Nucleic Acids

Question 1

What does ATP stand for?

Answer 1

adenine triphosphate (nucleotide)

Question 2

define nucleotide

Answer 2

polymers made from monomers known as nucleotides

Question 3

What are the components of a nucleotide?

Answer 3

Penrose sugar, phosphate group, organic nitrogenous base

Question 4

What are the components of ATP?

Answer 4

adenine, ribose, 3 phosphate groups

Question 5

why is ATP referred to as the universal energy currency?

Answer 5

usable form of energy used by all living cells. carries energy from energy releasing reactions to energy consuming reactions

Question 6

how does ATP release energy?

Answer 6

hydrolysis reaction with ATPase. exergoic reaction (produces 30.6KJ energy). becomes ADP

Question 7

how does ADP form ATP?

Answer 7

condensation reaction with ATP synthase. Endergonic reaction (takes energy). energy stored in bonds

Question 8

5 roles of ATP

Answer 8

1) active transport, 2) metabolic processes, 3) movement, 4) nerve transmission, 5) secretion

Question 9

why is ATP better than glucose as an energy source?

Answer 9

uses less enzymes, one step, immediate energy, can release small amounts of energy, easily transported

Question 10

What are pyramidine bases?

Answer 10

smaller and single rings. thynine, cytosine and uracil

Question 11

What are purine bases?

Answer 11

larger with double rings. adenine and guanine

Question 12

What does DNA stand for.

Answer 12

deoxyribonucleic acid

Question 13

What are the functions of DNA?

Answer 13

carries genetic code for protein synthesis which is replicated in cell division

Question 14

describe the structure of DNA

Answer 14

2 polynucleotide strands twisted in double helix held together between base pairs by hydrogen bonds. strands anti parallel. Penrose sugar= DEOXYRIBOSE. Bases: adenine, thynine, guanine, cytosine

Question 15

how is a polynucleotide formed?

Answer 15

covalent bond between sugar and phosphate formed by condensation. hydrogen bonds hold base pairs together.

Question 16

What is the bond between two nucleotides?

Answer 16

phosphodiester

Question 17

What is the bond between complimentary base pairs?

Answer 17

hydrogen

Question 18

describe the process of DNA replication

Answer 18

H bonds between bases break by DNA helicase. 2 strands separate so unwind. each strand is template. free DNA nucleotides align opposite complimentary bases. DNA polymerase catalysts condensation reaction to join them. each new molecule has one stand from original template and one new one.

Question 19

describe the conservative DNA theory

Answer 19

DNA produces two daughter DNA. one has both originals and one has two daughter chains

Question 20

describe the semi conservative theory

Answer 20

DNA molecules separate. each act as template and produce one new strand each.

Question 21

describe evidence for semi conservative replication

Answer 21

meselson-stahl experiment. bacteria grown from 15N (heavy) to label N containing base. put on culture of 14N to replicate. density of DNA of each generation extracted and centrifuged. first gen= all intermediate in mass. second gen= 1/2 intermediate, 1/2 light

Question 22

why was e.coli used?

Answer 22

easy to culture. DNA not in nucleus

Question 23

What does RNA stand for? what is it used for.

Answer 23

Ribonucleic acid for protein synthesis

Question 24

describe the structure of RNA

Answer 24

single stranded polynhcleotide. Penrose sugar= ribose. bases= adenine, uracil, guanine and cytosine

Question 25

two differences between DNA nucleotide and RNA nucleotide

Answer 25

1) deoxyribose vs ribose. 2) thymine vs uracil

Question 26

three differences between DNA polymer and RNA polymer

Answer 26

1) double stranded vs single stranded. 2) large vs small. 3) 1 type vs 3 types (rRNA, mRNA, tRNA)

Question 27

What is the function of mRNA?

Answer 27

messenger. single stranded that carries genetic code for specific protein from DNA in nucleus -> ribosomes in cytoplasm

Question 28

What is the function of rRNA?

Answer 28

ribosomal. this + protein = ribosomes. translates genetic code and hounds amino acids to form polypeptides. made by nucleolus.

Question 29

What is the function of tRNA?

Answer 29

transfer. transfers specific amino acid to ribosome. clover leaf shape held by H bonds. AA attaches one end with anticodon at opposite end.

Question 30

describe genetic code

Answer 30

DNA stores genetic info coded in sequence of bases. three determine sequence of amino acids that are joined together to form polypeptide.

Question 31

define gene

Answer 31

section of DNA that codes for specific polypeptide

Question 32

define codon.

Answer 32

series of 3 bases that code for amino acid in mRNA only

Question 33

how many possible codes? how many amino acids?

Answer 33

64 possible codes with 20 amino acids

Question 34

describe the properties of the genetic code

Answer 34

LINEAR, TRIPLET, NON-OVERLAPPING, DEGENERATE, UNABIGUOUS, UNIVERSAL CODE

Question 35

define introns

Answer 35

non coding nucleotide- repeated. spliced out after transcription. number of repeats that causes generic variation.

Question 36

define exons

Answer 36

coding sequences that are left behind and spliced together by ligase to form mature DNA

Question 37

difference between eukaryotes and prokaryotes regarding introns and exons

Answer 37

eukaryotes= introns= discontinuous genes. prokaryotes= exons= continuous genes

Question 38

what comes first: transcription or translation

Answer 38

transcription

Question 39

describe the process of transcription

Answer 39

1) gene unwind by DNA helicase- H bonds break. 2) activated rRNA nucleotides H bond with complimentary base pair by RNA polymerase-> mRNA. 3) mRNA= complimentary to template (T=U) 4) DNA reminds. 5) mRNA release out of nuclear pore to ribosome

Question 40

describe ribosomes

Answer 40

protein + rRNA. free in cytoplasm or RER. large and small subunit. large subunit= 2 attachment sites for tRNA. small subunit= binds to mRNA

Question 41

describe the process of translation

Answer 41

initiation: ribosome attaches to start codon on mRNA. codon on mRNA H bond to anticodon on tRNA. elongation: two amino acids form peptide bond. first tRNA leaves ribosome and ribosome moves along one codon. next tRNA binds. termination: stop codon reached

Question 42

two types of mutation

Answer 42

1) deletion: nucleotide removed which effects amino acid sequence. 2) substitution: base is change- less impact as other bases same

Question 43

describe protein production

Answer 43

DNA codes for amino acids. mRNA made in transcription. ribosomes synthesise mRNA. RER transports protein, Golgi body modifies and packages it, released by exocytosis