1B - DNA and RNA

Question 1

What are nucleic acids?

Answer 1

A group of the most important molecules.

A complex, organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain.

Question 2

What is a nucleotide made from?

Answer 2

A pentose sugar, and nitrogen containing (nitrogenous) base and a phosphate group.

Question 3

What are nucleotides?

Answer 3

Monomers that make up DNA and RNA.

Question 4

What does organic mean?

Answer 4

Contains carbon

Question 5

What is the pentose sugar in DNA called?

Answer 5

Deoxyribose

Question 6

What are the four possible bases on DNA nucleotides?

Answer 6

A, T, C, G

Adenine
Thymine
Cytosine
Guanine

Question 7

What is the pentose sugar in RNA called?

Answer 7

Ribose

Question 8

What are the four possible bases on RNA nucleotides?

Answer 8

A, U, C, G

Adenine
Uracil
Cytosine
Guanine

Question 9

What is the difference in the possible bases in the nucleotides for DNA and RNA?

Answer 9

In RNA, uracil (U) replaces thymine (the base that is only found in DNA).

Question 10

In brief, what are DNA and RNA and what do they do?

Answer 10

Types of nucleic acid found in all living cells and they both carry information.

Question 11

In more detail, what does DNA do?

Answer 11

Stores genetic information - all the instructions an organism needs to grow and develop from a fertilised egg to a fully grown adult.

Question 12

In more detail, what does RNA do?

Answer 12

Transfers genetic information from the DNA to the ribosomes.

Question 13

What is a polynucleotide?

Answer 13

A polymer of nucleotides.

Nucleotides join together to form polynucleotides.

Question 14

Nucleotides join together to form…

Answer 14

Polyneucleotides.

Question 15

How do 2 nucleotides join?

Answer 15

Via a condensation reaction between the phosphate group of one nucleotide and the sugar of another.

Question 16

What bond is formed between to joining nucleotides?

Answer 16

Phosphodiester bond (consisting of the phosphate group and two ester bonds).

Question 17

How is a phosphodiester bond formed and where?

Answer 17

Through a condensation reaction joining two nucleotides. It forms between the phosphate group of one nucleotide and the sugar of another

Question 18

What is the chain of sugars and phosphates known as?

Answer 18

The sugar-phosphate backbone.

Question 19

What is the sugar-phosphate backbone?

Answer 19

The chain of sugars and phosphates in a polynucleotide.

Question 20

What do two nucleotides form when bonded?

Answer 20

A dinucleotide.

Question 21

What is the structure of DNA?

Answer 21

• 2 DNA polynucleotide strands joined together by hydrogen bonding between the bases.
• Complementary base pairing.
• 2 hydrogen bonds form between A and T.
• 3 hydrogen bonds form between C and G.
• 2 antiparallel polynucleotide strands twist to form a double helix structure.

Question 22

What is complementary base pairing in DNA?

Answer 22

Each base can only join with one particular partner,

Adenine always pairs with thymine (A-T) and cytosine always pairs with guanine (C-G).

Question 23

What does complementary base pairing in DNA mean there is?

Answer 23

Equal amounts of adenine and thymine in a DNA molecule and equal amounts of cytosine and guanine.

Question 24

What does antiparallel mean?

Answer 24

Run in opposite directions.

Question 25

When was DNA first discovered and by who?

Answer 25

1953 by Watson and Crick.

Question 26

What is the name of the structure/shape of DNA?

Answer 26

Double helix

Question 27

What was thought about DNA when it was first observed in the 1800's?

Answer 27

Lots of scientists at the time doubted that it could carry the genetic code as it has a relatively simple chemical composition. Some argued that genetic information must be carried by proteins - which are more chemically varied.

Question 28

What had happened by 1953 in the discovery of DNA?

Answer 28

Experiments had shown that DNA was the carrier of the genetic code. Also, the double-helix structure, which helps DNA to carry out its function, was determined by Watson and Crick.

Question 29

In more detail, what is RNA made from?

Answer 29

A relatively short, single polynucleotide chain.

Question 30

What is the difference in the structure of DNA and RNA?

Answer 30

DNA has a double strand of polynucleotide chains whereas RNA is a single strand and is much shorter. DNA contains the base THYMINE whereas RNA contains the base URACIL

Question 31

Is the sugar-phosphate backbone reactive?

Answer 31

No it is unreactive.

Question 32

What does DNA stand for?

Answer 32

Deoxyribonucleic acid.

Question 33

What does RNA stand for?

Answer 33

Ribonucleic acid.

Question 34

What are the 3 forms of RNA?

Answer 34

Transfer or tRNA. Messenger or mRNA. Ribosomal or rRNA.

Question 35

What does the sugar phosphate backbone help to do for the DNA?

Answer 35

Protects the more reactive bases.

Question 36

What bonds form between the base pairs?

Answer 36

Hydrogen bonds.

Question 37

What does the fact that there are hydrogen bonds between complementary base pairs and that the phosphodiester backbone helps protect bases mean for DNA as a whole?

Answer 37

It makes DNA more stable and better suited for long term storage of DNA.

Question 38

What is the sugar-phosphate backbone also known as?

Answer 38

Phosphodiester backbone.

Question 39

What is the phosphodiester backbone?

Answer 39

Another name for the sugar-phosphate backbone.

Question 40

What base does thymine join to?

Answer 40

Adenine

Question 41

What base does adenine join to?

Answer 41

Thymine

Question 42

What base does cytosine join to?

Answer 42

Guanine

Question 43

What base does guanine join to?

Answer 43

Cytosine

Question 44

What is meant by the 3' end and the 5' end?

Answer 44

The carbon number on the pentose sugar. The nucleotide strands run antiparallel to each other so the 3' end and 5' ends of each strand will be at opposite ends.

Question 45

What do the hydrogen bonds holding the 2 strands together allow to happen?

Answer 45

Allows them to be separated easily during copying.

Question 46

What does DNA being a large molecule allow?

Answer 46

A lot of information to be stored and transferred.

Question 47

What does the double-helix structure help to do?

Answer 47

Protect the genetic information carried by the bases.

Question 48

What are the functional adaptations of DNA?

Answer 48

- Highly stable so passes through generations without change and rarely mutates. - 2 strands held together by hydrogen bonds allowing them to be separated easily during copying. - Double helix structure partly protects the genetic information carried by the bases. - Complementary base pairing makes DNA sequences and RNA compatible allowing RNA to transfer information from the DNA.

Question 49

What does the complementary base pairing allow to happen in DNA?

Answer 49

Makes DNA sequences and RNA compatible allowing the RNA to transfer information from the DNA.