Nucleotides and Nucleic acids Flashcards Preview

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Flashcards in Nucleotides and Nucleic acids Deck (27)
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1

What three components make up a nucleotide?

A phosphate group, a pentose sugar and a base

2

Draw the basic nucleotide structure

...

3

What is the pentose sugar in DNA

Deoxyribose

4

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

Adenine and Thymine
Cytosine and Guanine

5

What is the change in the four bases in RNA

Thymine is replaced by Uracil

6

What is the basic structure of purine?

2 carbon rings
(adenine and gyanine)

7

What is the basic structure of a pyrimidine?

1 carbon ring
(cytosine, thymine and uracil)

8

What structure does ADP have?

Base adenine
Ribose sugar
Two phosphate groups

9

What structure does ATP have?

Base adenine
Ribose sugar
Three phosphate groups

10

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

Polynucleotides
Phosphodiester bond

11

What is DNA composed of?

Two polynucleotide strands forming a double helix

12

How many bonds are formed between C and G?

3

13

How many bonds are formed between A and T

2

14

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

Strands run in opposite direction
This causes the strand to twist and form a double helix

15

How is DNA purified?

It can be purified by a precipitation reaction

16

Why does DNA replicate?

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

17

How is DNA replicated?

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

18

What is a gene?

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

19

What is a codon?

Three bases making up a amino acid

20

What is a single polynucleotide called?

RNA

21

What is the function of mRNA?

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

22

What is the function of tRNA?

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

23

What is the function of rRNA?

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

24

What is transcription?

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

25

How does transcription take place?

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

26

What is translation?

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)

27

How does translation take place?

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