Prokaryotic Cell

Prokaryotic CellCharacteristicsSmaller in sizeNo membrane bound organellesCell division by binary fissionTypes of motilityRun or swimTumblesSwarmStructures internal to the cell wallPlasma membraneMechanical boundary of cell, nutrientand waste transportLocation for metabolic processesDetection of environmental cuesfor chemotaxisCytoplasmsubstance of the cell within plasma membraneconsist of 80% water and primarily contain protein, carbohydrates and lipidsNuclear area or nucleoidcontain genetic informationRibosomessites for protein synthesisInclusionsStorage of carbon, phosphate and other substanceExternal structures to the cell wallGlycocalyxAttachment to surfaceProtect against dehydrationInhibit movement of nutrients out of cellsSource of nutrientsFlagellaLong filamentous appendages for motilityAxial filamentsPresent in spirochetesKnown as endoflagellaFor corkscrew movementFimbriaeOccur at poles or distributed over the entire surfaceFunction as attachmentCell WallResponsible for the shape of cellPrevent bacterial cells from rupturing due to changes in pressureThe point of anchorage for flagellaMay contain antigen if bacteria is infectiousTypes of cell wallGram +veGram -veAtypica

Characteristics

Smaller in size

No membrane bound organelles

Cell division by binary fission

Structures internal to the cell wall

Plasma membrane

Mechanical boundary of cell, nutrient
and waste transport

Location for metabolic processes

Detection of environmental cues
for chemotaxis

Function

Selectively permeable barrier

Synthesis cell wall components

Assists in DNA replications

Carries on respiration

Captures energy as ATP

Destruction

Disinfectants - alcohols and quatenary ammonium compounds

Cause leakage of intracellular contents

Plasmolysis: cells shrink

Lysis: cells burst

Uptake of Nutrients - Getting Through Barriers

Macroelements (macronutrients)

Micronutrients (trace elements)

Some unique substances may required

The movement of materials across membranes

Passive processes

Simple diffusion

Facilitated diffusion

Osmosis

Active process

Active transport

Group translocation

Cytoplasm

substance of the cell within plasma membrane

consist of 80% water and
primarily contain protein,
carbohydrates and lipids

Intracytoplasmic membranes

Plasma membrane infoldings

Anammoxosome in Planctomycetes

Nuclear area or nucleoid

contain genetic information

Plasmid

Ribosomes

sites for protein synthesis

RNA or rRNA

Inclusions

Storage of carbon, phosphate and
other substance

Types of inclusions

Metachromatic granules

Large inclusions

Stain red with certain blue dyes such as methylene blue

Polysaccharide granules

Consists glycogen and starch

Diffentiate by using iodine

glycogen granules: reddish brown

starch granules: blue

Lipid inclusios

Storage material -polymer poly-beta-hydroxybutyric acid

Sulfur granules

Energy reserve

Derive energy

oxidising sulfur

sulfur-containing compounds

Thiobacillus - sulfur bact.

Carboxysomes

Contain the enzyme ribulose 1,5-diphosphate carboxylase

Used for co2 fixation during photosynthesis

Magnetosomes

Iron oxide (Fe3O4) that act like magnet

Gas vesicles

Endospore

Cell wall

Responsible for the shape of the cell

Prevent bacterial cells from rupturing due to the change in pressure

The point of anchorage flagella

May contain antigen if the bacteria is infectious

Types of cell wall

Gram +ve

Gram -ve

Types of motility

Run or swim

Tumbles

Swarm

External structures to the cell wall

Glycocalyx

Attachment to surface

Protect against dehydration

Inhibit movement of nutrients out of cells

Source of nutrients

Flagella

Long filamentous appendages for motility

Axial filaments

Present in spirochetes

Known as endoflagella

For corkscrew movement

Fimbriae

Occur at poles or distributed
over the entire surface

Function as attachment