The Cell

October 6, 2009

• Organelles – structures found in eukaryotic cells that act as specialized “organs” for the cell.

1. Cytoplasm

• A fluid-like substance outside of the nucleus.

Cytoplasm

2. Nucleus

• 2. Nucleus – the “control center” of the cell. Contains cells’ DNA

• Surrounded by a nuclear envelope.– Nuclear pores allow material in and out of the

nucleus.• Contains chromatin

– Condenses to chromosomes during cell division

• Contains a nucleolus– Small, dense region in the center of the nucleus– Where ribosomes are assembled.

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

3. Ribosomes

• Site of protein assembly.

• Small particles of RNA and protein found throughout the cytoplasm

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

Ribosomes

4. Endoplasmic Reticulum

Two types:

a. Rough ER – lined with proteins• Involved in protein synthesis

b. Smooth ER – No ribosomes present• Contain enzymes that perform specialized tasks

such as synthesis of lipids and detoxification of drugs

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

RER

SER

Ribosomes

5. Golgi Apparatus

• The “packaging” area of the cell.– Modifies, sorts and

packages proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell.

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

RER

SER

Golgi

Apparatus

Ribosomes

6. Lysosomes

• The “clean-up crew” of the cell.

• Small organelles filled with enzymes that digests lipids, carbohydrates, and proteins in the cell so they can be used.

• Breakdown organelles that are too old to function correctly

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

RER

SER

Golgi

Apparatus

Lysosome

Ribosomes

7. Mitochondria

• “Power-house” of the cell.

• Convert chemical energy stored in food into compounds that are able to be used by the cell.

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

RER

SER

Golgi

Apparatus

Lysosome

Mitochondria

Ribosomes

8. Cytoskeleton

• Support structure and transportation system of the cell.

• Filaments help the cell maintain its shape and aid in movement.

• Contains 2 primary protein filaments – microfilaments and microtubules

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

RER

SER

Golgi

Apparatus

Lysosome

Mitochondria

Cytoskeleton

Ribosomes

9. Cell Membrane

• The “entry gate” of the cell.

• Controls what enters and exits the cell and also provides protection and support.

• Consists of a lipid bilayer.

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

RER

SER

Golgi

Apparatus

Lysosome

Mitochondria

Cytoskeleton

Cell Membrane

Ribosomes

10. Centriole

• – Aids in cell division.

11. Flagella

• Aids in movement of a cell.

Sperm Cell Bacteria

Cytoplasm

Nucleus

Nucleolus

Nuclear Envelope

RER

SER

Golgi

Apparatus

Lysosome

Mitochondria

Cytoskeleton

Cell Membrane

RibosomesFlagella

The Plant Cell

1. Cell Wall

• Found only in plants– Provides protection

and support for the cell.

– Lies outside the cell membrane.

Cell Wall

2. Vacuoles

• “Storage sac” of the cell.

• Found primarily in plant cells and small single-celled organisms.

• Function to store materials such as water, salts, proteins and carbohydrates.

Cell Wall

Chloroplasts

3. Chloroplasts

• Solar energy supply• Found only in plants• Capture the energy

from sunlight and convert it into chemical energy in the process called photosynthesis

Cell Wall

Vacuole

Chloroplasts