CELLS REVIEW QUESTIONS

Answer the following questions:

1. What is the function of the lysosome in the cell?

2. What is diffusion?3. Name 2 differences between prokaryotic and

eukaryotic cells. 4. What is osmosis?5. What is the function of the cell membrane?

1. WHAT IS THE FUNCTION OF THE LYSOSOMES IN THE CELL?

-Cleanup crew of the cell

- Small organelles filled with enzymes; will digest lipids, proteins, and carbohydrates into smaller molecules for the cell to use

2. WHAT IS DIFFUSION?

- Movement of particles from high concentration to areas of low concentration

- Diffusion requires NO ENERGY ( NO ATP!!!)

3. NAME 2 DIFFERENCES BETWEEN PROKARYOTIC AND EUKARYOTIC CELLS.

Prokaryotic Cells – DNA floats freely in nucleus, no nucleus, simple cells, BACTERIA

Eukaryotic Cells – DNA enclosed in the nucleus, contain a nucleus, more complex than prokaryotic cells,

Types: Animals, Plants, Fungi, Protists

4. WHAT IS OSMOSIS?

- Type of Diffusion

- Movement of WATER

5. WHAT IS THE FUNCTION OF THE CELL MEMBRANE?

- Regulates what goes in and out of the cell

- The cell membrane is selectively permeable

ACTIVE TRANSPORT

ACTIVE TRANSPORT

• Sometimes cells must move material against a concentration gradient – from *low to high*

(It’s sort of like pushing your bike up a hill! – you need ENERGY to get that bike to the top)

Active Transport requires ENERGY (ATP!!!)

Smaller molecules and ions carried across the membrane by proteins that act like energy (ATP!!!) requiring pumps

Examples: Calcium, Potassium, and Sodium ions

SODIUM-POTASSIUM PUMP

Na- ions are maintained at a lower concentration inside the cell, and K+ ions are maintained at higher concentration inside the cell

SODIUM-POTASSIUM PUMP

Active transport by protein molecules of the sodium and potassium ions is central to electrical impulses by nerve cells

The ions are squeezed through the transport proteins, as the proteins change their configuration to accommodate their riders

Sodium Potassium Pump ( A Short Animation)

TYPES OF ACTIVE TRANSPORT: ENDOCYTOSIS

Larger molecules must be transported across the membrane

Endocytosis process of taking materials into the cell by means of “infolding”, or making pockets, of the cell membrane

ENDOCYTOSIS CONTINUES:

The pocket that forms from the membrane breaks loose and forms a vacuole

Large molecules, like clumps of food, can be taken in this way

What is the function of the vacuole in the cell?

STORAGE!!!!

TWO EXAMPLES OF ENDOCYTOSIS:

Phagocytosis “cell-eating;” extension of cytoplasm surround particle and package it within a food vacuole

Cell engulfs it.

Amoebas use this method of taking in food

Endocytosis( a short animation)

TWO EXAMPLES OF ENDOCYTOSIS CONTINUED

Pinocytosis when cells take up liquid from surrounding environment.

----Tiny pockets form along membrane, fill with the liquid, and pinch off to form vacuoles within the cell

TYPES OF ACTIVE TRANSPORT:EXOCYTOSIS

When cells release a large amount of material from the cell

EXOCYTOSIS

* Membrane of the vacuole fuses with cell membrane, forcing the contents out of the cell*

The removal of water by contractile vacuole (AMOEBA) is one example of active transport

Exocytosis

REVIEW: ENDOCYTOSIS VS. EXOCYTOSIS

Endocytosis Vs. Exocytosis ( a short clip)

Endocytosis

Exocytosis

Endocytosis Exocytosis

1. Requires Energy (ATP!!!)

1.) Requires Energy (ATP!!!)

3. Two Types: Phagocytosis and Pinocytosis

2.) Takes larger molecules INTO the cell

2.) Takes molecules OUT of the cell

OVERVIEW

1. The cell membrane regulates what enters and exits the cell. The cell wall provides support and protection.

2. Particles move from an area of high concentration to an area of low concentration. This process is called diffusion

OVERVIEW

3. Osmosis is the diffusion of water through the selectively permeable membrane

4. The cell membrane is double layered and is made out of phosopholipids, that is where it gets one of its names: “the phospholipid bilayer”

OVERVIEW5. Phagocytosis – extensions of the cell

membrane surround a particle and package it within a food vacuole

6. Pinocytosis – tiny pockets form along cell membrane, fill with liquid, and pinch off to form vacuoles inside the cell

OVERVIEW

7. Active transport requires energy (ATP) but diffusion does not require energy (ATP)

Now: Using the Notes just given to you and your knowledge of cells complete the “Outlining the Notes” worksheet

What you do not complete will be homework. It is due TOMORROW 12/3