Genomics structure and function of the human genome

Question 1

What is the short and long arm in chromosmes?

Answer 1

1. p arm is the short arm
2. q arm is the long arm

Question 2

What are the 4 types of chromosomes and what does it depend on?

Answer 2

Depends on where the centromere:
1. Metacentric
2. Sub-metacentric
3. acrocentric
4. telocentric

Question 3

What are the 3 key features scientists use to identify chromosomes?

Answer 3

1. Size
2. Banding pattern
3. Centromere position

Question 4

What do chromosomes usually exist as?

Answer 4

Usually exist as chromatin

Question 5

What is DNA double helix bound to?

Answer 5

DNA double helix bounds to histones

Question 6

What forms nucleosome?

Answer 6

Octamer of histones form nucleosome

Question 7

What histones are present in the octamer that forms the nucleosome?

Answer 7

1. 2x(H2A, H2B, H3 and H4)

Question 8

What is histone H1 for in nucleosome?

Answer 8

H1 binds to these nucleosomal core particles close to the DNA entry and exit sites and protects the free linker DNA

Question 9

What is euchromatin?

Answer 9

Extended state, dispersed through nucleus

Question 10

What does euchromatin allow in terms of gene expression?

Answer 10

Allows gene expression

Question 11

What state is heterochromatin and hows the gene expression like?

Answer 11

Highly condensed, genes not expressed

Question 12

Steps in compaction of chromosome

Answer 12

Chromosome –> chromatin fiber –> histones –>Beads on a string(DNA wound on nucleosomes)–> double helix

Question 13

What do centromeres keep together?

Answer 13

Keep sister chromatids together

Question 14

What do centromeres attach to?

Answer 14

Attach to microtubules during cell division

Question 15

What are centromeres rich in?

Answer 15

Rich in heterochromatin

Question 16

What is the repetition like in centromeres?

Answer 16

Highly repetitive

Question 17

What do telomeres protect?

Answer 17

Telomeres protect the ends of the chromosomes

Question 18

What does telomerase repair?

Answer 18

Telomerase repairs telomeres
but is only active in certain cell
types

Question 19

What can telomerase being activated in the wrong cell lead to?

Answer 19

If telomerase is switched on in
the wrong cells this can lead to
cancer

Question 20

What are protein-coding genes known as?

Answer 20

Exomes

Question 21

What do exons code for?

Answer 21

code for amino acids except for Untranslated Regions (5’UTR & 3’UTR)

Question 22

What do UTR contain and what is it important for?

Answer 22

contain regulatory elements (important for control of protein synthesis)

Question 23

What are introns?

Answer 23

non-coding section of gene between exons

Question 24

What is the promoter region?

Answer 24

5’ of gene; contains important regulatory
elements for transcription

Question 25

How many autosomes and sex chromosomes are there in the nuclear genome?

Answer 25

-22 pairs of autosomes -1 pair of sex chromosomes

Question 26

What are transcribes units in the nuclear genome also known as?

Answer 26

Genes

Question 27

How many bases are in the mitochondrial genome?

Answer 27

16Kb

Question 28

What does the D-loop in the mitochondrial genome contain?

Answer 28

Contains promoters for light and heavy strands

Question 29

How many coding genes are there in mitochondrial genome?

Answer 29

13 coding genes

Question 30

How many non-coding genes are there in the mitochondrial genome?

Answer 30

24 non-coding genes

Question 31

What type of inheritance is mitochondria and why?

Answer 31

Maternal inheritance -This is because only OVA provide mitochondria

Question 32

What are the purines in DNA?

Answer 32

-Adenine -Guanine

Question 33

What are the pyrimidines in DNA?

Answer 33

-Cytosine -Thymine

Question 34

What is the epigenome and what are examples?

Answer 34

-Chemical compounds that attach to DNA or histones and can affect gene activity -E.g. DNA methylation, histone acetylation

Question 35

How does the epigenome affect gene activity?

Answer 35

* Alter chromatin structure * Recruit histone modifiers * Repress transcription * Genome-wide pattern established at fertilisation * Important for differential gene expression (transcription) * Responds to environmental cues (cellular and external)

Question 36

What is gene expression controlled by?

Answer 36

Controlled by DNA sequence and epigenome

Question 37

What is differential gene expression in time?

Answer 37

* Development (i.e. embryos versus adults) * In response to hormones, infection, other signals

Question 38

What is spatial differential gene expression?

Answer 38

Different tissues/cells express different genes (e.g. brain vs liver)

Question 39

What can a failure to regulate gene expression tightly lead to in metabolism?

Answer 39

Metabolic disease

Question 40

What can failure to regulate gene expression tightly lead to in cell shape/motility?

Answer 40

Metastasis

Question 41

What can failure to regulate gene expression tightly in cell differentiation?

Answer 41

Congenital disorders