cell organelles prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells....

Cell Organelles

Prokaryotic cells lack a nucleus and most internal structures of eukaryotic cells.• All cells share certain characteristics.

– Cells tend to be microscopic.Cells tend to be microscopic.– All cells are enclosed All cells are enclosed

by a membrane. by a membrane.– All cells are filled with All cells are filled with

cytoplasm.cytoplasm.– All cells have DNA.All cells have DNA.

Bacterium(colored SEM; magnification 8800x)

cell membrane

cytoplasm

Cell Organelles

There are two cell types: eukaryotic cells and prokaryotic cells.• Eukaryotic cells have a

nucleus.• Eukaryotic cells

have membrane-

bound organelles.

nucleus

cell membrane

organelles

Cell Organelles

There are two cell types: eukaryotic cells and prokaryotic cells.• Prokaryotic cells do

not have a nucleus.

• Prokaryotic cells do not have membrane-bound organelles.

nucleus

cell membrane

organelles

cytoplasm

Cell Organelles

Why do cells have different shapes?

Cell Organelles

KEY CONCEPT Eukaryotic cells share many similarities.

Cell Organelles

Cells have an internal structure.• The cytoskeleton has many functions.

– supports and shapes cell– transports organelles– provides strength– assists in cell division

Cell Organelles

A

B

C

D

Click to animate the image.

•The cytoskeleton helps the cell move, keep its shape, and organize its parts.

Cell Organelles

Several organelles are involved in making and processing proteins.• The nucleus stores genetic information.

Cell Organelles

The Nucleus

A

BC

D

The nucleolus produces ribosomes.

Cell Organelles

Several organelles are involved in making and processing proteins.• Many processes occur in the endoplasmic reticulum.

Cell Organelles

Several organelles are involved in making and processing proteins.

There are two types of endoplasmic reticulum.

Cell Organelles

Several organelles are involved in making and processing proteins.• The nucleus stores genetic information.• Many processes occur in the endoplasmic reticulum.• There are two types of endoplasmic reticulum.

– rough endoplasmic reticulum

– smooth endoplasmic reticulum

Cell Organelles

Rough ER has ribosomes and takes part in the production of protein

Smooth ER lacks ribosomes. Smooth ER makes lipids and breaks down drugs and alcohol.

Cell Organelles

• Ribosomes link amino acids to form proteins.

Cell Organelles

Golgi apparatus is a set of flattened, membrane-bound sacs that helps modify and package proteins for release from the cell.

Cell Organelles

• Vesicles are membrane-bound sacs that hold materials.

• Vesicles store and release a variety of substances as the cell needs them.

Cell Organelles

Cell Organelles

Other organelles have various functions.• Mitochondria supply energy to the cell.

Cell Organelles

Other organelles have various functions.• Vacuoles are fluid-filled sacs that hold materials.

Cell Organelles

Other organelles have various functions.• Lysosomes contain enzymes to digest material.

Cell Organelles

Other organelles have various functions.

• Centrioles help divide DNA and form cilia and flagella

Cell Organelles

Plant cells have cell walls and chloroplasts.• A cell wall provides rigid support.

Cell Organelles

Plant cells have cell walls and chloroplasts.

Chloroplasts convert solar energy to chemical energy.

(photosynthesis)