Chromosomes

Question 1

Are prokaryote chromosomes haploid or diploid?

Answer 1

haploid

Question 2

Do prokaryotes have nucleosomes?

Answer 2

No

Question 3

In eukaryotes, chromosomes are built from nucleoprotein particles called _______

Answer 3

nucleosomes

Question 4

Why are eukaryotic genes bigger than prokaryotic genes?

Answer 4

Introns

Question 5

In human genome, less than 2% encodes proteins. True or false?

Answer 5

True

Question 6

Each human cell contains approx 2m of DNA packaged into ___ chromosomes

Answer 6

46

Question 7

What are chromosomes made of?

Answer 7

Chromatin

Question 8

What is chromatin composed of?

Answer 8

50% DNA, 50% protein

Question 9

the main chromosomal proteins are histones. True or false?

Answer 9

True

Question 10

What are the 5 different types of histone proteins?

Answer 10

H1, H2A, H2B, H3 and H4

Question 11

Histones are acidic and have a negative charge. True or false?

Answer 11

False - they are basic and have a positive charge

Question 12

How do histones bind to DNA?

Answer 12

DNA has a negative charge, histones have a positive charge so they attract

Question 13

How many peptide chains does the nucleosome contain?

Answer 13

8

Question 14

What is meant by “the nucleosome has an octameric structure”?

Answer 14

Two of each H2A, H2B, H3 and H4

Question 15

What is the role of histone H1?

Answer 15

Helps to pack the nucleosome together

Question 16

Nucleosomes pack together to form an 11nm fibre. True or false?

Answer 16

False - pack together to form a 30nm fibre - the Solenoid model

Question 17

on a chromosome, what letter is given to the short arm?

Answer 17

p

Question 18

on a chromosome what letter is given to the long arm?

Answer 18

q

Question 19

After replication, the chromosome consists of two sister chromatids. What is the name given to the point at which the two chromatids join?

Answer 19

centromere

Question 20

What are the ends of a chromosome called?

Answer 20

telomeres

Question 21

What are chromosomes stained with to show their G banding pattern?

Answer 21

Giemsa

Question 22

Chromosomes are classified according to the position of the centromere. True or false?

Answer 22

True

Question 23

When the centromere is in the middle of the chromosome, what is the name given?

Answer 23

metacentric

Question 24

When the centromere is offset from the middle what is the name given to the chromosome?

Answer 24

sub-metacentric

Question 25

In a small chromosome, when the centromere is near the tip, what is the name given?

Answer 25

acrocentric

Question 26

There are 46 pairs of chromosomes. True or false?

Answer 26

False - there are 23 pairs of chromosomes (23 from mother, 23 from father)

Question 27

How many pairs of chromosomes are autosomes and how many are sex chromosomes?

Answer 27

22 pairs are autosomes and 1 pair are sex chromosomes

Question 28

What is karyotyping?

Answer 28

Diagnostic typing of nuclear contents

Question 29

In karyotyping, chromosomes are arranged in increasing size, meaning chromosome one is the smallest. True or false?

Answer 29

False - arranged in decreasing size therefore chromosome 1 is the biggest and has the most genes

Question 30

Which has fewer genes, the X or the Y chromosome?

Answer 30

Y

Question 31

What is the medical relevance of karyotyping?

Answer 31

It identifies chromosomal abnormalities

Question 32

What are the abnormalities that chromosomes can have?

Answer 32

Structural (difficult to detect) | Numerical

Question 33

What is meant by aneuploidy?

Answer 33

Abnormal number of chromosomes

Question 34

How is karyotyping used in pre-natal diagnosis?

Answer 34

Some chromosomal abnormalities can be identified by amniocentesis

Question 35

Down syndrome is a numerical aneuploidy known as ______

Answer 35

Trisomy 21

Question 36

Those who have Down syndrome have ___ copies of chromosome 21 instead of 2

Answer 36

3

Question 37

Incidence of having a child with Down Syndrome increases with age at which you have the baby. True or false?

Answer 37

True

Question 38

Karyotyping cannot be used for the diagnosis of malignant tumours. True or false?

Answer 38

False