Chapter 3 Video Notes Flashcards
Describe four major properties of living cells.
-growth: living things can grow/increase in size
-reproduction: organisms can increase in #, reproduce a/sexually
-responsiveness: living things respond to their environment, change themselves in reaction, & have taxis
-metabolism: the ability to take in nutrients from outside themselves & use the nutrients in a series of controlled chemical reactions to provide the energy & structure needed to grow, reproduce, & be responsive
What are the Three domains of life?
Archaea, Bacteria, Eukaryua
Prokaryotic Cells
Archea
Bacteria
Eukaryotic Cells
Eukaryua
What are prokaryotic cells?
Include bacteria and Archea.
Unicellular
Has a simple structure,
lacks membrane-bound nucleus
Lacks membrane-bound organelles
Are typically 1 um in diameter or smaller
What are Eukaryotic cells?
Includes fungi, Protozoa, animals, plants, and helminths.
Unicellular and multicellular
Have membrane-bound nucleus
Have membrane-bound organelles.
10-100 um in size
What do all cells have in common?
Cytoplasmic membrane
cytoplasm
ribosomes
Chromosomes/ genetic material
What is a Pathogen?
Microorganisms are capable of causing disease.
What is Pathogenicity?
A microorganism’s ability to cause disease.
What is Virulence?
A measure of pathogenicity
What is Disease?
Any condition in which normal structures or functions of the body are damaged or impaired.
What are Virulence Factors?
Enzymes, toxins, and other factors affect the relative ability of a pathogen to infect or cause disease.
What are the external structures of bacteria cells?
Flagella
Pili
Glycocalyx
Fimbriae
What is Glycocalyx?
Is a sugar coating surrounding the outside of the cell
Location - Outside to the cell wall
Composed of polysaccharides, polypeptides, or both.
What are the two types of Glycocalyx?
Capsule
-Composed of organized repeating units of organic chemicals
-Firmly attached to the cell surface
slime layer
-Loosely attached to the cell surface
-water-soluble
What are Biofilms?
Biofilms aggregate of many bacteria that are living together on the surface.
Capsulated bacteria vs encapsulated bacteria
Capsulated
-It has the presence of a capsule
- Able to cause disease
- Avoid destruction by the body cell defense
-Pathegeic
-Virulent
- ex Streptococcus pneumonia
Unencapsulated
- It has an absence of capsule
- not able to cause disease
-the body’s defense cell destroy them
-nonpathogenic
-Avirulent
- ex Streptococcus pneumonia
What is Flagella?
Long structure that extends beyond cell surface.
Are not present on all bacteria
Are responsible for movement/ motility
Rotation propels them through environment
What are the two types of taxis?
Phototaxis - move in response to light
chemotaxis - move in response to chemicals.
What are the Three Types of flagella?
Pertrichous- Dispersed randomly all over the structure of the cell.
Polar- are only at the ends of the flagella
Endo flagella - from an axial filament that wraps around the cell.
What is Fimrae?
Small, sticky, bristlelike projections
used by bacteria to adhere to one another and to substances in environment
There may be hundreds of fimbriae per cell
Shorter than flagella
What is a pili?
-A special type of fimbriae
-Also known as conjunction pilus
-Longer than fimbriae but shorter than flagella
-In Bacteria that normally have one or two cells
-Used during mating/ conjunction
-Transfer DNA from one cell to the other.
What is a cell wall and its three basic shapes?
The cell wall Provides the structure and shape of bacteria cells.
The Three shapes
Bacillus - Rod shape
Coccus - circle shape
Spiral- Spirillum , spirochete,
virbrio.
Arrangements of cell shapes.
Staphylo = Clusters
Sterpto= chains
Simple stain technique.
Simple stains
- Use one dye
-used to determine shape and size
Basic dyes
- dye is positively charged
-attracted to the negatively charged cell surface.
- Result cells appear the color of dye
- ex methylene blue
What are Gram-positive cell walls?
-A relatively thick layer of peptidoglycan
-Contain unique poly alcohols call teichoic acids
- Appear purple after gram staining.
What are teichoic acids?
- Stabilize peptidoglycan by increasing rigidity.
- Give gram-positive and negative charge.
-Play a role in the passage of ions through the wall.
What is a Gram-Negative bacterial cell wall?
- Have only a thin layer of peptidoglycan
- Has phospholipid bilayer
- Has Lipopolysachrides
- Contains lipid A
-Appear pink after Gram staining - protect against lysozyme
What is the structure of the cytoplasmic membrane?
- Referred to as phospholipid bilayer
-composed of lipids and associated proteins - internal proteins and peripheral proteins
-These proteins may act as recognition proteins, enzymes, receptors, carrier proteins, and channel proteins.
What is the function of the bacterial cytoplasmic membrane?
- Control the passage of substances into and out of the cell
- Nutrients are brought into the cell, and waste is removed
-Selective permeability
- Allows some substances to cross while preventing others to cross
-Enable the cell to concentrate chemicals on one side of the membrane or the other.
What is the structure of cytosol in bacteria?
-Present in all cells
-liquid portion of cytoplasm
-Mostly water
-contains cells DNA in region called nucleoid
What’s an endospore?
- Some genera of bacteria can form bacterial spores called endospores.
-Metabolically inactive structures that allow certain cells to enter a dormant state.
-Highly resistant to environmental stress
-serious concern to food processors, health care professionals, and governments. - not reproductive
How are they created?
- by bacillus or clostridum
ex anthrax
