RNA transcription and gene expression regulation

Question 1

what is transcription

Answer 1

synthesis of RNA under the direction of DNA

Question 2

what is translation

Answer 2

synthesis of protein under the direction of RNA

Question 3

DNA -> ….. ->

Answer 3

RNA
protein

Question 4

what is gene expression

Answer 4

process by which info from gene used in synthesis of a functional gene product

Question 5

what is a gene

Answer 5

segment of DNA containing instruction for making a particular protein or RNA molecule

Question 6

genes are …… ….

Answer 6

transcriptional units

Question 7

genes are composed of:

Answer 7

structural info coding for a protein or RNA molecule
regulatory sequences (control elements) giving instructions for expression - promoter + enhancers

Question 8

genome contains …

Answer 8

all the genetic info

Question 9

..% of the genes are coding

Answer 9

2%

Question 10

..% of the genes are non-coding

Answer 10

98%

Question 11

what are enhancers

Answer 11

regulatory sequences
both upstream and downstream from transcription start site
fine tune transcription regulation - responsible for tissue-specific transcription

Question 12

what are the 4 types of RNA

Answer 12

mRNA
tRNA
rRNA
snRNA

Question 13

describe mRNA

Answer 13

messenger RNA
encodes amino acid sequences of a polypeptide

Question 14

tRNA

Answer 14

transfer RNA
brings amino acid to ribosomes during translation

Question 15

rRNA

Answer 15

ribosomal RNA
ribosomal proteins makes up the ribosomes
the organelles that translate the mRNA

Question 16

snRNA

Answer 16

small nuclear RNA
with proteins, forms complexes that are used in RNA processing in eukaryotes

Question 17

describe transcription

Answer 17

• RNA polymerase recognises the promoter and begins transcription
• pre-mRNA is synthesised in a 5’ to 3’ direction
• as the polymerase moves along the DNA template the RNA is released and the DNA helix reforms
• once the polymerase hits the terminator sequence it STOPS and the full pre-mRNA transcript is released

Question 18

RNA is … …. …. …

Answer 18

single stranded ribonucleic acid

Question 19

RNA is made from a ….

Answer 19

ribose

Question 20

what are the 3 types of transcriptional control

Answer 20

regulatory sequences
regulatory proteins
chromatin sequences

Question 21

what are the post-transcriptional control

Answer 21

5’ capping
3’ poly-adenylation
RNA splicing
transport to cytoplasm + stability

Question 22

one gene has many …. = ….. ….

Answer 22

mRNAs
many proteins

Question 23

alternative splicing can be in a …-.. …. or … … ….

Answer 23

pre-B cell
mature B cell

Question 24

cell-type specific expression

Answer 24

= different proteins from the same gene

Question 25

describe gene expression

Answer 25

each cell expresses only a small fraction f it genes at a given time
which genes expressed = controlled on many levels, from which transcriptional control is predominant
gene expression controlled to reflect differentiation
cells constantly switch on/off genes = response to env signals
housekeeping = proteins needed by all cells
specialised proteins not essential for cell viability - are essential for organism

Question 26

what % of genes are expressed by the cell at a given time

Answer 26

3-5%

Question 27

what is a promoter

Answer 27

DNA sequence on the upstream from start of transcription
where general transcription factors bind
allow RNA polymerase to initiate transcription

Question 28

is the coding strand used as a template

Answer 28

no

Question 29

the coding strand is identical to what

Answer 29

the sequence to the mRNA
except all of the U’s + T’s

Question 30

what is the template strand used as

Answer 30

a template in the synthesis of mRNA

Question 31

RNA is single stranded ribonucleic acid that can form …. …..

Answer 31

hairpin structures

Question 32

what is RNA splicing

Answer 32

RNA processing removes introns and exons are spliced together
into a translatable RNA = mRNA