Chapter 3

Section 3: Cell Organelles

Prokaryote vs. Eukaryote

Prokaryote:

-has no

organelles

(no nucleus)

Eukaryote:

-has organelles

(has a nucleus)

Both:

-are living

-have DNA

-are cells

Cell PartsOrganelles: “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.

Nuclear Envelope

• Scattered over the surface of the nuclear envelope are many small channels called nuclear pores.

• Ribosomes are partially assembled in a region of the nucleus called the nucleolus.

• Ribosomal proteins and RNA are made in the nucleus.

Ribosomes

• Ribosomes are the cellular structures on which proteins are made.

Endoplasmic Reticulum

• The Endoplasmic Reticulum or ER is an extensive system of internal membranes that move proteins and other substances through the cell.

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 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.

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

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

Mitochondria

• Mitochondria are thought to be descendants of primitive prokaryotes.

• Mitochondria have their own DNA. Mitochondria reproduce independently of the cell. Mitochondrial DNA is similar to the DNA of prokaryotic cells.

“Typical” Plant Cell

Plant Cell StructurePlants have three unique structures that are not found in animal cells:1.Cell Wall2.Chloroplasts3.Central Vacuole Plant cell

Animal cell

• The cell membrane of plant cells is surrounded by a thick cell wall, composed of proteins and carbohydrates.

Cell Wall (plants only)

• The cell wall helps support and maintain the shape of the cell, protects the cell from damage, and connects the cell with adjacent cells.

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

• 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

• The central vacuole stores water and may contain ions, nutrients, and wastes.

• Most of a plant cell’s volume is taken up by a large, membrane-bound space called the Central Vacuole.

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