10.1 - Nucleotides

Question 1

What are nucleotides made up of?

Answer 1

• Pentose sugar
• Base (nitrogenous bases)
• Phosphate group (negatively charged)

Question 2

Elements in nucleotides?

Answer 2

• Phosphorus
• Nitrogen
• Carbon
• Oxygen
• Hydrogen

Question 3

Draw a diagram of a single nucleotide

Answer 3

…

Question 4

What do nucleotides do?

Answer 4

Used to form DNA and RNA

Question 5

Differences between general structure of nucleotides in DNA and RNA?

Answer 5

Sugar in DNA: deoxyribose
Sugar in RNA: ribose

Base in DNA: Thymine used
Base in RNA: Thymine not used. Replaced by uracil.

Question 6

Difference between deoxyribose and ribose sugar?

Answer 6

Deoxyribose sugar has one less oxygen atom

Question 7

Bases in DNA:

Answer 7

• Adenine
• Thymine
• Cytosine
• Guanine

Question 8

Which bases have a double ring structure?

Answer 8

• Adenine
• Guanine

Question 9

What are bases with double ring structure called?

Answer 9

Purines

Question 10

What are bases with a single ring structure called?

Answer 10

Pyrimidines

Question 11

What bases have a single ring structure?

Answer 11

• Thymine
• Cytosine

Question 12

Where does reaction occur to form polynucleotide?

Answer 12

Between phosphate group (on 5th carbon) of one nucleotide and the hydroxyl group (on carbon 3 of pentose sugar) of the other.

Question 13

Name of bond between two nucleotides?

Answer 13

Phosphodiester bond

Question 14

What type of reaction forms a phosphodiester bond?

Answer 14

Condensation (as water is produced).

Question 15

Two nucleotides joined by phosphodiester bond?

Answer 15

dinucleotide

Question 16

Examples of polynucleotides?

Answer 16

RNA and DNA

Question 17

Other name for polynucleotides?

Answer 17

Nucleic acids

Question 18

About the phosphate group?

Answer 18

Inorganic molecule that is acidic and slightly negatively charged

Question 19

About the nitrogenous base?

Answer 19

Complex organic molecule containing two or more carbon rings in structure as well as nitrogen.

Question 20

Role of phosphodiester bonds?

Answer 20

Form a strong, long sugar-phosphate ‘backbone’ with a base attached to each sugar.

Question 21

Structure of DNA:

Answer 21

Two strands of polynucleotides coiled into helix. Known as DNA double-helix.

Question 22

How are the two strands of double helix joined together?

Answer 22

Hydrogen bonds between bases.

Question 23

How do bases join?

Answer 23

Base on one strand is complementary to bases on the other strand

Question 24

Result of pyrimidine bases linking with Purine bases?

Answer 24

The distance between sugar-phosphate backbone is constant. Result in parallel nucleotide chains.

Question 25

How are the two polynucleotide strands in DNA antiparallel?

Answer 25

Run in opposite directions.

Question 26

How do polynucleotide strands run in opposite directions?

Answer 26

On the left, the carbon 5 is at the top and carbon 3 (-OH) is at the bottom. On the right, the carbon 3 (-OH)is at the top and the carbon 5 is at the bottom.

Question 27

Guanine and Cytosine hydrogen bonds?

Answer 27

Form 3 hydrogen bonds

Question 28

Adenine and Thymine hydrogen bonds?

Answer 28

Form 2 hydrogen bonds

Question 29

What is the result of complementary bases?

Answer 29

Proportion of Adenine to Thymine is always the same. Proportion of Guanine to Cytosine is always the same. Can calculate proportions of different nucleotides.

Question 30

20% of the nucleotides in a sample of DNA contain base guanine. What are the proportions of the other bases?

Answer 30

Guanine: 20% Cytosine: 20% Thymine: 30% Adenine: 30%

Question 31

What does pairing between bases allow for?

Answer 31

copied and transcribed - key properties of heredity.

Question 32

Where is DNA found?

Answer 32

Chromosomes in the nucleus

Question 33

Where is RNA found?

Answer 33

Cytoplasm

Question 34

Role of RNA?

Answer 34

In protein synthesis

Question 35

Difference between length of DNA and RNA?

Answer 35

DNA: long molecule RNA: relatively short molecule

Question 36

Difference between structure of DNA and RNA?

Answer 36

RNA: One polynucleotide strand DNA: Two polynucleotide strands in double helix

Question 37

What happens to RNA molecules after protein synthesis?

Answer 37

Degraded in cytoplasm - the phosphodiester bonds are hydrolysed in the cytoplasm. RNA nucleotides released and reused.

Question 38

Bonding of uracil to adenine?

Answer 38

2 hydrogen bonds