Transcript Diploma In Microbiology MIC102 CHAPTER 1 Cell Theory

Diploma in Microbiology
MIC102
CHAPTER 1
Cell TheoryStructure and Function
(PROKARYOTE)
Lecturer: Pn Aslizah Bt Mohd Aris
06-4832168 / 016-7377621
What is Cell Biology?
• is an academic discipline which studies
the physiological properties of cells, as well
as their behaviours, interactions, and
environment
• this is done both on a microscopic and
molecular level.
• researches both single-celled organisms
like bacteria and specialized cells in
multicellular organisms like humans.
SYLLABUS CONTENT
Chap 1
Chap 2
Cell Theory- Structure and Function
- Prokaryotic cell - Eukaryotic cell- Cell membrane
Movement In And Out Of Cell
- Diffusion, Osmosis, Active Transport, Endocytosis, Phagocytosis,
Pinocytosis, Excocytosis
Chap 3
Reproduction of Prokaryotic cell-Binary fission and conjugation
Chap 4
Reproduction of eukaryotic cell / Cell division
- Chromosome morphology and function, The cell cycle and
mitosis, Meiosis and gametogenesis
Overview: The Fundamental Units 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
How do cellular components cooperate to help
the cell function?
What is a Cell?
•Basic structural and functional unit of all organisms;
they may exist as independent units of life (as in
monads) or may form colonies or tissues as in higher
plants and animals.
•General characteristic of cells is their microscopic size.
•Typical size-Eukaryotic cell: 10-100 µm in diameter
-Prokaryotic cell: 1-10 µm in diameter
Cell Theory
•1665: Robert Hooke, 1st observed cells, naming
the shapes as “cork cellulae” (Latin= “small
rooms”).
•Anton van Leeuwenhoek, 1st observed live
cells, which he termed as “tiny animalcules”.
•1839: Theodor Schwann reported that all
animal tissues also consist of individual cells.
•Thus was born “CELL THEORY”
Cell Theory:The Principle
Three (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.
2.
Prokaryotic cells; refer to the presence
Eukaryotic cells.
@ absence of the cell
structures.
DOMAIN
KINGDOM
Prokaryotic cells  Archaea
 Bacteria
Eukaryotic cells  Plantae
 Fungi
 Animalia
 Protista
Prokaryotic Cells
• Bacteria and archaea are
prokaryotes. The figure (right)
reviews the structure of a
typical prokaryotic cell.
Eubacterium (plural, eubacteria):
-member of one of the two main
groups of prokaryotes, the other
being archaebacteria; includes
most present-day bacteria and
cyanobacteria.
Bacterium (plural, bacteria):
-single-celled organism with
no nucleus and little or no
intracellular
compartmentalization; a
prokaryote.
-Cyanobacterium (plural,
cyanobacteria):
-bacteria that have chlorophyll and
can carry out photosynthesis;
considered by the endosymbiont
theory to be the progenitor of
eukaryotic chloroplats.
The Structure of a Prokaryotic
Cell
• simplest organisms.
• small, consisting of cytoplasm
surrounded by a plasma membrane
and encased within a rigid cell wall,
lack complex interior organization.
• nucleoid is visible as a dense central
region segregated from the
cytoplasm.
• do contain complex structures, like
ribosome to carry out protein
synthesis.
• cell membrane carries out some of
the function s organelles perform in
eukaryotic cells.
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 lysis
 Made of peptidoglycan (in bacteria)
Figure 4.6
Peptidoglycan

Polymer of
disaccharide:
◦ N-acetylglucosamine
(NAG)
◦ N-acetylmuramic acid
(NAM)
Figure 4.12
Peptidoglycan in Gram-Positive
Bacteria

Linked by polypeptides
Figure 4.13a
Gram-Positive Bacterial Cell Wall
Figure 4.13b
Gram-Negative Bacterial Cell
Wall
Figure 4.13c
Gram-positive
Cell Wall
Gram-negative
Cell Wall
Thick peptidoglycan
 Teichoic acids
 Thin peptidoglycan
 Outer membrane
 Periplasmic space

Figure 4.13b–c
The Plasma Membrane
Figure 4.14a
The Plasma Membrane
Phospholipid bilayer
 Peripheral proteins
 Integral proteins
 Transmembrane
 Proteins

Figure 4.14b
The Plasma Membrane
Selective permeability allows passage
of some molecules
 Enzymes for ATP production
 Photosynthetic pigments on foldings called
chromatophores or thylakoids

Cytoplasm

The substance inside the plasma
membrane
Figure 4.6
The Nucleoid
Bacterial chromosome
 Contains genetic information

Figure 4.6
Ribosomes
• Sites of protein synthesis
Figure 4.6
The Prokaryotic Ribosome
Protein synthesis
 70S

◦ 50S + 30S subunits
Figure 4.19
Inclusions

Metachromatic
granules (volutin)









Polysaccharide
granules
Lipid inclusions
Sulfur granules
Carboxysomes
Gas vacuoles
Magnetosomes




Phosphate reserves
Energy reserves
Energy reserves
Energy reserves
Ribulose 1,5diphosphate
carboxylase for CO2
fixation
Protein-covered
cylinders
Iron oxide
(destroys H2O2)
Other characteristics




most 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.
Glycocalyx
Outside cell wall
 Usually sticky
 Capsule: neatly
organized

 Slime layer: unorganized
and loose
 Extracellular
polysaccharide allows
cell to attach
 Capsules prevent
phagocytosis
Figure 24.12
The Structure of a Prokaryotic Flagellum
outside cell wall
 made of chains of flagellin
 attached to a protein hook
 anchored to the wall and membrane by the basal body

Figure 4.8b
Arrangements of Bacterial
Flagella
Axial Filaments
Also called endoflagella
 In spirochetes
 Anchored at one end
of a cell
 Rotation causes cell
to move

Figure 4.10a
Fimbriae and Pili

Fimbriae allow attachment
Figure 4.11
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 !!!

Prokaryotic Cell Structure and Function
ACTIVITY
In pair discuss the
function of
bacteria/prokaryote
structure and try to
produce 1 table consist
of the function of each
structure
example:
STRUCTURES
1.
Flagellum
2.
Pilus
FUNCTIONS
Movement…
See u tomorrow..thank you….