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AS Biology > Chapter 6: Protein Synthesis > Flashcards

Chapter 6: Protein Synthesis Flashcards

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AP® Biology flashcards Biology 101 flashcards
1
Q

2 types of genetic material

A

DNA and RNA

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2
Q

what are DNA and RNA

A

macromolecules ie polymers made of repeated monomer nucleotides (polynucleotides)

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3
Q

difference between dna and rna

A

dna is double stranded

rna is single

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4
Q

important features of genetic material

A

it carries genetic info in form of genes that are responsible for characters
it is able to be copied when cell divides into daughter cells

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5
Q

components of a nucleotides

A 
phosphate group
pentose sugar (deoxyribose/ribose)
nitrogenous base (A,T/U,G,C)
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6
Q

difference between deoxyribose and ribose sugars

A

at position 2 carbon instead of hydroxyl group in ribose we find hydrogen in deoxyribose

recall structure

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7
Q

study structures of phosphate and both sugars and somewhat that of purines and pyramidines bases

A

okur

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8
Q

which of A T/U G C are purines and pyramidines

A

Purines- A, G

Pyrimidines- T/U, C

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9
Q

bonds between bases

A

hydrogen bonds
A double bond T
G triple bond C

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10
Q

why do purines only link with pyramidines and vice versa but not with their alike bases

A
  • purines are bigger molecules than pyramidines
  • in a dna double strand there is just enough room between the 2 strands for a purine and pyramidine
  • 2 purines will be too big and 2 pyramidines will be too small too fit in between
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11
Q

structure of DNA

A
  • double stranded
  • antiparallel in orientation (3’ to 5’ and 5’ to 3’)
  • 3’-5’ phosphodiester bond backbone
  • 2 strands held together by hydrogen bonds (nature) between bases via complementary base pairing
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12
Q

gene expression ie from dna to protein

A

DNA replicated this is catalysed by DNA polymerase
DNA transcripted to RNA this is catalysed by RNA polymerase
RNA is translated into protein

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13
Q

state the 3 models of DNA replication

A
  • conservative
  • semiconservative
  • dispersive
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14
Q

describe the 3 models of DNA replication

A
  • conservative: one fully new double helix daughter DNA made from one old parent, which doesnt change
  • semiconservative: 2 new molecules each contain one old parental strand and one new complementary daughter strand. H bonds broken
  • dispersive: new molecule made of bits of old and new bits randomly scattered
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15
Q

experimental evidence for the semiconservative model

A
  • meselson and stahl supplied E.coli bacteria with NH4Cl and N-15 isotope initially
  • left in NH4Cl to divide so almost all DNA had N15
  • then transferred to N14 medium for 3 gens
  • then this was centrifuged in caesium chloride solution
  • results of bacteria grown in only N15 had a band of DNA
  • then for those grown in N14 1st gen there is one thick band of DNA above then previous one
  • then for 2nd gen with N14 there were 2 bands (equal)
  • then for 3rd gen grown with N14 there was a thin band below and thick band above
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16
Q

explanation for results of the centrifuging of gens.

remember n15 is heavier than n14. use this to explain the bands

A
  • initial dna made to 2 n15 strands daughter
  • that replicated again to make 2 new dna each of 1 n15 and 1 n14 strands
  • those replicate to 4 dna. 2 are of 1 n15 and 1 n14 strands. other 2 are both n14 strands only
  • these 4 again lastly replicated to give 8 dna. 2 are of 1 n15 and 1 n14. 6 are of only n14 .

now relate this to the bands in previous fc

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17
Q

mechanism for dna replication

A

1) dna double helix unwinds and unzips as h bonds break
2) in nucleus, free activated nucleotides with 2 extra phosphates which activate and enable them to take part in reactions
3) bases on act.nucl. pair up with complementary bases on each old strand.
4) enzyme dna polymerase links sugar and phosphate of neighbouring molecules together. (only linked if bases are complementary. so errors are like 1 in ever 10^8)
5) phosphates broken off and released to nucleus
6) enzyme polymerises act.nucl. comp to nucls of comp strand in 5’-3’ orientation

18
Q

mRNA function

A

carries message from DNA to ribosome for protein synthesis

19
Q

mrna synthesis direction

A

5’-3’

20
Q

mrna formulation occurs complementary to which dna strand and which enyzyme catalyses this

A

template/sense strand which is 3’-5’

rna polymerase

21
Q

rRNA is present _ and has _ strands and function is

A

in ribosomes along with protein
single stranded
helps in protein synthesis

22
Q

ribosome made up of

A

large and small subunits, made of rRNA and proteins

23
Q

tRNA is found in

A

cytoplasm

24
Q

structure of tRNA

A
  • single stranded polynucleotide chain thats folded into a clover shape
  • runs 5’-3’ where 5’ is start of strand and ends with phosphate, and 3’ is amino acid attachment site and has CCA bases overhang always
  • at the bottom there are different anticodons loop ie 3 bases comp to mrna codon bases
  • some h bonds create some areas of base pairing within strand
25
Q

function of trna

A

transfer amino acids from cytoplasm to ribosome for protein synthesis

26
Q

what are polyribosomes

A

in prokaryotes many ribosomes work on same mrna strand at same time to translate it

27
Q

differences in translation between pro and eu karyotes

A

1) in pro tc and tl are simultaneous as nucleus is not bounded by membrane, in eu its not due to membrane
2) in pro 70s ribosomes involved, in eu its 80s
3) in pro mrna is in cytoplasm, in eu its in nucleus
4) in pro its fast, eu is slow

28
Q

james watson and crick model of dna as in size of height and width of turns
how many bp per turn

A

width- 2nm
height- 0.34nm
10bp

29
Q

what is the chargaff rule

A

A=T and G=C as in amounts of each
so
A/T=G/C=1

30
Q

why is rna more reactive than dna

A

hydroxyl group at position 2 carbon of ribose makes rna more sensitive
rna is single stranded while dna is double

31
Q

structure of ATP

A

adenine base attached to sugar which makes the nucleoside called adenosine
when this is attached to 3 phosphate groups it is ATP a nucleotide

check structure picture

32
Q

difference between atp and dna

A

pentose sugar in atp is ribose, dna is deoxyribose
atp has 3 phosphates, dna has 1
atp has adenine base, dna has ATGC

33
Q

difference between atp and rna

A

atp has 3 phosphates, dna is has 1

atp has adenine base, rna has AUGC

34
Q

difference between nucleotide and nucleoside

A

nt=pentose sugar+base+phosphate

ns+pentose sugar+base

35
Q

what is mutation

A

alteration in gene sequences where genes code for character, so mutation codes for altered character

36
Q

alternate form of gene called

A

allele

37
Q

dna and rna are polymers of _ and proteins are polymers of _

A

nucleotides

amino acids

38
Q

what do proteins do

A

control cell activities eg enzymes catalyse metabolic reactions

39
Q

sickle cell anaemia is

A
  • autosomal recessive disorder
  • on chromosome no 11 (an autosome)
  • due to base substitution mutation in DNA where CTT coding hydrophilic glutamine replaced with CAT coding hydrophobic valine amino acid
  • hence at position 6 of beta polypeptide chain theres a hydrophobic amino acid which changes circular rbc into a sickle shaped rbc
40
Q

what is translation

A

conversion of nucleotide sequence of mRNA to amino acid sequence of protein

41
Q

genetic code of amino acid

A

3 nucleotides ie bases

42
Q

expression used to find total no of amino acids in the world

A

4^n where 4 is no. of known nucleotides and n is no. of nucleotides coding for an amino acid ie 3
so 4^3=64 but only 20 aa in the world. this is because different base combinations can code for the same amino acid

AS Biology (11 decks)

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