RNA

Question 1

what is the central dogma

Answer 1

explanation of the flow of genetic information within a biological system

Question 2

which is more unstable and more prone to degradation, RNA or DNA

Answer 2

RNA because of the presence of the -OH group in

ribose sugar

Question 3

where is RNA found

Answer 3

nucleus, mitochondria and cytoplasm

Question 4

how many structures does RNA have

Answer 4

4. primary, secondary, tertiary and quaternary

Question 5

what subunits is bacterial enzymes composed of

Answer 5

two α, one β, one β’, one ⍵, one σ

Question 6

what is a holoenzyme

Answer 6

biochemically active compound formed by the combination of an enzyme with a coenzyme.

Question 7

give an example of a coenzyme and an enzyme forming a holoenzyme in bacteria

Answer 7

sigma factor and core enzyme

Question 8

what are the 4 functions of RNA

Answer 8

1. Storage/transfer of genetic information
2. Structural
3. Catalytic
4. Regulatory

Question 9

give three examples of single stranded RNA viruses

Answer 9

ebola, influenza and rhinovirus

Question 10

what is an example of double stranded RNA viruses

Answer 10

Rotaviruses, which cause severe gastroenteritis

Question 11

RNA in ribosome has …………..activity

Answer 11

peptidyltransferase

Question 12

what are small RNA enzymes called

Answer 12

ribozymes

Question 13

what are the regulatory roles of RNA

Answer 13

• defense
• in normal development
• gene therapy

Question 14

what do microRNAs do

Answer 14

regulate the expression of genes, possibly via binding to specific nucleotide sequences

Question 15

which RNA has frequent turnover

Answer 15

mRNA

Question 16

mRNA has long generation time. true or false

Answer 16

false, it is short

Question 17

which parts code for genes and dont, introns and exons

Answer 17

introns dont code while exons do

Question 18

why does eukaryotic mRNA have longer half-life than a prokaryotic mRNA

Answer 18

because it undergoes additional steps

Question 19

how longer does eukaryotic mRNA last than that of e coli

Answer 19

that of e coli lasts a few seconds while eukaryotic lasts several hours

Question 20

what are pre-RNAs first coated with

Answer 20

RNA-stabilizing proteins which protect from degradation while being processed

Question 21

what does pre-mRNA receive before being translated

Answer 21

(i) a 5′ cap and
(ii) a 3′ poly (A) tail before
(iii) introns are removed

Question 22

what is the name of the 5’ cap

Answer 22

7-methylguanosine cap

Question 23

what are the functions of the 5’ cap

Answer 23

protects from degradation and initiation factors recognize the cap to help initiate translation by ribosomes

Question 24

what cleaves off the rest of the pre-mRNA off the rest of the growing transcript before RNA Polymerase II has stopped transcribing

Answer 24

endonuclease -containing protein complex

Question 25

how does endonuclease-containing protein complex work

Answer 25

binds to an AAUAAA sequence upstream of the cleavage site and to a GU -rich sequence downstream of the cut site

Question 26

what catalyzes the addition of up to 200 A nucleotides to the 3′ end of the just-cleaved pre-mRNA

Answer 26

Poly (A) Polymerase (PAP)

Question 27

what does the poly A tail do

Answer 27

1. protects the mRNA from degradation, 2. aids in the export of the mature mRNA to the cytoplasm, 3. involved in binding proteins involved in initiating translation

Question 28

what is a spliceosome

Answer 28

large and complex molecular machine found primarily within the nucleus of eukaryotic cells

Question 29

what does a spliceosome do

Answer 29

removes introns from a transcribed pre-mRNA

Question 30

tRNA is double stranded, true or false

Answer 30

false, it is single stranded

Question 31

what are the two structural motifs that allow tRNA to function

Answer 31

1) 3’ terminus (which forms a covalent bond with a specific amino acid) 2) anticodon loop (contains three-base-pair sequence complimentary to the DNA triplet code for an amino acid)

Question 32

what is the most abundant form of RNA

Answer 32

ribosomal RNA

Question 33

what does S stand for in 80S

Answer 33

stands for svedbergs, a unit used to measure how fast molecules move in a centrifuge

Question 34

what does snRNA stand for

Answer 34

Small nuclear RNAs

Question 35

what is the primary function of snRNAs

Answer 35

process pre-mRNA

Question 36

what are snoRNAs and what is their function

Answer 36

Small nucleolar RNA, which guide chemical modifications of other RNAs

Question 37

what binds with the PIWI subfamily proteins that are involved in maintaining genome stability in germline cells

Answer 37

Piwi-interacting RNAs

Question 38

what is another function of Piwi-interacting RNAs

Answer 38

play a role in gametogenesis

Question 39

what RNA species mediate post-transcriptional gene | silencing

Answer 39

micro-RNA (it regulates translation)

Question 40

what is lncRNA in full

Answer 40

Long noncoding RNAs

Question 41

some ....... are capable of regulating cancer-associated genes in ways that facilitate tumor development

Answer 41

micro-RNA

Question 42

dysregulation of mirco-RNA metabolism can lead to what

Answer 42

linked to various neurodegenerative diseases, including Alzheimer disease

Question 43

what type of RNA binds to specialized proteins known as caspases, which are involved in apoptosis (programmed cell death) hence inhibiting cell death leading to cancer

Answer 43

tRNA

Question 44

what do tRNA-derived fragments (tRFs) play a role in

Answer 44

suspected to play a role in cancer

Question 45

what has increase in MALAT1 (metastasis associated lung adenocarcinoma transcript 1) been associated with

Answer 45

proliferation and metastasis (spread) of tumour cells

Question 46

what does sequestering of RNA binding proteins (RBPs) by RNAs containing repeat sequences lead to

Answer 46

formation of foci or aggregates in neural tissues leading to amyotrophic lateral sclerosis (ALS) and myotonic dystrophy

Question 47

true or false, RNA has small grooves which makes it hard for enzymes to attack

Answer 47

false, that is for DNA. RNA is easily attacked by enzymes because of its large grooves