Chapter 11

Question 1

What is the simplified central dogma?

Answer 1

DNA -> transcription -> RNA -> translation -> PROTEIN

Question 2

What is a phenotype v.s. genotype?

Answer 2

Phenotype: the trains that can be observed
Genotype: specific genes that is expressed under specific conditions

Genotypes determines phenotype

Question 3

What is the patterns of gene regulation/expression

Answer 3

Gene regulation/expression is in response to different environmental conditions. The modifications of genes is key to evolution and is about acclimation (physiological response)

Question 4

What are the building blocks for DNA?

Answer 4

dNTP!!! Deoxyribonucleotide triphosphate!!!

when incorporated in growing DNA strand, 2 end phosphate groups cleave,transfering energy to sugar phosphate bond.

Question 5

What is DNA polymerase?

Answer 5

DNA polymerase: Copies the DNA
** Synthesis of NEW strand from 5’ -> 3’ **

REQUIRE:
- a primer (DNA or RNA strand)
- dNTPs

Question 6

DNA replication (EUKARYOTES): START

Answer 6

Start: Origin of Replication
- Topoisomerase II relaxes supercoiled chromosomes and 2 replication forks form.
- Helicase separates DNA strands (coated by single-strand binding proteins to keep strands separated)
- 2 replication forks move in opposite directions.

Question 7

DNA replication (EUKARYOTES): LEADING STRAND
MOVES IN 5’ -> 3’ DIRECTION!!!

Answer 7

1. Primase (RNA primer) attaches to the 3’ end on the template strand making it the 5’ end of the primase. Primase synthesizes a short ssRNA oligonucleotide with sequence complementary to the template strand.
2. DNA Polymerase III attaches to Primase to synthesize new DNA strand
3. NEW STRAND synthesized from 5’ -> 3’ WHILE DNA POL III moves in the template strand from 3’ -> 5’. Has a sliding clamp in front of DNA pol III. Hybrid DNA:RNA molecule created.

New strand is uninterrupted and follows replication fork. making it the LEADING strand*

Question 8

DNA replication (EUKARYOTES): LAGGING STRAND
MOVES IN 5’ -> 3’ DIRECTION!!!

Answer 8

STARTS: same as leading, RNA primase synthesizes RNA primer, hybridizing w/ssDNA.
1. @ ssDNA:ssRNA region DNA polymerase III starts synthesizing
2. DNA pol III will reach previous RNA:DNA hybrid molecule and stop there.
3. Seconds strand of DNA is synthesized as multiple RNA:DNA molecules -> Okazaki fragments
4. DNA pol III detaches and is replaced by DNA pl I at the 3’ end of the Okazaki fragment
5. DNA pol I continues the synthesis of the DNA while digesting the RNA primer at the 5’ end of the Okazaki fragment located downstream (DNA pol I can remove the RNA but cant remove the DNA, when reaches DNA region of Okazaki fragment it stops)
6. Strands are connected by DNA ligase

Question 9

Eukaryotic chromosomes are…

Answer 9

Typically linear and has multiple origins of replication