W1 L2 gene structure, organization and regulation

Question 1

Prokaryotic cell component

Answer 1

• plasma membrane
• DNA
• Ribosome
• Cell wall
• Flagelum

Question 2

Factors influencing genome size

Answer 2

! Genes
! Gene density (intergenic regions)
! Introns (size and number)
! Repeats

Question 3

How does our gene fit inside the nucleaus

Answer 3

It is structured to fit inside a nucleus
DNA is wrap in Optimus of histone which are folded upon itself, creating a condense section of chromosome
This affect the gene availability to be transcribe

Question 4

Nuclear structure

Answer 4

• Highly structured of active and repressed gene expression
  -DNA and associated proteins along side RNA

Question 5

Genes to Gene Products

Answer 5

The DNA is transcript into mRNA via RNA polymerase
mRNA is translated by the ribosome into protein

Question 6

RNA Polymerases in eukaryote, their shared and different structure

Answer 6

We use DNA dependent RNA polymerase
! Three kinds in eukaryotes, each have alpha and beta subunit or alpha like and beta like in eukaryote one
Shared common subunit
Each have additional enzyme specific subunit (1-5,2-4,3-7)

Question 7

Three fuction of the DNA polymerase

Answer 7

Question 8

mRNA

Answer 8

Messenger RNA code for protein

Question 9

rRNA

Answer 9

ribosomal RNA, forms basic structure of ribosome and catalyst protein synthesis

Question 10

tRNA

Answer 10

transfer RNA, centrals to protein synthesis as adaptor between mRNA and amino acids

Question 11

snRNA

Answer 11

small nuclear RNAs, fuction in a variety of nuclear process including slicing pre mRNA

Question 12

snoRNA

Answer 12

small nucleolar RNAs , use to chemically modify rRNA

Question 13

scaRNAs

Answer 13

Use to modify sno and sn

Question 14

miRNA

Answer 14

Micro RNA, regulate gene expression typically by blocking translation of selective mRNA. single stranded

Question 15

siRNA

Answer 15

Small inferring RNA, Turn off gene expression by directing edge radiation of selective mRNA and the establishment of compact chromatin structure. double stranded

Question 16

Transcription steps at class 2

Answer 16

! 1. Formation of the pre-initiation complex
2. Promoter melting separation of the two DNA strands
! 3. Initiation
! formation of the first phosphodiester bond in the nascent mRNA
! 4. Promoter clearance
! 5. Elongation
! 6. Termination

Question 17

what is involve in the Initiation of transcription

Answer 17

There are many elements that is involve in the initiation, these need to be present for decent transcription rate
Each promoter contains a subset of these elements
e.g. TATA and Inr
! Each element is recognized by a general transcription factor (GTF), not RNA pol II

Question 18

What happen when gene does not have promoter element

Answer 18

! These genes often are transcribed at low rates
! Are so-called housekeeping genes
! Have multiple transcription start points
! Contain CG-rich sequences (CpG islands)

Question 19

General Transcription Factor TFIID structure and fuction

Answer 19

Contains:
! TATA binding protein (TBP)
! TBP associated factors (TAFs)
! Binds core promoter elements and initiates assembly of the pre-initiation complex (TFIID, transcription factors and RNA Pol II) on the promoter

Question 20

Other General Transcription Factor

Answer 20

TF2B for accurate positioning
TF2F to stablise and TBP and TF2B, attract other TF
TF2 E attract and regulate TF2H
TF2H unwind DNA at start point and release RNA polymerase

Question 21

Core RNA pol complex and GTFs Of Genes transcribed by RNA Pol I

Answer 21

Recognises Upstream Control Sequence (UCS)
! Selective Factor SL1/TIF-1B include TBP as a component
! Upstream Binding Factor (UBF) recognises UCS
! Rrn3/TIF-IA recruit SL1/UBF to RNA pol

Question 22

Ribosomal RNA (rRNA) genes (except 5S – Pol III) Of Genes transcribed by RNA Pol I

Answer 22

! Repeated clusters of rDNA repeat unit
! Each is transcribed into a pre-rRNA precursor which is processed into 18S, 5.8S and 28S rRNAs
! Transcription occurs in the nucleolus (where ribosomes are assembled)