Nucleotides and Nucleic acids

Question 1

What three components make up a nucleotide?

Answer 1

A phosphate group, a pentose sugar and a base

Question 2

Draw the basic nucleotide structure

Answer 2

…

Question 3

What is the pentose sugar in DNA

Answer 3

Deoxyribose

Question 4

Name the 4 bases in DNA and what 2 pairs they are in

Answer 4

Adenine and Thymine

Cytosine and Guanine

Question 5

What is the change in the four bases in RNA

Answer 5

Thymine is replaced by Uracil

Question 6

What is the basic structure of purine?

Answer 6

2 carbon rings

adenine and gyanine

Question 7

What is the basic structure of a pyrimidine?

Answer 7

1 carbon ring

cytosine, thymine and uracil

Question 8

What structure does ADP have?

Answer 8

Base adenine
Ribose sugar
Two phosphate groups

Question 9

What structure does ATP have?

Answer 9

Base adenine
Ribose sugar
Three phosphate groups

Question 10

What is it called when nucleotides join together and what bond is formed?

Answer 10

Polynucleotides

Phosphodiester bond

Question 11

What is DNA composed of?

Answer 11

Two polynucleotide strands forming a double helix

Question 12

How many bonds are formed between C and G?

Answer 12

3

Question 13

How many bonds are formed between A and T

Answer 13

2

Question 14

What is meant by antiparallel and how does this effect DNAs structure?

Answer 14

Strands run in opposite direction

This causes the strand to twist and form a double helix

Question 15

How is DNA purified?

Answer 15

It can be purified by a precipitation reaction

Question 16

Why does DNA replicate?

Answer 16

Before cell divisions o each new cell can have a full amount of genetic information
This is important in passing genes generation to generation

Question 17

How is DNA replicated?

Answer 17

1. DNA helicase breaks hydrogen bonds between the strands, forming two single strands
2. Each original strand acts as a template. Free floating DNA nucleotides join to exposed bases
3. DNA polymerase joins them together forming hydrogen bonds

Question 18

What is a gene?

Answer 18

It is a sequence of DNA nucleotides that codes for a polypeptide.

Question 19

What is a codon?

Answer 19

Three bases making up a amino acid

Question 20

What is a single polynucleotide called?

Answer 20

RNA

Question 21

What is the function of mRNA?

Answer 21

Made in transcription.

It carried genetic code from the DNA in the nucleus to the cytoplasm where it is used to make protein during translation

Question 22

What is the function of tRNA?

Answer 22

Carried the amino acids that are used to make proteins to the ribosomes

Question 23

What is the function of rRNA?

Answer 23

The rRNA in the ribosome helps to catalyse the formation of peptide bonds between the amino acids

Question 24

What is transcription?

Answer 24

The first stage of protein synthesis. Where mRNA makes a copy of a gene

Question 25

How does transcription take place?

Answer 25

1. RNA polymerase attaches to the DNA 2. Complementary mRNA is formed 3. RNA polymerase moves down the DNA strand 4. mRNA leaves the nucleus

Question 26

What is translation?

Answer 26

This is the second stage of photosynthesis. It takes place in the ribosomes in the cytoplasm. Amino acids are joined together by a ribosome to make a polypeptide chain (protein)

Question 27

How does translation take place?

Answer 27

1. mRNA attaches itself to a ribosome and tRNA molecules carry amino acids to the ribosome 2. tRNA begin joining base pairings 3. rRNA in the ribosome catalyses the formation of a peptide between the two amino acids