Anatomy Of Cells Flashcards
(110 cards)
1
Q
Early Microbiology Fails
Spontaneous generation
A
“life can arise from non-living matter”
2
Q
Spontaneous generation
Evidence for:
A
◦Fish in a puddle - Aristotle
◦Mice from leaky roof and moldy grain - Helmont
◦Contamination of broth - Needham
3
Q
Spontaneous generation
Evidence against:
A
• No maggots on covered meat - Redi
• No contamination of boiled broth - Spallanzani
• Sterilization - Pasteur
4
Q
Prokaryotic Cells
A
• No nucleolus
• No membrane-bound organelles
• Single, circular chromosome in the nucleoid
• Classified as bacteria or archaea
• Tend to be smaller than eukaryotic cells
5
Q
Cell Wall
A
• Maintains cell morphology
• Protects cells from changes in osmotic pressure
• Peptidoglycan
6
Q
Cell Membrane
A
Membranes = structures that enclose the cytoplasm and internal structures of a cell
◦All cells have a plasma membrane
◦Fluid mosaic model
◦Phospholipid bilayer
7
Q
Membrane Transport
Simple diffusion
A
with concentration gradient across bilayer
8
Q
Membrane Transport
Facilitated diffusion
A
with concentration gradient through membrane protein
9
Q
Membrane Transport
Active transport
A
against concentration gradient through membrane pump
◦Ex. contraction of the cardiac muscle
10
Q
Nucleoid
A
Concentrated region of prokaryotic DNA and nucleoid-associated proteins
◦Assist in organization and packaging of the chromosome
11
Q
Plasmids
A
◦Small, circular strands of DNA
◦Carry certain genes essential to survival
◦Essential in early stages of biomedical research
12
Q
Ribosomes
A
◦Responsible for protein synthesis
◦Made of ribosomal RNA (rRNA)
◦Prokaryotic cells are 70S (Svedberg or sedimentation units)
◦Two subunits (30S and 50S)
13
Q
Inclusion Bodies
A
◦Cytoplasmic structures for excess nutrients
◦Many inclusion bodies store glycogen and starch (energy)
14
Q
Volutin granules
A
store inorganic phosphates (biofilms)
15
Q
Sulfur granules
A
store sulfur (metabolism)
16
Q
Magnetsomes
A
store iron oxide or iron sulfide (alignment of cells along a magnetic field)
17
Q
Carboxysomes
A
carbonic anhydrase and carboxylase (metabolism)
18
Q
Appendages
Fimbriae
A
◦Short, bristle-like proteins
◦For surface or cellular attachment
19
Q
Appendages
Pili
A
◦Longer and less numerous
◦For surface or cellular attachment and the transfer of DNA
20
Q
Appendages
Flagella
A
◦Stiff filament
◦For moving in aqueous environments
21
Q
Endospores
A
structures that protect bacterial genome in a dormant state
22
Q
Sporulation
A
the process by which vegetative cells transform into endospores
23
Q
Prokaryotes (mostly bacteria) outnumber human cells 10:1 on/in the human body”
A
Mostly in moist areas
24
Q
Functions of Prokaryotes
Important for ecosystem stability
A
◦Soil formation
◦Development of biofilms
◦Nitrogen & carbon fixation
◦Degradation of toxic chemicals
25
Functions of Prokaryotes
But also dangerous
◦Pathogens (bacteria) account for ~1% of all prokaryotes
◦Food contamination
◦Climate change
26
Symbiotic Relationships
Prokaryotes exist in communities
groups of interacting populations of organisms
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Symbiotic Relationships
Populations
groups of individual organisms belonging to the same biological species in a certain geographical area
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Cooperative interactions
benefit each population
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Competitive interactions
populations compete for resources
30
Symbiosis
interactions between different organisms within a community
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Mutualism
both species benefit
◦Humans and bacteria of the intestinal tract (Bateroides thetaiotaomicron)
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Amensalism
one species harms the other without any benefit to itself
◦Bacteria on the skin (Staphylococcus epidermidis) and pathogens
33
Commensalism
one species benefits without harm to the other
◦Bacteria on the skin (Staphylococcus epidermidis) and human skin cells
34
Parasitism
one species benefits by harming the other
◦Humans and pathogens (Tetanus, diphtheria, tuberculosis)
35
Human Microbiome Project
Information gathered so far:
◦Reference database for organisms in/on the human body
◦Most are beneficial
◦Several pathogens exist in healthy microbiota
◦Ex. S. pneumoniae
◦Several new species have been identified using genetic screening
36
Human Microbiome Project
Difficulties:
◦Many species of bacteria cannot be cultured yet
37
How do pathogens cause some people harm but not others?
38
Rocky Mountain Spotted Fever
Proteobacteria
a phylum of gram-negative bacteria based on similar genomes
39
Rocky Mountain Spotted Fever
Alphaproteobacteria
◦Gram-negative
◦Oligotrophs are capable of living in low nutrient environments
◦Obligate intracellular pathogens require part of life cycle to occur within a host cell
40
Rocky Mountain Spotted Fever
R. ricettsii
Inflammation of brain tissue
41
Bacterial Meningitis
Betaproteobacteria
◦Gram-negative
◦Utilize a wide range of metabolic strategies and survive in a wide-range of environments
◦Some are pathogens
42
Bacterial Meningitis
N. meningitides
◦Cocci living on mucosal surfaces
◦Grow in diplococcal pattern
◦Microaerophilic
Require low levels of oxygen
43
Legionnaires Disease
Gammaproteobacteria
• Most diverse class of gram-negative bacteria
• Gram-negative
44
Legionnaires Disease
Legionella pneumophilia
• Aquatic (typically found in warm water)
•Spreads in aerosols
45
Chlamydia
Class of nonproteobacteria
• Gram-negative
• Extremely resistant to cellular defenses
• Spread rapidly via elementary bodies
Elementary bodes = metabolically and reproductively inactive form of bacteria, “endospore-like”
46
Tuberculosis
Mycobacterium
Actinobacteria = high G + C gram-positive bacteria (more than 50% guanine and cytosine)
47
Tuberculosis
Bacilli covered with a mycolic acid coat
◦Protection from antibiotics
◦Makes gram staining difficult
48
Tuberculosis
Treatment:
requires an extended treatment with a combination of several drugs
◦Drug resistance is an issue
49
Strep Throat
Streptococcus:
Lactobacillales = low G + C gram-positive bacteria
◦Includes both bacilli and cocci
”twisted chain” responsible for a variety of infectious diseass
50
Strep Throat
S. pyogenes:
Hemolytic = ability to lyse red blood cells
51
Eukaryotic Cells
Come in various shapes and sizes, but in general:
◦No cell wall (except some fungi, algae and plants)
◦Membrane-bound organelles and nucleus
◦Carefully ordered and regulated
52
Eukaryotic
Nucleus
• Houses cell's DNA organized into chromosomes
City bout condied stand of DNA
•Sureudit banueler membrane (or nuclear envelope)
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Eukaryotic
Endomembrane System
Endoplasmic reticulum
Golgi apparatus
Lysosome
54
Eukaryotic
Endoplasmic reticulum
interconnected array of tubules and sacs
◦Rough – covered in ribosomes
◦Smooth – involved in synthesis of lipids
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Eukaryotic
Golgi apparatus
stacks of membraneous disks for protein modification
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Eukaryotic
Lysosome
”vacuums up any dirt”
Vesicles- could be anywhere
57
Eukaryotic
Ribosomes
Organelle-associated ribosomes are 70S (just
like prokaryotic)
◦ Non-organelle-associated ribosomes are 80S (40S + 60S)
Antibiotics can selectively target prokaryotic ribosomes
58
Non-organelle-associated ribosomes are 80S (40S + 60S)
◦ Free ribosomes – in cytoplasm for synthesis of soluble proteins
◦ Membrane-bound ribosomes – on rough endoplasmic reticulum for membrane proteins or exported proteins
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Antibiotics can selectively target prokaryotic ribosomes
◦ Sometimes bad
◦ Ex. chloramphenicol
60
Cytoskeleton
Microfilaments:
◦ Intertwined strands of actin
◦ Muscle contraction
61
Cytoskeleton
Intermediate filaments:
◦ Thicker than actin, but thinner than
microtubules
◦ Maintain position of nucleus and interactions between cells
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Cytoskeleton
Microtubules
◦ Hollow tubes
◦ Help with movement of organelles and vesicles
◦ Make up flagella and cilia
63
Mitochondria
“The mitochondria is the powerhouse of the
cell”
◦ Site of aerobic cellular respiration
◦ Has its own genome and 70S ribosomes (from prokaryotes)
◦ Endosymbiotic theory
64
Cell Membrane
◦ Similar to that of prokaryotic cells
◦ Sterols alter membrane fluidity (Cholesterol)
◦ Lipids maintain membrane stability and participate in cell signaling (Sphingolipids)
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Membrane Transport
Endocytosis
uptake of matter through plasma membrane invagination or vacuole/vesicle formation
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Membrane Transport
Exocytosis
release of contents out of the cell
67
The Cell Cycle
◦ One cell divides to form two identical
daughter cells
◦ Interphase
68
The Cell Cycle
Interphase
normal growth processes and replication of DNA
◦ G1 – cell growth
◦ S – DNA synthesis ◦ G2 – cell growth
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The Cell Cycle
Mitotic phase
alignment and separation of chromosomes, division of nucleus
70
The Cell Cycle
Cytokinesis
physical separation of the cytoplasm into two daughter cells
71
Osmotic Pressure
Isotonic solution
Hypertonic solution
Hypotonic solution
72
Osmosis
the diffusion of water across a membrane
73
Isotonic solution:
• Same solute concentration
as another solution
• No new movement of water
particles
74
Hypertonic solution:
• Higher solute concentration
than another solution
• Crenation - water moves out
of cell
75
Hypotonic solution:
• Lower solute concentration
than another solution
• Water moves into the cell – expansion, then lysis
76
Prokaryotic cells are protected from…
changes in osmotic pressure
77
Eukaryotic cells are highly…
susceptible to changes in osmotic pressure
78
EUKARYOTES
Eukarya
Protists informally refers to a diverse group of microscopic eukaryotic organisms
•”animal-like”, “plant-like”, “fungus-like”
•Protists are named based on evolutionary history
79
EUKARYOTES
Polyphyletic:
lack a shared evolutionary history
80
EUKARYOTES
Important supergroups
1. Amoebozoa
2. Excavata
3. Chromalveolata
4. Opisthokonta
5. Rhizaria
81
Unicellular Eukaryotic Parasites
Protozoa
1. Nonphotosynthetic
2. Motile
3. Always unicellular
4. Many unique characteristics
82
Unicellular Eukaryotic Parasites
Protozoa
1. Nonphotosynthetic
2. Motile
3. Always unicellular
4. Many unique characteristics
83
Unicellular Eukaryotic Parasites
Amoebozoa
Includes protozoans that used amoeboid movement
84
Unicellular Eukaryotic Parasites
F. septica
1. Slime mold
2. One giant cell with many nuclei
85
Unicellular Eukaryotic Parasites
Chromalveolata
Includes but not limited to paramecium
86
Unicellular Eukaryotic Parasites
T. microti
Apicomplexan = parasite with apical complex
Apical complex: cluster of cellular components allowing for parasite to enter host
Transmitted by ticks
Can be fatal
87
Unicellular Eukaryotic Parasites
B. coli
1. Cilate = have cilia on surface
2. Only parasite cilate
88
Unicellular Eukaryotic Parasites
Excavata
Includes but not limited to Euglena
89
Unicellular Eukaryotic Parasites
T. brucei
1. African sleeping sickness
2. Tsetse fly bite leads to colonization in the blood and brain
90
Unicellular Eukaryotic Parasites
Parasitic Helminths
1. Belong to opisthokonta
2. Animals that are included due to identification of microscopic eggs and larvae
Roundworms (Nematoda)
Flatworms (platyhelminths)
c. Approximately half are parasitic
d. Form multicellular animals with full organ systems
91
Unicellular Eukaryotic Parasites
Fungi
1. Belong to opisthokonta
2. Mycoses are illnesses caused by fungi
3. Molds are multicellular fungal bodies
Hyphae = filaments that make up bodies of mold
4. Yeasts are unicellular fungi
Reproduce asexually via budding
92
Unicellular Eukaryotic Parasites
Algae
1. Belong to Chromalveolata and Archaeplastida
2. Autotrophic protists
3. Unicellular or multicellular
4. Responsible for the production of ~70% of the oxygen and organic matter in aqueous environments
5. Algal blooms occur when algae grows rapidly and out of control, producing high concentrations of toxins “red tide”
Paralytic shellfish poisoning
93
ACELLULAR PATHOGENS
Viruses
DNA + protein or RNA + protein
1. Capsid = protein coat
2. Enveloped vs nonenveloped
94
Acellular
no cell
95
Virions
new virus particles
96
Host
necessary for production of virions
97
Host range
species of organisms able to be infected by the virus
98
Bacteriophages
viruses that infect bacteria
99
Vector
animal that transmits pathogen from one host to another
100
Spikes
1. May be on naked or enveloped capsids
2. Allow virus to attach and enter cell
3. Influenza virus
H spikes – hemagglutinin
N spikes – neuraminidase
“H1N1”
101
Life Cycle in Prokaryotic Hosts
Virulent phages
1. Typically lead to death of the cell through cell lysis
2. Lytic cycle
102
Life Cycle in Prokaryotic Hosts
Temperate phages
Become part of a host chromosome and are replicated to make new viruses
103
Life Cycle in Prokaryotic Hosts
Transduction
1. Generalized – transfer of random bacterial chromosomal DNA during lytic cycle
2. Specialized = excision and integration of the phage into the host genome during lysogenic cycle
104
Life Cycle in Animal Hosts
i. Attachment, penetration, biosynthesis, maturation, and release are similar to that in prokaryotic hosts
Tissue tropism: virus can only infect a certain type of cells within a certain host tissue (host specificity)
1. Ex. Polio virus infects tissues of brain or spinal cord only
Life cycle is dependent on form of genetic information presented by virus
105
Life Cycle of HIV
i. HIV is enveloped, icosahedral retrovirus
ii. Retrovirus = carries a reverse transcriptase and single stranded RNA
iii. ssRNA ssDNA dsDNA
106
Isolation and Culture of Cells
Require cells within a host or tissue culture
Identification
Vaccine production
Research
107
HeLa Cells
i. Immortal cell line heavily used in biomedical research
Cervical cancer cells
*see powerpoint for possible bonus point opportunity*
108
Virus Identification
i. Cytopathic effects
ii. Hemagglutination assays
iii. PCR assays
iv. Enzymatic assays
109
Prions
Proteinaceous infectious particles
1. Acellular
2. DNA or RNAS
3. Misfolded, rogue form of a normal protein
110
Prions
Transmissible spongiform encephalopathy (TSE)
1. Rare degenerative disorder
2. Accumulation of rogue proteins causes brain tissue to become sponge-like
3. Creutzfeldt-Jakob disease
