DNA replication - biological molecules

Question 1

what is DNA’s main use

Answer 1

to store genetic information

Question 2

what is RNA’s main function

Answer 2

to transfer genetic information from DNA to the ribosomes

Question 3

what occurs in the ribosomes

Answer 3

translation - make polypeptide chains

Question 4

what is a nucleotide made from

Answer 4

a pentose sugar
a base made of nitrogen
a phosphate group

Question 5

a nucleotide is a m—–

Answer 5

monomer

Question 6

what monomers make up DNA and RNA

Answer 6

nucleotides

Question 7

what is the pentose sugar in DNA called

Answer 7

deoxyribose

Question 8

what do every DNA nucleotide have the same

Answer 8

sugar and phosphate group but different bases

Question 9

what are the 4 different bases in DNA

Answer 9

adenine, cytosine, guanine or thymine.

Question 10

what is the name for the sugar moelcule in RNA

Answer 10

ribose

Question 11

what are the 4 different bases in RNA

Answer 11

adenine, cytosine, guanine or uracil.

Question 12

which base gets replaced in RNA

Answer 12

T with Uracil

Question 13

what is a polynucleotide

Answer 13

a polymer of nucleotides

Question 14

what reaction forms polynucleotides

Answer 14

a condensation reaction

Question 15

what bonds in formation of polynucleotides

Answer 15

phosphate group of one nucleotide and sugar of another

Question 16

what bond forms in the condensation of nucleotides

Answer 16

phosphodiester bond

Question 17

what is the sugar-phosphate backbone

Answer 17

the chain of sugar and phosphates formed in condensation reaction

Question 18

how many chains is DNA made up of

Answer 18

2 polynucleotide chains

Question 19

how do the chains in DNA join up

Answer 19

hydrogen bonding

Question 20

what is complementary base pairing

Answer 20

each base can only join to another specific base

Question 21

which bases pair with each other

Answer 21

A-T
C-G

Question 22

how many hydrogen bonds form between A and T

Answer 22

2

Question 23

how may hydrogen bonds form between C and G

Answer 23

3

Question 24

how does DNA twist around

Answer 24

two antiparallel strands twist to form double helix

Question 25

what does antiparallel mean

Answer 25

they run in opposite directions

Question 26

what is RNA's polynucleotide chain like

Answer 26

relatively short

Question 27

why was DNA not believed to carry genetic code historically

Answer 27

its simple chemical composition

Question 28

what does semi conservative DNA replication mean

Answer 28

in the daughter DNA one strand is from parental DNA and one is new

Question 29

what does DNA helicase enzyme do

Answer 29

breaks the hydrogen bonds between bases

Question 30

what effect will helicase have on the double helix

Answer 30

causes the helix to unwind to form two single strands

Question 31

what does each original strand then do

Answer 31

acts as a template for a new strand

Question 32

what effect does complementary base pairing have on free floating nucleotides

Answer 32

causes free floating nucleotides to be attracted to their exposed base on original template strand

Question 33

what happens to adjacent nucleotides

Answer 33

they are joined together by a condensation reaction

Question 34

what is the function of DNA polymerase

Answer 34

to join together adjacent nucleotides

Question 35

what does each new DNA molecule contain

Answer 35

one strand from original DNA and one new strand

Question 36

what was the first step in Meselson and stahls experiment

Answer 36

they grew 2 samples of bacteria one containing 14N nitrogen and one containing 15N nitrogen

Question 37

what was known about the differences with 15N and 14N

Answer 37

15 was heavier so DNA would settle lower down the tube 14 n would settle at top of tube

Question 38

Describe the structure of DNA

Answer 38

Double helix Nucleotides held together by phosphodiester bonds Bases held by H bonds Polymer if nucleotides Each nucleotide made of deoxyribose, phosphate and base

Question 39

Describe how a phosphodiester bond is formed between two nucleotides

Answer 39

Condensation reaction Between phosphate and deoxyribose Catalysed by DNA polymerase

Question 40

Explain the process of DNA separation

Answer 40

DNA helicase seperates the two strands Breaking apart H bonds between bases

Question 41

What does DNA polymerase do

Answer 41

Joins adjacent nuclotides Catalyst for condensation reactions Catalyses formation of phosphodiester bonds

Question 42

What is the role of single stranded DNA fragment?

Answer 42

Template for DNA replication Determines order of nucleotides

Question 43

What is the role of DNA nucleotides?

Answer 43

Contains bases for complementary base pairing

Question 44

What two features of DNA help it with semi-conservative replication

Answer 44

Contains H bonds which allows strands to be separated Has Two strands and both can act as templates

Question 45

Describe the role of the 2 enzymes in semi conservative replication

Answer 45

DNA helicase breaks apart H bonds Dna polymerase joines adjacent nucleotides Forming phosphodiester bonds

Question 46

How is a gene a code for the production of a polypeptide?

Answer 46

Base sequence triplets Time in sequence of amino acids

Question 47

How does the phosphodiester form between two nucleotides within DNA?

Answer 47

During condensation reaction the bond forms between phosphate group and deoxyribose. It’s catalysed by DNA polymerase.