eukaryotic cell organelles - iteach.orgiteach.org/wmayorga/life/little_organs.pdfeukaryotic cell...

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Eukaryotic Cell Organelles

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Cell Membrane • Outermost living layer • Flexible and elastic barrier that surrounds the cell

• Made of a lipid bilayer (double layer)

• Separates and encloses the cell from its environment

• Protection and support • Communication • Controls what goes in and out of the cell (AKA gate of the cell)—selectively permeable or semi-permeable. � Passive transport vs. active transport � Peripheral vs. Integral proteins

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Cytoplasm • Jellylike, clear, aqueous (80%) substance that fills the cell.

• It contains all organelles, H2O, dissolved gasses, (O2 and CO2), salts, organic molecules, enzymes, and cytoskeleton.

• Responsible for the cell’s internal transport (cytoplasmic streaming)

See pages 10, 11, and 27 of

your textbook.

Ribosomes • Small, spherical, non-membrane-bounded, structures made primary of nucleic acid RNA and protein

• Most numerous organelles • Can be found floating in the cytoplasm or embedded in the RER.

• They are made in the nucleolus.

• Site of protein synthesis (protein factories of the cell)—It gets its instructions from the DNA of the cell.

Nucleolus • Small, dark area located inside the nucleus • Synthesis (or creation) of ribosomes.

Cilia & Flagella • Cilia (Lat. cilium, eyelash, hair) and flagella (Lat. flagello, whip) are hair like projections that can move either in an undulating fashion, like a whip, or stiffly, like an oar.

• They provide cells with locomotion (food and predators).

• Examples: A paramecium has cilia, while a sperm cell has a flagellum.

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1. 7.

2. 8.

3. 9.

4. 10.

5. 11.

6. 12.

Microvilli

1

Centrosome

2

3

4

5

6 7

8

10

11

12

9

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ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Nucleus • Large, oval structure that controls and regulates cell activities

• Double membrane; nuclear envelope.

• Nuclear pores allow movement of molecules in an out of nucleus through the cell membrane.

• Directs the synthesis of proteins that regulate most of the chemical processes that take place inside the cell.

• Transmit hereditary information contained in NDA

• DNA never leaves the nucleus • The nucleus directs cell’s reproduction

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Mitochondria Mitos «thread» Chondrion «grain»

• Large, rod-shaped organelles, with two membranes; one of which is folded to form cristae.

• Mitochondria contain their own circular mtDNA and ribosomes.

• They can grow, divide and give rise to others independently of the cell.

• Known as the “powerhouse” of the cell. • Food molecules are broken down in the presence of oxygen to release energy.

• Energy is stored in ATP. This conversion of food energy to ATP is known as cellular respiration.

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Lysosomes

• Discovered by Rene de Duve in 1950. • Small, round structure (vesicle) produced in the Golgi complex that are found floating in the cytoplasm of all eukaryotic cells

• Common in animals, fungi, and protists • Rare in plants • Contain potent hydrolytic digestive and destructive enzymes

• Known as the “clean up crew” or “recycling center”

• Break down large food molecules

• Digest old, worn-out organelles and debris

• Digest old or injured cells; self-destruct mechanism

• Protect the cell against invaders (self-defense mechanism)

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Cytoskeleton

• Protein fibers that extend through the cytoplasm of eukaryotic cells.

• They act as framework to give shape to the cell and enable structure within it, or the entire cells to move.

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Vacuole

• Large, round, water-filled sac that has a single membrane around it and it floats in the cytoplasm (vesicle).

• Lager in plant cell; known as the “storage tank” of the cell (water, enzymes, nutrients, water).

• Keeps plant cells firm and supports its shape; plants may wilt when the central vacuole loses water

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Plant Cell

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ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Endosplasmic

Reticulum (ER) • Network of clear membranes and sacs that forms and intracellular highway that spreads from the nucleus through the cytoplasm.

• SER lacks ribosomes • RER has ribosomes on its outer surface—make protein.

• Synthesizes and transport proteins, steroids, lipids and other materials throughout the cell needed by the cell or for export.

• The amount of ER depends on the cell’s job.

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Golgi Apparatus Golgi Body Golgi Complex Golgi

• Italian anatomist and microscopist Camillo Golgi in 1898

• Flattened membranes or sacs that works closely with RER

• Collects, processes, modifies packages and secretes protein for “export”

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Chloroplast • Contain pigments that capture solar energy—mainly chlorophyll.

• Found in both plant and algae cells • Larger than mitochondria • Provide energy for the cell • Double membrane • Own circular DNA • Own ribosomes • Reproduces by itself

• Takes solar energy to convert into chemical energy for storage, e.g., glucose and ATP.

• Site of photosynthesis

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Cell Wall • Strong, rigid, nonliving layer found outside the cell membrane of archaea, bacteria, fungi, plants, and algae.

• Made of cellulose (50% of wood) • It has openings called plasmodesmata

• It protects and support the cell

ORGANELLE STRUCTURE (DESCRIPTION) FUNCTION (JOB)

Chromosomes (Chroma, «color», soma, «body»)

• Thick, rod-shape, objects made of chromatin and protein

• Found in floating in the nucleoplasm • Clearly visible only when the cell is dividing • Made of nucleic acids—store information needed for protein synthesis

• Direct cell activities, including growth and reproduction

• Pass on traits of the cell to the new daughter cells