3.1.5- Nucleic Acids

Question 1

Our genetic code is

Answer 1

Composed of DNA

The same in all living organisms

Question 2

Chromosomes

Answer 2

23 pairs in every body cell

Made of DNA/proteins

store info for the body

Question 3

Genes

Answer 3

Short sections of DNA that code for 1 polypeptide or functional RNA

Question 4

Nucleotides

Answer 4

monomers of nucleic acids, make up DNA

Question 5

Structure of DNA

Answer 5

double helix, two polynucleotide chains linked by hydrogen bonds, chains are anti parallel

Question 6

phosphodiester bond

Answer 6

the type of bond that links the nucleotides in DNA or RNA. joins the phosphate group of one nucleotide to the hydroxyl group on the sugar of another nucleotide

Question 7

What do nucleotides consist of?

Answer 7

1. Nitrogenous base
2. Pentose sugar (deoxyribose)
3. Phosphate group

Question 8

Complementary Base Pairs

Answer 8

A&T, C&G

Question 9

A & T

Answer 9

Adenine & Thymine

Question 10

G & C

Answer 10

Guanine and Cytosine

Question 11

Non-coding DNA

Answer 11

components of an organism’s DNA that do not encode protein sequences. Also known as junk DNA

Question 12

What is RNA?

Answer 12

ribonucleic acid

Question 13

Pentose sugar in RNA

Answer 13

ribose sugars

Question 14

Bases in RNA

Answer 14

adenine, guanine, cytosine, uracil

Question 15

mRNA

Answer 15

messenger RNA

Question 16

tRNA

Answer 16

transfer RNA

Question 17

rRNA

Answer 17

ribosomal RNA

Question 18

Ribosomal RNA role

Answer 18

Combines with protein to make up the ribosomes structure

Question 19

Messenger RNA role

Answer 19

Copies of the dna sequence which leaves the nucleus through membrane pores and gives instructions to the ribosomes to make proteins

Question 20

Transfer RNA

Answer 20

Carries specific amino acids during the process of protein synthesis (called translation)

Question 21

Why is DNA replication important?

Answer 21

So new cells have the same DNA as old ones.

Growth, specialisation, reproduction

Question 22

3 models of DNA replication

Answer 22

semiconservative, conservative, dispersive

Question 23

conservative replication

Answer 23

A disproved model of DNA synthesis: suggests 1 of the DNA molecules contain both parental strands and the other contains only newly synthesised DNA

Question 24

dispersive replication

Answer 24

a disproved model of DNA synthesis suggesting more or less random interspersion of parental and new segments in daughter DNA molecules. Both strands have old and new

Question 25

semi-conservative replication

Answer 25

in each new DNA double helix, one strand is from the original molecule, and one strand is new

Question 26

What does DNA require to replicate?

Answer 26

A template, free nucleotides, energy, DNA helicase, DNA polymerase

Question 27

Role of DNA template

Answer 27

acts a copy/template so that a new strand can be created.

Question 28

role of free nucleotide

Answer 28

they make up a new stand of DNA and synthesise it so you have enough DNA strands.

Question 29

role of energy

Answer 29

enables reactions to occur

Question 30

Role of DNA helicase

Answer 30

enzymes break hydrogen bonds to break apart the strands and therefore the helix also

Question 31

role of DNA Polymerase

Answer 31

synthesizes new DNA strand by adding nucleotides covalently to the 3' end of a primer/ DNA strand. Resynthesises backbone and phosphodiester bond

Question 32

Step 1 of semi conservative replication

Answer 32

DNA helicase breaks the hydrogen bonds and therefore breaks the strands apart

Question 33

Step 2 of semi conservative replication

Answer 33

2 template strands are formed

Question 34

Step 3 of semi conservative replication

Answer 34

Free nucleotides join onto complementary bases of template strands

Question 35

Step 4 of semi conservative replication

Answer 35

hydrogen bonds are formed between free nucleotides and and template

Question 36

Step 5 of semi conservative replication

Answer 36

DNA polymerase forms the phosphodiester bonds which reforms the sugar-phosphate backbone

Question 37

step 6 of semi conservative replication

Answer 37

Two new DNA molecules are formed each containing half of the parent DNA

Question 38

A & T hydrogen bonds

Answer 38

2 hydrogen bonds

Question 39

G & C hydrogen bonds

Answer 39

3 hydrogen bonds