Cell Biology, Mitosis, and Enzyme Activity Principles

Chemical Processes and Molecular Interactions

Dehydration synthesis: Loss of a water molecule between each pair of monomers.

Hydrolysis: Addition of water between each pair of monomers.

Reducing Sugars and Detergents

What is a reducing sugar?

The ability to add electrons to (reduce) other molecules.

What is the function of detergent?

To lower the surface tension of a liquid.

Emulsions and Emulsifiers

• Emulsion: A mixture of two liquids, each insoluble in the other.
• Emulsifier: A substance that stabilizes an emulsion by increasing its kinetic stability.

Cell Structure and Function

Cellular Components and Identification

1. Know the structures of animal and plant cells and their functions.
2. Be able to identify the nucleus, cytoplasm, and cell membrane of an animal cell (e.g., a cheek cell).
3. Be able to identify the nucleus, cytoplasm, vacuole, chloroplasts, cell wall, and cell membrane of plant cells.

Understanding Tonicity

Understand tonicity and the following terms: hypotonic, isotonic, hypertonic, crenation, hemolysis, turgor pressure, plasmolysis, flaccid.

• Hypotonic: A lot of solute inside the cell.
• Isotonic: Same amount of water inside and outside the cell.
• Hypertonic: A lot of water inside the cell.
• Crenation: The cell explodes.
• Hemolysis: The rupturing of red blood cells and the release of their contents.
• Turgor pressure: The force within the cell that pushes the plasma membrane against the cell wall.
• Plasmolysis: The process in which cells lose water in a hypertonic solution.
• Flaccid: No water in the cell.

Mitosis and Meiosis

Stages of Cell Division

Identify cells in interphase and the different stages of mitosis:

• Interphase
• Prophase
• Metaphase
• Anaphase
• Telophase

Identify chromosomes, cytoplasm, nucleus, nucleolus, and cell wall.

Mitosis vs. Meiosis

Mitosis: Occurs as plant cell division and animal cell division.

Meiosis: Involves two successive nuclear divisions, which produce four daughter cells.

Enzyme Activity and Catalysts

How Enzymes Work

What are enzymes? They are catalysts used to speed up the rate of reaction by lowering activation energy (enzyme-substrate catalyst, vitamins).

Define denature: When the temperature is high, the protein's shape is altered, which prevents it from performing its function.

Factors Affecting Reaction Rates

Temperature: Changes the rate of molecular motion.

pH: Basic and acidic environments; the enzyme could be less able to bind to the substrate.

Experimental Observations

Rennin and Milk: Rennin is an enzyme secreted into the stomach that causes the curdling of milk. When the temperature rises, molecular motion increases; decreasing temperature decreases molecular motion. At boiling, denaturation occurs and there is no movement.

Catalase and Hydrogen Peroxide: The reaction bubbles because of the release of oxygen (O₂). Once the hydrogen peroxide hit the potato, O₂ was released.

Macerating Potatoes: Mashing the potatoes exposed more catalysts, which caused foaming.