chapter 2 Flashcards

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1
Q

what are the differences between DNA and RNA?

A
  1. RNA has ribose not deoxyribose sugar, meaning 1 extra oxygen atom
  2. RNA is single stranded, DNA double stranded
  3. RNA has uracil, while DNA has thymine
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2
Q

ends of a double helix

A

one 5’ (phosphate) one 3’ (sugar)

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3
Q

mRNA vs rRNA vs tRNA

A

mRNA is the result of transcription, goes to places to synthesise proteins
rRNA lives in ribosomes, tRNA translates mRNA into amino acids forming polypeptide chains

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4
Q

how does transcription occur, including processing

A
  1. RNA polymerase enzyme breaks apart DNA from the promoter to the terminator and attatches free complementary pairs to the template strand to form a pre-mRNA strand.
  2. a 5’ methyl-G cap is added, and poly-A tail to the 3’ end
  3. introns are spliced
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5
Q

the steps of translation

A
  1. mRNA binds to a ribosome, and a tRNA’s anticodon binds to its codon.
  2. the attatched amino acids of many tRNAs form a polypeptide chain.
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6
Q

exon vs intron

A

exon is a coding region, intron is not

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7
Q

promotor in eukaryotes is often:

A

TATAAA

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8
Q

what protein splices introns?

A

spliceosome

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9
Q

anticodon vs codon

A

the opposite of a codon, codon codes for 1 amino acid

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10
Q

polypeptide chain

A

a string of amino acids bonded togetehr

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11
Q

silent mutation

A

doesn’t affect amino acid sequence

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12
Q

coding strand

A

same as RNA but with T not U

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13
Q

template strand

A

what RNA binds to and is the opposite of

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14
Q

direction of movement in transcription

A

5’end to 3’end (nucleotides added to 3’end)

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15
Q

alternative splicing

A

exons being excluded or included to make different mature mRNA ! (NO ORDER SWITCHIGN THOUGH JUST THINGS LEFT OUT)

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16
Q

4 key structure things of an amino acid

A
  • amino group
  • carboxyl group
  • central carbon + hydrogen
  • r variable group
17
Q

how many r groups are there and what r their properties

A
  • 20 amino acids
  • polar/nonpolar
    hydrophillic/phobic
    acidic/basic
    charged/uncharged\
18
Q

how do amino acids bond

A

peptide bonds

19
Q

qualities of peptide bonds

A
  • produces water (condensaton reaction)
  • requires energy
  • anabolic (big molecule made from little ones)
  • amine joins to carboxyl
20
Q

proteins are one of the four:

A

biomacromolecules

21
Q

structures:

A

primary - the polypeptide chain
secondary- beta pleated or alpha helices of polypeptide
tertiary - r groups reacting
quarternary - optional, multiple poypeptide chains

22
Q

proteome

A

protein genome - all of an organisms proteins at one specific time, can change.

23
Q

quarternary also contains:

A

prosthetic group

24
Q

protein malfunction

A

conformational change due to mutations, heating, acidic change etc

25
Q

process of protein secretion

A
  1. proteins made in ribosomes on rough ER
  2. rough ER folds polypeptide chains, transport vesicle sends to golgi
  3. golgi apparatus sorts and packages the proteins
  4. secretory vesicle encloses proteins and does exocytosis (active transport)
26
Q

structural genes

A

produce proteins for structure/functions
often found towards 3’ end

27
Q

regulatory genes

A

produce regulatory proteins like repressor or activator proteins: which control splicing, increase/starting of gene expression, descrease/stopping of gene expression.

28
Q

operon

A

multiple genes that serve the same purpose controlled by the same promoter and operator

29
Q

explain the trp operon

A

the trp operon produces tryptophan in e-coli. when there is lots of trp, the trp binds to the repressor protein made by TrpR, which can then bind to the trp operator, stopping the production of tryptophan.

30
Q

non terminator hairpin vs terminator hairpin

A

terminator is between regions 3-4, stops transcription by deattatching RNA polymerase, nonterminator hairpin is between 2-3, doesnt stop transcription

31
Q

attenuation

A
  1. operator doesnt stop RNA polymerase despite high levels of trp
  2. ribosome doesnt pause at the two trp codons
  3. terminator hairpin forms between 3-4, which breaks the attenuator
  4. transcription stops
32
Q

disulphide bridge

A

bond formed between two cystine amino acids

33
Q

attenuation

A

a back up regulatory mechanism that stops transcription/translation of eg the trp operon when it is not needed eg when there is tryptophan

34
Q

why might the trp repressor not work?

A

trp isnt free floating but still attatched to tRNA
or repressor detatched with trp available

35
Q

leader region

A

trpL, goes before the exons for proteins, contains attenuator