Nucleic acid and inheritance

Question 1

Chargaffs rule?

Answer 1

DNA base composition varies among species but the percent of AT and GC have roughly equal in percentage.

Question 2

Purines?

Answer 2

Adenosine and Guanine

Question 3

Pyrimidines?

Answer 3

Thymine and Cytosine

Question 4

Semiconservative model?

Answer 4

The DNA replication since each of the 2 daughter strands will have an old strand and one new strand.

Question 5

Somatic cell?

Answer 5

Has 46 DNA molecules in the nucleus consisting of 1 long DNA molecule per chromosome

Question 6

Important in replication?

Answer 6

ORI
Bubble
Replication fork

Question 7

Helicase?

Answer 7

Untwist the double helix @ the replication forks and makes them available as template strands.

Question 8

Primase?

Answer 8

To initiate the synthesis a primer is paired up to a template strand and the new strand will start from the 3’ end of the primer by DNA Pol in 5’–>3’ direction.

Leading strand and lagging strand - okazaki fragments and DNA-ligase.

Question 9

Proofreading?

Answer 9

1 / 10^10 error rate by DNA Pol.

Question 10

Mismatch repair?

Answer 10

Other enzymes remove and replace incorrectly paired nucleotides.
¨
Nuclease cut out the damage parts and DNA Pol and Ligase fills in gaps using the undamage strand as template.

Nucleotide excesion repair

Question 11

Shorter DNA?

Answer 11

Because it gets shorter every time replication has occured and the length is then restored by telomerase in the germ cells.

Question 12

DNA and mitosis?

Answer 12

Complex of nucleotides and chromatin and during the preparation for mitosis the chromatin condenses and can be visible in a microscope.

Heterochromatin - in the interphase

Euchromatin - Looser packaging of DNA and allows transcription