2.1.3 nucleotides and nucleic acid

Question 1

what does a nucleotide consist of
2.1.3(a)

Answer 1

a pentose sugar
phosphate group
nitrogenous base

Question 2

what are nucleotides the monomer for
2.1.3(a)

Answer 2

nucleic acid

Question 3

what is deoxyribose
2.1.3(a)

Answer 3

the pentose sugar found in DNA nucleotides

Question 4

which ones are purine bases
2.1.3(a)

Answer 4

adenine and guanine
2 carbon and nitrogen based rings

Question 5

which ones are pyrimidine bases
2.1.3(a)

Answer 5

Thymine and cytosine
1 carbon and nitrogen based ring

Question 6

what is the difference between the pentose sugar in RNA vs DNA
2.1.3(a)

Answer 6

RNA-ribose (OH group)
DNA-deoxyribose (H group)

Question 7

where is thymine and Uracil present
2.1.3(a)

Answer 7

thymine-DNA
Uracil-RNA

Question 8

what is a phosphodiester bond
2.1.3(b)

Answer 8

bond between phosphate group and pentose sugar

Question 9

how many pentose sugars is one phosphate group able to join to
2.1.3(b)

Answer 9

one phosphate group is able to bind to two pentose sugars

Question 10

when is the sugar phosphate backbone of the nucleotide formed
2.1.3(b)

Answer 10

the pentose sugars are joined to each other by bonds with the phosphate groups

Question 11

what are ADP and ATP and what do they contain
2.1.3(c)

Answer 11

ATP and ADP are RNA nucleotides containing the nitrogenous base adenine

Question 12

what does the A in ADP and ATP stand for
2.1.3(c)

Answer 12

adenosine, which is what we call adenine bonded to a ribose

Question 13

what does the P stand for in ADP and ATP
2.1.3(c)

Answer 13

phosphate

Question 14

what is ATP and what does it contain
2.1.3(c)

Answer 14

adenosine triphosphate = adenine + ribose + three phosphate groups

Question 15

what is ADP and what does it contain
2.1.3(c)

Answer 15

adenosine diphosphate = adenine + ribose + two phosphate groups

Question 16

what is AMP and what does it contain
2.1.3(c)

Answer 16

adenosine monophosphate = adenine + ribose + one phosphate group

Question 17

what do ATP ADP and AMP provide
2.1.3(c)

Answer 17

they provide the immediate source of energy for every cellular process that requires energy

Question 18

what is the reaction that releases energy from ATP called
2.1.3(C)

Answer 18

The reaction that releases energy from ATP is hydrolysis, which also removes inorganic phosphate groups (Pi) to form ADP or AMP

Question 19

what is the purpose of respiration
2.1.3(c)

Answer 19

to make ATP

Question 20

draw the ATP/ ADP cycle
2.1.3(C)

Answer 20

in booklet

Question 21

what is the polymer DNA made up of
2.1.3(di)

Answer 21

nucleotide monomers bonded together via phosphodiester bonds formed during condensation reaction

Question 22

what is a molecule of DNA made out of
2.1.3(di)

Answer 22

two polynucleotide strands

Question 23

since the two strands run in opposite directions what are they described as
2.1.3(di)

Answer 23

anti parallel

Question 24

since a DNA molecule is long what can it store a lot of
2.1.3(di)

Answer 24

genetic information

Question 25

what is the shape of DNA
2.1.3(di)

Answer 25

double helix as it consists of two strands spiralling in a helix shape

Question 26

what are the bonds between nitrogenous bases
2.1.3(di)

Answer 26

hydrogen bonds

Question 27

what are the complementary base pairs in nucleotides and what hydrogen bonds do they have between them
2.1.3(di)

Answer 27

adenine and thymine- two hydrogen bonds
guanine and cytosine-three hydrogen bonds

Question 28

what would the strand be bonded to if it was
5’ to 3’
3’ to 5’
2.1.3(di)

Answer 28

the next nucleotide would be bonded to the OH group on C3
the next nucleotide would be bonded to the phosphate group on C5

Question 29

what are the steps for DNA extraction
2.1.3(dii)

Answer 29

1. blend/grind - break down the cell walls if they are present e.g. plant or fungi cells (not needed for animal cells)
2. Add salt - break hydrogen bonds between DNA and water molecules
3. Add detergent - dissolve the plasma membrane and nuclear envelope
4. Add protease enzyme to hydrolyse histone proteins
5. Add ethanol to precipitate the DNA. DNA is not soluble in ethanol so it will come out of solution forming a stringy white solid and can be collected.

Question 30

describe how you get 2 DNA molecules that are identical to eachother
2.1.3(e)

Answer 30

1. The DNA molecules is untwisted out of its double helix shape by the enzyme DNA gyrase
2. DNA helicase breaks hydrogen bonds between nitrogenous bases leaving 2 single strands of DNA with exposed bases
   -DNA nucleotides present in the nucleoplasm hydrogen bond to exposed base pairs following the complementary base pair rule
3. DNA polymerase catalyses the formation of phosphodiester bonds between free nucleotides in the 5’ to 3’ direction
   -if the new strand being made runs in the 3’ to 5’ direction DNA polymerase falls off and DNA ligase joins the short sections

Question 31

why is a DNA molecule semi-conservative
2.1.3(e)

Answer 31

each DNA molecule contains one original strand and one new strand

Question 32

what are alleles
2.1.3(e)

Answer 32

different versions of the same gene

Question 33

what is the triplet code
2.1.3(f)

Answer 33

three bases called a codon code for one amino acid

Question 34

what does it mean if the genetic code is universal
2.1.3(f)

Answer 34

a certain codon codes for the same amino acid in all living organisms

Question 35

what does it mean if the genetic code is non-overlapping
2.1.3(f)

Answer 35

each base only belong to one codon

Question 36

what does it mean if the genetic code is degenerate
2.1.3(f)

Answer 36

where a different sequence of bases code for the same amino acid

Question 37

what are the steps to transcription
2.1.3(g)

Answer 37

· A gene untwists by the enzyme DNA gyrase and hydrogen bonds between complementary base pairs are broken by DNA helicase
· Free RNA nucleotides that are complementary to the template strand form hydrogen bonds to the template strand

RNA polymerase catalyses the formation of phosphodiester bonds between the free RNA nucleotides

· mRNA is made

Question 38

what are the steps to translation
2.1.3(g)

Answer 38

mRNA moves out of the nucleus via a nuclear pore and attaches to a ribosome

· The anticodon of a tRNA molecule forms hydrogen bonds to the complementary codon on the mRNA

· The tRNA is carrying a specific amino acid, determined by its anticodon

· tRNA molecules line up, and an enzyme catalyses the formation of peptide bonds between the amino acids they are carrying

· After the polypeptide has been assembled, it is released from the ribosome and the mRNA breaks down over time

Question 39

which strand is used to make mRNA
2.1.3(g)

Answer 39

template strand not the coding strand

Question 40

is the mRNA complementary to the coding strand
2.1.3(g)

Answer 40

yes except the T is replace with U on the mRNA