Chromosomes

Question 1

What is a chromatid?

Answer 1

Chromatid are each side of a chromosome shared by a centromere.

Question 2

What is a chromosome?

Answer 2

Chromosome is a genetic material made of compact chromatin, containing all of an organisms genetic information.

Question 3

Euchromatin vs Heterochromatin?

Answer 3

Both sections of chromosomes. Euchromatin is an open structure with many active genes which can be transcribed. Heterochromatin is tightly condensed structure with many silenced genes which cant be transcribed

Question 4

Which part of a chromosome are euchromatin or heterochromatin?

Answer 4

Telomere and centromere are heterochromatin. middle of each chromatid are euchromatin

Question 5

How much of our total genome is protein coding?

Answer 5

2%

Question 6

Which non-coding parts of our DNA are important?

Answer 6

Centromeres and telomeres

Question 7

What is satellite vs mini-satellite DNA?

Answer 7

Satellite DNA is highly repeated DNA sequences, found in telomeres and centromeres. Minisatellite has far more repeats which mutate a lot and are used for DNA fingerprinting

Question 8

What is the structure of chromatin? add charges

Answer 8

negatively charged DNA wrapped around positively charged histone proteins. forms scaffold complex and eventually forms chromosome. This means it takes up less space

Question 9

What is the structure of a chromosome?

Answer 9

shorter P arm and Q arm with a centromere

Question 10

What are the 3 positions that centromeres may be found in?

Answer 10

Metacentric is in middle of p and q. Sub-metacentric is not in centre. Acrocentric is so far from centre that p arm has no functional DNA

Question 11

What is a karyotype? How is it arranged?

Answer 11

An individuals entire set of chromosomes, from analysis of blood. Its arranged in terms of positioning of centromere (meta, sub-meta or acrocentric)

Question 12

What are FISH probes?

Answer 12

fluorescent in-situ hybridisation is using a fluorescent dye to attach to certain parts of DNA on chromosomes to detect mutations

Question 13

What is X-Inactivation?

Answer 13

Process that occurs in females where one X chromosome is inactivated and packaged into heterochromatin structure, as we only need 1.

Question 14

What are some recessive conditions?

Answer 14

Sickle cell anemia and Cystic Fibrosis

Question 15

What are some dominant conditions?

Answer 15

Achondroplasia and huntngtons disease

Question 16

What are some X linked conditions?

Answer 16

Colour blindness, haemophilia. Far more common in men

Question 17

Who is mitochondrial DNA inherited from?

Answer 17

Mother

Question 18

What is hemizygousity?

Answer 18

Having only one copy of genes, e.g. men having only one X chromosome. This means the X chromosome on males is hemizygous

Question 19

Homozygous vs heterozygous?

Answer 19

homozygous is having 2 identical alleles of a gene. Having 2 different alleles is heterozygous

Question 20

Which phase of cell cycle are chromosomes most visible?

Answer 20

Metaphase

Question 21

Which process has more cell divisions, oogenesis or spermatogenesis?

Answer 21

Oogenesis