Nucleic acids, DNA, RNA, replication and transcription

Question 1

what is RNA processing?

Answer 1

modifying RNA in the nucleus

Question 2

what are the four basic synthetic genetic processes?

Answer 2

translation, transcription, RNA processing and replication

Question 3

what are the differences between purines and pyrimidines?

Answer 3

purines have two rings but pyrimidines have one

Question 4

examples of purines?

Answer 4

adenine and guanine

Question 5

examples of pyrimidines?

Answer 5

cytosine, thymine, uracil

Question 6

what are the characteristics of DNA?

Answer 6

hydrogen bonds hold the bases together
has a phosphodiester backbone
major and minor grooves

Question 7

what is the point in the grooves?

Answer 7

to allow factors to interact with the DNA during replication and transcription

Question 8

what are nucleosomes?

Answer 8

they have 8 highly basic proteins called histones

Question 9

what does DNA do to nucleosomes?

Answer 9

DNA wound around nucleosomes

Question 10

what is the centromere?

Answer 10

on chromosomes responsible for separating chromosomes to form two daughter cells

Question 11

what is the telomere?

Answer 11

protects the structure of the chromosome but is non-coding

Question 12

what is the role of nucleosomes?

Answer 12

‘Nucleosomes have a role in regulation of gene expression, or activity, by determining whether the DNA sequences can be accessed by transcription factors’

Question 13

what are the properties of RNA?

Answer 13

joined by 3’ to 5’ phosphodiester bonds
folds and base-pairs with itself to form tertiary structures
sometimes catalyses reactions

Question 14

what does the messenger RNA do?

Answer 14

‘Carries genetic information from DNA to the cytoplasm for translation into proteins’

Question 15

name two intracellular chemical signalling moelcules?

Answer 15

Cyclic adenosine monophosphate (cAMP) and guanosine monophosphate (cGMP)

Question 16

what is the role of transfer RNA?

Answer 16

clover leaf shape
carries amino acids to be assembled into proteins
inosine is important for the function of tRNA

Question 17

what is Guanosine triphosphate (GTP)?

Answer 17

an energy source for cells

Question 18

where is energy stored in ATP and GTP?

Answer 18

the covalent bonds that links the three phosphates

Question 19

what is the process of DNA replication?

Answer 19

starting at RNA primer, DNA polymerase copies DNA template strand from 3’ to 5’ direction forming a new strand in 5’ to 3’ direction
because DNA is antiparallel DNA is replicated continuous and lagging strand
after replication the RNA primers removed and okazaki fragments ligated together

Question 20

what is the job of DNA primase?

Answer 20

synthesises RNA primers needed for DNA replication,

Question 21

what enzyme unwinds DNA helix

Answer 21

Helicases and topoisomerases

Question 22

what is the job of DNA ligase?

Answer 22

to join DNA ends

Question 23

what is exonuclease activity?

Answer 23

removes errors in DNA replication

Question 24

what enzyme makes RNA primers?

Answer 24

primase

Question 25

what does mRNA processing include?

Answer 25

splicing out introns, 5′ end capping, and the addition of a poly(A) tail

Question 26

what does Pol II do?

Answer 26

DNA transcribed into RNA

Question 27

what does Pol I do?

Answer 27

transcribes ribosomal RNA

Question 28

what does Pol III do?

Answer 28

transcribes transfer RNA

Question 29

difference between RNA polymerase and DNA polymerase?

Answer 29

don't require primer don't have 3′-to-5′ exonuclease activity

Question 30

how and why is a transcription bubble created?

Answer 30

opening DNA helix to give access to proteins to regulate transcription

Question 31

how is transcription initiated?

Answer 31

promotor region

Question 32

what are promotor regions?

Answer 32

sequences in DNA that determine where RNA polymerase should bind for transciption

Question 33

how is the rate of transcription initiation effected?

Answer 33

DNA-binding proteins with RNA polymerase

Question 34

what is TFIID?

Answer 34

'TFIID consists of TATA binding protein (TBP) which binds to the TATA box'

Question 35

what do enhancers and response elements do?

Answer 35

Enhancers and response elements regulate gene expression

Question 36

what direction is DNA template and RNA transcript copied?

Answer 36

'The DNA template is copied in the 3′-to-5′ direction and the RNA transcript is synthesized in the 5′-to-3′ direction'