Nucleic acids

Question 1

What is DNA?

Answer 1

Double stranded polymer of nucleotides which carry the info for protein synthesis

Question 2

What pentose sugar does DNA contain?

Answer 2

Deoxyribose

Question 3

What is RNA?

Answer 3

Single stranded polymer of nucleotides

Question 4

What sugar does RNA contain?

Answer 4

Ribose

Question 5

What is a polynucleotide?

Answer 5

Polymer of nucleotide monomers covalently bonded together

Question 6

What is an organic nitrogenous base?

Answer 6

An organic compound containing nitrogen, which is part of all nucleotides

Question 7

What is a nucleotide made up of?

Answer 7

A phosphate, 5-carbon sugar, and a nitrogenous base

Question 8

Why is the pentose sugar called 5-carbon sugar?

Answer 8

Either a ribose or deoxyribose molecule, both of these contain 5 carbon atoms

Question 9

What are the organic nitrogenous bases?

Answer 9

A - adenine 
C - cytosine 
G - guanine 
T - thymine 
U - uracil

Question 10

What are the complementary base pairs?

Answer 10

All teachers care gently
a - t
c- g
a - u

Question 11

In which type of nucleic acid is the base Pais a with u instead of t?

Answer 11

RNA

Question 12

What are the two types of bases?

Answer 12

Pyrimidines and purines

Question 13

How many carbon-nitrogen rings does pyrimidine bases consist of?

Answer 13

1

Question 14

How many carbon-nitrogen rings does purine bases consist of?

Answer 14

2

Question 15

Which bases are pYrimidines?

Answer 15

ThYmine (Also have Y)
CYtosine (Also have Y)
Uracil (replaces T)

Question 16

Which bases are purINE?

Answer 16

AdenINE

GuanINE

Question 17

How is a polynucleotide formed?

Answer 17

The phosphate group of one nucleotide bonds to the sugar molecule of another, forming one long continuous polynucleotide (half a DNA strand)

Question 18

How do we go from a polynucleotide to the nucleic acid - DNA?

Answer 18

Two polynucleotide chains join together with hydrogen bonds between both polynucleotides nitrogenous bases (hydrogen bonds)

Question 19

After two polynucleotide chains have joined to form the nucleic acid, how does it fully become DNA?

Answer 19

Once it contains a sugar deoxyribose and the base thymine

Question 20

What is complementary base pairing?

Answer 20

A will only pair with T (forming two hydrogen bonds), and C will only pair with G (forming three hydrogen bonds)

Question 21

What is important about complementary base pairing?

Answer 21

Molecule will become very stable and same width all the way down the chain (due to bases holding backbone same width apart)

Question 22

Describe antiparallel in terms of DNA?

Answer 22

The two polynucleotides and in opposite directions top one another so that the bases meet and bond together in the middle

Question 23

What is semi-conservative replication?

Answer 23

Each new DNA molecule is made up of 1 conserved stand from original template, and 1 new strand of nucleotides

Question 24

What does the enzyme DNA helicase do in the first stage of DNA semi-conservative replication?

Answer 24

Unwinds and unzips the double stranded helix, breaking the hydrogen bonds, leaving 2 individual strands

Question 25

Into what shape is the now 2 singular strands of nucleotide, unzipped into?

Answer 25

A fork, one end becomes the leading strand and the other, the lagging strand

Question 26

Which strand is the lagging strand?

Answer 26

The one the wrong way up

Question 27

How does complementary base pairing occur once unzipped, in the second stage of S-CR?

Answer 27

New and free nucleotides in nucleus attach to exposed bases, forming hydrogen bonds

Question 28

What does DNA polymerase do?

Answer 28

Catalyses the condensation reaction which covalently bonds the new nucleotides to the adjacent base

Question 29

In stage 3 of S-CR what happens to the leading strand?

Answer 29

DNA polymerase zooms down the strand (in same direction as unzipping) , base pairing is an efficient and continuous process

Question 30

In stage 3 of S-CR what happens to the lagging strand?

Answer 30

Due do DNA polymerase moving in opposite direction to unzipping, process is a lot slower

Question 31

What is the triplet code?

Answer 31

The three nitrogenous bases read along the DNA strand that code for DNA

Question 32

What is the definition of transcription?

Answer 32

The process of exactly copying the genetic code to form a template of mRNA

Question 33

What is the genetic code?

Answer 33

The triplet code, 3 bases coding for an amino acid

Question 34

How is mRNA structured?

Answer 34

Single stranded, contains ribose (instead of deoxyribose) and contains uracil instead of thymine

Question 35

What are the two processes in protein synthesis?

Answer 35

Transcription and translation

Question 36

What is a gene?

Answer 36

A short length of DNA, a sequence of bases that code for the amino acids which make up an individual protein

Question 37

What are the two separate strands in a gene?

Answer 37

The coding strand and the template strand

Question 38

Why does protein synthesis occur?

Answer 38

When the cell needs to produce a specific protein

Question 39

What is the first stage of protein synthesis?

Answer 39

Enzyme RNA polymerase binds to the gene and unzips the two DNA strands

Question 40

What direction does the RNA polymerase move?

Answer 40

In the 3' to 5' direction

Question 41

What is the second thing the RNA polymerase does in protein synthesis?

Answer 41

Pairs free RNA nucleotides with complementary nucleotides on the DNA template strand (covalently linked by phosphodiester bonds)

Question 42

How is the mRNA formed from the RNA?

Answer 42

The complementary RNA nucleotides covalently link to those on the template strand by phosphodiester bonds, making a polynucleotide chain, growing in the 5' to 3' direction

Question 43

Whats the first stage of translation?

Answer 43

mRNA leaves the nucleus via the nuclear pore with small sub unit of ribosome and act as a template for proteins to be synthesised

Question 44

What is a codon?

Answer 44

A triplet

Question 45

What is an anticodon?

Answer 45

The complementary triplet to the mRNA codon

Question 46

What is a tRNA molecule?

Answer 46

Transfer molecule, has an anticodon one end, the sugar-phosphate backbone, and the other is the region for the particular amino acid to attach

Question 47

What happens after tRNA molecules attach to a ribosome?

Answer 47

The anti codon which is complementary to the codon, pair up on the mRNA

Question 48

What happens to amino acids transported by tRNA?

Answer 48

They join together by a condensation reaction forming peptide bonds

Question 49

When does translocation stop?

Answer 49

When tRNA molecules go back to cytoplasm, ribosome has moved along whole mRNA strand and all amino acids have joined, ending with a stop codon

Question 50

What is rRNA (ribosomal)?

Answer 50

Site of protein synthesis, when RNA molecules are attached to ribosomal protein molecules

Question 51

Whats the helical structure of RNA?

Answer 51

A polynucleotide chain twists into helix and coils back on itself, some sections of the chain join to other parts for tRNA/mRNA, however mRNA is linear