structure of DNA and RNA

Question 1

what does DNA do?

Answer 1

a molecule that stores genetic information

Question 2

what is RNA responsible for?

Answer 2

transferring genetic information from DNA to ribosmoes

Question 3

where are ribosomes formed from?

Answer 3

RNA, as well as proteins

Question 4

what is a nucleotide made up of?

Answer 4

• a pentose sugar
• a nitrogen-containing organic base
• a phosphate group

Question 5

why is a ‘pentose’ sugar so called?

Answer 5

it has 5 sugars

Question 6

what is the pentose sugar in DNA?

Answer 6

deoxyribose

Question 7

what is the pentose sugar in RNA?

Answer 7

ribose

Question 8

name all the organin is bases

Answer 8

• adenine
• cytosine
• guanine
• thymine
• uracil

Question 9

name all the organic bases present in DNA

Answer 9

• adenine
• cytosine
• guanine
• thymine

Question 10

name all the organic bases present in RNA

Answer 10

the same as DNA however with uracil instead of thymine

Question 11

name the bond formed when two neucleotides are joined

Answer 11

phosphodiester

Question 12

what type of reaction is used to join the nucleotides together ?

Answer 12

condensation

Question 13

what is the only way in which one polynucleotide chain can differ from another?

Answer 13

the sequenece of bases in the polynucleotide

Question 14

what are both DNA and RNA molecules examples of ?

Answer 14

a group of biological molecules called nucleic acids

Question 15

what are both DNA and RNA polymers made of?

Answer 15

monomer units called nucleotides

Question 16

how many components is a nucleotide made up of?

Answer 16

3

Question 17

what do many nucleotides together form?

Answer 17

a polynucleotide strands

Question 18

why is it referred to as a sugar phosphate backbone?

Answer 18

the phosphate group and the sugar are identical throughout the chain

Question 19

give examples of purines

Answer 19

adenine and guanine

Question 20

give examples of pyrimidines

Answer 20

thymine and cytosine

Question 21

which base is larger out of purines and pyrimidines?

Answer 21

purines are larger bases the pyramdines

Question 22

how are the vases in each strand of DNA held together?

Answer 22

with hydrogen bonds

Question 23

which bases are always paired with each other in DNA?

Answer 23

adenine always pairs with thymine

cytosine always pairs with guanine

Question 24

what term is used to describe the pairing of bases?

Answer 24

complementary base pairing

Question 25

how many hydrogen bonds do adenine and thyine form ?

Answer 25

2

Question 26

how many hydrogen bonds do cytosine and guanine fom?

Answer 26

3

Question 27

A sample of DNA was analysed and 15% of the nucleotides contained adenine. what % of the nucleotides would u expect to contain guanine? explain your answer

Answer 27

``` 35% 15 x 2 =30 100 - 30 =70 70 / 2 =35 if 15% are adenine then 15% must be thymine as they are complementary, so the rest is guanine and thymine, guanine and cytosine are present equally ```

Question 28

describe the structure of DNA?

Answer 28

two long polynucleotide chains one running the opposite way to the other twisting to form a double helix the bases on each strand held together by hydrogen bonds

Question 29

some viruses have single stranded DNA. hoe could an analysis of a piece of DNA tell you if it was sngle stranded ?

Answer 29

there would not be an equal proportions of adenine, thymine, guanine and cytosine, due to no base pairing

Question 30

what makes DNA a stable molecule?

Answer 30

it is a double helix many hydrogen bonds the covalent bonds in the sugar phosphate backbone

Question 31

what allows DNA to replicate exactly when cells divide?

Answer 31

complementary base paring

Question 32

why is complementary base pairing useful in the structure of DNA?

Answer 32

allows DNA to replicate exactly

Question 33

in DNA replication what do weak hydrogen bonds allow for ?

Answer 33

the separation of the DNA strand

Question 34

in DNA what controls protein synthesis?

Answer 34

it has a precise genetic code, determined by the sequence of bases

Question 35

what does the double helix shape of DNA allow for ?

Answer 35

DNA molecules are long, so contain large amounts of coded information, so the double helix shape allows it to fit inside the nucleus of cells

Question 36

how many different bases are there in DNA?

Answer 36

4

Question 37

how many different amino acids are there in proteins?

Answer 37

20

Question 38

which base is not found in RNA?

Answer 38

thymine

Question 39

is uracil a purine or pyrimidine base?

Answer 39

pyrimidine

Question 40

describe the structure of RNA

Answer 40

relatively short | single stranded polynucleotide made up of RNA nucleotides

Question 41

where does protein synthesis occur?

Answer 41

on ribosomes found in the cytoplasm and on the rough enodplasmic reticulm

Question 42

why did scientists think proteins were more likely to contain the genetic information than DNA?

Answer 42

they had a greater chemical diversity , more monomer units meaning a greater number of combinations of how they can be joined together