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Prokaryotic Cell Structure and Function - Prof. Meiling Wu, Lecture notes of Sports Law

A comprehensive overview of the structure and function of prokaryotic cells, including details on the plasma membrane, cell wall, capsule, flagella, pili, and internal structures such as the nucleoid, plasmids, ribosomes, and endospores. It covers the key differences between gram-positive and gram-negative bacteria, as well as the importance of the cell wall in antibiotic targeting. The document also includes two case studies related to bacterial infections, providing real-world examples of the clinical relevance of prokaryotic cell biology. This information would be highly valuable for students studying microbiology, cell biology, or infectious diseases, as it offers a deep dive into the fundamental characteristics of the simplest form of life.

Typology: Lecture notes

2020/2021

Uploaded on 04/28/2024

zahra-munir
zahra-munir 🇺🇸

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CELL
Introduction
All living things are made up of
cells the smallest unit of life
1 cell = unicellular
>1 cell = multicellular
All cells arise from pre-existing
cells
Called?
Scientist?
Types of cells
Contain unicellular
organisms called “prokaryotes” with
prokaryotic cells
Contains unicellular and multicellular
organisms called “eukaryotes” with
eukaryotic cells
Types of cells
Compartments DNA within nucleus
No compartments DNA naked
Pro= before, karyon= nucleus Eu = true, karyon= nucleus
Origin of cells
All cells arose from a common prokaryotic ancestor 3.5-4
billion years ago
Prokaryotic vs. eukaryotic cells
PROKARYOTIC CELL
Structure
Morphology shape and arrangement
Coccus spherical
Diplococci in pair (Neisseria gonorrhoeae)
Streptococci in chain (Streptococcus
pyogenes strep throat)
Staphylococci in grape-like cluster
(Staphylococcus aureus HAIs like sepsis,
pneumonia...)
Rod (bacillus)
Coccobacillus short rod
Bacillus anthracis, E. coli, Clostridium tetani
Structure
Morphology shape and arrangement
Vibrio short curved rod
Vibrio cholerae cholera
Spirillum rigid long curved rod
Helicobacter pylori stomach ulcers
Campylobacter jejuni diarrhea
Spirochete flexible long curved rod
Treponema pallidum syphilis
Borrelia burgdorferi Lyme disease
Structure
Size: 0.3 – 2 µm
Components
Plasma membrane
Cell wall (+/-)
Capsule (+/-)
Flagella (+/-)
Pili (+/-)
Cytoplasm with cytosol, cytoskeleton and internal
structures including nucleoid
Structure
Plasma membrane
Structure
Phospholipid bilayer
Proteins
Functions
Protects, forms border
Semipermeable membrane
Senses environment
Transport
Energy production
Plasma membrane
Plasma membrane
Transport
Passive
No energy required
From high to low concentration down the gradient
Types
Simple diffusion
e.g. O2, CO2
Facilitated diffusion
e.g. glucose
Plasma membrane
Transport
Passive
Osmosis movement of water across a selectively
permeable membrane towards more solute
Osmotic pressure
Solution
outside cell
Solute
Concentration
Net water
movement
Result
Isotonic In = Out No None
Hypotonic In > Out Inside cell Lysis
Hypertonic In < Out Outside cell Plasmolysis
Plasma membrane
Plasma membrane
Transport
Active
energy required to move solute from low to high concentration
Comprehension Check
Which of the following is not a function of the prokaryotic
plasma membrane?
1. Protein production
2. Energy production
3. Osmosis
4. Protection
Cell wall
Structure
Peptidoglycan (PG) in bacteria
Proteins peptide bridges
Carbohydrates sugar (glycan) chains
Functions
Rigid border that provides protection
Prevents cell lysis
Cell wall
Gram-positive vs. Gram-negative
Cell wall Gram-positive
Examples
Bacillus
Staphylococcus
Streptococcus
Many PG layers (up to 30)
Teichoic acids – help
stabilize and anchor PG
layers to plasma
membrane
wall teichoic acids
lipoteichoic acids
Cell wall
Cell wall Gram-negative
Examples
E. coli
Pseudomonas
Salmonella
One to a few PG layers
Outer membrane
Bilayer with porins that acts as
another permeability barrier
Lipopolysaccharides (LPS) form
outer part of bilayer
O and core polysaccharides
Lipid A is endotoxin
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff
pf12
pf13
pf14
pf15
pf16
pf17
pf18
pf19
pf1a
pf1b
pf1c
pf1d
pf1e
pf1f
pf20
pf21
pf22
pf23
pf24
pf25
pf26
pf27
pf28
pf29
pf2a
pf2b
pf2c
pf2d
pf2e
pf2f
pf30
pf31
pf32
pf33

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CELL

Introduction

  • All living things are made up of

cells – the smallest unit of life

  • 1 cell = unicellular
  • 1 cell = multicellular

  • All cells arise from pre-existing

cells

  • Called?
  • Scientist? plasamem: protection from

outside aged

= Biogenesis

Luis Pastner

Types of cells

No compartments – DNA naked Compartments – DNA within nucleus “Pro” = before, “karyon” = nucleus Eu ^ = true, “karyon” = nucleus^ Yes

iFl*^ en Similarities are

organelles- No

Yee

size

  • small^ big nucleus

and

inges or 2 DNA-NUceoid

Origin of cells

  • All cells arose from a common prokaryotic ancestor 3.5-

billion years ago

--

PROKARYOTIC CELL

Structure

Morphology – shape and arrangement

  • Coccus – spherical
  • Diplococci – in pair ( Neisseria gonorrhoeae )
  • Streptococci – in chain ( Streptococcus

pyogenes – strep throat)

  • Staphylococci – in grape-like cluster

( Staphylococcus aureus – HAIs like sepsis, pneumonia...)

  • Rod (bacillus)
  • Coccobacillus – short rod
  • Bacillus anthracis, E. coli, Clostridium tetani

lab test & looks coccus^ but not

Structure

Size: 0.3 – 2 μm

Components

  • Plasma membrane
  • Cell wall (+/-)
  • Capsule (+/-)
  • Flagella (+/-)
  • Pili (+/-)
  • Cytoplasm with cytosol, cytoskeleton and internal

structures including nucleoid

  • may

or may not

Structure

Plasma membrane (^) proteins fr

go through

0 gases

somewhat

Plasma membrane

Transport

  • Passive
  • No energy required
  • From high to low concentration – down the gradient
  • Types
  • Simple diffusion
  • e.g. O 2 , CO 2
  • Facilitated diffusion
  • e.g. glucose arora -> p Mormones on th

M

a protein to

Plasma membrane

Plasma membrane

Transport

  • Active think^ •^ energy required to move solute from low to high concentration many

o

Cell wall

Structure

  • Peptidoglycan (PG) in bacteria
  • Proteins – peptide bridges
  • Carbohydrates – sugar (glycan) chains

Functions

  • Rigid border that provides protection
  • Prevents cell lysis
    • peptide chain famor acid) -- (^) yourmesh

and

->Igive call (^) shape &from burst

Cell wall

  • Gram-positive vs. Gram-negative be^ there^
cel
ma

ar I dy