Chapter 3 Section 3: Cell Organelles

Prokaryote vs. Eukaryote -has no organelles (no nucleus) Both: -are living -have DNA -are cells Eukaryote: -has organelles (has a nucleus) Prokaryotic- “simple” cells Eukaryotic- “complex” (complejo) cells Most living things you are familiar with (including humans) have eukaryotic cells.

Organelles: “little organs” Cell Parts Organelles: “little organs” Think of a cell as a factory- lots of separate people, departments, and machines that each have their own task, but they work together to get a job done.

Nucleus The Nucleus is an internal compartment that houses the cell’s DNA. Most functions of a eukaryotic cell are controlled by the cell’s nucleus. The nucleus is surrounded by a double membrane called the nuclear envelope. Cell nucleus (like the factory central office): the “boss” of the cell Directs all cell activities Separated by a nuclear membrane (it’s own “cell wall”) Contains genetic material - DNA

Nuclear Envelope Scattered over the surface of the nuclear envelope are many small channels called nuclear pores. Ribosomal proteins and RNA are made in the nucleus. Ribosomes are partially assembled in a region of the nucleus called the nucleolus.

Ribosomes Ribosomes are the cellular structures on which proteins are made. Ribosomes (like the factory assembly line): put together proteins Each cell contains thousands Found on reticulum and floating throughout the cell

Endoplasmic Reticulum The Endoplasmic Reticulum or ER is an extensive system of internal membranes that move proteins and other substances through the cell. Endoplasmic reticulum (like factory conveyor belts): move materials around in cell Smooth type: has no ribosomes Rough type (pictured): has ribosomes in surface

Why do they call me the “rough ER”? The rough ER helps transport proteins that are made by the attached ribosomes. The part of the ER with attached ribosomes is called the Rough ER. . Why do they call me the “rough ER”?

Vesicles New proteins enter the ER. The portion of the ER that contains the completed protein pinches off to form a Vesicle. A Vesicle is a small membrane-bound sac that transports substances in cells. The ER moves proteins and other substances with eukaryotic cells.

Packaging and Distribution of Proteins Vesicles that contain newly made proteins move through the cytoplasm from the ER to an Organelle called the Golgi Apparatus Golgi bodies (like the factory packing and shipping department): the UPS or Fed-Ex of the cell Transports and packages proteins and other materials in the cell Moves materials within the cell Moves materials out of the cell

Golgi Apparatus The Golgi Apparatus is a set of flattened, membrane-bound sacs that serve as the packing and distribution center of the cell.

Lysosomes Lysosome is a small spherical vesicle that contains digestive enzymes that break down waste. Lysosomes (like the factory waste management dpartment): the “wrecking crew” and “trash can” of the cell Transports undigested material to cell membrane for removal Cell breaks down if lysosome explodes or ruptures 

Mitochondria Mitochondria are organelles that harvest energy from organic compounds to make ATP. ATP is the main energy currency of cells. Most ATP is made inside the Mitochondria. Mitochondria (like the factory generator): the “power plant” of the cell Produces energy through chemical reactions – breaking down fats & carbohydrates

Mitochondria Mitochondria have two membranes. The outer membrane is smooth. The inner membrane is greatly folded, and has a large surface area.

Mitochondria Mitochondria have their own DNA. Mitochondria reproduce independently of the cell. Mitochondrial DNA is similar to the DNA of prokaryotic cells. Mitochondria are thought to be descendants of primitive prokaryotes.

“Typical” Plant Cell

Plant Cell Structure Plants have three unique structures that are not found in animal cells: Cell Wall Chloroplasts Central Vacuole Plant cell Contain a nucleus and other organelles (smaller parts) surrounded by membranes Most living organisms have these type of cells Animal cell

Cell Wall (plants only) The cell membrane of plant cells is surrounded by a thick cell wall, composed of proteins and carbohydrates. The cell wall helps support and maintain the shape of the cell, protects the cell from damage, and connects the cell with adjacent cells. Cell Wall (like factory outer walls): further protects the cell and provides strength

Chloroplast (plants only) Chloroplasts are organelles that use light energy to make carbohydrates from carbon dioxide and water. Cholorplasts like mitochondria, supply much of the energy needed to power the activities of plant cells. Chloroplasts (like factory solar energy plants): turns energy from the sun (with CO2 and water) into food Contains green chlorophyll Where photosynthesis takes place

Chloroplasts Chloroplasts, like mitochondria, have their own DNA and reproduce independently of the plant cell. Chloroplasts, like mitochondria, are thought to be descendants of ancient prokaryotes.

Central Vacuole Most of a plant cell’s volume is taken up by a large, membrane-bound space called the Central Vacuole. The central vacuole stores water and may contain ions, nutrients, and wastes. Vacuoles (like factory storage/factory water tower): the “storage container” of the cell Sacs for storage, digestion, and waste removal Help plants maintain shape- very large in plants

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