BI 305 Exam 1 Chp 1-3 Flashcards
1
Q
Definition of Microbiology
A
Microbiology=study of organisms too small to be seen with the naked eye.
2
Q
Why are microbes important?
A
Contribute to human health
Digesting food we can’t, providing vitamins for us, and so much we don’t know.
There is some evidence that can contribute to our mood and overall general health.
Nutrient cycling.
Carbon, nitrogen, etc.
Provide oxygen.
While plants do this as well, cyanobacteria still provide a lot of oxygen.
Break down waste.
Can be seen as part of the cycling they play a role in.
3
Q
What are bacteria? Some common characteristics?
A
Has a cell wall of peptidoglycan.
Peptidoglycan=peptide linked sugar molecules that restrict expansion of the cell to maintain cell turgor.
Replicate through binary fission.
Eat organic substances, inorganic substances, or photosynthesize.
4
Q
What are archaea?
A
They don’t have organelles or a nucleus but they don’t have any peptidoglycan.
Live in extreme environments.
Ex: Methanogens, thermophiles, halophiles.
5
Q
What are protoza?
A
Protoza=unicellular eukaryotic microorganisms.
6
Q
What are algae?
A
Algae=photosynthetic eukaryotes.
Can complete asexual and sexual reproduction.
Cell walls contain cellulose.
7
Q
What are fungi?
A
Fungi=unicellular or multicellular eukaryotic organisms.
Cell wall made of chitin.
Asexual and sexual reproduction.
Obtains food by absorbing it from the environment.
8
Q
What are viruses?
A
Viruses=acellular microbe.
DNA or RNA as genetic material.
Only reproduces through a host.
Parasites
Only does things required by the “living” definition inside of a host.
Thus, one argument is that viruses are only alive when they are inside of a host.
9
Q
What is a +RNA virus?
A
+RNA virus=contains mRNA that can be directly translated into proteins.
They contain the sense strand.
No transcription needed.
5’-3’.
10
Q
What is a -RNA virus?
A
-RNA virus=contains antisense RNA that is complementary to mRNA.
Needs to be transcribed then translated.
3’-5’
11
Q
What are some reasons that viruses are alive?
A
They need energy to survive.
Evolved from cells.
Not for all viruses but for some of them.
They make copies of themselves.
12
Q
What are some reasons that viruses are not alive?
A
They need a host to survive.
Can only replicate while inside of a host.
They are not a cell.
13
Q
What significant experiment is Carl Woese do?
A
Used 16S RNA as a molecular clock to understand the evolution of microorganisms.
Proposed the 3 domain idea between bacteria, archaea, and eukaryotes.
16S RNA was used because it mutates at a slow but stable rate.
By comparing microorganisms, he could see how different their 16S RNA was, how closely they were related to each other, and when they diverged.
14
Q
Who used faster sequencing techniques to sequence the entire genome of H. influenza?
A
Claire Fraser-Legget
15
Q
Who was Florence Nightingale?
A
Most notable known as a nurse.
In addition, she founded medical statistics by showing how many soldiers die more from infections than on the battlefield.
16
Q
Who was Robert Hooke?
A
First used a microscope to see cells.
Named the term cells.
17
Q
Who was Antoine van Leeuwenhoek?
A
Antoine van Leeuwenhoek generated better microscopes up to 300X to see microbes.
18
Q
How have microbes shaped humans and human history?
A
Plagues such as the bubonic plague.
In our gut to influence us.
We use microorganisms for fuel, and research into medicines, antibiotics, and antivirals.
19
Q
What is spontaneous generation? Why did people believe this?
A
Spontaneous generation=living things suddenly generate from non-living matter.
People thought that microorganisms did this since they seemed to randomly appear.
20
Q
What were some experiments to disprove spontaneous generation?
A
Experiments included:
Letting meat sit in a closed container vs an open one.
The open one was spoiled.
Pasteur’s S-shaped flask.
The air was allowed in and out but microorganisms could not.
21
Q
Who was Pasteur?
A
S-neck flask to prove that microorganisms couldn’t grow on boiled broth.
Founded autoclaving.
Autoclaving=killing microbes in high heat.
The high heat is achieved by increased pressure.
Discovered yeast developed alcohol by fermentation.
Before this, people couldn’t determine why some products became an alcohol and some didn’t.
Developed vaccine for rabies.
22
Q
Who was Joseph Lister?
A
First to propose handwashing and sanitation for doctors.
23
Q
What are Koch’s postulates?
A
See if the people with the same symptoms have the same microbe.
This microbe must be absent in healthy individuals.
Microbe must be isolated from the diseased host.
Put isolated microbe from the diseased host into a healthy individual.
Do they develop the same disease?
Isolate microbe from the newly infected host.
Is it the same?
24
Q
How are Koch’s postulates viewed today?
A
Still holds up okay today.
The major issue is ethical problems with infecting someone who is healthy.
Other methods such as contract tracing can show how people got sick.
25
What did the Hesse couple develop?
Developed agar as an organic solid substrate for culturing microorganisms.
26
What are single colonies? Why are they important?
Single colonies=colonies grown from a single microbe.
| They are more likely to be genetically similar.
27
How does immunization work?
The virus is attenuated (slightly alive but weakened by being left outside of a host), uses an mRNA vaccine, heat the virus to kill it, or inoculate someone with a small piece of the virus.
28
What was the first immunization/vaccine?
Edward Senner first vaccinated people from smallpox by infecting them with cowpox.
Cowpox was a similar but much less dangerous disease.
This occurred 70 years before Koch.
29
Why did it take so long for people to realize that microbes cause disease?
They couldn’t see the microorganisms so they didn’t know they existed for a long time.
Because they were so small and it was hard to separate them, it was hard to see what was a pathogen and what was a healthy microbe.
30
What were some innovations to connect microbes to disease?
Microscopes.
Culturing microorganisms
Agar.
S-shaped flasks.
31
What is immunity?
Immunity=protection from the disease by recovering from it or getting a vaccine.
Immunity does not guarantee that you can’t still get it, be asymptomatic, and spread it to others.
32
What is chemotherapy?
Chemotherapy=treating diseases with a chemical substance.
33
What are synthetic drugs? What was the first synthetic drug?
Synthetic drugs=chemicals manufactured in a lab.
Salvarsan by Paul Ehrlich was the first synthetic drug.
Treated syphilis.
34
What are antibiotics? What was the first antibiotic?
Antibiotics=chemicals produced by bacteria that are toxins to other bacteria.
Alexander Fleming made the first antibiotic, Penicillin.
35
What experiment led to the discovery of viruses?
Dmitiri Ivanosky identified the virus causing tobacco-mosaic disease.
Ivanosky used smaller and smaller filters until no bacteria were small enough to go through.
The only thing that it could be was a virus because viruses are smaller than bacteria.
36
What are Winogradsky columns?
Winogradsky columns=studies microbio ecology by observing how microorganisms arrange themselves in the environment and what they produce.
37
What are chemolithotrophs?
Chemolithotrophs=mircobes that feed on inorganic substances.
Cannot grow on agar because it is organic.
Enrichment cultures can grow chemolithotrophs.
38
What is nitrogen fixation?
Bacteria turning N2->NH3 for plants to use it.
39
What are endosymbionts?
Endosymbioant=organism living inside of a larger organism.
40
Who proved that mitochondria and chloroplasts are endosymbionts? What was the evidence for this theory?
Lynn Margulis proposed this theory.
Evidence:
Same size as bacteria.
Same DNA and RNA as bacteria.
41
What is biofilm?
Biofilm=microbial community containing several different species adhered to a surface.
42
What is gene therapy?
Gene therapy=inserting a missing gene into a genome to provide the missing instructions whose lack of presence is causing a disease.
Delivered through a depleted virus.
43
What is the difference between antiseptics and antibiotics?
Anti-septics kills off all microbes (including human cells) while anti-biotics kill only certain bacteria.
44
What types of organisms live at the top of Winogradsky columns? What types of organisms live at the bottom of Winogradsky columns?
Aerobic; anaerobic.
45
What is the difference between the microbiota and the microbiome?
Microbiota=ecological community of microorganisms living on or within an organism.
The microbiome is very similar to microbiota but emphasizes their collective DNA sequences.
46
Why is it hard to classify microbe species? When do two microbes become different species?
It is hard to classify microbial species because they produce asexually and can exchange genetic information with other species.
A working definition to classify includes that two different microorganism species will not be more than 95% alike.
47
What is the chemiosmotic theory?
Chemiosmotic theory=energy storage for redox reactions comes from the movement of H+ ions across a membrane.
Like in photosynthesis and cellular respiration.
48
Who was Rosalind Franklin?
Used X-ray crystallography to determine the structure of DNA.
Watson and Crick used her data of the structure of DNA but denied it.
She died of ovarian cancer before the Nobel Prize could be awarded to her.
49
What is resolution?
Resolution=smallest difference where two separate objects can be distinguished as separate.
Naked eye resolution is around 150 um.
50
What is detection? How is it different than resolution?
Detection=an object is determined as present.
We can detect what we can’t resolve.
Ex: See bacterial colonies but can’t see the individual cells.
51
What is magnification?
Magnification=increases the image of the object so our eye can resolve the object.
52
What is a millimeter?
1 millimeter=10^-3
53
What is a micrometer?
1 micrometer=10^-6
54
What is a nanometer?
1 nanometer=10^-9
55
What are the different bacterial shapes?
```
Bacilli=rod
Spirochete=tightly coiled spiral
Cocci=round
Spirillum=wide, rigid spiral cell.
Unrelated to the spirochete.
```
56
What is contrast?
Contrast=difference between light and dark.
57
What is absorption?
Absorption=the object gains the photon’s energy.
Results in heat.
The specimen is dark.
58
What is reflection?
Reflection=the light bounces off the object.
| Bright-field microscopy.
59
What is refraction?
Refraction=the bending of light as it enters a substance that lowers its speed.
60
What is the scattering of light?
Scattering=wavefront is converted to a spherical wave originating from the object.
The object looks hazy.
61
What does parfocal mean?
Parfocal=while switching between objective lenses, it should remain in focus.
62
What is the refractive index?
Refractive index=how much light bends as it passes through a medium.
63
What is fixation?
Fixation=adhereing specimen to the slide.
Usually kills the organism.
Doesn’t burst the specimen open.
Ex: Methyl alcohol.
64
What is staining?
Staining=application of a compound with a chromophore.
65
What is a mordant?
Mordant=additive to a stain that can intensify the stain by adhering it tighter.
Ex: Iodine.
66
Explain the difference between acidic dyes and basic dyes.
Acidic dye=chromophore (colored ion) is on the negative ion.
Called negative staining.
Ex: Acid fuchsin, and nigrosin, and eosin.
Basic dye=chromophore is on the positive ion.
Ex: Crystal violet, safranin, and methyl blue.
67
What is an acid-fast stain?
Acid-fast stain=binds to bacteria with a waxy material in their cell wall.
68
What is an endospore?
Endospore=dessicated (dried up) cell.
| Can survive very harsh conditions.
69
What is negative staining? What is it used for?
Negative staining=stains the background. To see capsules.
70
What is the function of capsules?
Capsules make them slippery.
Helps to survive inside a lysosome if they are eaten.
Makes it harder for the immune system to identify them.
If a bacterium has a capsule, it makes them more virulent (more likely to cause disease).
71
How does fluorescence microscopy work?
UV light excites the fluorophore and it releases a wavelength with a lower wavelength that we can see.
Images can be blurry.
72
What is DAPI?
DAPI=fluoroescent that intercalates with DNA.
| Can interact with nucleus and mitochondria DNA.
73
What is the focal point?
Focal point=point when all rays of light converge on a single spot.
74
What is Fluorescence in situ hybridization (FISH)?
Fluorescence in situ hybridization (FISH)=species specific DNA probes attach to a sample containing different species.
Each probe fluoresces a different color.
75
What is peptidoglycan?
Peptidoglycan=peptide linked sugars that maintain the cell’s turgor pressure.
It limits the size of the cell so the water and cytoplasm of the cell fill it and cause pressure.
76
What is cell fractionation and what can it tell us?
Cell fractionation=how we separate subcellular components such as membranes, ribosomes, and flagella.
Fractionation can tell us a lot about what is in the cell but less about what they do.
77
What are the functions of membrane proteins?
Structural support.
They can attach the membrane to other parts of the cell envelope, cytoskeleton, and cell components such as flagella.
The direction of environmental signals.
Membrane proteins can detect certain environmental signals such as temperature and pH.
Secretion of communication signals.
Cells can excrete products and proteins and when other cells receive them, it sends a message such as to continue to stop producing a certain product.
Transport of ions.
Transporting of ions generates energy for the cell to store.
78
How can molecules be transported over the membrane?
Passive diffusion.
Works for small, non-polar molecules so they can get past the hydrophobic tails.
Osmosis=movement of water.
There is a lower concentration of water inside to outside with all the solutes inside.
Thus, water moves down the concentration gradient into the cell.
This increases the volume and pressure in the cell.
This is countered by the cell wall.
Without the cell wall, the cell would continue expanding until it lysed.
Penicillin has this effect on cells.
Weak bases and acids:
They are in equilibrium between their charged and uncharged forms.
The uncharged forms can cross the membrane.
Once inside, they form their charged forms again.
Many drugs are weak acids or bases that perform this.
It is important to keep the acid and alkali balance the same so that acid or alkali stress does not occur.
Passive transport=transport along the concentration gradient through channel proteins.
Active transport=transport against the gradient.
Requires energy.
79
What changes occur to the membrane under cold and hot conditions?
Fatty acid chains can develop kinks by becoming unsaturated (formation of double bonds).
This increases the fluidity of the membrane because the tails cannot pack together as tightly.
This is useful under cold temperatures.
Membranes can form cyclopropane rings or use reinforcing agents to increase the rigidity of the membrane.
Required under starvation or acid stress.
Reinforcing agents fit between the hydrophobic tails.
In eukaryotes, this role is played by cholesterol.
In bacteria, this role is played by pentacyclic called hopanoids or hopanes. These increase the rigidity of the membrane.
80
What are teichoic acids?
Teichoic acids=phosphodiester links with sugars or amino acids in the middle.
Negatively charged.
The teichoic acids (because they are negatively charged) and the thickness of the peptidoglycan help the Gram-positive cells retain the primary stain in Gram staining.
81
What is the S-layer?
S-layer=surface layer of proteins or glycoproteins with large enough pores to allow a range of other substances through.
Pathogens can bind easier to the S-layer.
The S-layer helps bacterium form biofilms by helping them stick together.
82
What are endotoxins?
Endotoxins are harmless in the cell but when released in a lysed cell, they overstimulate the host’s immune defenses.
83
What are porins? How do porins change over time?
Porins=outermembrane protein that allows transport of nutrients such as sugars and peptides.
Not found in the inner membrane.
Porins differ in size and shape due to the external environment. They are bigger when nutrients are rich and smaller when nutrients are scarce.
84
What is septation?
Septation=growing of the septum.
| The septum divides the two daughter cells.
85
What is FtsN? What happens if a cell doesn't have it?
FtsN forms a Z-ring around the growing spetum.
Divisome=protein complex (FtsN) that oversees septation.
In mutants without FtsN, the septum does not constrict enough, and the membrane balloon out.
86
What is the origin of replication?
Origin of replication=midpoint of the chromosome that is attached to the cell envelope at the midpoint of the cell.
87
What is the replisome?
Replisome=DNA polymerase and its protein accessories.
88
What factors can contribute to a cell's life cycle being faster?
Length of DNA.
Whether new replication begins before the old one ends. Whether the septum is made during or after replication of DNA.
Replication is a lot faster for prokaryotes because they only have 1 gene instead of two for each character.
Also has fewer non-coding genes.
89
How do bacteria have rudimentary cell differentiation?
When the divide the poles are not the same. This can be the difference between a new pole and an old pole or one pole can have different structures of chemicals on it.
90
What is the main function of membrane vesicles, nanotubes and sex pili? What is the benefit of these?
Can offer some protection. Membrane vesicles can act as distractions. Nanotubes and sex pili can help the cell gain new proteins and antibiotic resistance.
91
What are thylakoids?
Thylakoids=intracellular membranes that are highly folded and contain chlorophyll and electron carriers.
92
What are carboxysomes?
Carboxysomes=polyhedral protein covered body that contains rubisco for the dark reaction of photosynthesis.
93
What are gas vesicles?
Gas vesicles=protein structures that contain gas.
| This increases the buoyancy of the cell.
94
What is conjugation?
Conjugation=sex pili can attach to other bacteria and transfer DNA.
95
What is twitching?
Twitch=bacteria's version of walking.
96
What are flagella?
Rotary flagella=helical propellers that move the cell.
| Powered by a flagellum motor embedded in the membrane that gains energy from H+ transfer across the membrane.
97
How is cell movement coordinated?
Cells move in the direction that chemoreceptors sense nutrients in. Flagella move counterclockwise to go forward. Flagella move clockwise to stop and go backwards.
98
What is chemotaxis?
Chemotaxis=attraction to specific chemicals.
99
What is the Gram staining process?
A primary stain is added to the sample.
This is usually a basic stain as the chromophore is on the positive ion and thus will stick to the bacteria more.
Both Gram-negative and Gram-positive bacteria are colorized.
However, the stain sticks better to the Gram-positive bacteria because of its layers of peptidoglycan and not having an outer membrane.
The stain is able to get under the cell wall.
A mordant (ex: iodine) is added.
This helps the stain adhere to the cell stronger.
Turns primary stain into a crystal.
A decolorizer (ex: ethanol or methanol) is added.
This removes stain where it weakly adheres.
Thus, the stain is removed from Gram-negative bacteria.
A secondary stain (ex: safranin) is added.
This stains all cells in the sample.
However, because the Gram-positive bacteria still has the primary stain, under the microscope, the primary stain is what shows.
The Gram-positive bacteria show the primary stain and the gram-negative bacteria show the secondary stain.
100
Describe the process of transport of weak acids and bases across the membrane.
Outside of the cell, they exist in their charged forms.
To cross the membrane, they can’t be charged so they join together as their neutral form.
Once, they cross, they dissociate again.
The weak acids and bases follow a gradient so if there is more on the outside, then they are more likely to cross the membrane.
101
How many layers of peptidoglycan do Gram-positive bacteria have? What about Gram-negative bacteria?
Gram-positive: 5-20.
| Gram-negative=1-2.
102
Describe the cell envelope of a Gram-positive cell.
Inner membrane.
Multiple layers of peptidoglycan (cell wall).
Possible S-layer, glycerol on top, or a capsule.
103
Describe the cell envelope of a Gram-negative cell.
Inner membrane.
Few layers of peptidoglycan.
Periplasm between inner and outer membrane.
Lipoproteins (ex: murine) connect peptidoglycan to the outer membrane.
Lipopolysaccharides on top of the outer membrane.
LPS contains endotxoins.
Pores like OmpF can help bring in different nutrients.
104
What is the periplasm?
Periplasm has enzymes and transport proteins.
| Transport proteins help get nutrients past the inner membrane.
105
What does the LPS layer consist of?
LPS: Glucosamine, core polysaccharide, and O polysaccharide.
O polysaccharide is repeating.
Used to identify different strains of bacteria.
Ex: E. coli O157: H7
O 157 says which type of O antigen it is.
H 7 represents an H antigen which is on the flagella.
106
How is peptidoglycan held together?
Peptidoglycan has chains of disaccharides. The main disaccharides are N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM). Those parallel disaccharide chains are connected by amino acid cross-bridges. NAM is connected to amino acids. There are two terminal D-alanines. One D-alanine is kicked off and the cross-bridge with m-Diaminopimelic acid on the other disaccharide chain is formed.
107
How does vancomycin work?
It prevents the second D-alanine from leaving. Thus, the cross-bridge cannot be formed.
108
What are the amino acids in the cross-bridge of peptidoglycan?
```
L-alanine.
D-glutamic
m-Diaminopimelic acid.
And D-alanine.
There are two of these at the end. One breaks off and then the cross-bridge forms between D-alanine and m-Diaminopimelic acid.
```
109
Why does cell fractionation work?
By spinning at high speeds, cell components of different densities separate.
110
What are the steps of cell fractionation?
Ethylenediamine-tetraacetic acid (EDTA) disrupts the outer membrane by removing Mg2+ and Ca2+ ions.
This disrupted membrane allows sucrose to cross.
Sucrose fills the periplasm.
Lysozyme cleaves peptidoglycan and breaks down the cell wall.
What is left is a spheroplast (inner membrane and cytoplasm).
The periplasm and inner membrane are still intact.
Cells are transferred to distilled water, and this causes osmotic shock because the outer membrane, peptidoglycan, and cell wall are not there.
As a result, the periplasm leaks out.
Its proteins are still collected in the ECM though.
After the first ultracentrifugation step, the supernatant contains the periplasm.
The pellet contains the cytoplasm, spheroplasts, and the outer membrane.
111
Which cell density goes in the pellet? What about the supernatant?
Pellet=higher density.
| Supernatant=lower density.
112
What is macromolecular crowding?
The fact that the inside of the cell is very crowded.
113
Do phospholipids always stay the same? If not, why?
Different phospholipids can be made to meet certain stress conditions. Ex: Cardolipins are made when the cell is stressed.
Different phospholipid functions are due to the different terminal group on the phospholipid head.
114
Explain differentiation in biofilms.
Ex: Ones at the bottom make more glycoproteins and attachment proteins.
Ex: Ones at the top make more proteins to gain nutrients.
Like forming small tissues.
1,000X more resistant to antibiotics.
115
Explain antibiotic resistance comparing Gram-positive and Gram-negative.
Gram-negative is more resistant because the peptidoglycan is not as directly exposed.
116
Does the wavelength need to be smaller or bigger than an object to resolve it?
Needs to be smaller.
| If it is bigger, then it will just pass through the object.
117
Light microscope
Light microscope=uses light to view live of dead samples and to resolve the general shape of a cell.
Limited by the bright field and resolution limit by the wavelength of light.
118
Fluorescent microscope
Fluorescence=uses fluorophores to tag objects and samples.
Can view live or dead samples.
Track the placement of genes, proteins, cell structures.
119
Dark-field microscope
Dark-field=directed light misses the object from scattered wavefronts from the objects illuminated on a dark-field.
Can view live or dead organisms.
Can resolve capsules and harder to see cell structures as flagella.
Because wavefronts are used, the samples appear hazy and bigger than they actually are.
120
Phase-contrast
Phase-contrast can view live organisms.
Contrast is created by light that passes through the stage being cut off while the light that passes through the sample is not.
Because of refraction as light goes through the sample and another lens that provides refraction, the waves are ½ wavelength off.
This provides contrast around the sample and in intracellular structures.
121
Differential interference contrast (DIC)
Differential interference contrast is very similar to phase-contrast but it accentuates small differences in interference bands.
Can also view live or dead samples.
122
Transmission electron microscopy (TEM)
Transmission electron microscopy (TEM) uses electrons with a sample wavelength than light to view the intracellular components of smaller dead samples.
Staining with electron heavy materials may be required for more scattering of electrons to occur.
Sample must be sliced into layers.
123
Scanning electron microscopy (SEM)
Scanning electron microscopy (SEM) uses electrons to view a detailed picture of the outside of dead samples.
124
Cryo-electron microscopy
Cryo-electron tomography uses flash-frozen samples that do not need staining to generate a 3D model of the intracellular structures of dead cells.
125
Scanning probe microscopy
Scanning probe microscopy scans unstained, live cells in water or air by measuring atomic forces.
126
Atomic force microscopy
Atomic force microscopy scans details of the exterior of unstained, live cells by measuring Van der Waal forces.
127
Scanning tunneling microscopy
Scanning tunneling microscopy uses tungsten probes to scan the contours and depressions of cells.
Can even resolve DNA.
128
X-ray crystallography
X-ray crystallography uses X-rays on crystallized samples to fix the position of even individual atoms.
A computational method is generated by interference patterns.
129
Cyrocrystallography
Cryocrystallography uses X-rays on flash-frozen samples to provide even clearer resolution than X-ray crystallography.
A computational method is generated by interference patterns.
130
Which type of microscopy is particularly useful to study the surfaces of live bacteria?
Atomic force.
131
What best visualized using a negative stain?
Capsule.
132
Which microscope would be MOST appropriate to visualize viral particles being assembled inside an infected bacterial cell?
TEM.
133
Which type of microscopy provides a “false 3-D image”?
Differential Interference Contrast (DIC).
134
What cellular structures do cells use to avoid phagocytosis?
Capsules.
135
Bacteria respond to cold and heat by...
increasing or decreasing their synthesis of unsaturated phospholipids.
136
What is common between prokaryotes and eukaryotes?
Membrane, genetic material, cytoskeleton, transcription, translation.
137
What is different between prokaryotes and eukaryotes?
```
No nucleus in prokaryotes.
Smaller ribosomes in prokaryotes.
Peptidoglycan in prokaryotes.
Complex envelope in prokaryotes.
Prokaryotes have own immune system with CRISPR.
Prokaryotes divide by binary fission.
```
