PROKARYOTES

Include :

Archae

3-5 kingdoms

Survive in extream environment

Thin flagella

Closely related to eukarya

Bacteria

10-15 kingdoms

Classified by Gram-negative and Gram-positive

Rotating flagellum

Peptidoglycen cell wall

Size range from 0.2-2.0 um (diameter) and 2-8 um (length)

Lack of :

Membrane-bound nucleus

Cytoskeleton

Membrane-bound organelles

Internal membranous structures such as ER and Golgi apparatus

Locomotion

Flagellum

Propulsion

Gliding

Squirming

Staining

Gram-negative

Can be decolorized to accept counterstain (safranin) and stain pink or red

Gram-positive

Retain rystal violet dye and stain blue or purple

Nutrient requirements

Pigments

Shape

Suffix

Bacillus = rod

Spirullum = spiral

Coccus = round

Prefix

Staphylo-

Strepto-

Diplo-

Size of cell

Typically 0.2-2.0 um in diameter

Nucleus

No nuclear membrane or nucleoli

Membraned-enclosed
organelles

Absent

Flagella

Consist of two protein building blocks

Swimming motility

Glycocalyx

Present as a capsule or slime layer

Resistance to phagocytosis, adherence to surfaces; are in Archea

Cell wall

Usually present; chemically complex
(typical bacteria cell wall includes peptidoglycen)

Provides shape and protection from osmotic stress

Rigid structure which helps the bacterium maintain its shape

Plasma membrane

No carbohydrates and generally lacks sterols

Selectively permeable barrier, mechanical boundary of cell,
nutrient and waste product, location of many metabolism process (respiration and photosynthesis), detection of environmental cues for chemotaxis

Separates the cell from the environment

Cytoplasm

No cytoskeleton or cytoplasmic streaming

No membrane-bound organelles

Ribosomes

Smaller size (70S)

Protein synthesis

Chromosome (DNA)

Usually single circular chromosome; typically lacks histone

Cell division

Binary fussion

Sexual recombination

None; transfer of DNA only

Nucleoid

Localisation of genetic material

Gas vacuole

Buoyancy for floating in aquatic environment

Periplasmic space

Gram-positive

Contains hydrolytic enzymes and binding proteins for nutrient processing and update

Gram-negative

Small or absent

Fimbriae and pili

Attachment to surfaces, bacterial conjugation and transformation, twitching and gliding mobility

Endospore

Survival under harsh environment conditions; only observed in Bacteria

Cytoplasm

location of ribosomes for protein synthesis

location for metabolic enzymes

semi-fluid cell interior

Structures external
to the cell wall

Glycocalyx

coating secreted by bacteria

composed of

polysaccaride

polypeptide

functions :

Capsule

bacterial virulence

protect phatogenic bacteria from phagocytosis by the cells of the host

Glycocalyx

attachment to surface

Protect against dehydration

Inhibit movement of nutrients out of cells

Source of nutrient

Flagella

Types

Monotrichous

Peritrichous

Amphitrichous

Lophotrichous

Basic structure

Filament

Hook (flexible coupling between filament and basal body)

Basal body

Motility

Types

"Run" or "swim"

moves in one direction for a length of time

"Tumbles"

runs interrupted by periodic, abrupt, random changes in direction

"Swarm"

rapid wavelike movement

Advantages

Ability to move toward a favorable environment or away from adverse one (known as taxis)

Stimuli

Types

Chemical

Chemotaxis (oxygen, ribose, galactose)

Light

Phototaxis

Positive = Attractant
Negative = Repellent

Axial Filaments

Corkscrew movement

also known as endoflagella

Fimbriae and Pili

Shorter, straighter and thinner than flagella in sstructure

Cell Wall

Functions

Responsible for shape of cell

Prevent bacterial cells from rupturing due to changes in pressure

The point of anchorage for flagella

May contain antigen if bacteria in infectious

Atypical Cell Wall

certain types have no cell wall

eg : Mycoplasma

smallest known bacteria

plasma membrane have lipids cell sterols

with special content of cell wall

eg : Mycobacterium

Structure internal
to the cell wall

Plasma (cytoplasmic) membrane

Phospholipids

Polar head

Non-polar tails

Proteins

Periferal protein

Integral protein

Glycoproteins

Carbohydrates attach to protein

Glycolipids

Carbohydrates attach to lipids

Functions

selective barrier

breakdown of nutrients

production of energy

Cytoplasm

Nuclear area

Ribosomes

Inclusions

Efficient nutrient uptake

Surface-to-volume ratio

Size can be selective value

Epulopiscium fishelsoni has a highly convoluted plasma membrane

Decreased susceptibility to predation

Filamentous

Have prostheca

Shapes