PROPERTIES OF WATER


1. Polarity

  • Definition: Uneven distribution of charges within a molecule.

  • Water is Polar:

    • Oxygen is slightly negative, and hydrogen is slightly positive.

    • This allows water molecules to attract each other.

2. Hydrogen Bonding

  • Definition: Weak bonds formed between the slightly positive hydrogen of one water molecule and the slightly negative oxygen of another.

  • Key: Responsible for many of water's unique properties.

3. Cohesion

  • Definition: Water molecules stick to each other due to hydrogen bonding.

  • Example: Formation of droplets.

4. Surface Tension

  • Definition: The "skin" on the water’s surface due to cohesion.

  • Example: Bugs walking on water.

5. Adhesion & Capillary Action

  • Adhesion: Water sticks to other substances (e.g., glass).

  • Capillary Action: Movement of water against gravity in narrow spaces (e.g., in plants).

6. Diffusion

  • Definition: Movement of particles from high concentration to low concentration.

  • Key: Does not require energy.

7. Enzymes and Substrates

  • Enzymes: Proteins that speed up reactions.

  • Substrates: Molecules that enzymes act upon.

  • Example: Enzyme breaks down a substrate into smaller products.



CELL STRUCTURE

1. Cell Theory

  • All living things are made of cells.

  • Cells are the basic unit of life.

  • All cells come from pre-existing cells.

2. Prokaryotes and Eukaryotes

  • Prokaryotes:

    • No nucleus (e.g., bacteria).

    • Simple structure.

    • Lack membrane-bound organelles.

  • Eukaryotes:

    • Have a nucleus (e.g., plant and animal cells).

    • Complex structure.

    • Contain membrane-bound organelles.

3. Semi-Permeable Membrane

  • Definition: Allows certain substances to pass through while blocking others.

4. Cell Wall

  • Definition: Rigid outer layer in plants, fungi, and bacteria.

  • Function: Provides structure and protection.

5. Nucleus

  • Definition: Control center of the cell containing DNA.

6. Chromosomes

  • Definition: DNA organized into structures inside the nucleus.

7. Cytoplasm

  • Definition: Gel-like substance in the cell where organelles are found.

8. Rough Endoplasmic Reticulum (RER)

  • Definition: Covered in ribosomes.

  • Function: Makes proteins.

9. Smooth Endoplasmic Reticulum (SER)

  • Definition: No ribosomes.

  • Function: Makes lipids and detoxifies.

10. Mitochondria

  • Definition: Powerhouse of the cell, produces energy (ATP).

  • Key: Has its own DNA and reproduces as needed.

11. Ribosomes

  • Definition: Produce proteins.

12. Golgi Bodies

  • Definition: Package and transport proteins and lipids.

13. Lysosomes

  • Definition: Contain enzymes to break down waste.

14. Vacuoles

  • Definition: Storage sacs for water, nutrients, or waste.

  • Key: Larger in plant cells.

15. Cytoskeleton

  • Definition: Network of proteins for structure and movement.



CELL TRANSPORT

1. Osmosis

  • Definition: Diffusion of water across a semi-permeable membrane.

2. Diffusion

  • Definition: Movement of molecules from high to low concentration.

3. Facilitated Diffusion

  • Definition: Uses protein channels to move substances across the membrane.

4. Cell Membrane

  • Definition: Semi-permeable membrane made of lipids and proteins.

5. Cell Transport

  • Definition: Movement of substances in and out of the cell.

6. Active Transport

  • Definition: Movement of substances against the concentration gradient, requiring energy (ATP).

7. Exocytosis

  • Definition: Process of removing substances from the cell.

8. Endocytosis

  • Definition: Process of bringing substances into the cell.

9. Hypotonic

  • Definition: Solution with less solute, water enters the cell (cell swells).

10. Hypertonic

  • Definition: Solution with more solute, water leaves the cell (cell shrinks).

11. Isotonic

  • Definition: Equal solute concentration, no water movement.



CELL MEMBRANE COMPONENTS

1. Lipid Bilayer

  • Definition: Double layer of phospholipids forming the cell membrane.

2. Protein Channels

  • Definition: Help transport substances across the membrane.

3. Peripheral Proteins

  • Definition: Sit on the surface of the membrane.

4. Integral Proteins

  • Definition: Embedded in the membrane, some act as channels.

5. Carbohydrate Chains

  • Definition: Attached to proteins or lipids, involved in cell recognition.

6. Receptor

  • Definition: Detects signals and triggers a response.

7. Receptor Protein

  • Definition: Protein that binds to a specific molecule to trigger a reaction.

8. Phospholipids

  • Definition: Molecules with hydrophilic heads and hydrophobic tails.

9. Cholesterol

  • Definition: Stabilizes the cell membrane, making it flexible.

10. Cell Recognition

  • Definition: Process where cells identify each other using proteins and carbohydrate markers.