication, transcription, translation

Question 7

What are the regulatory regions of genes known as?

Answer 7

Promoter / enhancer

Question 8

What is true about prokaryotic GENES?

Answer 8

Prokaryotic genes are simultaneously transcribed + translated.

Prokaryotic genes are SPLIT into coding exons and NON- coding introns.

Question 9

How many chromosomes do we have?

Answer 9

46

Question 10

Humans have 2 sex chromosomes. What are these called?

Answer 10

X chromosome and Y chromosome

XX  = female. 
XY =  male.

Question 11

What are our remaining chromosomes called?

Answer 11

autosomal chromosomes

Question 12

What are the two arms of a chromosome called?

Answer 12

Short = P arm
Long = Q arm

Question 13

When is highest level of DNA packaging achieved?

Answer 13

Mitosis

Question 14

DNA and associated proteins in nucleus form a material known as Chromatin.

True or false?

Answer 14

TRUE

Question 15

What does this picture show?

Beads on a string

Answer 15

Nucleosomes

Question 16

Which of the following HISTONES are found in nucleosome core?

Answer 16

H2A

H2B

H3

H4

Question 17

Which of these describes the Nucleosome Core?

Answer 17

An Octamer

Question 18

How much DNA is wound around the HISTONE core in the nucleosome?

Answer 18

146 nucleotides

Question 19

Which ADDITIONAL protein is used to twist the Beads-on-a-String form of Chromatin into 30nm fibre?

Answer 19

H1

Question 20

What structure are chromatin loops attached?

Answer 20

Nuclear Scaffold

Question 21

What is active DNA and highly packaged SILENT DNA known as?

Answer 21

Active - Euchromatin

Silent - Heterochromatin

Question 22

What is MAXIMUM level of DNA packaging possible?

Answer 22

10 000

Question 23

Nuclear Envelope consists of 2 membranes (inner and outer) which meet at nuclear PORES.

True or false?

Answer 23

TRUE

Question 24

Which type of cytoskeletal element support the nuclear envelope?

Answer 24

Intermediate filaments /

Nuclear Lamina

Question 25

Label diagram of Nuclear Pore Complex A ( squiggly things poking out top) B ( green thing holding on) C (blue squiggly things coming out bottom of opening)

Answer 25

A - Cytoplasmic Fibrils B- Central ring / Transporter C - Nuclear Basket

Question 26

Nuclear pores regulate the flow of ALL molecules into OR out of nucleus. True or false?

Answer 26

False

Question 27

Nuclear Localisation Signals are REMOVED from proteins after they have been transported INTO nucleus. True or false?

Answer 27

False

Question 28

Nuclear import receptors are called… and export receptors are called…

Answer 28

Importins Exportins

Question 29

What statement about Nuclear Localisation Signals (NLSs) is FALSE?

Answer 29

NLSs are removed on entry of the protein into the nucleus.

Question 30

Lopped domains are directly involved in…

Answer 30

Packaging Chromatin in chromosomes

Question 31

Core nucleosomes consist of the following histones:

Answer 31

2 EACH of H2A, H2B, H3, H4

Question 32

What fold level of packaging does the ‘beads-on-a-string’ form of CHROMATIN cause?

Answer 32

3