Aki Biology: Cell Structure Summary

Plant Cell Structure

• Cell Membrane: Determines what goes in and out of the cell.
• Cell Wall: Important for structure.
• Vacuole: Important for structure.
• Cytoplasm: Where most reactions take place.
• Ribosomes: Responsible for protein synthesis.
• Chloroplasts: Involved in photosynthesis (green bits).
• Mitochondria: Energy production (pink ones).
• Nucleus: Control center and holds DNA.

Animal Cell Structure

• Cell Membrane: Controls what goes in and out.
• Mitochondria: Energy production.
• Ribosomes: Protein synthesis.
• Cytoplasm: Where most reactions take place.
• Nucleus: Control center, holds DNA.
• Differences from Plant Cells: Lacks cell wall, vacuole, and chloroplasts.

Bacterial Cell Structure

• Cell Membrane: Controls what goes in and out.
• Cytoplasm: Where most reactions take place.
• Chromosome: DNA not in a nucleus.
• Flagella: Used for locomotion.
• Ribosomes: Protein synthesis.
• Cell Wall: Present in bacteria.

Differentiated and Specialized Cells

• Wide range of differentiated/specialized cells.
  • Examples: Leaf cells, muscle cells, skin cells, gut cells.
• Stem Cells: Have potential to turn into any other type of cell.

Microscopy

• Various techniques: From basic lenses to sophisticated electron microscopes.
• Magnification Calculation: Magnification = Image height / Object height.

Bacterial Growth

• Bacteria divide rapidly: Can go from 1 to millions in a short time.
• Uncontaminated Culture: Use flame sterilization, work near the flame, minimize contamination.
• Growth Conditions: 37°C in incubators, 25°C on bench.

Antibiotics and Antiseptics

• Safety Precautions: Clean work area, label agar plates, use forceps.
• Measurement of Clear Zones: Indicator of antibacterial effectiveness.

DNA and Mitosis

• DNA Structure: Long strand of deoxyribonucleic acid (A, T, C, G), double helix.
• Chromosomes: DNA further twisted, located in the nucleus.
• Mitosis Process:
  1. DNA condenses into chromosomes.
  2. Chromosomes line up in the middle.
  3. Chromosomes pulled apart to cell ends.
  4. Form new nuclei, separate into two daughter cells.

Stem Cells

• Uses: Grow new brain cells, bones, organs.
• Controversy: Ethical concerns over creating and destroying human embryos.

Diffusion

• Movement from high to low concentration areas (diffusion gradient).
  • Examples: Gas exchange in lungs (alveoli), nutrient absorption in gut (villi).

Osmosis

• Specifically water: Movement through a partially permeable membrane.
• From high water concentration to low water concentration.
  • Example: Uptake of water in root hair cells.

Active Transport

• Movement from low to high concentration (against concentration gradient).
• Examples: Glucose transport in the gut, mineral uptake in roots.