Chapter 7

• Cell Structure and Function

• Cell Boundaries

• Movement in and out of cells

• Organization of cells within multicellular organisms

What does it mean to be alive?

1. Ability to grow and develop

2. Ability to reproduce

3. Ability to adapt to the environment

4. Have a structure

Do you know what the components of the Cell Theory are?

1. All living things are composed of ________ (atoms is not right word)

2. Cells are the basic _______of structure and function in living things.

3. New cells are produced from _________

__________. (two words)

Discovery of the Cell

• Early microscopes – Robert Hooke in 1665 looked at cork.

• Called the tiny, “empty” chambers CELLS, because they reminded him of monastery chambers

• Later, other scientists proposed the three parts of the cell theory, as on slide two

Advancements in Microscopes

• First microscopes – single lens• Compound microscope – multiple lenses

Limited on detail and resolution because light is scattered as it passes through matter

• Electron microscope – beam of electrons is aimed at the cell

Electrons are not scattered as easily

1000x resolution of best light microscopeLimitation – subject can’t be alive – done in a vacuum

• Can now visualize molecules and single atoms

Two Kinds of Organisms

• Prokaryotes

• Eukaryotes

Prokaryote

Prokaryotes: Bacteria and other simple cells

• Very Basic Cells with no membrane bound organelles.

• DNA is not separate from the rest of the Cell

• Maximum Size of bacteria is about 0.001mm (1μm)

Eukaryote

• Eukaryote: Complex unicellular organisms and all multicellular organisms.

• Cells that contain membrane bound organelles.

• The DNA is separated from the rest of the cell by a nucleus.

• Maximum size is 0.1mm (100μm) ---Larger than Prokaryotes.

Classify as eukaryote or prokaryote

• Human

• Bacteria

• Algae

• Mold

• Virus

The Cell Structure and Function

Organelle

• “little organ” of cells

• A structure inside a cell that has a specialized function.

• They are the machinery of a Cell

• Example: Nucleus, chloroplasts, etc.

The Cell Membrane

• Found in both plant and animal cells

• Function: – Protection– Allows something to

pass through it, both in and out.

• Semipermiable: Only certain molecules can pass through

Cell walls

• Made of cellulose in Plants

• Made of Chitin in Fungus

• Bacteria and Some Protists have cell Walls

• Provide support

Cytoplasm

• Fluid that surrounds the organelles and fills the cell

• Function: Provides a medium for chemical reactions to occur

Nucleus

• The Cell’s command center. Contains the DNA of the cell

• Function: Control the activity of the cell and stores genetic information. DNA is the code for the proteins produced by a cell.

Found in the Nucleus

• Chromatin: Structure of DNA found in the nucleus

• DNA/Genes: The genetic message used to make proteins. Found on the chromosome.

Nucleolus

• Nucleolus: Where the ribosomes are made.

• Found within the nucleus

RNA

• Ribonucleic Acid. Carries the instructions for making protein from the DNA to the ribosome.

Ribosomes

• Makes the Proteins• One of the few organelles also found in

Prokaryotic Cells.• Not a membrane bound organelle.

Mitochondria

• The “Powerhouse” of the cell.

• Respiration occurs here: Biomolecules (esp. Glucose) broken down into CO2 and water to produce energy

• Present in all Eukaryotic Cells

Chloroplasts

• Found in Plant Cells and some Protists• The site where photosynthesis occurs:

Producing sugar from CO2, Water, and Sunlight.

• Contain Green Pigment called Chlorophyll

Endoplasmic Reticulum

• Rough ER: Produces and transports Proteins

• Smooth ER: Produces and Transports Lipids

Golgi

• Flattened membrane sacs

• Packages, modifies, and transports the protein for specific uses.

Vacuole• Vacuole: Storage in the cell. Plants cells have

Large Water Vacuoles. Animal Cells’ are smaller

• Vesicle: Small Vacuole that contains Proteins.In both Plants and Animals

Vacuole

Lysosomes

• Suicide Sacs

• Used to digest food and old parts.

• When the cell gets worn out, the lysosomes will burst and digest the whole cell.

Cytoskeleton

• Function: Maintains cell shape and “directs traffic” within the cell. Done By…

– Microtubules– Microskeleton

Movement

• Cilia: Short and numerous Hairlike structures that move a cell– Ex. Paramecium

• Flagella: A long threadlike structure used to propel the cell– Ex. Sperm, Euglena

Level of organization within an organism

1. Cell: The Basic Unit of Life

2. Tissue: A collection of cells that work together for a common purpose.

3. Organ: Two or more tissues acting together. (Lung)

4. Organ System: A group of organs that work together in a system. (Respiratory System)

List Three differences between Plant and Animal Cells:

1. Plant Cells have a cell wall, animal cells do not

2. Animal Cells lack a chloroplast

3. Plant cells have a large vacuole

Label Me

1.

2.

3.

4.

5.

6.

7.