General Biology 1 - Cells Quiz

General Biology 1 - Quarter 1, Module 1: Cells

• This module covers the fundamental concept of cell theory, the structure and functions of cells, and the comparison between prokaryotic and eukaryotic cells.
• It also covers specialized cells and cell modifications.

Lesson 1: Cell Theory

• Cell theory is a fundamental concept in biology describing the properties of cells.
• It has three main principles:
  • All living organisms are composed of cells. Cells are the basic units of life.
  • The cell is the smallest unit of life. It is the basic structural and functional unit in living organisms.
  • All cells arise from pre-existing cells. Cells are produced by the division of existing cells (e.g., mitosis or binary fission).

Lesson 2: Cell Structure and Functions

• Cells have specific parts, each playing a particular role, to function effectively.
• Structure:
  • Plasma Membrane: A semi-permeable membrane made of a lipid bilayer. Controls the movement of substances in and out of the cell.
  • Cytoplasm: Jelly-like substance filling the cell and housing organelles.
  • Nucleus: Stores genetic material (DNA) and regulates cellular activities such as growth, metabolism, and reproduction.
• Organelles in Eukaryotic Cells:
  • Mitochondria: The powerhouse of the cell; the site of ATP (energy) production.
  • Endoplasmic Reticulum (ER):
    • Rough ER: Studded with ribosomes; synthesizes proteins.
    • Smooth ER: Synthesizes lipids and detoxifies substances.
  • Golgi Apparatus: Modifies, packages, and transports proteins and lipids.
  • Lysosomes: Contain enzymes for digestion and waste removal.
  • Ribosomes: Synthesize proteins.
  • Chloroplasts (in plant cells): Site of photosynthesis.
  • Vacuoles: Store water, nutrients, and waste (large in plants).
  • Cytoskeleton: Provides structure and facilitates movement.

Lesson 3: Prokaryotic vs. Eukaryotic Cells

• Prokaryotic Cells: Simple, unicellular organisms lacking a true nucleus and membrane-bound organelles.
  • The genetic material is present in a region called the nucleoid.
  • Examples include bacteria and archaea.
• Eukaryotic Cells: Complex cells with a true nucleus enclosed by a nuclear membrane and containing membrane-bound organelles.
  • Found in multicellular and some unicellular organisms (plants, animals, fungi, and protists).
• Note: Key differences are summarized in a table (size, nucleus, DNA, organelles, examples, reproduction)

Lesson 4: Cell Types

• Categorizations:
  • By organism: Prokaryotic (bacteria, archaea) and Eukaryotic (plants, animals, fungi, protists)
  • By function: Somatic (body cells like skin, muscle) and Germ (reproductive cells like sperm, egg).
• Specialized Cells:
  • Red Blood Cells (RBCs): Transport oxygen.
  • Neurons: Transmit signals in the nervous system.
  • Muscle Cells: Responsible for movement.
  • Plant Cells (e.g., Guard Cells): Regulate gas exchange.

Lesson 5: Cell Modifications

• Cells adapt their structures for specific functions.
• In Animals:
  • Microvilli: Increase surface area for absorption (e.g., intestines).
  • Cilia and Flagella: Aid in movement and locomotion (e.g., sperm, respiratory tract).
  • Pseudopodia: Extensions of the cytoplasm for movement or engulfing food (e.g., amoeba).
• In Plants:
  • Cell Wall Thickening: Provides strength and protection (e.g., xylem cells).
  • Plasmodesmata: Channels between plant cells for transport and communication.
  • Storage Vacuoles: Adapted to store nutrients, waste, or water.
• Other examples:
  • Keratinization: Formation of a protective layer in skin cells.
  • Formation of Endospores: Prokaryotes like bacteria form endospores under harsh conditions.