3.1.5.1 Structure of DNA and RNA Flashcards Preview

SHHS - Science - NEW AQA A-Level Biology (Year 1) > 3.1.5.1 Structure of DNA and RNA > Flashcards

Flashcards in 3.1.5.1 Structure of DNA and RNA Deck (43)
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1
Q

DNA is made from which monomer?

A

Mononucleotides (or just nucleotides)

2
Q

Name the 3 components of a nucleotide

A

Phosphate group

Pentose sugar

Organic base (containing nitrogen)

3
Q

In DNA, which base complements guanine?

A

cytosine

4
Q

In RNA, which base complements adenine?

A

uracil

5
Q

In DNA, which base complements thymine?

A

adenine

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.

7
Q

Identify the molecule.

A

Ribose

8
Q

In RNA, which base complements guanine?

A

cytosine

9
Q

In DNA, which base complements cytosine?

A

guanine

10
Q

In RNA, which base complements uracil?

A

adenine

11
Q

Which atoms will react to join the two nucleotides?

A

Which atoms will react to join the two nucleotides?

12
Q

What shape does a molecule of DNA take?

A

A double helix

13
Q

In DNA, which base complements adenine?

A

thymine

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’)
15
Q

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

A

3

16
Q

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

A

Phosphodiester bond

17
Q

What is the function of RNA?

A

To transfer genetic information from DNA to the ribosomes.

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.
19
Q

Name the 3 Scientists who discovered the structure of DNA

A

James Watson

Francis Crick

Rosalind Franklin

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.

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 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

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