The Cell All Living things are composed of cells All Living things are composed of cells All Cells have/contain the following: All Cells have/contain the following: Cell Membrane - Lipid Bilayer - Separates inside from outside Cell Membrane - Lipid Bilayer - Separates inside from outside

Cytoplasm Cytoplasm - everything but DNA/Nucleus Cytoplasm - everything but DNA/Nucleus

Two Cell types Prokaryotic Cells  Prokaryotic Cells 1. Primitive cells – include bacteria 1. Primitive cells – include bacteria 2. No nucleus 2. No nucleus 3. No Membrane-bound organelles 4. Very Small 1-10 micrometers 5. Single Strand of Circular “naked” DNA 6. Contain Ribosomes

Typical Prokaryotic Cell

Eukaryotic Cells Eukaryotic Cells Eukaryotic Cells Contain a Nucleus which protects DNA / Chromosomes Much larger than prokaryotic cells Have many different types of Membrane bound organelles - compartmentalization = efficiency

Eukaryotic Cells Animal Eukaryotic Cell Plant Eukaryotic Cell

Organelles Membrane-Bound organelles only found in Eukaryotes Membrane-Bound organelles only found in Eukaryotes Localize Chemical Reactions making the cell far more efficient Localize Chemical Reactions making the cell far more efficient

Major Organelles of the Eukaryotic Cell The Nucleus The Nucleus “eukaryotic” means “true nucleus” “eukaryotic” means “true nucleus” Contains & protects the cell’s DNA Contains & protects the cell’s DNA Helps coordinate the division of cells Helps coordinate the division of cells Surrounded by a Nuclear Envelope Surrounded by a Nuclear Envelope Envelope is double layered with an Inner & Outer membrane Envelope is double layered with an Inner & Outer membrane Has perforations called Nuclear Pores which allow large molecules to pass in/out of the nucleus Has perforations called Nuclear Pores which allow large molecules to pass in/out of the nucleus Contains a Nucleolus Contains a Nucleolus Ribosomes are made in this region Ribosomes are made in this region Contains DNA packaged in structures called chromosomes Contains DNA packaged in structures called chromosomes Chromosomes

Mitochondria Serves as the “powerhouse of the cell” by generating chemical energy Serves as the “powerhouse of the cell” by generating chemical energy Has it’s own DNA* Has it’s own DNA* Can divide on its own* Can divide on its own*

Chloroplasts (Plant Cell Only) Is the “cell’s farm” - meaning food is generated here. Is the “cell’s farm” - meaning food is generated here. Does this by photosynthesis - the conversion of CO 2, H 2 O and sunlight into sugar Does this by photosynthesis - the conversion of CO 2, H 2 O and sunlight into sugar Contain Chlorophyll - a green pigment - which does this Contain Chlorophyll - a green pigment - which does this Has it’s own DNA* Has it’s own DNA* Can divide on its own* Can divide on its own*

Ribosomes Are NOT membrane- bound & also exist in prokaryotes Are NOT membrane- bound & also exist in prokaryotes Are used to manufacture proteins Are used to manufacture proteins Granular in appearance Granular in appearance Often found on “rough” endoplasmic reticulum* Often found on “rough” endoplasmic reticulum*

Endoplasmic Reticulum Are folds of membranes used to package & modify proteins made by ribosomes. They also make lipids Are folds of membranes used to package & modify proteins made by ribosomes. They also make lipids 2 types 2 types “Rough” - which is usually near nucleus and covered with ribosomes giving it its “rough” appearance. (Finishes proteins) “Rough” - which is usually near nucleus and covered with ribosomes giving it its “rough” appearance. (Finishes proteins) “Smooth” - which is usually away from the nucleus (produce lipids) “Smooth” - which is usually away from the nucleus (produce lipids)

Examples of Endoplasmic Reticulum Smooth ER Rough ER

Golgi Bodies Are the post offices of the cell Modify (address) proteins & lipids and send them in packages (vessicles) throughout (or out of) the cell.

Lysosomes Small Vessicles which serve to digest particles and clean-up cells Contain Lysozyme – a powerful digestive enzyme Digests food particles Destroys worn-out organelles Self-Destructs worn-out cells

Centrioles (Animal Cell Only) Serve as construction/organization points for cellular microtubules Serve as construction/organization points for cellular microtubules Organize and transfer chromosomes and other organelles during Meiosis & Mitosis Organize and transfer chromosomes and other organelles during Meiosis & Mitosis Occur in some prokaryotes, protists & animals. Do not occur with fungi and plants Occur in some prokaryotes, protists & animals. Do not occur with fungi and plants Tube like structures usually at right angles to each other. Tube like structures usually at right angles to each other. Some animals have centriole- like structures at the base of flagella called basal bodies. Some animals have centriole- like structures at the base of flagella called basal bodies.

Tonoplast (water vacuole) (plant cells only) Large H 2 O / Lipid / waste storage tank Large H 2 O / Lipid / waste storage tank Provides pressure (Turgor pressure) to maintain cell structure Provides pressure (Turgor pressure) to maintain cell structure

Cell Wall Provides support / protection for plant cell Provides support / protection for plant cell Two layers of cell wall Two layers of cell wall Primary Cell Wall – Outer – Cellulose only Primary Cell Wall – Outer – Cellulose only Secondary Cell Wall – Inner – Cellulose & Lignin Secondary Cell Wall – Inner – Cellulose & Lignin Cell membrane is innermost layer Cell membrane is innermost layer

Cytoskeleton Network of fibers which help organize the internal arrangement within cells. Network of fibers which help organize the internal arrangement within cells. Three basic types of fibers compose cytoskeleton: Three basic types of fibers compose cytoskeleton: Actin Filaments Actin Filaments Thinnest fibers ~7nMThinnest fibers ~7nM Formed from protein ActinFormed from protein Actin Microtubules Microtubules Largest component of cytoskeleton ~25 nMLargest component of cytoskeleton ~25 nM Formed from protein TubulinFormed from protein Tubulin Intermediate filaments Intermediate filaments Intermediate in size and can varyIntermediate in size and can vary Form from several proteins inluding vimentin & keratinForm from several proteins inluding vimentin & keratin