Prokaryotes

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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

External structures to the cell wall

Fimbriae

Function as attachment

Occur at poles or distributed over the entire surface

Axial filaments

For corkscrew movement

Known as endoflagella

Present in spirochetes

Flagella

Long filamentous appendages for motility

Glycocalyx

Source of nutrients

Inhibit movement of nutrients out of cells

Protect against dehydration

Attachment to surface

Types of motility

Swarm

Tumbles

Run or swim

Cell wall

Types of cell wall

Gram -ve

Gram +ve

May contain antigen if the bacteria is infectious

The point of anchorage flagella

Prevent bacterial cells from rupturing due to the change in pressure

Responsible for the shape of the cell

Structures internal to the cell wall

Endospore

Inclusions

Types of inclusions

Gas vesicles

Magnetosomes

Iron oxide (Fe3O4) that act like magnet

Carboxysomes

Used for co2 fixation during photosynthesis

Contain the enzyme ribulose 1,5-diphosphate carboxylase

Sulfur granules

Thiobacillus - sulfur bact.

Derive energy

sulfur-containing compounds

oxidising sulfur

Energy reserve

Lipid inclusios

Storage material -polymer poly-beta-hydroxybutyric acid

Polysaccharide granules

Diffentiate by using iodine

starch granules: blue

glycogen granules: reddish brown

Consists glycogen and starch

Metachromatic granules

Stain red with certain blue dyes such as methylene blue

Large inclusions

Storage of carbon, phosphate and other substance

Ribosomes

RNA or rRNA

sites for protein synthesis

Nuclear area or nucleoid

Plasmid

contain genetic information

Cytoplasm

Intracytoplasmic membranes

Anammoxosome in Planctomycetes

Plasma membrane infoldings

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

substance of the cell within plasma membrane

Plasma membrane

The movement of materials across membranes

Active process

Group translocation

Active transport

Passive processes

Osmosis

Facilitated diffusion

Simple diffusion

Uptake of Nutrients - Getting Through Barriers

Some unique substances may required

Micronutrients (trace elements)

Macroelements (macronutrients)

Destruction

Disinfectants - alcohols and quatenary ammonium compounds

Lysis: cells burst

Plasmolysis: cells shrink

Cause leakage of intracellular contents

Function

Captures energy as ATP

Carries on respiration

Assists in DNA replications

Synthesis cell wall components

Selectively permeable barrier

Prokaryotic cells are characterized by their smaller size and lack of membrane-bound organelles. They reproduce through binary fission and exhibit various types of motility, such as running, swimming, and tumbling.