Nucleic Acids Flashcards

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1
Q

what are the 4 nitrogenous bases in DNA

A

cytosine
thymine
guanine
adenine

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2
Q

what are the 4 nitrogenous bases in RNA

A

cytosine
uracil
guanine
adenine

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3
Q

which nitrogenous DNA bases are purines

A

adenine and guanine

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4
Q

which nitrogenous DNA bases are pyrimidines

A

thymine and cytosine

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5
Q

how many rings do purines have

A

2

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6
Q

how many rings do pyrimidines have

A

1

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7
Q

what is the monomer of DNA

A

nucleotides

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8
Q

what do DNA nucleotides consist of

A

a nitrogenous base
a phosphate group
pentose deoxyribose sugar

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9
Q

what are the bonds involved in DNA

A

phosphodiester bonds
hydrogen bonds

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10
Q

where do phosphodiester bonds form in DNA

A

between phosphate group of one nucleotide and a sugar of the next which forms the sugar phosphate backbone.

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11
Q

DNA is …… stranded. The 2 strands are held together by …….. bonding between the ….. of the 2 strands

A

double
hydrogen
bases

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12
Q

A purine always pair with a ……….

A

pyrimidine

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13
Q

what are the complementary base pairs in DNA

A

thymine and adenine
cytosine and guanine

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14
Q

what is antiparallel

A

the two strands run parallel to eachother but in opposite directions

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15
Q

state 2 main types of nucleic acids

A

RNA- ribonucleic acid
DNA- deoxyribonucleic acid

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16
Q

nucleotide definition

A

monomers used to form nucleic acids

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17
Q

DNA strand definition

A

one of two polynucleotide chains that make up the double helix structure

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18
Q

state 3 main types of activity for which cells require energy

A

synthesis
transport
movement

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19
Q

2 similarities between ATP, DNA, RNA

A

-all have a pentose sugar in the middle
-all of them contain nitrogenous bases

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20
Q

2 differences between ATP, DNA, RNA

A

-DNA pentose sugar=deoxyribose, ATP and RNA= ribose
-ATP contains 3 phosphate groups per nucleotide, RNA and DNA contain 1 per nucleotide

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21
Q

Nucleic acid definition
chemical elements in them

A

large polymers formed from nucleotides
C H N P O

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22
Q

polymer definition

A

long-chain molecules composed of multiple bonded individual molecules (monomers) in a repeating pattern

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23
Q

double helix definition

A

two strands that wind around each other like a twisted ladder

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24
Q

outline structure of pyrimidines

A

smaller, contain single carbon ring structures

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25
Q

outline structure of purines

A

larger, contain double carbon ring structures

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26
Q

5 properties of ATP and why each makes it ideally suited to function as an energy transfer molecules

A

-small- moves easily into/out of and within cells
-water soluble- energy requiring processes happen in aq
-bonds between phosphates with intermediate energy- large enough to be useful for cellular reactions but not so large that energy is wasted as heat
-releases energy in small quantities- quantities are suitable to most cellular needs so energy is not lost as heat
-easily regenerated- can be recharged w energy

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26
Q

5 properties of ATP and why each makes it ideally suited to function as an energy transfer molecules

A

-small- moves easily into/out of and within cells
-water soluble- energy requiring processes happen in aq
-bonds between phosphates with intermediate energy- large enough to be useful for cellular reactions but not so large that energy is wasted as heat
-releases energy in small quantities- quantities are suitable to most cellular needs so energy is not lost as heat
-easily regenerated- can be recharged w energy

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27
Q

similarities and differences between nucleotides of DNA and RNA

A

components
RNA= a nitrogenous base and a ribose sugar and a phosphate group
DNA= deoxyribose sugar, nitrogenous base, phosphate group

DNA= deoxyribose sugar
RNA= ribose sugar

DNA= A T C G
RNA= A U C G

28
Q

polynucleotide definition

A

polymer composed of 13 or more nucleotide monomers covalently bonded in a chain

29
Q

complementary base pairing definition

A

specific hydrogen bonding between nitrogenous bases

30
Q

monomer definition

A

individual molecules that make up a polymer

31
Q

significance of double-stranded, complementary base paired nature of DNA for its function

A

allows to be copied and transcribed
this means the very large DNA molecule does not need to leave the nucleus in order for a cell to receive info for protein synthesis

32
Q

why does a DNA molecule have equal amounts of adenine and thymine and cytosine and guanine

A

DNA is double stranded and has complementary base pairing
this therefore means that for every nitrogenous base there will be an equal amount of its complementary base pair present on the opposite strand

33
Q

importance of the steps in the isolation and purification of DNA by precipitation

A

grind sample in mortar and pestle- breaks down cell walls
mix with detergent- breaks down cell membrane, releasing cell contents into sol
add salt- breaks the H bonds between DNA and water mol
add protease enzymes- break down proteins associated with DNA in nuclei
add layer of ice cold ethanol at 45 degree angle- causes DNA to precipitate
DNA will be seen as white strands forming between layer of sample and layer of alcohol.

34
Q

why is sample grinded in DNA extraction

A

breaks down cell wall

35
Q

why is detergent added in DNA extraction

A

breaks down cell membrane releasing contents into sol

36
Q

why is salt added in DNA extraction

A

breaks hydrogen bonds between the DNA and water molecules

37
Q

why is protease added in DNA extraction

A

break down the proteins associated with the DNA in nuclei

38
Q

why is ethanol added in DNA extraction

A

alcohol causes DNA to precipitate

39
Q

name of reaction that joins nucleotides

A

condensation

40
Q

name of reaction that breaks phosphodiester bonds

A

hydrolysis

41
Q

define sugar-phosphate backbone

A

forms structural framework of nucleic acids.
composed of alternating sugar and phosphate groups and defines directionality of the molecule.

42
Q

define phosphorylation

A

addition of phosphate to an organic compound

43
Q

significance of the sequence of bases in a DNA strand for its function

A

sequence carries the genetic info of an organism
3 consecutive bases code for a single amino acid

44
Q

define universal code

A

refers to the fact that the same specific codons code for the same amino acids in all living organisms

45
Q

process of transcription

A
  • DNA uncoiled by DNA helicase
  • RNA polymerase adds free complementary ribonucleotides to the template (antisense) strand
  • sense strand (new) of DNA contains triplet code in correct order but is not transcribed
    -antisense strand of DNA= complementary to the sense strand & is transcribed to make mRNA (copy of the sense strand)
  • condensation (phosphodiester) joins ribonucleotides to form mRNA
    -mRNA separates from DNA and leaves nucleus through nuclear pores
46
Q

transcription definition

A

process of copying sections of DNA base sequence to produce smaller molecules of mRNA which can be transported out of nucleus via nuclear pores to site of protein synthesis

47
Q

structure of mRNA

A

-linear, single stranded molecule
-contains ribose
-contains bases A U G C
-carries codon sequence complementary to the sequence of the gene.

48
Q

structure of tRNA

A

-single strand of RNA folded into clover leaf shape with 3 bases (anticodon) at one end of molecule
-contains ribose
-contains bases A U G C
-carries an anticodon which is complementary to the codon on mRNA

48
Q

structure of tRNA

A

-single strand of RNA folded into clover leaf shape with 3 bases (anticodon) at one end of molecule
-contains ribose
-contains bases A U G C
-carries an anticodon which is complementary to the codon on mRNA

49
Q

structure of DNA

A

-double stranded
-antiparallel
-double helix
-contains deoxyribose
-contains bases A T G C
- carries the original codon complementary to mRNA

50
Q

function of mRNA

A

carries genetic information (amino acid sequence order) copied from DNA

51
Q

function of tRNA

A

delivers correct amino acids to the ribosome in order to make up a polypeptide

52
Q

function of DNA

A

carries the genetic material of an organism

53
Q

how are polynucleotide strands made and broken down

A

condensation reaction between nucleotides form strong phosphodiester bonds (S-P backbone)
Hydrolysis reactions use a molecule of water to break these bonds
enzymes can catalyse these reactions

54
Q

name complementary base pairs in RNA and DNA and n. H bonds

A

DNA= 2 H bonds between adenine and thymine
RNA= 2 H bonds between adenine and uracil
BOTH= 3 H bonds between cytosine and guanine

55
Q

why is DNA replication described as semi conservative

A

strands from OG DNA molecule act as templates
new DNA consists of 1 new and 1 old strand

56
Q

explain role of DNA helicase in semiconservative replication

A

breaks H bonds between base pairs and unzips to form 2 single strands which can act as a template

57
Q

how is a new strand formed in SC replication

A
  1. free ribonucleotides from nucleoplasm/nuclear sap attach to exposed complementary bases
  2. DNA polymerase joins adjacent nucleotides on new strand in a 5-3 direction via condensation reaction to form phosphodiester bonds
  3. H bonds reform
58
Q

identify 3 features of genetic code

A

non-overlapping (each triplet is only read once)
degenerate (more than one triplet codes for each amino acid)
universal (same bases and sequences used by all species)

59
Q

how does a gene determine sequence of amino acids in a protein

A

consists of base triplets that code for specific amino acids

60
Q

what does transcription produce

A

mRNA

61
Q

where does transcription occur

A

nucleus

62
Q

what happens after strand of mRNA is transcribed

A
  1. RNA polymerase detaches at terminal region
  2. H bonds reform, DNA recoils
  3. splicing removes introns from pre-mRNA in eukaryotes
  4. mRNA moves out via nuclear pore and attaches to ribosome (translation)
63
Q

what does translation produce

A

proteins

64
Q

where does translation occur

A

in cytoplasm on ribosomes

65
Q

outline translation

A
  1. ribosome moves along mRNA until start codon
  2. tRNA anticodon attaches to comp codon on mRNA
  3. condensation R forms peptide bonds between amino acids on tRNA
    (requires energy ATP from hydrolysis)
  4. process continues to form polypeptide chain until stop reached
66
Q

describe structure of ATP and ADP

A

nucleotide derivative of adenine
ATP has 3 inorganic phosphate groups
ADP has 2

67
Q

what is a mutation

A

alteration to DNA base sequence, often arise spontaneously during DNA replication