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Biology > Unit 3 Chapter 2 - Nucleic acids and proteins > Flashcards

Unit 3 Chapter 2 - Nucleic acids and proteins Flashcards

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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
What do genes do when they are active?
their instructions are decoded and expressed in the phenotype of the organism (gene expression)
26
What is a phenotype?
visible expression of a gene
27
What occurs at the promoter?
RNA polymerase attaches to begin transcription (TATA box)
28
What are exons?
coding regions of DNA
29
What are introns?
non-coding region of DNA
30
What occurs at the terminator sequence?
signals end of transcription
31
What is the difference between eukaryotes and prokaryotes in gene structure?
prokaryotes don't have introns and have a operator region instead
32
What does the operator region do?
Serves as a binding site for repressor proteins
33
What is the main goal of transcription?
formation of mRNA
34
Where does transcription occur?
nucleus
35
What does transcription form?
mRNA which is complementary in sequence to the template DNA strand
36
What are the 3 parts to transcription?
initiation elongation termination
37
What occurs in initiation?
- gene on - DNA unwinds as template strand - RNA polymerse attatches to promoter
38
What occurs in elongation?
- RNA polymerase moves along template strand - brekas down hydrogen bonds - complementary pre-mRNA strand made
39
What occurs in termination?
- process continues until stop signal reaches - pre-mRNA is released - DNA zips back up
40
What modifications occur at RNA processing?
- methylated cap (5' end) - poly-A tail (3') - introns are cut out - exons spliced together
41
What are introns?
non-coding regions of DNA
42
What are exons?
coding-regions of DNA
43
What does alternative splicing result in?
different proteins being made off the same gene
44
What is the genetic code?
how genetic information is stored within nucleotides and transcribed and translated into a protein
45
What are 3 nucleotides called in DNA?
triplet
46
What are 3 nucleotides called in mRNA?
codon
47
What are the key features of the genetic code?
universal unambiguous degenerate
48
What does universal mean?
mostly all living things use same codons to code for specific amino acids
49
What does unambiguous mean?
each codon is only capable of coding for 1 specific amino acid
50
What does degenerate mean?
even though there are unambiguous, might be multiple codons for same amino acid
51
What is translation?
- 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
What is your genome?
organisms complete set of DNA including all its genes
53
Where is your genome?
in humans, a copy of the entire genome is contained in all cells that have a nucleus
54
What is the different between between the main chromosome in prokaryotic vs eukaryotic cells?
prokaryotes = circular molecule of DNA eukaryotes = linear molecule
55
2 differences betwen gene reg in prokaryotes and eukaryotes
p = exons only no introns e = exons and introns p = plasmids e = no plasmids
56
What are structural genes?
code for any RNA or proteins that are not involved in gene reg
57
What are regulatory genes?
controlling the expression of structural genes by the production of transcription factors
58
What is an operon?
segment of DNA containing adjacent structural genes, promoter and operator
59
What is the repressible operon on trp?
E.coli.
60
What is the role of the repressor protein?
protein which binds to the operator regions and blocks RNA polymerase from binding
61
What is the role of the promoter?
DNA sequence on which RNA polymerase attatches
62
What is the role of the operator?
DNA region where repressor protein attatches
63
What are the 2 mechanisms of regulating the trp operon
repression attenuation
64
Explain what happens where there are HIGH leves of trp? (repression)
- 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
Explain what happens where there are LOW leves of trp? (repression)
- 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
What does the L stand for in sequence of DNA?
leader sequence
67
What does the leader sequence do?
codes for short polypeptide
68
What is the attenuator?
short sequence of DNA where transcription can be halted
69
Why do we need attenuation?
bound trp but not free trp so no trp to bind to repressor so transcription is not blocked
70
What is the structure of the mRNA leader transcript
- has 4 domains or regions called 1,2,3,4 - stop codon - 2 trp codons
71
What can these domains do?
bind to the one next to it 1-2,2-3,3-4
72
Where is the stop codon in the leader sequence?
between domains 1-2
73
Where is the trp codons in the leader sequence?
adjacent to each other domain 1
74
What happens when trp is present (low)? (attenuation) 9 dot points
- 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
What happens when trp is absent? (attenuation) 8 dot points
- 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
What is excocytosis?
involves the movement of vesicles containing large molecules around the cell and out of the cell
77
What is endocytosis?
involves the uptake of large molecules into vesicles into the cell
78
What is the plasma membrane made of?
phospholipid bilayer
79
What are the 3 stages of exocytosis?
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
What is the role of ribosomes?
synthesises proteins
81
What is the role of ER?
folds and transports proteins
82
What is the role of transport vesicle?
transports proteins from rough ER to golgi apparatus
83
What is the role of golgi body?
modifies and packages proteins
84
What is the role of secretory vessel?
transports proteins from the golgi apparatus to plasma membrane
85
What are some examples of the protein secretory pathway?
- 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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