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Unit 3 Chapter 2 - Nucleic acids and proteins Flashcards

1
Q

What is a proteome?

A

All the proteins expressed by a cell or organism at a given time

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2
Q

How are amino acids joined togehter?

A

Condensation polymersation reaction

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3
Q

What is the bond formed between 2 amino acid monomers?

A

Peptide bond

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4
Q

What makes an amimo acid unique?

A

R group (changes chemical properties)

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5
Q

What are the 4 levels of organisation in protein structure?

A

Primary
Secondary
Tertiary
Quaternary

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6
Q

What is the primary structure?

A
  • linear structure of amino acids linked by condensation polymerisation reaction forming peptide bonds between them
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7
Q

What is the secondary structure?

A
  • alpha helices (tight coils)
  • beta pleated sheets (folds)
  • random coils

hydrogen bonds form between the R groups, helping stabilise a 3D shape

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8
Q

What is the tertiary structure?

A

PROTEINS FUNCTIONAL 3D SHAPE
- interactions between R groups make polypeptide chain folded, coiled and twisted
- disulphide bonds often form
- ionic bonds

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9
Q

What is the quaternary structure?

A

2+ polypeptide chains joined together to form a fully functional protein

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10
Q

What are 8 functions of proteins?

A

enzymes
transport
structure
hormones
receptors
defence
motor/contractile
storage

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11
Q

What is functional diversity?

A

all cells have the same genome but their proteomes are different which leads to cell specialisation/differentiation

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12
Q

How many hydrogen bonds do C-G have?

A

3

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13
Q

How many hydrogen bonds do A-T have?

A

2

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14
Q

Which bases are purines?

A

Adenine Guanine

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15
Q

Which bases are pyrimidines?

A

Cytosine Thymine

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16
Q

What is the name of the bond between nucleotides?

A

Phosphodiester bond

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17
Q

Where is the bond between nucleotides formed?

A

Phosphate to the sugar

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18
Q

What does mRNA do?

A

carry genetic material to ribosome to make specific protein

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19
Q

What does rRNA do?

A

make up ribosomes

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20
Q

What does tRNA do?

A

carries amino acids to ribosomes to build up proteins

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21
Q

What are the 3 parts to a nucleotide?

A

phosphate
5 carbon sugar (ribose/deoxyribose)
nitrogenous base

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22
Q

What is the process involved in the production of mRNA?

A

transcription

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23
Q

What is the monomer of DNA?

A

nucleotides

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24
Q

What is the monomer of proteins?

A

amino acids

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25
Q

What do genes do when they are active?

A

their instructions are decoded and expressed in the phenotype of the organism (gene expression)

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26
Q

What is a phenotype?

A

visible expression of a gene

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27
Q

What occurs at the promoter?

A

RNA polymerase attaches to begin transcription (TATA box)

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28
Q

What are exons?

A

coding regions of DNA

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29
Q

What are introns?

A

non-coding region of DNA

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30
Q

What occurs at the terminator sequence?

A

signals end of transcription

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31
Q

What is the difference between eukaryotes and prokaryotes in gene structure?

A

prokaryotes don’t have introns and have a operator region instead

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32
Q

What does the operator region do?

A

Serves as a binding site for repressor proteins

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33
Q

What is the main goal of transcription?

A

formation of mRNA

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34
Q

Where does transcription occur?

A

nucleus

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35
Q

What does transcription form?

A

mRNA which is complementary in sequence to the template DNA strand

36
Q

What are the 3 parts to transcription?

A

initiation
elongation
termination

37
Q

What occurs in initiation?

A
  • gene on
  • DNA unwinds as template strand
  • RNA polymerse attatches to promoter
38
Q

What occurs in elongation?

A
  • RNA polymerase moves along template strand
  • brekas down hydrogen bonds
  • complementary pre-mRNA strand made
39
Q

What occurs in termination?

A
  • process continues until stop signal reaches
  • pre-mRNA is released
  • DNA zips back up
40
Q

What modifications occur at RNA processing?

A
  • methylated cap (5’ end)
  • poly-A tail (3’)
  • introns are cut out
  • exons spliced together
41
Q

What are introns?

A

non-coding regions of DNA

42
Q

What are exons?

A

coding-regions of DNA

43
Q

What does alternative splicing result in?

A

different proteins being made off the same gene

44
Q

What is the genetic code?

A

how genetic information is stored within nucleotides and transcribed and translated into a protein

45
Q

What are 3 nucleotides called in DNA?

46
Q

What are 3 nucleotides called in mRNA?

47
Q

What are the key features of the genetic code?

A

universal
unambiguous
degenerate

48
Q

What does universal mean?

A

mostly all living things use same codons to code for specific amino acids

49
Q

What does unambiguous mean?

A

each codon is only capable of coding for 1 specific amino acid

50
Q

What does degenerate mean?

A

even though there are unambiguous, might be multiple codons for same amino acid

51
Q

What is translation?

A
  • mRNA attaches to ribosome in cytoplasm
  • ribosome moves along mRNA strand reading condons
  • tRNA deliver specific amino acids
  • if anti codon is complementary, amino acid joins growing polypeptide chain
  • stop codon reached (polypeptide released)
52
Q

What is your genome?

A

organisms complete set of DNA including all its genes

53
Q

Where is your genome?

A

in humans, a copy of the entire genome is contained in all cells that have a nucleus

54
Q

What is the different between between the main chromosome in prokaryotic vs eukaryotic cells?

A

prokaryotes = circular molecule of DNA
eukaryotes = linear molecule

55
Q

2 differences betwen gene reg in prokaryotes and eukaryotes

A

p = exons only no introns
e = exons and introns

p = plasmids
e = no plasmids

56
Q

What are structural genes?

A

code for any RNA or proteins that are not involved in gene reg

57
Q

What are regulatory genes?

A

controlling the expression of structural genes by the production of transcription factors

58
Q

What is an operon?

A

segment of DNA containing adjacent structural genes, promoter and operator

59
Q

What is the repressible operon on trp?

60
Q

What is the role of the repressor protein?

A

protein which binds to the operator regions and blocks RNA polymerase from binding

61
Q

What is the role of the promoter?

A

DNA sequence on which RNA polymerase attatches

62
Q

What is the role of the operator?

A

DNA region where repressor protein attatches

63
Q

What are the 2 mechanisms of regulating the trp operon

A

repression
attenuation

64
Q

Explain what happens where there are HIGH leves of trp?
(repression)

A
  • trp binds to repressor protein
  • repressor protein undergos conformational change and becomes active
  • can bind to operator
  • RNA polymerase is blocked from attatching to promoter
  • structural genes are not transcribed
  • trp is not made and energy is saved
65
Q

Explain what happens where there are LOW leves of trp?
(repression)

A
  • trp cannot bind to repressor protein
  • repressor protein undergos conformational change and becomes inactive
  • cannot bind to operator
  • RNA polymerase attatches to promoter
  • structural genes are transcribed
  • trp is produced
66
Q

What does the L stand for in sequence of DNA?

A

leader sequence

67
Q

What does the leader sequence do?

A

codes for short polypeptide

68
Q

What is the attenuator?

A

short sequence of DNA where transcription can be halted

69
Q

Why do we need attenuation?

A

bound trp but not free trp so no trp to bind to repressor so transcription is not blocked

70
Q

What is the structure of the mRNA leader transcript

A
  • has 4 domains or regions called 1,2,3,4
  • stop codon
  • 2 trp codons
71
Q

What can these domains do?

A

bind to the one next to it
1-2,2-3,3-4

72
Q

Where is the stop codon in the leader sequence?

A

between domains 1-2

73
Q

Where is the trp codons in the leader sequence?

A

adjacent to each other domain 1

74
Q

What happens when trp is present (low)? (attenuation) 9 dot points

A
  • ribosome begins translation
  • moves past trp codons
  • halted by stop codon
  • 1-2 domain can’t bind due to ribosome between
  • stop ribosome prevents 2-3 binding
  • 3-4 form a hairpin termination loop
  • causes mRNA to pull away from attenuator region
  • RNA polymerase breaks away before structural genes
  • transcription is terminated
75
Q

What happens when trp is absent? (attenuation) 8 dot points

A
  • ribosome reaches trp codons
  • can’t move past as trp tRNA molecules have no trp
  • ribosome pauses in domain 1
  • 2-3 form a hairpin anti-termination loop
  • doesn’t pull on the mRNA
  • mRNA and DNA remain bound to each other
  • RNA polymerase remains attacthes to DNA of attenuator
  • transcription is switched on and 5 genes can be transcribed
76
Q

What is excocytosis?

A

involves the movement of vesicles containing large molecules around the cell and out of the cell

77
Q

What is endocytosis?

A

involves the uptake of large molecules into vesicles into the cell

78
Q

What is the plasma membrane made of?

A

phospholipid bilayer

79
Q

What are the 3 stages of exocytosis?

A
  1. vesicle containing secretory products is transported to plasma membrane
  2. membrane of vesicle fuses with plasma membrane
  3. secretory products are released from cell into extracellular environment
80
Q

What is the role of ribosomes?

A

synthesises proteins

81
Q

What is the role of ER?

A

folds and transports proteins

82
Q

What is the role of transport vesicle?

A

transports proteins from rough ER to golgi apparatus

83
Q

What is the role of golgi body?

A

modifies and packages proteins

84
Q

What is the role of secretory vessel?

A

transports proteins from the golgi apparatus to plasma membrane

85
Q

What are some examples of the protein secretory pathway?

A
  • release of digestive enzymes in the stomach
  • release of antibodies from WBC
  • release of hormones such as insulin from glands

Biology (4 decks)

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