Final Flashcards
(122 cards)
1
Q
DNA
A
Master blue print
Never leaves the nucleus
2
Q
Purpose of Transcription and Translation
A
DNA directs protein synthesis
DNA -> RNA -> protein
3
Q
Transcription
A
Synthesis of mRNA from DNA
Occurs in the nucleus
Only transcribes what we need
4
Q
Translation
A
Synthesis of polypeptide/protein by using an mRNA template
Occurs in Ribosome in cytosol
5
Q
T/T in Prokaryotes
A
Transcription and translation occur together because there is no nuclear envelope
Different polymerases
6
Q
T/T in Eukaryotes
A
Transcription in nucleus
Transcription requires many transcription factors
Pre-mRNA modified before becoming mRNA and moving to translation in cytosol
Allows for regulation
7
Q
RNA vs. DNA
A
DNA is a double helix, made of deoxyribose sugar, CGAT
RNA is single stranded, made of ribose sugar, CGAU
8
Q
RNA Polymerase
A
Pries helix apart and reads 1 strand, adding nucleotides to RNA (using uracil instead of thymine)
9
Q
3 Stages of Transcription
A
Initiation, Elongation, Termination
10
Q
Initiation - Transcription
A
Promoters (TATA box and transcription factors) signal initiation of RNA synthesis- tell the polymerase to attach
11
Q
Transcription Factors
A
Help eukaryotic RNA polymerase recognize the promoter sequence
12
Q
Elongation - Transcription
A
RNA polymerase moves along DNA making RNA strand
13
Q
Termination (Prokaryotes) - Transcription
A
terminator sequence-> polymerase detaches
14
Q
Termination (Eukaryotes) - Transcription
A
Transcribes polyadenylation sequence
Proteins cut mRNA free
Polymerase falls away from DNA
15
Q
RNA Processing
A
Only happens in eukaryote cells
Modifies pre-mRNA after transcription
Splicing occurs
Occurs in nucleus
5’ end gets modified nucleotide cap
3’ end gets poly-A tail - helps to export mRNA to cytosol, protects mRNA from degradation, helps ribosomes attach
16
Q
RNA Splicing
A
Removes introns and joins exons
17
Q
Introns
A
Non coding
Allow for alternate RNA splicing
Increase the number of different proteins possible
18
Q
Exons
A
Expressed
19
Q
Spliceosomes
A
snRNP - small nuclear ribonucleoproteins
Recognize splice sites
20
Q
Ribozymes
A
Catalytic RNA molecules
Function as enzymes
Can splice RNA
21
Q
mRNA
A
Messenger RNA
Carries messages as a series of codons
22
Q
Codons
A
Triplet sequence of bases along mRNA
Codes for amino acid or as stop signal
Pairs with anticodon on tRNA
20 amino acids
More than one codon per amino acid
23
Q
tRNA
A
Transfer RNA
Shuttle amino acids to building polypeptide
Each tRNA is specific for an amino acid
Anticodon binds to codon
L-shaped
24
Q
Aminoacyl-tRNA Synthetase
A
Joins each amino acid to correct tRNA
Binding site specific to amino acid
25
Ribosomes
Free in cytosol or bound to ER
Synthesis starts on free ribosomes, may move to ER if protein needed for export
Made of proteins and ribosomal RNA(rRNA)
Facilitate coupling of codons with anticodons during protein synthesis
```
Has three binding sites for tRNA - A P E
Reads from A to E
A -add
P -polypeptide
E -exit
```
26
Stages of Translation
Initiation, elongation, termination
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Initiation - Translation
At start codon
Brings together mRNA, initiator tRNA (with first amino acid met), and two subunits of a ribosome together
28
Elongation - Translation
Amino acids are added one by one to the polypeptide
29
Termination - Translation
Ribosome reaches a stop codon on the mRNA
30
Polyribosome
Many ribosomes can translate one mRNA at once, forming multiple proteins at once
31
After Translation
Possible Changes to help control function of protein: enzyme may be cleaved (e.g. insulin needs to be activated when needed), sugar or lipids may be attached, removal of lead amino acids
32
Signal Recognition Particle
Draws proteins to ER for export
33
Mutations
One wrong nucleotide leads to one wrong amino acid which leads to a dysfunctional protein
Wobble position- 3rd unit in codon results in mismatch of bases
Substituions, insertions, deletions produce nonsense or mutations
34
Epigenetics
Chemical mechanisms control the expression of genes
Methylation-repressors
Histones- repress larger section
35
Bacteria
Prokaryote- no nuclear membrane
36
Bacterial Appendages
Protein surface Structures
Flagella
Pili(short hair like)- attach to tissue
37
Bacteria Cell Wall
Made of peptidoglycan
38
Capsule or Glycocalyx
Polysaccarides
For attachment and protection
39
Inside the Bacteria
Genome (DNA nucleus and plasmids)
Ribosomes
Inclusions (Granules- reserve materials)
40
Bacteria Shapes
Rods, Spheres, Spirals
41
Rods
Bacillus
Single or in chains
42
Spheres
Coccus
Chains(streptococci) or Clusters(staphylococci)
Not usually motile
43
Spirals
Spirilla
Usually Motile
44
Gram Negative
Staining- thin wall
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Gram Positive
Staining- thick wall
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Normal Flora
Natural to the human body
Can synthesize and secrete vitamins (E.g. enteric bacteria makes B12 and K)
Prevents colonization by pathogens - compete for space
Produce substances that harm non-indigineous bacteria
Staphylococcus (transfer from nasal passage to susceptible host)
Streptococcus mutano(tooth decay)
Streptococcus pneumonia (normal in upper respiratory tract, cause pneumonia in lower)
Neisseria Meningitidis
E Coli.
47
Spirilla
Pathogenic
Transmitted by untreated drinking water and undercooked meat
Causes diarrhea and peptic ulcers
48
Spirochetes
Treponema Pallidum- agent of sypilis
Borrelia Burgdorferi- causes lyme disease
49
Vibrios
Gram negative rods
Found in fresh and saltwater
Vibrio Cholerae- causes cholera- diarrhea, deadly by dehydration
50
Pseudomonas
In urinary tract
Attacks weakened host
Respiratory tract
51
Enteric Bacteria
Gram negative rods
Live anaerobically
E Coli
52
Pyrogenic Cocci
Gram postive spheres
Produce pus
Cause 1/3 of infections
Includes staph and strep classes
53
Staphylococcus
Staphylococcus epidermis- not pathogenic, slows fungi growth, lives on skin and mucous membranes
Staphylococcus aureus- can cause disease, boils/pimples, wound infections, pneumonia, food poisoning, toxic shock syndrome
54
Sterptococcus
Streptococcus Pyogenes- wound infections, autoimmune disease, tonsillitis or strep throat
Streptococcus pneumoniae- cause of bacterial pneumonia, ear infections, meningitis
55
Blood
RBC - erythrocytes, 45%
WBC - leukocytes, <1%
Platelets - <1%
Plasma - 55%
56
White Blood Cells
Neutrophils, Monocytes, Eosinophils, Basophils, Lymphocytes
57
Neutrophils
Phagocytes
Looking to eat thing marked with antibodies
Most common
58
Monocytes
Macrophages
59
Eosinophils
Allergy response
60
Basophils
Histamine
61
Lymphocytes
T and B cells
Specific immune response
62
Immune System
Defence against bacteria, virus, worms
Removes old cells
Helps with repair (injuries)
63
Antigen
Binds with antibody
Example- Virus, bacteria
64
Antibody
Flag, marks for destruction
65
Non- Specific Immune Response
Innate
Quick
External defences, inflammation, interferon, natural killer cells, complement system
66
Specific Immune Response
Acquired
Slower but stronger
T and B cells
67
External Defences
Skin, mucous membrane, acid, cough, sneeze, cilia
68
Inflammation
Increased blood flow to injury/ infection site
Red/Hot
Increased permeability of capillary - allows WBCs and clot factors to go to site
Water flows because of osmosis- swelling
69
Interferon
Chemical messenger response
Cytokine from infected cell
Prevents infection from other cells- saves its neighbours
70
Natural Killer Cells
T-cells but very general effect
Macrophages- kill off bacteria/cancers
71
Phagocytic Defence
Neutrophils and Macrophages
1. Phagocytes go to infection
2. Adhere to target
3. Ingest or engulf target particle
4. Intracellular digestion and egestion
72
Complement System
Circulating proteins
Form attack complex- kills anything marked by antibodies
Forms holes/pores in cell membrane
73
B-cells
Attack free virus
Antibody reaction
74
T-cells
Attack infected cells
75
B-lymphocytes
Bind to antigen
Divide and differentiate into:
Plasma cells- secrete antibodies
Memory cells- stronger second response
76
T-lymphocytes
Helper T-cells, Cytotoxic T-cells, Suppressor T-cells
77
Helper T-cells
Secretes cytokines
Mediate fever
Bigger B-cell and cytotoxic T-cell response
78
Cytotoxic T-cells
Directly attacks infected cells
Recognizes antigen marker
79
Suppressor T-cells
Limits response
80
Viruses
Smaller than bacteria
Contain DNA or RNA
Genome contained in a capsid (protein shell)
Envelopes- contain capsids- helps to infect host
81
Virus Reproductive Cycle
1. Enters host cell
2. Replicates DNA
3. Transcribes mRNA
4. Makes capsid proteins
5. Assembles new virus
6. Exits host cell
82
Bacteriophages
Infect bacteria
Reproduces by lytic cycle (virulent phage) or lysogenic cycle (temperate phage)
83
Lytic Cycle
1. Phage attaches to host cell
2. Degrades host DNA
3. Synthesis of virus genome and proteins
4. Assembly of capsid
5. Lyse (rupture) host cell
6. Release of virus (100-200)
84
Lysogenic Cycle
1. Virus DNA is incorporated into host genome(prophage)
2. Virus DNA is replicated with bacteria DNA (spreads to daughter cells)
Virus is silent
Trigger (environment) causes switch to lytic cycle
85
Viral Envelope
Made go host membrane
Glycoproteins bind to receptor site
86
HIV Virus
Retrovirus
1. Virus enters helper T-cell
2. Reverse transcription
3. DNA joins host genome (provirus)
4. Transcribes provirus into RNA (RNA for new virus/ mRNA for protein capsid)
5. New virus assembly
6. Exits cell
7. Provirus always remains in host (always infected)
87
Retrovirus
Uses reverse transcription
RNA to DNA
88
Spread of Disease
Mutations of virus- previously harmless
Global travel- more psreadb
89
Bacteria
Ring DNA
Reproduce by binary fission
90
Genetic Recombination
Genetic variation by transformation, transduction, conjugation, transposition
91
Transformation
Uptake of naked foreign DNA from the environment
Cell recognizes related DNA
Incorporates it into its genome
92
Transduction
Phages carry genes from one bacteria to another
Lytic cycle
Some bacterial DNA in phage head
Recombines with new host DNA
93
Conjugation
Direct transfer of DNA between bacteria
Formation of mating bridge
F DNA factor needs to donate DNA
94
Plasmid
Small circular DNA segment
95
F Plasmid
Transfer single strand of DNA to mate
Each mate replicates plasmid strand
96
Hfr cell
High frequency recombination
F factor(plasmid) incorporated into genome
97
Mating Bridge
Single strand of DNA transferred
Often partial
98
Transposition
DNA in a single bacteria can recombine
Transpose gene- cut and paste DNA
99
Transposons
Code for transposes plus other genes
Cut and pastes new genes in new location
100
Operons
Control production of mRNA and therefore the production of proteins
101
Repressible Operons
Turns off system thats usually on
Binds to operator to stop promoter which stops mRNA production
102
Inducible Operons
Turns on system thats usually off
Inducer binds to repressor, its released and promoter makes RNA
Usually start product
103
Recombinant DNA
DNA from more than one source
Allows for DNA sequencing
Allows for gene manipulation/production
104
Restriction Enzymes
Cuts DNA at specific sequences (restriction sites)
Produces fragments with sticky ends that can bond to a fragment with another sticky end (through ligase)
Produces a DNA fingerprint
105
DNA Cloning
Production of multiple copes of a specific gene or DNA segment
Used for mass production of protein or enzymes (e.g. insulin)
Uses bacteria and plasmids
106
Ways to Deliver Recombinant DNA into Bacterial Cells
Transformation, Transduction, Infection
107
Cloning Vector
DNA plasmid carrying foreign DNA
Enters bacterium cell to replicate
Clones carry the gene of interest
108
Uses for DNA Cloning
Forensic science, agriculture, medicine, environment
109
Gene Therapy
Alteration of a gene
Potential for treating disorders of a single defective gene
Uses various vectors for delivery of genes
110
Uses for Gene Therapy
Large scale production of human hormones
Production of safer vaccines
Curing of genetic based diseases (potentially, tech not at this level)
111
Agriculture Genetic Engineering
Is being used to improve agricultural productivity
Can insert gene for larger plant size, better flavour, faster maturation, etc.
112
Transgenic Plants
Allows for choice of traits
Like seedless, thinner skin, larger size, resistance
113
Golden Rice
Rice that can create vitamin A in the plant to combat the worldwide problem of vitamin A deficiency
Engineered genes from the beta-carotene pathway in daffodils
Problems: Decreased biodiversity, health risks, environmental risks, economic exploitation of farmers
114
Ventria Rice
Puts protein in rice to prevent diarrhea
Human gene put in plant to allow for hydration
115
Transgenic Animals
Contains genes from other organisms
E.g. can put different characteristics in milk
116
Totipotent Cell
Capable of turning into any cell
Capable of generating a complete new organism
Embryonic
117
Pluripotent
Can become many types of cells but not all
Already differentiated
E.g. Bone marrow
118
Animal Cloning
Using one of more somatic cell to make another genetically identical individual
Problems: Most animals don't develop normally, have a short life with health/social problems
119
Nuclear Transplant
Nucleus of an unfertilized egg cell or zygote is replaced with a nucleus of a differentiated cell
120
Plant Cloning
Some differentiated cells are totipotent (e.g. cut the top off a carrot, you can grow a whole new carrot)
121
Stem Cells
Relatively unspecialized cell
Can reproduce indefinitely
Can differentiate into many types of specialized cells in appropriate conditions
Can be pluripotent or totipotent
122
Cell Differentiation
Different cell types result from different gene expression in cells with the sam eDNA
Genes are expressed to suppressed
No difference in genome
