DNA and RNA

Question 1

Central dogma

Answer 1

DNA contains information coded in the sequence of its base pairs, is transcribed into RNS, which is translated into a protein

Question 2

Nucleotide

Answer 2

A deoxyribose bonded to a phosphate group and nitrogenous base

Question 3

Purine

Answer 3

Adenine and guanine

2-ring base

Question 4

Pyrimidines

Answer 4

Cytosine and thymine

1-ring base

Question 5

Watson-Crick DNA model

Answer 5

Double-stranded helices of complementary strands with the sugar-phosphate chains on the backbone and nitrogenous bases on the inside forming hydrogen bonds in an antiparallel arrangement

Question 6

Base-pairing

Answer 6

T-A = 2 H bonds
C-G = 3 H bonds

Question 7

Topoisomerase

Answer 7

Unwind and separate DNA helix into 2 single strands

Question 8

DNA helicase

Answer 8

Breaks the hydrogen bonds between nitrogenous bases

Question 9

Replication fork

Answer 9

The opening in the double-stranded DNA

Question 10

Semiconservative replication

Answer 10

Each new daughter helix contains an intact strand from the parent helix and a newly synthesized strand

Question 11

DNA polymerase

Answer 11

Reads the parent DNA strand (3’ to 5’) and creates a complementary, antiparallel daughter strand (5’ to 3’)

Question 12

Leading strand

Answer 12

Continually synthesized

Question 13

Lagging strand

Answer 13

Synthesized discontinuously because the 5’ end of the parent strand is the one exposed

Question 14

Okazaki fragments

Answer 14

Short fragments of replicated DNA that result from discontinuous synthesis

Question 15

DNA ligase

Answer 15

Joins Okazaki framents

Question 16

Codons

Answer 16

Transcribed mRNA arranged into triplets

Translated into amino acids

Question 17

Redundancy

Answer 17

Amino acids have more than one codon coding for them

64 different codons possible for the triplet code but only 20 amino acids

Question 18

DNA

Answer 18

Deoxyribose sugar
A, T, G, C
Double-stranded

Question 19

RNA

Answer 19

Ribose sugar
A, U, G, C
Single-stranded

Question 20

Messenger RNA (mRNA)

Answer 20

Complement of DNA sequence
Transports from the nucleus to the ribosome for protein synthesis
Monocistronic: 1 mRNA = 1 polypeptide

Question 21

Transfer RNA (tRNA)

Answer 21

In the cytoplasm

Recognizes the mRNA codon and brings in the corresponding amino acid

Question 22

Aminoacyl-tRNA synthetase

Answer 22

Active site that binds the amino acid and its corresponding tRNA
Catalyze attachment to form an aminoacyl-tRNA complex

Question 23

Ribosomal RNA (rRNA)

Answer 23

Structural component of ribosomes

mRNA passes through 2 subunits of rRNA and is translated

Question 24

Anticodon

Answer 24

Complementary to mRNA codons

Question 25

Transcription

Answer 25

The process through which info coded in the base sequence of DNA is used to direct the synthesis of a strand of mRNA

Question 26

Promoter region

Answer 26

Short DNA sequence found upstream from the transcription site TATA box

Question 27

RNA polymerase

Answer 27

Bind to DNA and initiates transcription | Recruits and adds complementary RNA nucleotides based on the DNA sequence

Question 28

Hetero-nuclear RNA (pre-RNA)

Answer 28

Contains extra nucleotides not necessary to create the corresponding protein

Question 29

Introns

Answer 29

Extra mRNA sequence not necessary to create a protein

Question 30

Exons

Answer 30

Nucleotides necessary to make a protein

Question 31

Spliceosome

Answer 31

Splice out introns

Question 32

Post-transcriptional processing

Answer 32

Splicing Guanine cap Poly-A tail

Question 33

Translation

Answer 33

The process through which mRNA codons are translated into a sequence of amino acids

Question 34

Initiation

Answer 34

The ribosome binds to the mRNA near its 5' end, scans until it binds a start codon (AUG) Initiator aminoacyl-tRNA complex (methionine-tRNA) base pairs with the start codon

Question 35

Elongation

Answer 35

Hydrogen bonds form between mRNA codon in the A site | Peptide bond formed between the amino acid attached to the tRNA in the A site and P site

Question 36

Translocation

Answer 36

Ribosome advances 3 nucleotides Uncharged tRNA from the P site is expelled Peptidyl-tRNA from the A site moves into the P site

Question 37

Termination

Answer 37

``` Stop codon (UAA, UAG, UGA) arrives in the A site Signal ribosome to terminate translation ```

Question 38

Polyribosome

Answer 38

Numerous ribosomes simultaneously translating a single mRNA

Question 39

A site

Answer 39

Aminoacyl-tRNA complex binding site | Binds the incoming tRNA

Question 40

P site

Answer 40

Peptidyl-tRNA binding site | When tRNA contributes its amino acid to the growing peptide chain

Question 41

E site

Answer 41

Exit site | Releases tRNA