Eukaryotic Cells

Eukaryotic Cells

Eukaryotic cell – 1st cell with internal compartments called organelles; an organism whose cells have a nucleus.

Organelle- structure that carries out specific activities in the cell

2 Types: – Animal Cell – Plant Cell

2 Types of Eukaryotic Cell

Animal Cell

Plant Cell

Organelles

1. Cell membrane– Doubled layer of phospholipids:

• Hydrophilic ( water loving) layer • Hydrophobic ( water fearing) layer

– Proteins embedded in the bilayer, which allows sodium,

potassium, chloride, and calcium to pass through.

2. Cytosol: – The cytosol is the "soup" within which all the

other cell organelles reside – where most of the cellular metabolism occurs. – Though mostly water, the cytosol is full of

proteins that control cell metabolism

3. Cytoplasm: – This is a collective term for the cytosol plus the

organelles suspended within the cytosol.

4. Cell Wall (plant cells only): – Plant cells have a rigid, protective cell wall made up of

polysaccharides. – In higher plant cells, that polysaccharide is usually

cellulose. – provides and maintains the shape of these cells– serves as a protective barrier. – Fluid collects in the plant cell vacuole and pushes out

against the cell wall. • This turgor pressure is responsible for the crispness of fresh

vegetables.

5. Cytoskeleton: – helps to maintain cell shape. – Prevents cell motility. – The internal movement of cell organelles, as well as cell

locomotion and muscle fiber contraction could not take place without the cytoskeleton.

– Organized network of three primary protein filaments:• microtubules• actin filaments (microfilaments)• intermediate fibers

6. Nucleus– Double membrane – Communicates with surrounding cytosol by nuclear pores– DNA is present

7. Nucleolus: - prominent structure in the nucleus - produces ribosomes, which move out of the nucleus and take positions on the rough endoplasmic reticulum

8. Mitchondria– Provides ATP as a energy source to the cell for movement, dividing,

and producing secretory products.

– Doubled membrane- bound organelles.

9. Chloroplast (plant cells only): – specialized organelles found in all higher plant cells.

– These organelles contain the plant cell's chlorophyll responsible for the plant's green color.

– a double outer membrane.

– Within the stroma are other membrane structures - the thylakoids.

– Thylakoids appear in stacks called "grana" (singular = granum).

10. Endoplasmic Reticulum (ER) Two types:

1. Smooth ER – Has different functions depending on the cell. One of its functions includes producing lipid and steroid.

2. Rough ER – Ribosomes are present on its surface for transport throughout the cell.

11. Ribosomes– Composed of a large and a small unit– Produces protein

12. Golgi Appartus– Stack of membrane-bound vesicles that package

macromolecules for transport.

13. Secretory Vesicle: – Cell secretions - e.g. hormones, neurotransmitters - are

packaged in secretory vesicles at the Golgi apparatus. – The secretory vesicles are then transported to the cell

surface for release.

14. Vacuole:– A vacuole is a membrane-bound sac that plays roles in

intracellular digestion and the release of cellular waste products.

– In animal cells, vacuoles are generally small. – Vacuoles tend to be large in plant cells and play several

roles:• storing nutrients and waste products,• helping increase cell size during growth, • even acting much like lysosomes of animal cells.

– The plant cell vacuole also regulates turgor pressure in the cell. Water collects in cell vacuoles, pressing outward against the cell wall and producing rigidity in the plant.

– Without sufficient water, turgor pressure drops and the plant wilts.

15. Centrosome: – The centrosome, or MICROTUBULE ORGANIZING CENTER

(MTOC), is an area in the cell where microtubles are produced. – Plant and animal cell centrosomes play similar roles in cell

division, and both include collections of microtubules, but the plant cell centrosome is simpler and does not have centrioles.

16. Centriole (animal cells only): – Each centriole is a ring of nine groups of fused microtubules. – There are three microtubules in each group.– Microtubules (and centrioles) are part of the cytoskeleton. – In the complete animal cell centrosome, the two centrioles are

arranged such that one is perpendicular to the other.

17. Lysosome:– Contain hydrolytic enzymes necessary for intracellular digestion. – They are common in animal cells, but rare in plant cells. – Hydrolytic enzymes of plant cells are more often found in the

vacuole.

18. Peroxisome: – Membrane-bound packets of oxidative enzymes. – In plant cells, peroxisomes play a variety of roles including

converting fatty acids to sugar and assisting chloroplasts in photorespiration.

– In animal cells, peroxisomes protect the cell from its own production of toxic hydrogen peroxide.

Animal Organelles

1. Cell membrane2. Cytosol3. Cytoplasm 4. Cytoskeleton5. Nucleus6. Nucleolus7. Mitochondria 8. ER

1. Smooth 2. Rough

9. Ribosome10. Secretory Vesicle11. Vacuole12. Centrosome13. Lysosome14. Peroxisome15. Centriole (only in animals)

Plant Organelles

1. Cell membrane2. Cytosol3. Cytoplasm 4. Cytoskeleton5. Nucleus6. Nucleolus7. Mitochondria 8. ER

1. Smooth 2. Rough

9. Ribosome10.Secretory Vesicle11.Vacuole12.Centrosome13.Lysosome14.Peroxisome15.Cell wall16.Chloroplast

Did You Know:Jewel Plummer Cobb

Born: January 17, 1924 Birthplace: Chicago, IL

Biologist (Cell), Physiologist (Cell) Bachelor of Science from

Talladega College in 1944 Master of Science from New

York University in 1947. Ph.D. in Cellular Biology

from New York University in 1950.

https://webfiles.uci.edu/mcbrown/display/cobb.html