Prokaryotic and Eukaryotic Cells

Cells Smallest living unit Most are microscopic

Cell Size

•Cells Have Large Surface Area-to-Volume Ratio

Cell Size

Cells have a high surface to volume ratio to allow materials (food, O2, water) to come in and waste (CO2, etc.) to move out at an efficient rate

If cells were any bigger waste products would not move out as quickly as other materials move in and the cell would quickly die

Characteristics of All Cells1. A surrounding membrane called the cell

membrane

2. Protoplasm or cytoplasm– cell contents in thick fluid

3. Control center with DNA

4. All cells have ribosomes which make protein

Cell Types

Prokaryotic

Eukaryotic

These are two distinct types of cells with STRUCTURALSTRUCTURAL differences.

Prokaryotes

Eubacteria

Eukaryotes

Animal PlantArchaea Bacteria

Protists

Fungi

Prokaryotic Cell Structures and Functions

Prokaryotic Cells Are single celled organisms Include Eubacteria and Archaebacteria

cells

Prokaryotic Cells Characteristics

No membrane bound nucleus DNA (genetic material) is in the

Nucleoid region No “real” or membrane bound

organelles

Prokaryotic Cells Characteristics

Prokaryotes have the following Structures:Cell wall- made of peptidoglycans; for protection

and support for the shapeDNA- is circular; used for reproduction, repair, and

maintenanceFlagellum (or flagella pl.)- for movementRibosomes- to make proteinsCytoplasm- suspend/hold internal structures in

place Pili- to stick to surface and exchanging DNA

Prokaryotic Cell Structure

Shapes of Prokaryotes

Coccus or Cocci (pl.) – circular or sphere like

Spirillum – spiral shaped

Bacillus – rod shaped

Harmful Prokaryotes Disease- Some bacteria will directly attack

the tissues of plants and animals that could potentially be fatal Ex: Bubonic Plague caused by Yersinia pestis

Toxins- Some bacteria will attack organisms by releasing chemicals that are poisonous to plants and animals. Ex: Clostridium tetani causes tetanus or lockjaw, a disease in which the toxin paralyzes any muscle tissue

Benefits of Prokaryotes

Digest food – Many types of bacteria live in the digestive systems of animals to help break down cellulose and make essential vitamins

Decomposers- bacteria break down waste materials into simple substances that can be used by plants

Production of human food- bacteria help create a variety of dairy products, vinegar, sauerkraut, and beverages

Prokaryotic Cell Drawing Complete the Prokaryotic Cell

Worksheet

Animal and Plant Structures and Functions

Eukaryotic Cells

Characteristics or Features:Nucleus bound by membraneInclude fungi, protists, plant, and

animal cellsWill have many organelles

Protozoan

Structures for Support Structures for Support and Movementand Movement Exterior Structures

Cell membraneCell WallFlagellaCilia

Interior structures include:CytoplasmCytoskeleton

Plasma/Cell Membrane

Functions:Contains cell contentsRegulates what materials are

allowed in and what materials move out

Fluid mosaic model – describes fluid nature of a lipid bilayer with proteins

Cell Walls Found in plants, fungi, & many protists Surrounds plasma membrane It protects the cell and gives it shape Cell Wall Differences:

Plants – mostly celluloseFungi – contain chitin

Cilia & Flagella

Provide ability to move Cilia

Short, hair-like structuresUsed to move substances

outside human cells Flagella

Long tail-like extensionslocomotion

Cytoskeleton Filaments & fibers

Made of 3 fiber typesMicrofilamentsMicrotubulesIntermediate filaments

3 functions: mechanical support anchor organelles help move substances

Cytoplasm Viscous fluid containing organelles Components of cytoplasm

Interconnected filaments & fibers Fluid = cytosolOrganelles (not nucleus)

Organelles Cellular machinery Organelles are “little organs” inside the cell

that have a special function or job Different Organelles inside the cell are:

Golgi BodiesLysosomesMitochondriaRough and Smooth ERChloroplastsVacuolesCentrioles and Centrosomes

Centrioles Pairs of microtubular structures Play a role in cell division

Nucleus Control center of cell Contains the DNA Double membrane Contains:

Chromosomes/ chromatin

NucleolusNucleoplasm

DNA

Hereditary material

ChromosomesDNAProteinsForm for cell division

Chromatin – loosely spread out DNA

Nucleolus

Most cells have 2 or more Directs synthesis of RNA Forms ribosomes

Endoplasmic Reticulum

Helps move substances within cells

Network of interconnected membranes

Two typesRough endoplasmic reticulum (Rough ER)Smooth endoplasmic reticulum (Smooth ER)

Rough ER Ribosomes attached to surface

Manufacture proteinsNot all ribosomes attached to rough ER

May modify/change proteins from ribosomes

Ribosomes

Ribosomes are made of ribosomal RNA or rRNA

They may be found on Rough ER or floating freely in the cytoplasm

They help synthesize proteins

Smooth ER No attached ribosomes

Functions:Has enzymes that

help build molecules○Carbohydrates○Lipids

Also helps detoxify foreign substances

Stores calcium

Golgi Bodies Involved in synthesis of plant cell wall Packaging & shipping station of cell

Golgi Apparatus Function1. Molecules come in vesicles

2. Vesicles fuse with Golgi membrane

3. Molecules may be modified by Golgi

4. Molecules pinched-off in separate vesicle

5. Vesicle leaves Golgi apparatus

6. Vesicles may combine with plasma membrane to secrete contents

Lysosomes Contain digestive enzymes Functions

Aid in cell renewalBreak down old cell parts Digests invaders

Vacuoles Membrane bound storage sacs In plants it is called the central vacuole; it

contains: WaterFoodWastes

In protists, they are called contractile vacuoles

Mitochondria Have their own DNA Bound by double membrane Break down fuel molecules (cellular

respiration)GlucoseFatty acids

Release energyATP (energy molecule

Of cell)

Chloroplasts Found in plant cells and some unicellular organisms Contains a green pigment called chlorophyll Organelle that uses sunlight to create carbohydrates

(photosynthesis)