Cell Theory and Cell Structure Quiz

Cell Theory

• All living organisms are composed of cells.
• Cells are the fundamental units of life from single-celled to multi-celled.
• Cells perform all life processes (metabolism, reproduction).
• All new cells emerge from pre-existing cells.

Animal and Plant Cells

Animal Cells

• Typically round or irregular shapes.
  • Nucleus: Contains DNA, controls cell activity.
  • Mitochondria: Site of cellular respiration (energy production).
  • Ribosomes: Synthesize proteins.
  • Endoplasmic Reticulum (ER): Rough (protein) and smooth (lipid) synthesis, transport.
  • Golgi Apparatus: Modifies, sorts, and packages proteins.
  • Lysosomes: Contain enzymes to break down waste.
  • Cytoplasm: Jelly-like substance where reactions occur.

Plant Cells

• Typically rectangular or box-like shapes.
  • Cell Wall: Provides structural support and protection (cellulose).
  • Chloroplasts: Site of photosynthesis.
  • Vacuole: Large central vacuole for water storage and turgor pressure.
  • Plasmodesmata: Channels connecting plant cells.

Organelle Functions

• Nucleus: Stores genetic material, directs cell activities.
• Mitochondria: Create ATP (energy) via cellular respiration.
• Ribosomes: Synthesize proteins.
• Endoplasmic Reticulum (ER): Rough ER makes proteins, smooth ER makes lipids and detoxifies.
• Golgi Apparatus: Modifies, packages, and transports proteins.
• Lysosomes: Digest cellular waste and foreign material.
• Vacuoles: Store nutrients, waste, and maintain pressure in plant cells.
• Cell Membrane: Regulates materials entering and leaving the cell.

Osmosis and Diffusion

• Osmosis: Water movement across a membrane from low to high solute concentration. (e.g., water entering plant cells).
• Diffusion: Movement of molecules from high to low concentration (e.g., oxygen into blood cells).

Energy Generation in Cells

• Location: Mitochondria.
• Reaction: Cellular respiration converts glucose and oxygen into carbon dioxide, water, and ATP (energy).
• Equation: C₆H₁₂O₆ + O₂ → CO₂ + H₂O + ATP

Microscope Calculations

• Total Magnification: Eyepiece magnification x objective lens magnification (e.g., 10x eyepiece x 40x objective = 400x).
• Field of View: Field of view at lower magnification x magnification at higher magnification / magnification at lower magnification
• Cell Size: Field of view / Number of cells across the field.

Importance of DNA

• DNA carries genetic instructions for development, growth, function, and reproduction.
• Accurate DNA is crucial for proper cellular function.
• Mutations in DNA can cause diseases (e.g., cancer).

Cell Division and Mitosis

• Reasons for division: Growth, repair, and asexual reproduction.
• Interphase: Cell grows & DNA replicates (G1, S, G2 phases).
• Mitosis Stages: Prophase, Metaphase, Anaphase, Telophase.
  • Prophase: Chromosomes condense, nuclear envelope breaks down.
  • Metaphase: Chromosomes align at the center.
  • Anaphase: Sister chromatids separate.
  • Telophase: Nuclear envelope reforms.
• Cytokinesis: Cytoplasm divides, producing two daughter cells.
• Plant vs. Animal Mitosis: Plant cells form a cell plate during cytokinesis; animal cells form a cleavage furrow.

The Cell Cycle

• Cycle Steps: Interphase, Mitosis, Cytokinesis.
• Checkpoints: Control points in the cell cycle that ensure accuracy (G1, G2, M checkpoints).
• Problems from Disturbances: Uncontrolled cell division (cancer), genetic disorders.