3.1.5.1 Structure of DNA and RNA Flashcards

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1
Q

DNA is made from which monomer?

A

Mononucleotides (or just nucleotides)

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2
Q

Name the 3 components of a nucleotide

A

Phosphate group

Pentose sugar

Organic base (containing nitrogen)

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3
Q

In DNA, which base complements guanine?

A

cytosine

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4
Q

In RNA, which base complements adenine?

A

uracil

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5
Q

In DNA, which base complements thymine?

A

adenine

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6
Q

Idenitfy the 5’ and 3’ carbon atoms of the deoxyribose molecule.

A

Idenitfy the 5’ and 3’ carbon atoms of the deoxyribose molecule.

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7
Q

Identify the molecule.

A

Ribose

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8
Q

In RNA, which base complements guanine?

A

cytosine

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9
Q

In DNA, which base complements cytosine?

A

guanine

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10
Q

In RNA, which base complements uracil?

A

adenine

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11
Q

Which atoms will react to join the two nucleotides?

A

Which atoms will react to join the two nucleotides?

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12
Q

What shape does a molecule of DNA take?

A

A double helix

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13
Q

In DNA, which base complements adenine?

A

thymine

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14
Q

DNA is a stable molecule because…

A
  • The phosphodiester backbone protects the chemically reactive base pairs.
  • C-G base pairs contain 3 hydrogen bonds, so the more C-G base pairs in a DNA molecule the more stable it is.
  • Interactive forces between base pairs add further stability (‘base stacking’)
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15
Q

How many hydrogen bonds are formed between Cytosine and Guanine in a DNA molecule?

A

3

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16
Q

Name the bond that forms between the 2 nucleotides of a dinucleotide.

A

Phosphodiester bond

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17
Q

What is the function of RNA?

A

To transfer genetic information from DNA to the ribosomes.

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18
Q

How is DNA adapted to carry out its function as a means of passing genetic information from generation to generation?

A
  • Very stable - rarely mutates
  • Hydrogen bonds between strands easy to separate for replication and protein synthesis.
  • Very long - carries a lot of genetic information.
  • Base pairs protected from chemical/physical forces by phosphodiester backbone.
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19
Q

Name the 3 Scientists who discovered the structure of DNA

A

James Watson

Francis Crick

Rosalind Franklin

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20
Q

Describe how are 2 DNA nucleotides form a dinucleotide

A

A condensation reaction occurs between the hydroxyl (OH) group on the 3’ carbon of Deoxyribose on 1 nucleotide and the hydroxyl group of the phosphate group on another nucleotide.

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21
Q

In RNA, which base complements cytosine?

A

guanine

22
Q

How many hydrogen bonds are formed between Adenine and Thymine in a DNA molecule?

A

2

23
Q

How are the 2 strands of DNA that make up the double helix held together?

A

Hydrogen bonds between complementary organic bases

24
Q

What is the function of DNA

A

To carry genetic information

25
Q

Name the 2 nucleic acids

A

Deoxyribonucleic acid (DNA)

Ribonucleic Acid (RNA)

26
Q

Identify the molecule.

A

Phosphoric Acid

(phosphate)

27
Q

Name the organic bases that can become part of a DNA nucleotide

A

Adenine

Thymine

Cytosine

Guanine

28
Q

The phosphate group, pentose sugar and organic base of a DNA or RNA nucleotide are joined through which type of reaction?

A

Condensation reaction

29
Q

The phosphate group attaches to which carbon atom of a ribose or deoxyribose molecule when forming a nucleotide?

A

The 5’ carbon atom (pronounced 5 prime)

30
Q

Name the organic bases that can become part of a RNA nucleotide

A

Adenine

Uracil

Cytosine

Guanine

31
Q

Identify the molecule.

A

Deoxyribose

32
Q

Describe how are 2 RNA nucleotides form a dinucleotide

A

A condensation reaction occurs between the hydroxyl (OH) group on the 3’ carbon of Ribose on 1 nucleotide and the hydroxyl group of the phosphate group on another nucleotide.

33
Q

Which type of bond are the arrows pointing at?

A

Phosphodiester bond

34
Q

If the bases on one strand of DNA are TGGAGACT, determine the base sequence on the other strand.

A

ACCTCTGA

35
Q

If 19.9% of the base pairs in human DNA are guanine, calculate the percentage that is Thymine. Show your reasoning.

A

30.1%

If 19.9% is guanine - 19.9% is cytosine as it is paired with it.

19.9 + 19.9 = 39.8%.

The remaining DNA is made from Adenine and Thymine, which is 60.2%. Thymine = 60.2% divided by 2 = 30.1%.

36
Q

what is meant by degenerate when talking about the genetic code?

A

more than one triplet for each amino acid

37
Q

What is meant by the term non overlapping when talking about the genetic code?

A

each base only read the once

38
Q

How do the organic bases help to stabilise structure of DNA?

A
  1. Hydrogen bonds between the base pairs holds two strands together;
  2. Many hydrogen bonds provides strength;
39
Q

Function of DNA helicase?

A

break H bonds between bases

40
Q

Function of DNA polymerase?

A

join nucleotides together/reforrms phosphodiester backbone

41
Q

Give 2 differences between the nucleotide in ATP (nucleotide derivative) and the nucleotides in DNA

A
  1. ATP has 3 phosphates DNA 1 phosphate group per nucleotide
  2. ATP has ribose, DNA deoxyribose
  3. ATP - base always adenine, DNA it varies
42
Q

Name the bone between the deoxyribose and the phosphate in a nucleotide

A

phosphodiester

43
Q
A
44
Q

suggest a reason for the difference in dna length between humans and bacteria?

A

human genes bigger

45
Q

hydrogen bonds occur between water molecules. explain how these affect the properties of water as a habitat for organisms?

A
  • provides medium for gametes to travel
  • extra H bonds on freezing makkes ice float - insulates water below
  • high latent of heat vaporisation - less likely to evaporate
46
Q

what are the advantages of scientists questioning the validity of a current theory rather than automatically accepting it?

A
  • alternative theories can be explored and investigated
  • new facts may emerge
  • so scientific progress can be made
47
Q

explain what is meant by the term hypothesis in the scientific sense?

A

suggested explanation of something based on some logical scientific reasoning / idea

48
Q

a new scientific discovery often presents moral, economic and ethical issues. justify why it is necessary for society to analyse the risks and benefits of these discoveries before they are developed?

A
  • society affected by new discoveries
  • society should be able to have say on what they can/cannot do
49
Q

suggest what the term ‘in vivo’ means in the context of synthesising DNA?

A
  • in life
  • synthesis of dna by living organisms rather than in labratory
50
Q

from your knowledge of the way enzymes work, explain why dna polymerase can only attach nucleotides to the hydroxyl (OH) group on the 3’ carbon molecule?

A
  • dna polymerase active site = specific shape to substrate
  • shape of 3’ end with OH mol group fits active site of DNA polymerase
  • whereas shape of 5’ end doesnt