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Carry out all chemical activities needed to sustain life Cells are the building blocks of all living things Tissues are groups of cells that are similar in structure and function. Cells and Tissues. Cells are not all the same All cells share general structures - PowerPoint PPT Presentation
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CELLS AND TISSUES Carry out all chemical activities needed
to sustain life Cells are the building blocks of all living
things Tissues are groups of cells that are
similar in structure and function
ANATOMY OF THE CELL Cells are not all the same All cells share general structures Cells are organized into three main
regions Nucleus Cytoplasm Plasma membrane
Figure 3.1a
THE NUCLEUS Control center of
the cell Contains
genetic material (DNA)
Three regions Nuclear
membrane Nucleolus Chromatin
Figure 3.1b
NUCLEAR MEMBRANE Nuclear Membrane
Barrier of nucleus Consists of a double phospholipid membrane Contain nuclear pores that allow for
exchange of material with the rest of the cell Nucleoli Nucleus contains one or more nucleoli Sites of ribosome production
Ribosomes then migrate to the cytoplasm through nuclear pores
CHROMATIN Composed of DNA and protein Scattered throughout the nucleus Chromatin condenses to form
chromosomes when the cell divides
PLASMA MEMBRANE Barrier for cell contents Double phospholipid layer
Hydrophilic heads Hydrophobic tails
Also contains protein, cholesterol, and glycoproteins
Microvilli Finger-like projections that increase surface
area for absorption
PLASMA MEMBRANE
Figure 3.2
Extracellular fluid(watery environment)
Sugargroup
Polar heads ofphospholipidmolecules
Bimolecularlipid layer containingproteins
Nonpolar tailsof phospholipidmolecules
Glycoprotein
Proteins Filaments ofcytoskeleton Cytoplasm
(watery environment)
Channel
CholesterolGlycolipid
Plasmamembranes ofadjacent cells
Desmosome(anchoring junction)
Tight(impermeable) junction
Microvilli
Gap(communicating) junction
Extracellularspace betweencells
Underlyingbasementmembrane
Connexon
Figure 3.3
CYTOPLASM Material outside the nucleus and inside
the plasma membrane Cytosol
Fluid that suspends other elements Organelles
Metabolic machinery of the cell “Little organs”
Inclusions Non-functioning units (stored nutrients, cell
products, etc.)
Ribosomes
Golgi apparatus
Secretion being releasedfrom cell by exocytosisMicrotubule
Centrioles
Mitochondrion
Lysosome
Cytosol
Smooth endoplasmicreticulum
Chromatin
NucleolusNuclear envelope
Nucleus
Plasmamembrane
Roughendoplasmicreticulum
Intermediatefilaments
Peroxisome
Figure 3.4
CYTOPLASMIC ORGANELLES Ribosomes
Made of protein and RNA Sites of protein synthesis Found at two locations
Free in the cytoplasm Attached to rough endoplasmic reticulum
CYTOPLASMIC ORGANELLES Endoplasmic reticulum (ER)
Fluid-filled tubules for carrying substances Two types of ER
Rough Endoplasmic Reticulum Studded with ribosomes Site where building materials of cellular
membrane are formed Smooth Endoplasmic Reticulum
Functions in cholesterol synthesis and breakdown, fat metabolism, and detoxification of drugs
CYTOPLASMIC ORGANELLES Golgi apparatus
Modifies and packages proteins Produces different types of packages
Secretory vesicles Cell membrane components Lysosomes
Figure 3.20
Protein-containing vesicles pinch off rough ERand migrate to fuse with membranes ofGolgi apparatus. Proteins aremodified withinthe Golgi compartments.
Proteins arethen packagedwithin differentvesicle types, depending ontheir ultimatedestination.
Plasmamem-brane
Secretion byexocytosis
Vesicle becomeslysosome
Golgiapparatus
Rough ER ERmembrane
Phagosome
Proteins incisterna
Pathway B:Vesicle membraneto be incorporatedinto plasmamembranePathway A:
Vesicle contentsdestined for exocytosis Extracellular fluid
Secretoryvesicle
Pathway C:Lysosome containing acid hydrolaseenzymes
1
3
2
CYTOPLASMIC ORGANELLES Lysosomes
Contain enzymes that digest nonusable materials within the cell
Packaged by Golgi apparatus Peroxisomes
Membranous sacs of oxidase enzymes Detoxify harmful substances Break down free radicals
(highly reactive chemicals) Replicate by pinching in half
CYTOPLASMIC ORGANELLES Mitochondria
“Powerhouses” of the cell Change shape continuously Carry out reactions where oxygen is used
to break down food Provides ATP for cellular energy
CYTOPLASMIC ORGANELLES Cytoskeleton
Network of protein structures that extend throughout the cytoplasm
Provides the cell with an internal framework
Figure 3.7a
Figure 3.7a-c
(a) Microfilaments (b) Intermediate filaments (c) Microtubules
Actin subunit
7 nm 10 nm
Fibrous subunitsTubulin subunits
25 nm
Microfilaments form the bluenetwork surrounding the pinknucleus.
Intermediate filaments formthe purple batlike network.
Microtubules appear as goldnetworks surrounding thecells’ pink nuclei.
CYTOPLASMIC ORGANELLES Centrioles
Rod-shaped bodies Direct formation of mitotic spindle during
cell division
CELLULAR PROJECTIONS Not found in all cells Used for movement
Cilia moves materials across the cell surface
Flagellum propels the cell
CELL DIVERSITY
Figure 3.8a–b
CELL DIVERSITY
Figure 3.8c
CELL DIVERSITY
Figure 3.8d–e
CELL DIVERSITY
Figure 3.8f–g