What is a cell?

Cell Cell – Basic unit of structure and function in all living things

Cell Study and DiscoveryCell Study and Discovery

• .• Matthias Schleiden (1888) – All plants are made up of

cells• Theodore Schwann (1889) – All animals are made up

of cells• Rudolph Virchow (1889) – Cells come from pre-

existing cells.

The Cell TheoryThe Cell Theory • All living things are made up of cells

• Cells are the basic unit of structure and function in all living things

• Cells come from pre-existing cells

ShapeShape – Form reflects functionForm reflects function.Red Blood Cells are like tubes at Sesame

Place so they flow easier

Nerve cells are like electrical wires

Cheek cells (Epithelial cells) are flat to act like a shield

White Blood cells are amoeboid shaped to move and squeeze into all areas

Types of cellsTypes of cells 1.1. Prokaryotic cellsProkaryotic cells

– Primitive cells – “before the nucleus”

– No membrane bound organelles

– No nucleus– Found in Eubacteria and

Archaeabacteria– Cell wall, cell membrane,

cytoplasm, DNA & ribosomes

2.2. EukaryoticEukaryotic

“True nucleus”

– Have membrane – bound organelles

– All other kingdoms but Archaeabacteria & Eubacteria

– Organelles such as: Mitochondria, endoplasmic reticulum, vacuoles, lysosomes, and chloroplasts.

Comparing the Two

Cell Membrane

Cytoplasm

DNA

Structures common to both Prokaryotic and Structures common to both Prokaryotic and

Eukaryotic cellsEukaryotic cells • Cell Membrane• Ribosomes• DNA• Cytoplasm• Cell Walls (not in Animal or some Protist

cells though!)

OrganelleOrganelle – small structures in cells that have a specific function

Cell Organelles and Their FunctionsCell Organelles and Their Functions 1.1. Cell MembraneCell Membrane

– Outermost boundary in all Animal Cells.- Separates the cell’s internal environment

from the external environment.- Allows for the passage of some

substances based on size and concentration

- Selectively Permeable due to pores being present

Made up of a bilipid layer (lipid bilayer) – 2 layers of lipids with proteins floating

through it.

• In the "fluid mosaic model" of membrane structure, the membrane is a fluid bilipid layer in which protein molecules are either partially or wholly embedded. These layers easily move around

ProteinLipids

Rap

2. Nucleus2. Nucleus– Only in Eukaryotic cells. – *Stores hereditary information. – Surrounded by a double nuclear membranedouble nuclear membrane

or envelope w/ pores – ChromatinChromatin (strands of a combination of DNA

and protein within nucleus. These will later become Chromosomes.

– NucleolusNucleolus (1 or >) produces ribosomes

Nuclear Membrane

Nucleolus

Chromatin

3. Cytoplasm – “cell’s liquid”- Made of a gelatinous fluid

(Cytosol) between the nucleus and cell membraneCyclosis – streaming movement of

the cytoplasm.*Suspends organelles in place

and carries material in solution around cell

4.4. Cytoskeleton Cytoskeleton- Network of protein

strands that provide support and mobility of organelles in cytoplasm.

- 2 components of cytoskeleton - Microfilaments and Microtubules (both made of protein)

55. Mitochondria. Mitochondria

- *Powerhouse of the cells.

- Changes chemical bond energy of glucose into a usable form

- *Site of Cellular respiration

- Contains Cristae or folds to increase surface area

- Has its own DNA and ribosomes and can replicate!

- Found in greater numbers in cells such as muscle cells & liver cells (2500/cell)

Cristae

Double Membrane

6.6. Ribosomes Ribosomes – Most numerous organelle.

*Site of protein synthesis.

Made up of RNA and protein.

May be free floating in cytoplasm or attached on Endoplasmic Reticulum

7.7. Endoplasmic ReticulumEndoplasmic Reticulum

– Channels or passageways in the cell. • There are two types of ER:

1 – Rough w/ ribosomes attached for production & distribution of proteins.

2 – Smooth – Synthesis of lipids & detoxification of toxins

8. Golgi Apparatus (Bodies)8. Golgi Apparatus (Bodies)

– Stack of smooth flat sacs

- Modifies, collects, packages & distributes molecules to all

parts of a cell

9.9. Lysosomes Lysosomes

- *Produces digestive enzymes – Are the cells' garbage disposal system.

They breakdown worn out organelles – Clean up dead cells– Responsible for the un-webbing of hands

of fetus while developing in utero– These are rare in plant cells

10. Vacuoles10. Vacuoles

- *Stores food, water and wastes

- Plant cells have a very large central water vacuole for support (turgor)

- Animal cells have many small vacuoles

11. Centrioles11. Centrioles

– Found in animal cells 2 perpendicular bundles of microtubules

- Function during cell division      

Plant Cells’ Unique structures PlastidsPlastids

–Store starch or fats and many contain pigments to absorb light. - Chloroplasts - Double membraned.

Contain Chlorophyll and DNA Convert solar energy into chemical bond energy of

glucose (Photosynthesis)

Amyloplasts (Leucoplasts)Store starch

Cell WallCell Wall – Gives cell rigidity, support and protection.

- Made up of cellulose with pectin (glue) between adjacent cells.

Typical Plant Cell

1. Nucleus

2. Ribosomes

3. Mitochondria

4. Chloroplasts

5. Cell Membrane

6. Cytoplasm

7. Cell Wall

8. Central Vacuole

9. Golgi Apparatus

10.Endoplasmic

Reticulum

Cheek Cells Nucleus

Cytoplasm

Cell Membrane

ElodeaCyclosis

Onion Cells

Potato Cells

Amyloplast

Cell Wall

1. _______________2. _______________3. _______________ (Dots)4. _______________5. _______________6. _______________7. _______________8. _______________9. _______________10._______________11._______________12._______________13._______________

Typical Animal Cell

1. Nucleolus

2. Nucleus

3. Ribosome

4. Vacuole

5. Rough ER

6. Golgi Apparatus

7. Microtubule

8. Smooth ER

9. Mitochondria

10. Vacuole

11. Cytoplasm

12. Lysosome

13. Centriole

Typical Animal Cell

Organelle Function Plant Cells Animal Cells

MitochondriaSite of cellular respiration - transfer of energy - Folds

called CristaeYes Yes

Ribosomes Site of Protein synthesis Yes Yes

Endoplasmic ReticulumRough - Protein packaging & transport site

Smooth - Sythesis of lipidsYes Yes

Golgi Apparatus Processing & packaging center for cell secretions Few Many

Lysosomes Produce hydrolytic enzymes Few Many

CytoskeletonNetwork of protein filaments - keep cell's shape and for

movementYes Yes

Microfilaments & microtubules

Support, movement and cell division Yes Yes

Cilia & FlagellaCell movement & circulation Cilia - many & short,

Flagella - 1or 2 & longYes Yes

Nucleolus Production of ribosomes Yes Yes

Nucleus Contains DNA, synthesizes RNA & Ribosomes Yes Yes

Chromatin DNA & protein - genetic information Yes Yes

Cell WallOutmost layer of plant cell - support & protection Made

of cellulose & pectin glue between wallsYes No

VacuoleStores enzymes, wastes, water & food Large water in

plants - support

Yes, large water

vacuoleMany

PlastidStores food and pigments - Chloroplasts

(photosynthesis) & leucoplasts (stores starch)Yes No

Centrioles Microtubules that function during cell division No Yes

Cell Membrane Selectively permeable - made of a bilipid layer & proteins Yes Yes