Procaryot c eucaryot c cells
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PROCARYOTİC &EUCARYOTİC CELLS. Prof. Dr. Gönül KANIGÜR. Microorganisms can be divided into 2 groups :. CELLS. The microscopic study of cells reveals 2 types of cells: prokaryotic and eukaryotic. Two Main Classes of Cells • Prokaryotic ( Bacteria and Archaea )

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PROCARYOTİC &EUCARYOTİC CELLS

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Procaryot c eucaryot c cells

PROCARYOTİC &EUCARYOTİC CELLS

Prof. Dr. Gönül KANIGÜR


Microorganisms can be divided into 2 groups

Microorganisms can be divided into 2 groups :


Cells

CELLS

  • The microscopic study of cells reveals 2 types of cells: prokaryotic and eukaryotic.


Procaryot c eucaryot c cells

  • Two Main Classes of Cells

  • • Prokaryotic (BacteriaandArchaea)

  • – Pro = “Before”; Karyon = “Kernel”

  • – No nucleus, DNA coiled up inside cell

  • • Eukaryotic (Everything else)

  • – Eu = “True”

  • – DNA inside membraneboundorganelle inside

  • cell, thenucleus


Prokaryotic cells are relatively simple

Prokaryotic Cells are relatively simple

  • 1. Bacteria are prokaryotic cells

  • 2. 1-10 um in diameter, just visible with light microscopes.

  • 3. Metabolically diverse.

  • 4. No True Nucleus


Morphology of prokaryotic cells

MORPHOLOGY OF PROKARYOTIC CELLS

  • Prokaryotes exhibit a variety of shapes

    • Most common

      • Coccus

        • Spherical

      • Bacillus

        • Rod or cylinder shaped


Procaryot c eucaryot c cells

Cellular Structure

  • A typical bacterial (procaryotic) cell has the following basic structures :

    (1)Cell Wall,

    (2)Cell Membrane,

    (3)Ribosomes,

    (4)Nuclear Region


Cell wall

CELL WALL

  • Bacterial cell wall

    • Rigid structure

    • Surrounds cytoplasmic membrane

    • Determines shape of bacteria

    • Holds cell together

    • Prevents cell from bursting

    • Unique chemical structure

      • Distinguishes Gram positive from Gram-negative


Cytoplasmic membrane

Cytoplasmic membrane

  • A.Structure

  • -A phospholipid bilayer with proteins

  • -contains carbonhydrates

  • -contains sterols

  • B-Function

  • -transport:simple diffusion,facilitated diffusion,osmosis and active transport

  • -Endocytosis:phagocytosis and pinpcytosis


Procaryot c eucaryot c cells

Cellular Structure

(3)Ribosomes

  • Small particles composed of protein and ribonucleic acid (RNA).

  • A single cell may have as many as 10,000 ribosomes.

  • Part of the translation apparatus, synthesis of cell proteins take place upon these structures.


Internal structure

INTERNAL STRUCTURE

  • Ribosome

    • Involved in protein synthesis

    • Composed of large and small subunits

      • Units made of protein 40% and ribosomal RNA 60%

    • Prokaryotic ribosomal subunits

      • Large = 30S

      • Small = 50S

    • Small than eukaryotic ribosomes

      • Difference often used as target for antimicrobials


Procaryot c eucaryot c cells

Cellular Structure

(4)Nuclear Region

  • Nuclear region is primitive in procaryotic cell, i.e. bacteria.

  • Procaryotic cells DO NOT possess a true nucleus.

  • The functions of the nucleus are carried out by a single long strand of deoxyribonucleic acid (DNA)

  • The nuclear region where the DNA is present is sometimes known as a nucleoid, NOT a nucleus.


Procaryot c eucaryot c cells

  • Bacterial chromosome is not directly intereact with the proteins such as histons

  • DNA contents range from about 0.6 million to five milion bp.5000 proteins are coded from the chromosomal DNA

  • Bacteria may also contain plasmids,double stranded DNA molecules.they are not essential for growth and reproduction.


Procaryot c eucaryot c cells

  • Plasmids carry functional genes that give certain properties of the bacterial cell for ex.drug rezistance .some bacteria are rezistance to some antibiotics.


Procaryot c eucaryot c cells

Movement

Many bacteria are motile, able to move independently due to a special structure known as Flagellum (plural : Flagella)


Procaryot c eucaryot c cells

Rigid tubular structure made of pilin protein

Found only in Gram negative cells

Functions

Sexual pili—joins bacterial cells for DNA transfer (conjugation)

Common pili—adhesion

PILI


Eucaryotic cells

EUCARYOTIC CELLS


I organisms and general properties

I. Organisms and general properties

  • A. Organisms

    • 1. Microorganisms

      • Fungi

      • Protozoa

      • Algae

    • 2. Other

      • Higher plants

      • Animals


I organisms and general properties cont

I. Organisms and general properties, cont.

  • B. General properties

    • More complex than procaryotes

    • Larger than procaryotes

    • Have a true nucleus

    • Have membrane-bound organelles


Iii the cell wall and glycocalyx

III. The cell wall and glycocalyx

  • A. Cell wall

    • Rigid structure

    • Found on plant cells

    • Not made of peptidoglycan, but of long polysaccharide, e.g., cellulose

  • B. Glycocalyx A carbohydrate-containing structure on the surface of a cell.

    • May strengthen membrane of animal cells.

    • Serves as an adhesin, i.e., holds adjacent cells together


Eukaryotic cells components

Eukaryotic Cells Components

Cell Wall

  • contains cellulose

  • support and protection

    Cell membrane / Plasma membrane

  • Phospholipid bilayer with embedded proteins

  • boundary layer and transport

    Nucleus

  • nuclear envelope, nucleoplasm, chromatin, nucleoli

  • storage and synthesis of genetic material.

    Nucleolus

  • Ribosome formation


Iv the cytoplasmic membrane

IV. The cytoplasmic membrane

  • A. Structure

    • A phospholipid bilayer with proteins

    • Contains carbohydrates

    • Contains sterols

  • B. Function

    • Transport: simple diffusion; facilitated diffusion; osmosis; and active transport

    • Endocytosis: phagocytosis; and pinocytosis


Vi organelles

VI. Organelles

  • Organelle A membrane-enclosed structure.

  • A. Nucleus

    • Has a double membrane with pores

    • Contains nucleoli where ribosomal RNA is synthesized

    • Contains chromatin: DNA + histones (basic proteins)

    • Chromosomes divide by mitosis.


Procaryot c eucaryot c cells

  • İts diameter is aprox. 5um

  • İt contains genetic material of the cell.

  • The Dna content is l.5 x10 – 7 to 5xl0 -9 bp

  • 30.000 protein are coded.

  • The nucleus is the site of DNA replication and RNA synthesis.


V cytoplasm

V. Cytoplasm

  • The substance outside the nucleus and inside the plasma membrane

  • Similar in composition to that of procaryotes, but has a cytoskeleton that provides shape, support, and transport within cell

  • Cytoskeleton consists of:

    • Microfilaments

    • Intermediate filaments

    • Microtubules


Vi organelles cont

VI. Organelles, cont.

  • B. Endoplasmic reticulum (ER)

    • Membrane network from nucleus to plasma membrane

    • Rough ER

      • Has ribosomes attached

      • Site of protein synthesis

    • Smooth ER

      • No ribosomes attached

      • Site of lipid synthesis


Vi organelles cont1

VI. Organelles, cont.

  • C. Golgi apparatus

    • Stacks of membranes in cytoplasm

    • Receives proteins & lipids from ER

    • Ends pinch off forming secretory vesicles

    • Transports proteins & lipids within cell


D ribosomes

D. Ribosomes

  • The site of protein synthesis

  • In cytoplasm: 80S variety consisting of 60S & 40S subunits

  • In mitochondria:70S variety consisting of 50S & 30S subunits


G lysosomes

G. Lysosomes

  • Contains hydrolytic enzymes

  • Especially important in phagocytes


Organelles cont

. Organelles, cont.

  • H. Vacuoles - membrane bound cavities

    • Diverse functions:

      • Store proteins, sugars, etc.

      • Store metabolic waste

      • Store water (plant cells)


Organelles cont1

Organelles, cont.

  • E. Mitochondria

    • The site of respiration

    • Has 2 membranes:

      • Outer one has sterols

      • Inner one has no sterols,

      • Has DS circular DNA

    • Has 70S ribosomes

    • Replicates autonomously


Vi organelles cont2

VI. Organelles, cont.

  • F. Chloroplasts

    • The site of photosynthesis

    • In algae and other plant cells

    • Contain 70S ribosomes

    • Contain DS DNA

    • Replicate autonomously


Procaryot c eucaryot c cells

  • An endosymbiotic orijin for these organels mitochondria,chloroplast) is now generally accepted


I centrioles

I. Centrioles

  • Near nucleus

  • Functions: cell division, and formation of cilia and flagella


Ii structures external to the cell wall

II. Structures external to the cell wall

  • A. Flagella

    • Surrounded by the cytoplasmic membrane.

    • Contains microtubules in a 2 + (2 x 9) arrangement

    • Function: motility

    • Found on some protozoa and algae

    • Only a few per cell


Vii comparisons

EUCARYOTE

Larger

Simple wall structure

Sterols in membrane

2 + (9x2) flagella

True nucleus

Histones

PROCARYOTE

Smaller

Peptidoglycan wall

No sterols in memb.

Flagellin in helix

No nucleus

No histones

VII. Comparisons


Vii comparisons cont

EUCARYOTES

Several chromosomes

Membrane-bound organelles

80S ribosomes

PROCARYOTES

One chromosome

No membrane-bound organelles

70S ribosomes

VII. Comparisons, cont.


Vii comparisons cont1

PROCARYOTES

1 chromosome

No membrane-bound organelles

70S ribosomes

Replicates autonomously

MITOCHONDRIA

Multiple copies

no membrane-bound organelles

70S ribosomes

Replicates autonomously

VII. Comparisons, cont.


Vii comparisons cont2

PROCARYOTES

About 1- 8 m

Peptidoglycan wall

No sterols in membrane

No nucleus

No histones

MITOCHONDRIA

About 1 m

No wall

No sterols in inner membrane

No nucleus

No histones

VII. Comparisons, cont.


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