Bacterial Morphology

Week 3

is the branch of microbiology that studies bacteria: their structure, classification, physiology, genetics, ecology, and their roles in health, disease, industry, and the environment.

Bacteriology

Bacteriology is the study of bacteria, especially those that cause disease in humans, and their prevention and control.

True

small rod

Bakterion

study of

Logos

are cellular and prokaryotic microorganism with simpler structure compare with eukaryotic organisms.

Bacteria

Is used for identification

Bacterial Shapes

are rod-shaped bacteria

Bacilli

are spherical bacteria

Cocci

corkscrew-shaped microorganisms.

Spiral

Single cocci

Coccus

Pairs

Diplococci

chains

Streptococci

clusters

Staphylococci

groups of four

Tetrads

cubical groups

Sarcinae

Single bacilli

Bacillus

pairs

Diplobacilli

chains

Streptobacilli

short, oval rods

Coccobacilli

side by side

Pallisades

comma-shaped

Vibrios

rigid spiral forms

Spirilla

thin, flexible spirals

Spirochetes

is the unit of measurement used in bacteriology and is equal to one-thousandth of a millimeter.

Micrometer

Bacteria are generally one-tenth the size of eukaryotic cells.

True

smallest pathogenic bacillus

Haemophilus

largest pathogenic bacillus

Bacillus anthracis

Bigger size helps bacteria survive and adapt.

False

They can thrive in diverse environments, including marine sediments.

True

is a sticky, gelatinous layer that surrounds the cell wall of some bacteria.

Glycocalyx

well-organized, firmly attached; protects bacteria from phagocytosis

Capsule

loosely attached; helps in adhesion to surfaces

Slime layer

protects bacteria from antibiotic and immune response

Biofilm

• Protects bacteria against osmotic pressure

• Gives shape to the bacteria

• Confer the gram’s reaction of the bacteria

• A usual target of anti-microbial drugs

Cell Wall

Cell wall is important for identification.

True

Composed of very thick peptidoglycan layer

Gram-Positive Cell Wall

Negatively charge and contributes to the negativity of cell wall; may also bind and regulate the movement of cation in and out of the cell.

Teichoic Acids

includes acidic and neutral sugars

Polysaccharides

Composed of a thin layer of peptidoglycan.

Gram-Negative Cell Wall

Gram-negative cell walls have no teichoic acids.

True

fluid filled space between outer membrane and gram-negative cell wall

Periplasmic Space

anchor the outer membrane to the peptidoglycan layer and stabilizes the outer membrane

Lipoprotein

only in Gram (-) bacteria

Outer membrane

outer membrane major constituent; toxic

Lipid A

allows small molecules (nutrients, ions, antibiotics) to pass into or out of the cell

Porins

vital to evade the host defenses; contributes to negative charge of the bacterial surface and also comprises endotoxins.

Lipopolysaccharides

• Causes Gram-negative sepsis

• Can trigger fever, inflammation, hypotension, and septic shock.

• Activate the immune system, sometimes excessively (dangerous in severe infections).

Endotoxins

• Has a Gram-Positive Reaction

• Specialized bacterial cell wall that resists decolorization by acid-alcohol after staining

Acid-Fast Cell Wall

three layered/triple unit membrane instead of wall

Sterols

causing atypical pneumonia

Mycoplasma

causes urogenital infection

Ureaplasma

possess flagella for locomotion

Motile Bacteria

no flagella

Atrichous

single flagellum at one pole

Monotrichous

single flagellum at each pole

Amphitrichous

tuft of flagella at one or both poles

Lophotrichous

flagella all over the organism

Peritrichous

Monotrichous and Peritrichous bacteria are most common pathogen.

True

Hair-like extension that extend into the environment Relatively shorter and finer than a flagella.

Fimbriae

its structural protein

Pilins

for attachment

Common Pili

for bacterial gene exchange

Conjugate Pili

Specialized flagella located within the periplasmic space of certain bacteria; found in Spirochetes

Endoflagella

• Site of energy production / energy metabolism

• Essential component for Gram(+) and Gram(-) bacteria

• Also called as Cell Sac

Cell Membrane

Region containing the bacterial DNA; No nuclear membrane; Controls cell replication and function

Nucleoid

An invagination of the cell wall for cell respiration and division.

Mesosome

Protein synthesis

Ribosome

Storage materials for nutrients; Help bacteria survive during unfavorable conditions

Granules

Survival response to certain adverse nutritional condition such as depletion of a certain resource

Endospore

spore production

Sporulation

return to vegetative state when environmental condition is favorable

Germination

The endospore is helpful in identifying some species of bacteria.

True

Clostridium tetani

Terminal Spores

Clostridium botunilum

Subterminal Spores

Bacillus anthracis

Central Spores

cutaneous, inhalation, or gastrointestinal

Anthrax

flaccid paralysis due to neurotoxins

Botulism

muscle rigidity and spasm

Tetanus

It involves replication of cellular structures and components.

Bacterial Growth

refers to an increase in the number of cells, not cell size.

Microbial Growth

consists of thousands of bacteria.

Bacterial Colony

Visible colonies on culture media actually contain ________ of bacterial cells.

billions

Bacteria require specific nutrients and physical conditions to ___________.

grow

Understanding growth requirements is important for culturing bacteria and controlling infections.

True

• Main source of energy and cell structure

• Required for synthesis of carbohydrates, proteins, lipids, and nucleic acids

Carbon

do not require preformed organic compound for growth because they can synthesize them from inorganic compound and carbon dioxide

Autotrophs/Lithotrophs

required preformed organic compound like sugar and amino acids, for growth. This includes most medical important bacteria

Heterotrophs/Organotrophs

needed for proteins and nucleic acids

Nitrogen

required for some amino acids and enzymes

Sulfur

essential for ATP, nucleic acids, and phospholipids

Phosphorus

• is a component of cytochromes essential for electron transport in cellular respiration

• Important for enzyme function, osmotic balance, and cell metabolism

Iron

Include iron, potassium, magnesium, calcium, and sodium

Inorganic Ions

• Essential to promote the growth and development of the bacterial cell

• Includes Vitamin B complex and amino acids.

Growth Factor

Serves as the medium from which bacteria acquire their nutrients.

Moisture/Water

Bacterial cell is composed mainly of water.

True

>40°C, typically 50°C - 55°C

Thermophiles

Optimal Temperature of 20°C - 40°C, best at 30°C - 37°C

Mesophiles

<10°C, optimum at 10°C - 20°C

Psychrophiles

grows in the presence of atmospheric (free) oxygen

Aerobe

cannot grow without oxygen, which serves as final electron acceptor. Contain superoxide dismutase, which protects from toxic oxygen

Obligate Aerobes