Diploma in Microbiology Diploma in Microbiology

MIC102MIC102 CHAPTER 1 CHAPTER 1 Cell Theory-Cell Theory-

Structure and Function Structure and Function(PROKARYOTE)(PROKARYOTE)

Lecturer: Pn Aslizah Bt Mohd Aris06-4832168 / 016-7377621

What is Cell Biology?What is Cell Biology?

• is an academic discipline which studies is an academic discipline which studies the physiological properties of cells, as well the physiological properties of cells, as well as their behaviours, interactions, and as their behaviours, interactions, and environmentenvironment

• this is done both on a microscopic and this is done both on a microscopic and molecular level. molecular level.

• researches both single-celled organisms researches both single-celled organisms like bacteria and specialized cells in like bacteria and specialized cells in multicellular organisms like humans. multicellular organisms like humans.

SYLLABUS CONTENT SYLLABUS CONTENT

Chap 1Chap 1 Cell Theory- Structure and Cell Theory- Structure and FunctionFunction

- - Prokaryotic cellProkaryotic cell - Eukaryotic cell- Cell membrane- Eukaryotic cell- Cell membrane

Chap 2Chap 2 Movement In And Out Of CellMovement In And Out Of Cell

- Diffusion- Diffusion, , Osmosis, Active Transport, Endocytosis, Osmosis, Active Transport, Endocytosis, Phagocytosis, Pinocytosis, ExcocytosisPhagocytosis, Pinocytosis, Excocytosis

Chap 3Chap 3 Reproduction of Prokaryotic cellReproduction of Prokaryotic cell--

-Binary fission and conjugation-Binary fission and conjugation

Chap 4Chap 4 Reproduction of eukaryotic cell / Reproduction of eukaryotic cell / Cell divisionCell division - Chromosome morphology and function, The cell cycle and - Chromosome morphology and function, The cell cycle and mitosis, Meiosis and gametogenesismitosis, Meiosis and gametogenesis

Overview: The Overview: The FundamentalFundamental Units of LifeUnits of Life

The cell is the simplest collection of matter that can live.

All organisms are made of cell.Cell structure is correlated to

cellular function.All cells are related by their descent

from earlier cells.

Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings

HowHow do cellular components cooperate to do cellular components cooperate to help the cell function?help the cell function?

•Basic structural and functional unit of all Basic structural and functional unit of all organisms; organisms;

they may exist as independent units of life (as they may exist as independent units of life (as in in

monads) or may form colonies or tissues as in monads) or may form colonies or tissues as in higher higher

plants and animalsplants and animals..

•General characteristic of cells is their General characteristic of cells is their microscopic size.microscopic size.

•Typical size-Eukaryotic cell: 10-100 µm in Typical size-Eukaryotic cell: 10-100 µm in diameterdiameter

-Prokaryotic cell: 1-10 µm in -Prokaryotic cell: 1-10 µm in diameterdiameter

What is a Cell?What is a Cell?

Cell TheoryCell Theory

•1665: Robert Hooke, 11665: Robert Hooke, 1stst observed cells, observed cells, naming the shapes as “cork cellulae” naming the shapes as “cork cellulae” (Latin= “small rooms”).(Latin= “small rooms”).

•Anton van Leeuwenhoek, 1Anton van Leeuwenhoek, 1stst observed observed live cells, which he termed as “tiny live cells, which he termed as “tiny animalcules”.animalcules”.

•1839: Theodor Schwann reported that 1839: Theodor Schwann reported that all animal tissues also consist of all animal tissues also consist of individual cells.individual cells.

•Thus was born “CELL THEORY”Thus was born “CELL THEORY”

Cell Theory: The PrincipleThree (3) principles involves:1. All organisms are composed of

one or more cells, and the life processes of metabolism and heredity occur within these cells.

2. Cells are the smallest living things, the basic units of organization of all organisms.

3. Cell arises only by division of previously existing cell.

Basic Cellular Architectures:1. Prokaryotic cells; refer to the

presence2. Eukaryotic cells. @ absence of the

cell structures.

DOMAIN KINGDOM

Prokaryotic cells

Archaea Bacteria

Eukaryotic cells

Plantae Fungi Animalia Protista

Prokaryotic Cells

• Bacteria and archaeaBacteria and archaea are are prokaryotes. Theprokaryotes. The figure (right) figure (right) reviewreviewss the the structure of a structure of a typical prokaryotic cell.typical prokaryotic cell.

Bacterium (plural, bacteria):Bacterium (plural, bacteria):

-single-celled organism with single-celled organism with no nucleus and little or no no nucleus and little or no intracellular intracellular compartmentalization; a compartmentalization; a prokaryoteprokaryote..

Eubacterium (plural, eubacteria):Eubacterium (plural, eubacteria):

-member of one of the two main member of one of the two main groups of prokaryotes, the other groups of prokaryotes, the other being archaebacteria; includes being archaebacteria; includes most present-day bacteria and most present-day bacteria and cyanobacteria. cyanobacteria.

-Cyanobacterium (plural, Cyanobacterium (plural, cyanobacteria):cyanobacteria):

-bacteria that have chlorophyll and bacteria that have chlorophyll and can carry out photosynthesis; can carry out photosynthesis; considered by the endosymbiont considered by the endosymbiont theory to be the progenitor of theory to be the progenitor of eukaryotic chloroplats. eukaryotic chloroplats.

The Structure of a Prokaryotic Cell

• simplest organisms.simplest organisms.

• small, consisting of cytoplasm small, consisting of cytoplasm surrounded by a plasma surrounded by a plasma membrane and encased within a membrane and encased within a rigid cell wall, lack complex rigid cell wall, lack complex interior organization.interior organization.

• nucleoid is visible as a dense nucleoid is visible as a dense central region segregated from central region segregated from the cytoplasm.the cytoplasm.

• do contain complex structures, do contain complex structures, like ribosome to carry out like ribosome to carry out protein synthesis.protein synthesis.

• cell membrane carries out cell membrane carries out some of the function s some of the function s organelles perform in eukaryotic organelles perform in eukaryotic cells. cells.

Figure 4.6

The Cell Wall• Strength of the cell comes

primarily from its rigid cell wall, protects the cell, maintain its shape & prevent excessive uptake and loss of water.

Prevents osmotic lysisMade of peptidoglycan (in

bacteria)

Figure 4.12

Peptidoglycan

Polymer of disaccharide:◦N-

acetylglucosamine (NAG)

◦N-acetylmuramic acid (NAM)

Figure 4.13a

Peptidoglycan in Gram-Positive BacteriaLinked by polypeptides

Gram-Positive Bacterial Cell Wall

Figure 4.13b

Gram-Negative Bacterial Cell Wall

Figure 4.13c

Thick peptidoglycan

Teichoic acids

Gram-positiveCell Wall

Figure 4.13b–c

Thin peptidoglycan Outer membrane Periplasmic space

Gram-negativeCell Wall

Figure 4.14a

The Plasma Membrane

Figure 4.14b

The Plasma Membrane

Phospholipid bilayerPeripheral proteinsIntegral proteinsTransmembraneProteins

The Plasma Membrane

Selective permeability allows passage of some molecules

Enzymes for ATP productionPhotosynthetic pigments on

foldings called chromatophores or thylakoids

Figure 4.6

Cytoplasm

The substance inside the plasma membrane

Figure 4.6

The NucleoidBacterial chromosomeContains genetic information

Figure 4.6

Ribosomes• Sites of protein synthesis

Figure 4.19

The Prokaryotic Ribosome

Protein synthesis70S

◦50S + 30S subunits

InclusionsMetachromatic

granules (volutin)

Polysaccharide granules

Lipid inclusionsSulfur granulesCarboxysomesGas vacuolesMagnetosomes

Phosphate reservesEnergy reservesEnergy reservesEnergy reservesRibulose 1,5-

diphosphate carboxylase for CO2 fixation

Protein-covered cylinders

Iron oxide (destroys H2O2)

Other characteristicsmost have no membrane bounded

organelles, which characterize the eukaryotes.

lack of the elaborate cytoskeleton found in eukaryotes.

The DNA, enzymes, and other cytoplasmic constituents have access to all parts of the cell.

cell contain no membrane bounded organelles;

whole prokaryotes operate as a single unit rxns, not compartmentalized as in eukaryotes.

“one room cabin in which eating, sleeping and watching TV is all occur”.

External Structures to the Cell Wall Glycocalyx. Flagella Axial filaments Fimbriae and pili.

Figure 24.12

GlycocalyxOutside cell wallUsually stickyCapsule: neatly

organized

Slime layer: unorganized and loose

Extracellular polysaccharide allows cell to attach

Capsules prevent phagocytosis

Figure 4.8b

outside cell wallmade of chains of flagellinattached to a protein hookanchored to the wall and membrane by the

basal body

The Structure of a Prokaryotic Flagellum

Arrangements of Bacterial Flagella

Figure 4.10a

Axial Filaments

Also called endoflagella

In spirochetesAnchored at one end

of a cellRotation causes cell

to move

Figure 4.11

Fimbriae and PiliFimbriae allow attachment

Fimbriae and Pili

may have hairlike growth (called pili) on the outside of the cell).

• Facilitate transfer of DNA from one cell to another◦Gliding motility◦Twitching motility

LETS WATCH MOVIE !!!LETS WATCH MOVIE !!!Prokaryotic Cell Structure and Function

ACTIVITYACTIVITY

In pair discuss the function of bacteria/prokaryote structure and try to produce 1 table consist of the function of each structure

STRUCTURESSTRUCTURES FUNCTIONSFUNCTIONS1.1. FlagellumFlagellum Movement…Movement…

2. Pilus2. Pilus

example:example:

See u tomorrow..thank you….See u tomorrow..thank you….