DNA and RNA synthesis

Question 1

what is static

Answer 1

genome

- every cell in our body has a copy of the same genome

Question 2

a cell is

Answer 2

dynamic
repsonds to external conditions
most cells follow a cell cyle of division

Question 3

psuedogenes

Answer 3

related to real genes

contain biological and evolutionary histories within their sequences

Question 4

what is junk DNA used for

Answer 4

1) Landing sports for proteins that influence gene activity
2) Strands of RNA with myriad roles
3) Places where chemical modifications silence stretches on chromosome

Question 5

what is gene regulation infleunced by

Answer 5

multiple stretches of regualtory DNA

- non coding RNA

Question 6

what does mRNA do

Answer 6

contains info to make one single polypeptide chain

Question 7

DNA bases

Answer 7

adenine
guanine
cytosine
thymine

Question 8

RNA bases

Answer 8

adenine
guanine
cytocine
uricil

Question 9

uricil vs thyine

Answer 9

simular structure
both bind to adenine via hydrogen bonds
identical shapes where it matters

Question 10

transcription deficnition

Answer 10

process where information in a gene in a DNA strand is is transferred to an RNA molecule

Question 11

2 strands in transcripton

Answer 11

coding strand

template strand

Question 12

types of RNA

Answer 12

mRNA
tRNA
non coding RNA
small nuclear RNA
small nucleoalr RNA
micro RNA

Question 13

which RNA regulate expression

Answer 13

non coding RNA
small nuclear RNA
small nucleoalr RNA
micro RNA

Question 14

mRNA

Answer 14

different sizes reflecting size of polypeptide

needed by all cells, spefcif for types of cells

Question 15

rRNA

Answer 15

build ribosomes, (requried for synthesising protiens by trnaslating mRNA

Question 16

different kinds and eukaroytes of rRNA and their purpose

Answer 16

18s
- make up small subunit of riosome alongside other protiens
28s
5.8s
5s
- one of these with45 other protiens make up the large subunit

Question 17

what is the s related to in eukaryotes

Answer 17

sedimentation rate, related to mass and shape

Question 18

tRNA

Answer 18

each has 20 aa at 3’ end

Question 19

fucntion of non coding RNA

Answer 19

modify protien levels by mechanisms independant of trnascrpiton
- ncRNA play major roles in cellular physiology, development,
metabolism and are implicated in disease process

Question 20

what are small nucelar RNA part of

Answer 20

spilceosome

Question 21

what is transcription

Answer 21

process where information in a gene in a DNA strand is transferred to an RNA molecule§

Question 22

what does RNA polymerase do

Answer 22

picks the correct DNA strand and finds the start

Question 23

what are the 3 types of eukaryotes

Answer 23

1) Polymerase I
- Nucleolar region of nucleus
- transcribes large ribosomal RNA
2) Polymerase II
- mRNA precursors
3) Polymerase III
- small RNAs (tRNA)
- regulatory RNAs

Question 24

polymerase II

Answer 24

• composed of several subunits
• requires several accessory proteins
• All added to the complex in a defined order to initiate and carry out transcription
  Enzyme wraps around both strands
• big enough to enclose both the promotor and beginning of the gene

Question 25

enhancers and promotors

Answer 25

DNA sequences which can control efficiency and rate of transcription
- found on the same molecule as the gene, referred to as cis acting elements as they’re on the same side

Question 26

promotor

Answer 26

necessary to start transcription

- usually on the 5’ side of gene to be transcribed

Question 27

activators

Answer 27

proteins that facilitate looping

Question 28

repressors

Answer 28

inhibit looping

Question 29

what happens during transcription steps

Answer 29

• unwinds DNA
• Splits them apart
• bubble moves down the DNA, closing up once the RNA has been produced
• RNA polymerase moves down the gene
• Places a cap* on the 5’ end to stabilise the mRNA
• alternative splicing can occr
• PolyA tail on the 3’ end added

Question 30

capping

Answer 30

Takes place during transition from transcription initiation and elongation

• protects from degradation
• serves as assembly point for proteins needed to recruit small subunit of ribosomes to begin translation

Question 31

alternative spilcing

Answer 31

• alternative selection of splice sites within pre mRNA

- leads to production of different mRNA isoforms of a gene

Question 32

what do splicoesomes regonsei

Answer 32

borders between introns and exons

Question 33

types of splicosomes

Answer 33

major and minor (remove only 0.5%)

Question 34

function of spliceosome

Answer 34

1) Recognition of intron/exon boundaries

2) Catalysis of cut and paste reactions which remove non coding introns and stitch flanking exons back together

Question 35

mutations of a spliceosome

Answer 35

• mis splicing =rapid degermation of mRNA

- mis regulation of splicing factor levels (cancer)

Question 36

what do small nucleolar RNA do

Answer 36

• help make ribosomes by cutting large precursors of eg 28s
• also implicated in alternative splicing of pre-mRNA
• template for synthesis of telomers

Question 37

micro RNA

Answer 37

• regulate gene function post transcriptionally
• bind to mRNA and cause degradation (inhibits protein synthesis)
• 18-25 nucleotides
• involved in regulation of developmentally timed events
• exhibit tissue specific expression
• implicated in cancer development