Microbiology

Major categories of microbes

Acellular and cellular microbes

Acellular microbes

infectious particles

Cellular microbes

microorganisms

Cell

The fundamental unit of any living organism

Cells exhibit -

the basic characteristics of life = metabolism, responsiveness, movement, growth, differentiation, reproduction

Prokaryote

Archaea and bacteria

Eukaryote

Protista, Fungi, Plantae, Animalia

Cell Membrane of Eukaryote

Separates the contents of the cell from the outside world, regulates passage of nutrients, waste products, and secretions into and out of cell, only certain substances may enter and leave.

Types of cell membrane in eukaryote

Plasma membrane/plasmalemma, cytoplasmic membrane, cellular membrane

Components of the cell membrane in eukaryote

Phospholipid, cholesterol, proteins

Nucleus in eukaryote

Command center of the cell, control the function of the entire cell

Nucleoplasm

The gelatinous matrix or base material of the nucleus

Nucleus membrane in eukaryote

Separates the nucleus from the cytoplasm

Nuclear pores in eukaryote

Holes through which large molecules can enter and exit the nucleus

Nucleolus in eukaryote

RNA molecules are manufactured

Chromosomes in eukaryote

Suspended in the nucleoplasm, linear DNA molecules, proteins (histones and nonhistone proteins), Genes

Cytoplasm in a Eukaryote

A semifluid, gelatinous, nutrient matrix, contains insoluble storage granules and cytoplasmic organelles, where most of the cell’s metabolic reactions occur, cytosol

Ribosomes in Eukaryote

play an important part in the synthesis of proteins

Endoplasmic reticulum in eukaryote

A network of membranes in the form of flattened sacs or tubules

Types of endoplasmic reticulum

Rough and smooth endoplasmic reticulum

Rough endoplasmic reticulum in eukaryote

Synthesizes proteins are transferred into cellular organelles

Smooth endoplasmic reticulum in eukaryote - synthesizes

Fatty acids and steroids, such as estrogen and testosterone

Smooth endoplasmic reticulum in eukaryote - Inactives/detoxifies

drugs and other potentially harmful substances

Smooth endoplasmic reticulum in eukaryote - Stores and releases

calcium ions that trigger contraction in muscle cells.

Golgi complex/Golgi Apparatus/Golgi Body in eukaryote

Completes the transformation of newly synthesized proteins into mature, functional ones packages them into small, membrane enclosed vesicles. A packaging plant.

Lysosomes in eukaryote - Vesicles that

Originate at the golgi complex

Lysosomes in eukaryote - Contain

lysozyme and other digestive enzyme that break down foreign materials taken into the cell

Lysosomes in eukaryote - Aid in

Breaking down worn out parts of the cell

Lysosomes in eukaryote - May

Destroy the entire cell if the cell is damaged or deteriorating

Peroxisomes in eukaryote - Contain

Enzymes that oxidize certain molecules normally found in the cell, notably fatty acids and amino acids

Peroxisomes in eukaryote - Membrane-bound vesicles

Where hydrogen peroxide is both generated and broken down through oxidation reaction of amino acids and fatty acids

Peroxisomes in eukaryote - Contains Catalase

That breakdown hydrogen peroxide into water and oxygen

Peroxisomes in eukaryote - prominent

In mammalian liver cells

Mitochondria in eukaryote

Power plants, powerhouse, energy factory, where most of the ATP molecules are formed by cellular respiration

Plastids in eukaryote

Membrane bound structures contain photosynthetic pigments, site of photosynthesis

Cytoskeleton in eukaryote

System of fibers present throughout the cytoplasm

Cytoskeleton in eukaryote components

microtubules, microfilaments (actin filaments), intermediate filaments

Cell Wall in eukaryote

External structures that provide rigidity, shape, and protection. Pectin, lignin, and mineral salts

Cell Wal in eukaryotel - Cellulose

Of algae and plants

Cell Wall in eukaryote - Chitin

Of fungi, beetles and crabs

Flagella in eukaryote

Large projections that extend from the surface of the cell for locomotion

Examples of microbes with flagella in eukaryote

Bacteria, sperm cell, protozoans

Cilia in eukaryote

Small projections that extend from the surface of the cells

Cilia in eukaryote microbes example

Protozoans, epithelial cells of respiratory tract

Prokaryotic cell structure

10 times smaller than eukaryotic cell. Simple cells compared to eukaryotic cells but are able to perform the necessary processes of life.

How do prokaryotic cells reproduce

Binary Fission

Cell membrane in Prokaryote

similar in structure and function to the eukaryotic cell membrane. Metabolic processes takes place, mesosomes.

Mesosomes

Inward folding of cell membrane where cellular respiration occurs

Chromosome in Prokaryote

450-8,000 genes​ , codes for enzymes, proteins, and rRNA and tRNA

Nucleoid in Prokaryote

Single, long, supercoiled, circular DNA molecule, serve as the control center of the bacterial cell, single copy per cell

Plasmids

Small circular, double stranded DNA molecules in bacteria, extra chromosomal DNA

Plasmids contain up to

10 to several hundred genes

Plasmids are able to make how many copies

1-20 copies per cell

Plasmids are sometimes present in

Achaea and Eukaryotes

Plasmids contain genes that enhance the survival of an organism either by

killing other organisms or by defending the host cell by producing toxins. Some plasmids facilitate the process of replication in bacteria.

Fertility F-plasmids

Also known as F-Plasmids, contain transfer genes that allow genes to be transferred from one bacteria to another through conjugation

Fertility F-plasmids can be inserted into

Chromosomal DNA

Bacteria that have the F-Plasmid are known as

F-positive and bacteria without it are F negative

When an F+ bacterium conjugates with an F- bacterium. The result is___

Two F+ bacterium, there can only be one F- plasmid in each bacterium.

Resistance Plasmids

Contains genes that help a bacterial cell defend against environmental factors such as poisons or antibiotics

Some resistance plasmids can transfer themselves through__

Conjugation, when this happens, a strain of bacteria can become resistant to antibiotics.

The bacterium that causes gonorrhea has become resistant to antibiotics called quinolones. What is the new class of antibiotics?

Cephalosporins

The bacteria may even become resistant to these antibiotics within five years. What causes this?

Overuse of antibiotics, it may lead to the proliferation of drug-resistant strains.

Virulence Plasmids

Help bacteria infect humans, animals, or even plants, by a variety of mechanisms

When a virulence plasmid is inside a bacterium, what happens?

It turns that bacterium into a pathogen, which causes a disease that can be easily spread and replicated among affected individuals.

The bacterium Escherichia coli has several virulence plasmids. E. Coli is found naturally in the human gut and in other animals, but___

Certain strains of E. Coli can cause severe diarrhea and vomiting.

Degradative Plasmids

Help the host bacterium to digest compounds that are not commonly found in nature, such as camphor, xylene, toluene, and salicylic acid.

Degradative plasmids contain

Genes for special enzymes that break down specific compounds, conjugative.

Col Plasmids

Contain genes that make bacteriocins (also known as colicins),w hich are proteins that kill other bacteria and thus defend the host bacterium.

Bacterions are found in many types of bacteria including E. Coli, where do they get the bacterions?

They get them from the plasmid ColE1

Types of Plasmids

Fertility F-Plasmids, Resistance plasmids, Virulence Plasmids, Degradative Plasmids, Col Plasmids.

Cytoplasm in Prokaryote

Contains water, dissolved oxygen, waste products, essential nutrients, proteins, carbohydrates, and lipids

Cytoplasm particles in Prokaryote

Ribosomes (polyribosomes), cytoplasmic granules that contain starch, lipids, sulfur, iron, and other substances.

Cell Wall in Prokaryote

Defines the shape of bacterial cells, provides rigidity, strength and protection

Cell Wall- Peptidoglycan (murein)

Polysaccharide chains linked together by small peptide (protein) chains.

Cell wall type of bacteria

Gram-positive bacteria and gram-negative bacteria

Gram-positive bacteria and gram-negative bacteria in Crystal Violet

All purple

Gram-positive bacteria and gram-negative bacteria in iodine

All purple

Gram-positive bacteria and gram-negative bacteria in alcohol

G+ = purple G- = colorless

Gram-positive bacteria and gram-negative bacteria in safranin

G+ = purple G- = Red

Glycocalyx was discovered

By Martinez and Palomo in 1970

Glycocalyx in Prokaryote

Slimy gelatinous material produced by cell membrane and secreted outside of the cell wall

A glycoprotein and glycolipid covering

surrounds the cell membranes of some bacteria, epithelia, and other cells

Glycocalyx types

A slime layer and a capsule

Glycocalyx provides

An extra layer to guard against desiccation

Glycocalyx Protects the cells from

Phagocytosis (S. pnneuomniae)

Glycocalyx is used as an attachment

Such as in tooth decay bacteria (S. mutans)

Slime layer

It is not highly organized and is not firmly attached to the cell wall, thinner, less rigid globular, enable certain bacteria to glide or slide surfaces.

Bacteria with Slime Layers

R-Colonies (dry, rough colonies) and Pseudomonas spp.

Capsule

Highly organized and firmly attached to the cell wall, polysaccharides, lipids and proteins. Negative stain, serve an antiphagocytic function, encapsulated bacteria survive longer in the human body.

Types of bacteria with capsule cell walls

H. Influenzae, K. pneumoniae, N. meningitidis, S. pneumoniae, S-colonies (smooth, mucoid, and glistening)

Flagella in Prokaryote

Threadlike, protein appendages that enable bacteria to move. Composed of protein flagellin, not membrane bound, spirochaetes (axial filaments)

Flagella in prokaryote thickness

10-20 nm thick (not observable by compound light microscope)

Atrichous bacteria

Bacteria without flagella

Amphiloportrichous bacteria

The flagellar tuft is present at both ends

Peritrichous bacteria

The entire surface of bacteria possess flagella

Lopotrichous bacteria

With a tuft of flagella at one end

Amphitrichous bacteria

Having one flagellum at each end

Monotrichous bacteria

Possessing a single polar flagellum

Pili / Fimbrae

Rigid, hair-like structures and much thinner and flagella. Not associated with motility, most often observed on G- bacteria, protein PILIN