Microbiolgy Lecture 11

Question 1

What is DNA made of?

Answer 1

sugars
nitrogenous bases
phosphate

Question 2

DNA replication is semi…

Answer 2

Semi conservative

Question 3

Describe DNA replication in E Coli

Answer 3

• It starts at ori where DnaA binds to ori and unwinds DNA
• It continues around in both directions
• Replication stops at terminator

Question 4

What is the coordination at replication fork?

Answer 4

1. Helicase unwinds parental DNA/ when enough DNA is unwound, primase synthesizes an RNA primer and lagging strand synthesis begins
2. Lagging strand generates Okazaki fragments
3. Core enzyme reaches okazaki and is released from DNA template
4. Another core enzyme moves in same direction as replication fork and synthesizes DNA

Question 5

What happens during transcription?

Answer 5

Process of making RNA copy of DNA sequence

- Carried out by RNA polymerase

Question 6

What happens during translation?

Answer 6

Reading or translation of mRNA to generate protein

- Carried out by ribosomes

Question 7

What are the parts of RNA synthesis by RNAP

Answer 7

Promoter
Termination
Signma

Question 8

What is promoter?

Answer 8

DNA sequence that is recognized by sigma

Question 9

What is terminator?

Answer 9

Sequence of DNA that signals the RNAP to stop transcribing

Question 10

What is sigma?

Answer 10

A subunit of RNAP that aids in promoter recognition

Question 11

Bacterial genes are often transcribed as what?

Answer 11

polycistronic mRNA

Question 12

Why are tRNAs important in translation

Answer 12

They read mRNA to add correct amino acid to polypeptide chain

Question 13

What carries out translation?

Answer 13

Ribsomes

Question 14

Ribosomes are made of what?

Answer 14

RNA and protein

Question 15

What S are ribosome?

Answer 15

70s (30s + 50s)

Question 16

Ribsomes use .. rRNA

Answer 16

16s rRNA

Question 17

Why are 16s important in ribosomes?

Answer 17

They recognize shine dalgarno sequence and important for ribosome structure

Question 18

what reads the genetic code?

Answer 18

tRNA

Question 19

The ribosome binding site is also known as what?

Answer 19

Shine Dalgarno sequence

Question 20

What are the parts of the process of translation?

Answer 20

Intitation
Elongation
Termination

Question 21

What happens during translation

Answer 21

1. The tRNA base pairs with start codon and occupies p site
2. A tRNA that recognizes next codon fills unoccupied A site
3. The ribosome catalyzes the joining of amino acid carried by the tRNA in the p site to the one carried by tRNA in the A site

Question 22

What happens during Elongation?

Answer 22

• The ribosome advances a distance of one codon/ A tRNA that recognizes the next codon quickly fills the empty A site
• The ribosome continues advancing along the mRNA in 5’ to 3’ direction

Question 23

What happens during termination?

Answer 23

• Translation continues until a stop codon is reached, signaling the end of the process
• The components disassemble

Question 24

Which happens first? Transcription or translation

Answer 24

They occur simultaneously