Post on 23-Dec-2015
Enlarges imageformed by objectivelens
Magnifies specimen,forming primaryimage
Eyepiece
Focuses lightthrough specimen
Ocularlens
Specimen
Objective lens
Condenserlens
Lightsource
Transmission electron microscopy (TEM) micrograph of a peroxisome from the marine snail Gibulla umbilicalis.
Head Louse
INTRODUCTION TO THE CELL
Copyright © 2009 Pearson Education, Inc.
Nucleoid
Ribosomes
Plasma membrane
Cell wall
Capsule
Flagella
Bacterialchromosome
A typical rod-shapedbacterium
Pili
A thin section through thebacterium Bacillus coagulans(TEM)
Smooth endoplasmicreticulum
Roughendoplasmicreticulum
CYTOSKELETON:
NUCLEUS:
Chromosomes
Nucleolus
Ribosomes
Golgiapparatus
Plasma membrane
Mitochondrion
Lysosome
Microtubule
Intermediatefilament
Microfilament
Animal Cell Organelles
Smooth endoplasmicreticulum
Rough endoplasmicreticulum
CYTOSKELETON:
NUCLEUS:
Chromosome
NucleolusRibosomes
Golgiapparatus
Plasma membrane
Mitochondrion
Peroxisome
Cell wall
Central vacuoleMicrotubule
Intermediatefilament
Microfilament
Cell wall ofadjacent cell
Chloroplast
Plant Cell Organelles
4.4 Eukaryotic cells are partitioned into functional compartments
There are four life processes in eukaryotic cells that depend upon structures and organelles
– Manufacturing
– Breakdown of molecules
– Energy processing
– Structural support, movement, and communication
Copyright © 2009 Pearson Education, Inc.
4.4 Eukaryotic cells are partitioned into functional compartments
Manufacturing involves the nucleus, ribosomes, endoplasmic reticulum, and Golgi apparatus
– Manufacture of a protein, perhaps an enzyme, involves all of these
Copyright © 2009 Pearson Education, Inc.
Cellular Organelles - Nucleus
The nucleus contains most of the DNA in a eukaryotic cell
In the nucleus, DNA and proteins form genetic material called chromatin
Chromatin condenses to form discrete chromosomes (during cell division)
Two membranes ofnuclear envelope Nucleus
Nucleolus
Chromatin
Pore
Endoplasmicreticulum
Ribosomes
Ribosomes: Protein Factories
• Ribosomes are particles made of ribosomal RNA and protein
• Ribosomes carry out protein synthesis
• Cells that must synthesize large amounts of protein have a large number of ribosomes
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-11
Cytosol
Endoplasmic reticulum (ER)
Free ribosomes
Bound ribosomes
Large subunit
Small subunit
Diagram of a ribosomeTEM showing ER and ribosomes
0.5 µm
The endomembrane system: all these membranes are related through direct contact or through vesicles
• Components of the endomembrane system:– Nuclear envelope
– Endoplasmic reticulum
– Golgi apparatus
– Lysosomes
– Vacuoles
– Plasma membrane
• A vesicle is a tiny spherical package of molecules surrounded by a membrane
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Endoplasmic Reticulum: Biosynthetic Factory
• There are two distinct regions of ER:
– Smooth ER, which lacks ribosomes
– Rough ER, with ribosomes studding its surface
– One synthesizes lipids and the other functions in protein synthesis. Which do you think is which?
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
4.9 The endoplasmic reticulum is a biosynthetic factory
• Smooth ER is involved in a variety of diverse metabolic processes
– involved in the synthesis of lipids, oils, phospholipids, and steroids
Copyright © 2009 Pearson Education, Inc.
4.9 The endoplasmic reticulum is a biosynthetic factory
• Rough ER makes additional membrane for itself and proteins destined for secretion
– Once proteins are synthesized, they are transported in vesicles to other parts of the endomembrane system
Copyright © 2009 Pearson Education, Inc.
4.10 The Golgi apparatus finishes, sorts, and ships cell products
• The Golgi apparatus functions in conjunction with the ER by modifying products of the ER
– Products travel in transport vesicles from the ER to the Golgi apparatus
– One side of the Golgi apparatus functions as a receiving dock for the product and the other as a shipping dock
– Products are modified as they go from one side of the Golgi apparatus to the other and travel in vesicles to other sites
Copyright © 2009 Pearson Education, Inc.
Golgi apparatusGolgi apparatus
“Receiving” side ofGolgi apparatus
Transportvesiclefrom ER
New vesicleforming
“Shipping” sideof Golgi apparatus
Transportvesicle fromthe Golgi
Lysosomes: Digestive Compartments
• A lysosome is a membranous sac of hydrolytic enzymes that can digest macromolecules
• Lysosomal enzymes can hydrolyze proteins, fats, polysaccharides, and nucleic acids
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
• Some types of cell can engulf another cell/bacteria by phagocytosis; this forms a vacuole
• A lysosome fuses with the vacuole and digests the molecules
• Lysosomes also use enzymes to recycle the cell’s own organelles and macromolecules, a process called autophagy
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Fig. 6-14
Nucleus 1 µm
Lysosome
Digestiveenzymes
Lysosome
Plasmamembrane
Food vacuole
(a) Phagocytosis
Digestion
(b) Autophagy
Peroxisome
Vesicle
Lysosome
Mitochondrion
Peroxisomefragment
Mitochondrionfragment
Vesicle containingtwo damaged organelles
1 µm
Digestion
Video• Examples
• Lets follow the path of insulin
– This is a protein that will be secreted from the pancreatic cell
• Antibodies
– These are defensive proteins that will be secreted from the white blood cell
Transport vesiclebuds off
Secretoryproteininside trans-port vesicle
GlycoproteinPolypeptide
Ribosome
Sugarchain
Rough ER
1
2
3
4
Video
4.4 Eukaryotic cells are partitioned into functional compartments
Breakdown of molecules involves lysosomes, vacuoles, and peroxisomes
– Breakdown of an internalized bacterium by a phagocytic cell would involve all of these
Copyright © 2009 Pearson Education, Inc.
Digestiveenzymes
LysosomePlasmamembrane
Food vacuole
Digestion
4.12 Vacuoles function in the general maintenance of the cell
Vacuoles are membranous sacs that are found in a variety of cells and possess an assortment of functions
– Examples are the central vacuole in plants with hydrolytic functions, pigment vacuoles in plants to provide color to flowers, and contractile vacuoles in some protists to expel water from the cell
Copyright © 2009 Pearson Education, Inc.
Nucleus
Chloroplast
Centralvacuole
4.4 Eukaryotic cells are partitioned into functional compartments
Energy processing involves mitochondria in animal cells and chloroplasts in plant cells
– Generation of energy-containing molecules, such as adenosine triphosphate, occurs in mitochondria and chloroplasts
Copyright © 2009 Pearson Education, Inc.
Mitochondrion
Intermembranespace
Innermembrane
Cristae
Matrix
Outermembrane
Chloroplast
Stroma
Inner and outermembranes
Granum
Intermembranespace
4.4 Eukaryotic cells are partitioned into functional compartments
Structural support, movement, and communication involve the cytoskeleton, plasma membrane, and cell wall
– An example of the importance of these is the response and movement of phagocytic cells to an infected area
Copyright © 2009 Pearson Education, Inc.
Microfilament
Actin subunit
7 nm
Intermediate filament
Fibrous subunits
10 nm
Microtubule
Tubulin subunit
25 nm
Nucleus
Nucleus
Centralmicrotubules
Outer microtubuledoublet
Radial spoke
Dynein arms
Plasmamembrane
Triplet
Cross sections:
Flagellum
Basal body
Basal body
4.4 Eukaryotic cells are partitioned into functional compartments
There are four life processes in eukaryotic cells that depend upon structures and organelles
– Manufacturing
– Breakdown of molecules
– Energy processing
– Structural support, movement, and communication
Copyright © 2009 Pearson Education, Inc.
Nucleus Golgi apparatus
Smooth ERRough ERRibosome
LysosomesVacuoles
Perixisomes
ChloroplastMitochondria
a.
b.
c.
d.
e.
f.
g.
h.
i.
j.
k.
l.
Quiz 3
Copyright © 2009 Pearson Education, Inc.
1. Which organelle is involved in manufacture of protein?
2. Which organelles acts as a kind of recycling center for the cell and breaks down old molecules so they can be used again?
3. Which organelle acts as an energy transformer?
4. A cell that’s primary function is to produce protein would have a lot of_____________.
a. Mitchondria
b. Vacuole
c. Ribosome
d. Lysosome
Matching: can be used more than once
Quiz 3
Copyright © 2009 Pearson Education, Inc.
5. Name one difference between plant and animal cells.
6. What is the most important macromolecule found the nucleus of a cell?
7. T/F One function of the cytoskeleton is to give support to the cell.
8. T/F Vesicles are similar to little circular bubbles that can carry proteins around in the cell.
9. T/F The Golgi apparatus stores, modifies, and packages proteins.
10. Would you like to get a point for answering this question?
Hydrophilic heads
Hydrophobic tails
Proteins
Hydrophobic region ofprotein
Inside cell Hydrophilic region ofprotein
Outside cell
4.5 The structure of membranes correlates with their functions
The plasma membrane controls the movement of molecules into and out of the cell, a trait called selective permeability
– The structure of the membrane with its component molecules is responsible for this characteristic
– Membranes are made of lipids, proteins, and some carbohydrate, but the most abundant lipids are phospholipids
Copyright © 2009 Pearson Education, Inc.
Hydrophilic head
Hydrophobic tails
Symbol
Phosphategroup
4.20 The extracellular matrix of animal cells functions in support, movement, and regulation
Cells synthesize and secrete the extracellular matrix (ECM) that is essential to cell function
– The ECM is composed of strong fibers of collagen, which holds cells together and protects the plasma membrane
Copyright © 2009 Pearson Education, Inc.
EXTRACELLULAR FLUID
Microfilaments
Collagen fiber
Connectingglycoprotein
Integrin
Plasmamembrane
Glycoproteincomplex with longpolysaccharide
CYTOPLASM
4.21 Three types of cell junctions are found in animal tissues
Adjacent cells communicate, interact, and adhere through specialized junctions between them
– Tight junctions prevent leakage of extracellular fluid across a layer of epithelial cells
– Anchoring junctions fasten cells together into sheets
– Gap junctions are channels that allow molecules to flow between cells
Copyright © 2009 Pearson Education, Inc.
Animation: Desmosomes
Animation: Gap Junctions
Animation: Tight Junctions
4.21 Cell junctions are found in plant tissues
Plasmodesmata
Cytoplasmic streaming
Copyright © 2009 Pearson Education, Inc.
Tight junctions
Anchoring junction
Gap junctions
Plasma membranesof adjacent cells
Extracellular matrix