DNA, protein And The Central Dogma

Question 1

Which nucleotides pair together?

Answer 1

Adenine-Thymine (or Uracil for RNA)
Guanine-Cytosine

Question 2

What is the job of the helicase?

Answer 2

Break the parental double helix at the separation fork

Question 3

Which enzyme unzips DNA?

Answer 3

Helicase

Question 4

What stabilises the unwound DNA?

Answer 4

Binding protein

Question 5

What does the binding protein do?

Answer 5

Stabilises the template strands

Question 6

Why is DNA replication called semi conservative?

Answer 6

Because one strand is made up of conserved DNA

Question 7

What is the job of a topoisomerase?

Answer 7

To break, swivel and rejoin the parental strand to fix it being too wound up

Question 8

Which enzyme fixes the DNA being too wound up?

Answer 8

Topoisomerase

Question 9

What does the primase do?

Answer 9

Places a RNA primer to begin synthesis of the okazaki fragment for a lagging strand and a single RNA primer on the leading strand

Question 10

Which enzyme places the primers for the Okazaki fragments?

Answer 10

Primase

Question 11

What does DNA polymerase 3 do?

Answer 11

Leading: continuously synthesises in the 5’ 3’ direction
Lagging: synthesises fragments by finding the RNA primer and completing the Okazaki fragment

Question 12

What does polymerase 1 do?

Answer 12

Removes the RNA primer from the 5’ fragment and replaceling it with nucleotides, leaving the end open

Question 13

Which enzyme removes the primer and replaces it with nucleotides?

Answer 13

DNA polymerase 1

Question 14

What does DNA ligase do?

Answer 14

Leading: joins the open 3’ and 5’ ends together
Lagging: does the same within the Okazaki fragments

Question 15

Which enzyme joins the 3’ and 5’ together in DNA synthesis?

Answer 15

DNA Ligase

Question 16

What bond holds DNA nucleotides together?

Answer 16

A weak hydrogen bond (not covalent)

Question 17

Why is DNA held together with a weak hydrogen bond?

Answer 17

Because DNA needs to break apart and remake itself a lot, so the bond needs to be easy to break and reattach together, using minimal energy

Question 18

How many hydrogen bonds does Thymine and Adenine have?

Answer 18

2 hydrogen bonds

Question 19

How many hydrogen bonds does Guanine and Cytosine have?

Answer 19

3 hydrogen bonds

Question 20

Name the 5 nucleotides

Answer 20

Adenine
Thymine
Cytosine
Guanine
Uracil

Question 21

What are the 2 sugars?

Answer 21

Deoxribose (DNA)
Ribose (RNA)

Question 22

What is the name of the 2 nitrogenous bases?

Answer 22

Pyrimidines: cytosine, thymine, uracil

Purines: adenine, guanine

Question 23

How do nitrogenous bases pair together? (Think p and p)

Answer 23

Purine to Pyrimidine because the width of them together will fit in the 2nm diameter of the double helix.

2x purine together is too wide
2x pyrimidine is too narrow

Question 24

What are the steps to the central dogma in DNA?

Answer 24

1. DNA transcribes pre mRNA inside the nucleus
2. Pre mRNA is made into mRNA and pushed out of the nucleus, into the cytoplasm
3. Ribosomes then translate it to polypeptides, which, when long enough become proteins

Question 25

What is the start codon?

Answer 25

AUG (met)

Question 26

How many steps in the central dogma does RNA have?

Answer 26

1. Transcription 2. Translation They happen simultaneously

Question 27

How many steps in the central dogma does DNA have?

Answer 27

1. Transcription 2. RNA processing 4. Translation

Question 28

What is a promotor?

Answer 28

A sticky part of DNA that allows a polymerase moelcule to bind to it

Question 29

What is a promotor?

Answer 29

A sticky part of the DNA that is attached just before the stat of a DNA gene sequence that allows an RNA polymerase to attach to the DNA to start mRNA synthesis

Question 30

What are the 3 steps to mRNA synthesis?

Answer 30

1. Initiation: RNA polymerase attaches and creates a bubble to start elongation. 2. Elongation: RNA is made and the DNA is stitched back together 3. Termination: RNA is complete and detaches, along with the polymerase

Question 31

What is the purpose of the 5' guanine cap and poly A tail?

Answer 31

To protect the mRNA going from the nucleus to the cytoplasm

Question 32

What does UTR stand for?

Answer 32

Untranslated region

Question 33

What is the purpose of an untranslated region?

Answer 33

If the mRNA is degraded too much the UTR is fine to be degraded as the main part of the RNA will still stay intact

Question 34

What is an intron?

Answer 34

A non coding sequence that needs to be cut out before the whole and intact gene sequence needs to be translated

Question 35

name 8 protein structures and give examples hint: SCREDTHS

Answer 35

Structural: support, keratin Contractile and Motor: movement, actin and myosin contracts muscles Receptor: response of the cell to chemical stimuli, nerve cell receptors Enzymatic: selective acceleration of chemical reactions, digestion of food at a cellular level amylase Defensive: disease protection, Antibodies destroy viruses Transport: moves substances, molecules across membranes Hormonal: co-ordinates an organisms activities, insulin Storage: stores amino acids, casein for babies in milk

Question 36

What is the primary structure of proteins?

Answer 36

The list of the 20 amino acids in their order, in a 2D shape

Question 37

What is the secondary structure?

Answer 37

A 3D shape, either as an alpha helix or beta pleated sheet due to the primary structures amino acids having side chains, a positive or a negative charge. Thet have a hydrogen bond so they are relatively stable.

Question 38

What is a tertiary strucutre?

Answer 38

Where the secondary structure has been folded on itself and held together (normally) with a disulfide covalent bond and usually folds into an oval, globular shape

Question 39

What is a quartenary structure?

Answer 39

When multiple tertiary structures are independently fused together and interacting with each other

Question 40

Why does DNA have 1 direction?

Answer 40

Because DNA polymerase 3 add nucleotides to the leading or lagging template in the 5'-3' direction

Question 41

Why do we have a leading and lagging strand?

Answer 41

1. Antiparrallel 2. Reverse complimentary sequencing 3. Semi-conservative replication 4. 5' and 3' sequences 5. Polynucleotides structured to attache that way

Question 42

what are the 4 R groups of amino acids?

Answer 42

1. Polar 2. non polar 3. positively charged 4. negatively charged

Question 43

What are the 3 stop codons?

Answer 43

1. UAA 2. UAG 3. UGA