2.3 nucleic acids

Question 1

what is a gene?

Answer 1

a length of DNA that codes for a polypeptide or length of RNA

Question 2

why do you add ethanol when extracting DNA?

Answer 2

so the DNA forms a precipitate

Question 3

why do you add pineapple juice when extracting DNA?

Answer 3

• a source of protease enzymes

they break down the proteins associated with the DNA is the nuclei

Question 4

why do you add salt when extracting DNA?

Answer 4

To break down the hyrodgen bonds between the DNA and water molecules

Question 5

why do you add washing-up liquid when extracting DNA?

Answer 5

to break down the cell membrane

Question 6

why do you grind your sample when extracting DNA?

Answer 6

to break down the cell walls

Question 7

What are mutations?

Answer 7

a change in the genetic code, leading to a change in the structure of the protein

Question 8

what elements make up nucleic acids?

Answer 8

• Hydrogen
• Carbon
• Oxygen
• Nitrogen
• Phosphorus

Question 9

What is a codon?

Answer 9

a triplet of bases on mRNA

Question 10

What is an anticodon?

Answer 10

a triplet of bases on tRNA

Question 11

What is a base triplet?

Answer 11

a triplet of bases on DNA

Question 12

Why is DNA universal?

Answer 12

almost all living organisms have the same genetic code

Question 13

why is DNA degenerate?

Answer 13

each amino acid has more than 1 codon

Question 14

why is DNA non-overlapping?

Answer 14

each base is only part of one codon

Question 15

what is the structure of DNA?

Answer 15

• 2 polynucleotide chains
• antiparallel
• long

Question 16

what bond joins the phosphate group and pentose sugar in a nucleotide molecule?

Answer 16

a phosphodiester bond

Question 17

How many hydrogen bond do adenine and thymine make?

Answer 17

2

Question 18

how many hydrogen bonds do cytosine and guanine make?

Answer 18

3

Question 19

what is a nucleotide?

Answer 19

a molecules consisting of a
- pentose sugar
- phosphate group
- nitrogenous base

Question 20

what are pyrimidine bases?

Answer 20

Cytosine
Uracil
Thymine

Question 21

what are purine bases?

Answer 21

Adenine
Guanine

Question 22

What are the 3 theories for DNA replication?

Answer 22

• conservative
• semi-conservative
• dispersive

Question 23

How does DNA replicate in prokaryotes?

Answer 23

a bubble sprouts from the DNA loop, causing the loop to unwind and unzip. The complementary nuclotides join to the expose nuclotides. Eventually the whole loop is copied.

Question 24

what is semi- conservative repliacation?

Answer 24

• where the DNA produces is made from 1 original chain and 1 newly synthesised chain

Question 25

how is DNA organised in prokaryotic cells?

Answer 25

DNA is found in a loop in the cytoplasm.

Question 26

Where is DNA found in eukaryotic cells?

Answer 26

- nucleus - mitochondria - chloroplats

Question 27

What sugar is found in DNA?

Answer 27

deoxyribose

Question 28

what bases are found in DNA?

Answer 28

thymine adenine guanine cytosine

Question 29

what bases are found in RNA?

Answer 29

uracil adenine guanine cytosine

Question 30

what sugar is found in RNA?

Answer 30

ribose

Question 31

what are the types of RNA?

Answer 31

mRNA tRNA rRNA

Question 32

What is the process of transcription?

Answer 32

1- the gene unwinds and unzips 2- hydrogen bonds between the complementary bases are broken by DNA helicase 3- DNA polymerase catalyses the formation of phosphodiester bonds between nucleotides to form RNA 4- a complementary length of RNA is produced 5- the mRNA passes out of the nucleus to the ribosomes

Question 33

what is the proces of tanslation?

Answer 33

1- mRNA attatches itself to the ribosomes, tRNA molecules carry amino acids to the ribosomes 2- tRNA moleculw=e with an anticodon attatches itself to a codon on the mRNA 3- a second tRNA molecules attatches itslef to the next codon 4- rRNA catalyses the formation of peptide bonds between the two amino acids 5- this process continues until it reaches a STOP codon on the mRNA

Question 34

what base is found in ATP?

Answer 34

adenine

Question 35

how many phosphate groups are on ATP?

Answer 35

3

Question 36

what sugar is found in ATP?

Answer 36

ribose

Question 37

What are the components of ATP?

Answer 37

- ribose - 3 phosphate groups - adenine.