lesson 1 prokaryoticcellspowerpoint
TRANSCRIPT
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
1/25
Lecture 1
Prokaryote CellStructure & Function
Cell Diagram: Mariana Ruiz, pub domain
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
2/25
Size of Living Things
Diagrams: http://www.cellsalive.com/howbig.htm
1 m = 100 cm = 1,000mm = 1,000,000 m = 1,000,000,000nm
1mm = 1000 m = 1000000nm
1 m = 1000nm
http://en.wikipedia.org/wiki/Image:Relative_scale.svghttp://en.wikipedia.org/wiki/Image:Relative_scale.svg -
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
3/25
The Cellular Level of Organization
Living things are constructed of cells.
Living things may be unicellularor multicellular.
Cell structure is diverse but all cells share common characteristics.
Cells are smallso they can exchange materials with their surroundings.
Surface area relative to the volume decreases as size of cell increases.- limits the size of cells
___________________ states:
1. All organisms are composed of one or more cells.
2. Cells are the basic unit of structure and function in organisms.
3. All cells come only from other cells.
CELL THEORY
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
4/25
Two basic types of cells
Diagrams:Prokaryotic & Eukaryotic Cell, Mariana Ruiz
__________________________________________
PROKARYOTIC CELLS
(PROKARYOTES)
EUKARYOTIC CELLS
(EUKARYOTES)
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
5/25
Prokaryotes
Tell me about Prokaryotes
Binary Fission
Diagrams:Prokaryotic Mariana Ruiz
Binary Fission, JW Schmidt
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
6/25
Prokaryote Genetics
___________
Region of cytoplasm where chromosomal DNA is located.
Usually a singular, circular chromosome
____________
Small extra piece of chromosome/genetic material.
5 - 100 genes
Not critical to everyday functions.
Can provide genetic information to promote:
- Antibiotic resistance- Virulence factors
(molecules produced by pathogen that specifically influence host's function toallow the pathogen to thrive)
- Promote conjugation(transfer of genetic material between bacteria through cell-to-cell contact)
CONJUGATION OF MICROBIAL CELLS
NUCLEOID
PLASMID
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
7/25
Prokaryotes
______________
Also known as proto-plasm.
Gel-like matrix of water, enzymes,nutrients, wastes, and gases and containscell structures.
Location of growth, metabolism, andreplication.
______________
Bacterias way of storing nutrients
Staining of some granules aids inidentification
STRUCTURE OF MICOBIAL CELLS
CYTOPLASM
GRANULES
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
8/25
Prokaryotes
_______________
Found within cytoplasm or attached to plasma membrane.
What are they made of?
What do they do?
Composed of a small (30S) subunit and a large (50S) subunit.Cell may contain thousands of ribosomes.
_________________
Cellular "scaffolding" or "skeleton" within the cytoplasm.
Major advance in prokaryotic cell biology in the last decadehas been discovery of the prokaryotic cytoskeleton.
Previously thought to be a feature only of eukaryotic cells.
Eukaryotic Cells
Diagrams/Photos:
Fluorescent Cell: NIH, Pub Domain
RIBOSOME
CYTOSKELETON
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
9/25
Prokaryotes - Plasma Membrane
Diagrams:
Prokaryotic Cell, Mariana Ruiz
Membrane: NIST
Separates the cell from its environment.
Phospholipid molecules oriented so that hydrophilic heads directed outward and
hydrophobic tails directed inward.
Proteins embedded in two layers of lipids (lipid bilayer).
___________________ to allow substances to pass into and out of the cell.SEMI-PERMEABLE
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
10/25
Prokaryotes Plasma Membrane as a arrier
Primary function of plasma membrane regulate
movement of molecules entering or leaving cell.
Movement of molecules across plasma membrane requiresenergy.
PASSIVE TRANSPORTMovement of molecules is passive if no energy sources ofthe cell are expended.
_____________ = when molecules move from a higher toa lower concentration.
What type of things might affect the rate of diffusion?
Diffusion Animation: biologycorner.com
DIFFUSION
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
11/25
Prokaryotes Plasma Membrane as a Barrier
PASSIVE TRANSPORT (Continued)
_____________ DiffusionProteins assist in diffusion of molecules across plasma membrane.
Movement only occurs in the presence of a concentration gradient.
Some molecules move across the membrane more quickly if diffusion is facilitatedby a carrier molecule.
Diagram:
Facilitated diffusion, Mariana Ruiz
FACILITATED
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
12/25
Prokaryotes Plasma Membrane as a Barrier
Osmosis
Diffusion of ________ across the plasma membrane.
Environment surrounding cells may contain amounts ofdissolved substances (solutes) that areequal toless thangreater thanthose found within the cell.
Tonicity
_________________: no net movement of waterbetween cell and environment
_________________: a higher concentration ofsolute.
_________________: a lower concentration of solute.
Water will always move toward a hypertonicenvironment!!
Diagrams:
Osmosis - www.scienceaid.co.uk/biology/plants/osmosis.html
Blood Cells: Mariana Ruiz
WATER
ISOTONIC
HYPERTONIC
HYPOTONIC
http://www.scienceaid.co.uk/biology/plants/osmosis.htmlhttp://www.scienceaid.co.uk/biology/plants/osmosis.html -
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
13/25
Prokaryotes Plasma Membrane as a Barrier
_______________ TRANSPORT
How most molecules move across the plasma membrane.Analogous to a pump moving water uphill.
Types of active transport are classified by type of energy used to drive molecules acrossmembranes.
ATP Driven Active TransportEnergy from adenosine triphosphate (ATP) drives substances across the plasma membrane
with the aid of carrier molecules.
Diagram:
Source unknown
ACTIVE
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
14/25
Peptidoglycan- Rigid mechanical support- Freely permeable to solutes
Peptidoglycan is a huge polymer of interlocking chains ofidentical peptidoglycan monomers.
Backbone of peptidoglycan molecule composed of twoderivatives of glucose:
N-acetylglucosamine (NAG)N-acetlymuramic acid (NAM)
NAG / NAM strands are connected by interpeptide bridges.
Prokaryotes Cell Wall
Image:
Peptindoglycan Structure: NicolasGrandjean
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
15/25
From the peptidoglycan inwards all bacteria are very similar. Goingfurther out, the bacterial world divides into two major classes (plus acouple of odd types). These are:
Gram-positive Gram-negative
Prokaryotes - Cell Wall
Images: PHIL Public Health Image Library
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
16/25
Prokaryotes - Cell Wall: Gram-Negative & Gram-Positive
Image:
Prokaryotic Cell, Mariana Ruiz
Gram +-, Julian Onions
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
17/25
Why are these differencesin cell wall structure so
important?
Images: Sources unknown
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
18/25
Prokaryotes - Glycocalyx
Some bacteria have anadditional layeroutside of the cell wallcalled the glycocalyx.
This additional layer cancome in one of twoforms:
1. Slime Layer2. Capsule
STRUCTURE OF MICOBIAL CELLS
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
19/25
Prokaryotes - Glycocalyx
Some bacteria have an additional layer outside of the cell wallcalled the glycocalyx.
This additional layer can come in one of two forms:
1.______________________glycoproteins loosely associated with the cell wall.
Slime layers cause bacteria to adhere to solid surfaces and helpprevent the cell from drying out.
StreptococcusThe slime layer of Gram+ Streptococcus mutans allows it toaccumulate on tooth enamel (yuck mouth and one of the causes ofcavities).
Other bacteria in the mouth become trapped in the slime and forma biofilm & eventually a buildup of plaque.
StaphylococcusThe slime layer of Gram+ Staphylococcusallows it to thrive in thesalty, hypertonic environment of the skin.
Glycocalyces are not specific to Gram+ or Gram- bacteria,sometimes only some members of a certain species (strains) have aglycocalyx, whereas others dont.
STRUCTURE OF MICOBIAL CELLS
SLIME LAYER
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
20/25
Prokaryotes - Glycocalyx
2.___________________polysaccharides firmly attached tothe cell wall.
Capsules adhere to solid surfaces and tonutrients in the environment.
Adhesive power of capsules is a majorfactor in the initiation of some bacterialdiseases. Capsule also protect bacteriafrom being phagocitized by cells of thehosts immune system.
STRUCTURE OF PROKAROTIC CELLS
CAPSULE
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
21/25
Prokaryotes - Glycocalyx
Bacterial Capsule and Meningococcal Infection
Meningococcal infection is caused by meningococcalbacteria (Neisseria meningitidis).
Causes:1. meningococcal meningitis (infection of the
meninges/spinal cord)2. meningococcal septicaemia (blood poisoning).
Of the two forms, meningococcal septicaemia is themost dangerous.
Meningococcal bacteria are the most common causeof bacterial meningitis.
Approximately 5% of people who suffer frommeningococcal meningitis will die.
STRUCTURE OF PROKAROTIC CELLS
Meningococcal bacteria grow
in pairs called diplococci often
surrounded by a capsule coat.
Over a million of these would
fit on the head of a pin.
http://www.meningitisuk.org/about-meningitis/bacterial-meningitis.htm
http://www.meningitisuk.org/about-meningitis/bacterial-meningitis.htmhttp://www.meningitisuk.org/about-meningitis/bacterial-meningitis.htm -
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
22/25
Prokaryotes - Endospores
Dormant, tough, non-reproductive
structure produced by smallnumber of bacteria.
Primary function of endospores:Allow bacteria to survive in
suspended animation whenenvironmental conditions arenot suitable. When conditions
are right the endospore willsprout a living bacterium.
Resistant to radiation,desiccation, lysozyme,temperature, starvation, andchemical disinfectants.
Endospores commonly found in soiland water, where they maysurvive for long periods oftime.
A stained preparation of Bacillussubtilis showing endospores as green
and the vegetative cell as red
Image:
Stain: Jerry Keplinger, James H. Quillen College of Medicine
Procedure: Source link no longer works
STRUCTURE OF PROKAROTIC CELLS
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
23/25
_____________________
The most significant cause of pseudomembranous colitis
Severe infection of the colon, often happening after normal gut flora is eradicated byuse of antibiotics. The C. difficile bacteria naturally resides in the body, butbecomes overgrown.
C. difficile overgrowth is harmful because the bacterium releases toxins that cause:
* Bloating and constipation* Diarrhea with abdominal pain* Severe diarrhea with mucus and blood present in feces* Body aches and severe abdominal pain caused from ulcerated intestines
Treatment includes specific anticlostridial antibiotics, e.g. metronidazole orvancomycin.
News story link: http://www.thesun.co.uk/sol/homepage/news/article860499.ece
STRUCTURE OF PROKAROTIC CELLS
Clostridium difficile (aka C dif or CDF)
http://www.thesun.co.uk/sol/homepage/news/article860499.ecehttp://www.thesun.co.uk/sol/homepage/news/article860499.ece -
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
24/25
Prokaryotes Surface Appendages
Some prokaryotes have distinct appendages that allow themto move about or adhere to solid surfaces.
Consist of delicate stands of proteins.
___________Long, thin extensions that allow some bacteria to move about
freely in aqueous environments.
__________________ (endoflagella)Wind around bacteria, causing movement in waves.
____________Most Gram- bacteria have these short, fine appendages
surrounding the cell. Gram+ bacteria dont have.
No role in motility. Help bacteria adhere to solidsurfaces. Major factor in virulence.
____________Tubes that are longer than fimbriae, usually shorter than
flagella. Use for movement, like grappling hooks, and alsouse conjugation pili (singular = pilus) to transfer plasmids.
Images:
Flagella: Mike Jones Wiki
Axial Filament: Indiana USchool of Med
EColi: Pub Library of Science
FLAGELLA
AXIAL FILAMENTS
FIMBRIA
PILI
-
7/25/2019 Lesson 1 ProkaryoticCellsPowerPoint
25/25
Neisseria gonorrhoeae
Gonorrhoeae one of the most communicable disease in the US.
125 cases per 100,000. Teens 15-19 yo 634 cases per 100,000. Young adults20-25 460 per 100,000.