gene expression and nucleic acids

Question 1

what is a nucleic acid?

Answer 1

DNA and RNA

Question 2

What are the monomers of nucleic acids?

Answer 2

nucleotides

Question 3

what are the polymers

Answer 3

DNA or RNA

Question 4

what is the structure of DNA?

Answer 4

double stranded, bases A T C and G, deoxyribose sugar and phosphates

Question 5

what is mRNA

Answer 5

takes a copy of a genetic code that encodes for a specific protein to the ribosome

Question 6

what is tRNA

Answer 6

brings an amino acid to ribosome through a complementary anti-codon to the mRNA’s codon

Question 7

what is rRNA?

Answer 7

ribosomal RNA, forms a ribosome along with other proteins

Question 8

what is the general structure of a nucleotide?

Answer 8

phosphate group, deoxyribose/ribose sugar and a nitrogenous base

Question 9

what is condensation polymerisation?

Answer 9

used to join amino acids by creating a peptide bond through the creation of a water molecule from a hydroxyl group on the 3’ end and a hydrogen from the 5’ end of another amino acid

Question 10

what is the anti parallel nature of DNA?

Answer 10

one strand runs 5’ - 3’ with the 5’ carbon pointing up while the other runs 3’ - 5’ with the 5’ carbon pointing downwards (opposite directions)

Question 11

what does it mean why the genetic code is universal?

Answer 11

all organisms contain the same 4 bases that make up DNA, meaning all amino acids are coded for by the same codons in all organisms

Question 12

what does it mean by the genetic code is degenerate

Answer 12

a single amino acid can be coded for by more than one codon

Question 13

what are the steps of transcription or translation?

Answer 13

initiation, elongation and termination

Question 14

what does initiation do in transcription?

Answer 14

RNA polymerase (transcription factor) binds to the promoter region and unwinds and unzips the DNA, breaking the hydrogen bonds and exposing nitrogenous bases

Question 15

what does elongation do in transcription?

Answer 15

free nucleotides are added in a 5’ to 3’ direction as the RNA polymerase moves along (DNA recoils after polymerase has passed)

Question 16

what is termination in transcription?

Answer 16

where transcription ends when RNA polymerase reaches the termination site (stop triplet), chemicals are released causing polymerase to detach

Question 17

what are the three steps of RNA processing?

Answer 17

methyl cap, poly-a-tail and splicing

Question 18

what is a methyl cap?

Answer 18

added to 5’ end of pre-mRNA

Question 19

what is a poly-a-tail?

Answer 19

added to the 3’ end of the pre-mRNA molecule, increases stability and prevents degrading

Question 20

what is splicing?

Answer 20

a spliceosome removes introns and joins exons together

Question 21

what is alternative splicing?

Answer 21

the removal of different exons to give arise to different proteins

Question 22

what is initiation in translation?

Answer 22

ribosome attaches to the 5’ end of mature mRNA and moves along until it reaches the AUG start codon when the corresponding tRNA will bring the amino acid met

Question 23

what is elongation in translation?

Answer 23

the ribosome continues reading and the tRNA bring corresponding amino acids, they join the growing polypeptide chain via condensation polymerisation

Question 24

what is termination in translation?

Answer 24

the ribosome reaches a stop codon where it detaches

Question 25

what is the structure of a gene?

Answer 25

promoter region - where transcription factors bind
exons and introns
stop and start triplets

Question 26

what are proteins made of

Answer 26

amino acids - monomer

Question 27

what is the structure of an amino acid?

Answer 27

amino group, acid (COOH), hydrogen and an r group which varies depending on the amino acie

Question 28

what is the primary structure

Answer 28

the linear sequence of amino acids

Question 29

what is the secondary structure?

Answer 29

random coiling, alpha helix and beta pleated sheets (hydrogen bonds)

Question 30

what is the tertiary structure

Answer 30

the total irregular folding of the 3D protein (hydrogen bonds, ionic and covalent bonds)

Question 31

what is the quaternary structure?

Answer 31

two or more polypeptide chains interacting to form a functional protein

Question 32

when is a protein deemed biologically functional?

Answer 32

tertiary