U3AOS1 Molecules of Life Flashcards

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1
Q

DNA

A

Deoxyribonucleic Acid

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2
Q

Nucleotide Structure

A

Phosphate group - Five-carbon pentose sugar - Nitrogenous bases

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3
Q

Purine vs Pyrimidine

A

Purine = Nitrogenous base with two rings, pyrimidine = nitrogenous base with one ring

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4
Q

Nitrogenous bases

A

Adenine, thymine, guanine, cytosine, uracil (RNA only)

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5
Q

DNA vs RNA

A

DNA = highly stable, linear or circular chromosomes - RNA = unstable, mRNA, tRNA, rRNA

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6
Q

Which direction do DNA strands follow?

A

5’ (prime) to 3’ (prime)

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7
Q

Semi-conservative replication

A

Replication of DNA in which one strands of the original DNA is kept or ‘conserved’ while the other is a new strand. Creates 2 double-stranded DNA strands.

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8
Q

Gene expression

A

The process of synthesising a protein from DNA

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9
Q

rRNA

A

Ribosomal RNA, makes up the ribosome

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10
Q

tRNA

A

Transfer RNA, delivers amino acids for protein synthesis

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11
Q

mRNA

A

Messenger RNA, transports or carries instructions for protein synthesis from the nucleus (DNA) to the ribosome.

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12
Q

Transcription

A

(AT NUCLEUS) The creation of pre-mRNA using DNA, RNA polymerase reads the DNA template strand from left to right, starting at the promoter. pre-mRNA is created as a complementary strand to the template strand using free nucleotides from nutrients.

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13
Q

RNA processing

A

(AT NUCLEUS) A spliceosome cuts out introns in the pre-mRNA from left to right. Then a methyl cap is added to the left side of the strand and a poly-A tail is added to the right. This creates mRNA.

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14
Q

Introns

A

Non-coding regions

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15
Q

Exons

A

Coding regions

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16
Q

Translation

A

(AT RIBOSOME) The mRNA is read by the ribosome and tRNA matches with the codons on the mRNA through their anticodons. Each codon corresponds to an amino acid. Once all of the codons have been read, including the stop codon, a polypeptide chain has been formed, with each amino acids joined via peptide bonds. The polypeptide chain folds in a specific way to form a protein.

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17
Q

Types of proteins

A

Structural, transport, signalling, receptor, enzyme, motility

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18
Q

Triplet

A

Three bases in DNA

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19
Q

Codon

A

Three bases in mRNA

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20
Q

Anticodon

A

Three bases in tRNA

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21
Q

Two types of genes

A

Regulatory (creates a protein which switches on and off a structural gene) - Structural (codes for RNA and every protein besides regulatory ones)

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22
Q

Regulatory proteins

A

Repressor, Inducer

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23
Q

Repressor - INACTIVE

A

Doesn’t bind to operator (Gene is ON)

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24
Q

Inducer - ACTIVE

A

Doesn’t bind to operator (Gene is ON)

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25
Q

Inducer - INACTIVE

A

Binds to operator (Gene is OFF)

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26
Q

Repressor - ACTIVE

A

Binds to operator (Gene is OFF)

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27
Q

Low levels of TRP

A

Repressor is inactive

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28
Q

High levels of TRP

A

Repressor is active

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29
Q

TRP Operon

A

Promoter, operator, trpE-A, stop sequence

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30
Q

TRP Operon - Mech 1

A

Active and inactive repressor, all trpE-A create enzymes which are put together to make tryptophan, overtime tryptophan degrades and breaks off of the operator, restarting the process

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31
Q

TRP Operon - Mech 2

A

(ONLY PROKARYOTES) In between, operator and trpE there is a ‘leader sequence’ made up to tryptophan and complementary base pairs, A and A’, B and B’, C and C’ (ATTENUATOR).
Low TRP = ribosomes delayed = anti-terminator hairpin = full mRNA length = high TRP
High TRP = ribosomes fast and fall off = associated terminator and terminator hairpin = mRNA cut short = low TRP
ATTENUATION

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32
Q

Amino acid structure

A

IN MIDDLE: Carbon
Clockwise rotation: Variable group, carboxyl group, hydrogen, amino acid

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33
Q

Variable group

A

Distinguishes amino acids

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34
Q

Denaturation (PROTEINS)

A

Permanent change in protein 3D shape = permanent change in protein function

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35
Q

Primary structure of proteins

A

Sequence/order of amino acids (PEPTIDE BONDS)

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36
Q

Secondary structure of proteins

A

Pattern of polypeptide - alpha helix, beta-pleated sheet, random loops (HYDROGEN BONDS)

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37
Q

Tertiary structure of proteins

A

Combination of patterns (HYDROGEN, IONIC, DISULFIDE BONDS)

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38
Q

Quaternary structure of proteins

A

Multiple polypeptides put together (HYDROGEN, IONIC, DISULFIDE BONDS)

39
Q

Exocytosis

A

Releasing of content in SECRETORY vesicles

40
Q

Endocytosis

A

Opposite of exocytosis

41
Q

Transport vesicle

A

After translation protein is packaged into a transport vesicle to go to the Golgi apparatus

42
Q

Modification (protein secretory pathway)

A

Polypeptide has things added and removed, is then packaged and exported out of the cell.

43
Q

Central Dogma of DNA

A

(Main Purpose) To make proteins

44
Q

Bonds that hold DNA strands together

A

Weak hydrogen bonds

45
Q

Bonds that hold nucleotides together

A

Phosphodiester bonds

46
Q

Insertion, targeted insertion, targeted inactivation

A

Transgenic, Knock-in, Knock-out

47
Q

Transgenic organism

A

An organism that has had genes added from another species in a non-specific location or locus EXPRESSED ALL THE TIME

48
Q

Knock-in

A

An organism that has had genes added to a specific locus (therefore controlled by that specific promoter and only expressed in specific conditions)

49
Q

Knock-out

A

An organism that has had genes removed or inactivated (specific)

50
Q

Wild type

A

Non-edited type, naturally occurring organism

51
Q

Reporter gene

A

Inserted into the locus of a gene to determine the pattern of expression.

52
Q

PCR

A

Polymerase Chain Reaction - Used to amplify DNA

53
Q

Restriction endonucleases

A

Cuts or cleaves genetic material (EcoRl, Alul)

54
Q

Two types of ends (ENDONUCLEASES)

A

Sticky end, goes in-between the two strands, blunt end, cuts directly through.

55
Q

Ligases

A

(LIGATION) Joins or reconnects genetic material together.

56
Q

CRISPR stands for

A

Clustered Regularly Interspaced Short Palindromic Repeats

57
Q

CRISPR

A

Genome editing system (based on bacterial defence mech)

58
Q

crRNA vs guide RNA

A

crRNA is only bacterial defence mech and guide RNA is in DNA

59
Q

Knock-in Therapy (CRISPR)

A

Guide RNA attaches to DNA and Cas9 cuts, allowing for a space to add the new target gene

60
Q

Knock-out Therapy

A

Two guide RNAs attach to the DNA and tell the Cas9 protein where to cleave in order to eliminate the gene. Ligase or cell glues restriction fragments together.

61
Q

CRISPR in bacterial defence system

A
  1. Virus infects bacterial cell (inserts viral DNA)
  2. Bacteria integrates short segments of viral DNA into CRISPR locus
  3. crRNA is transcribed
  4. When another virus attacks the crRNA is attracted to the viral DNA due to the complementary bases
  5. crRNA guides Cas protein and Cas9 cleaves viral DNA complementary to the crRNA.
62
Q

Steps of PCR

A

Denaturation, Annealing, Extension, Repeat

63
Q

Denaturation (PCR)

A

DNA heated to 95 DEGREES, strands will separate as heat causes hydrogen bonds to break

64
Q

Annealing (PCR)

A

DNA cooled to 50-60 DEGREES, primers attached to each DNA strand, PRIMERS SET THE BORDERS FOR THE DNA WHICH NEEDS TO BE COPIED

65
Q

Extension (PCR)

A

Heat to 72 DEGREES, Taq polymerase formed new DNA strands

66
Q

Repeats (PCR)

A

Process is repeated to exponentially increase DNA sample

67
Q

Gel Electrophoresis

A

Lab method to separate DNA segments and sort them by length. DNA segments, which have been cut by restriction enzymes, are placed into wells with Agarose gel. Electricity is run through the gel and due to the negative charge of DNA (phosphate) it will move towards the positive end of the gel. Smaller strands move further down as they can quickly move through the gel while larger strands stay towards the wells. The strands are then compared against a molecular marker to measure their size.

68
Q

Molecular marker

A

= standard DNA ladder = standard column USED TO CALCULATE SIZE OF DNA SEGMENTS

69
Q

Buffer solution

A

SALT SOLUTION, keeps DNA in suspensions, strands travel smoothly

70
Q

Fluorescent dyes in gel electrophoresis

A

Used to examine results as DNA is invisible in Agarose gel

71
Q

DNA profiling

A

Genetic engineering used to compare the DNA of two or more people. Shows relation via short tandem repeat alleles (STRs)

72
Q

Short Tandem Repeats

A

STRs, short base pairs (2-6) which are repeated multiple times, every person has same STRs but number of time its repeated distinguishes people.

73
Q

DNA profiling process

A

DNA is isolated from a somatic cell and amplified via PCR. Up to 17 STRs are isolated from the sample using restriction enzymes, separated via electrophoresis.

74
Q

Recombinant plasmid

A

Plasmid with foreign DNA inserted and attached

75
Q

Plasmid

A

Circular piece of DNA found in bacteria, reproduce without interaction with the bacterial chromosomes, VECTORS (carriers) FOR DNA FRAGMENTS

76
Q

Gene cloning

A

Alternative to PCR, replicates larger segments of DNA using recombinant plasmids, plasmids used to insert DNA into the bacteria.

77
Q

PLASMIDS to make INSULIN

A

Genes inserted for each of the two insulin polypeptides next to highly expressed gene for B-galactosidase.
Recombinant plasmids added to bacterial cells, left in a incubator with antibiotics, eliminates cells without antibiotic resistance.
Fusion proteins are purified and insulin polypeptides and chemically removed from the B-galactosidase protein.
A and B insulin polypeptides are combined via a Di-sulfide bridge to produce functional insulin.

78
Q

Restriction site

A

Where the endonuclease cuts

79
Q

Restriction fragment

A

The product(s) of the endonuclease cutting

80
Q

Rules for restriction site

A

Even number of base pairs.
4-8 base pairs.
Palindrome (SAME BACKWARDS ON EACH STRAND).

81
Q

Advantages of sticky end

A

Specific (complementary bases)
Orientation (can’t flip)

82
Q

Polymerase

A

Enzyme that creates more genetic material. 5’ to 3’

83
Q

CRISPR vs Restriction Endonucleases

A

CRISPR: Guide RNA doesn’t have to be a palindrome, 20 bases long, SUPER-SPECIFIC
Restriction Endonuclease: Must be Palindrome, 4-8 base pairs long, cuts all (non-specific)

84
Q

Sickle Cell Anemia (CRISPR)

A

Repressor protein is stopping transcription of haemoglobin gene. CRISPR can be used to knock-out gene which makes repressor protein, therefore stopping sickle cell anemia.

85
Q

Polymorphism

A

Refers to variation between genomes that distinguish individuals.

86
Q

Are the wells in Gel Electrophoresis on the positive or negative side

A

NEGATIVE

87
Q

Bacterial Transformation

A

Used to make lots of copies of proteins

88
Q

Genetic Engineering in Agriculture

A

Increasing crop yields, improving food quality, increasing shelf life, providing disease resistance.

89
Q

Ethics

A

System of moral principles that considers what’s bad and what’s good.

90
Q

Bioethical Approaches

A

Consequences, Virtues, Duty

91
Q

Integrity

A

Being honest as a scientist (not changing data, referencing information)

92
Q

Justice

A

Consider competing claims

93
Q

Respect

A

Giving value to living things, considering their welfare and freedom