Epidermal and Epithelial Cells Quiz

Epidermal Cells

• External cells of plants providing protection against water loss and pathogens such as fungi.
• Closely packed with minimal intracellular spaces, enhancing their protective function.
• Covered by a waxy cuticle, which helps to reduce water loss.
• Found on plant stems, leaves, roots, and seeds.

Types of Epidermal Cells

• Pavement Cells: Help maintain the plant's internal temperature.
• Stomatal Guard Cells: Regulate water availability and manage gas exchange by opening and closing stomata through turgor pressure.
• Trichomes: Also known as epidermal hairs, they trap and deter animal predators, playing a significant role in plant defense.

Animal Cells

• Generally smaller than plant cells and characterized by irregular shapes due to the absence of a cell wall.

Epithelial Tissue

• Comprises layers of contiguous cells lining organ surfaces and cavities.
• Found covering the external body surface, lining interior tracts like the respiratory and gastrointestinal systems, and enclosing spaces like blood vessels.

Types of Epithelial Cells

• According to Layers:

  • Simple Epithelia: One cell layer thick.
  • Stratified Epithelia: Multiple layers with at least one anchored to a basal membrane.

• According to Shape:

  • Cuboidal: For secretion.
  • Simple Columnar: Brick-shaped, involved in secretion and absorption.
  • Simple Squamous: Plate-like, facilitating material exchange through diffusion.
  • Stratified Squamous: Multilayered for protection, regenerates quickly.
  • Pseudo-stratified Columnar: Appears multilayered but is actually a single layer; lines the respiratory tract and often has cilia.

Connective Tissue Cells

• Blood: Comprises plasma, erythrocytes (RBCs for oxygen transport), leukocytes (WBCs for defense), and platelets for clotting.

Cell Cycle Stages

• Interphase: Comprises G1, S, and G2 phases, wherein cells grow, replicate DNA, and prepare for division.
  • G1 Phase: Prepares cell for division through metabolic changes.
  • S Phase: DNA synthesis occurs; each chromosome doubles, forming sister chromatids.
  • G2 Phase: Prepares cytoplasmic materials necessary for mitosis.

Cell Division Processes

• Mitosis: The process of aligning and separating duplicated chromosomes into two identical daughter cells.
• Meiosis: A two-step division process that produces haploid gametes with genetic variation.
  • Meiosis 1: Involves homologous chromosomes separating.
  • Meiosis 2: Sister chromatids separate, leading to four genetically diverse daughter cells.

Cellular Division Phases

• Mitosis Phases: Prophase, Prometaphase, Metaphase, Anaphase, Telophase.
• Meiosis 1 & 2: Each with distinct phases including Prophase, Metaphase, Anaphase, and Telophase.

Cell Cycle Checkpoints

• G1 Checkpoint: Assesses cell size and protein synthesis before synthesis phase.
• S Checkpoint: Verifies correct DNA replication before moving to mitosis.
• M Checkpoint: Ensures mitosis is complete before cell division.

Transport Mechanisms

• Simple Diffusion: Small, nonpolar molecules passing through membranes.
• Osmosis: Movement of water across a semipermeable membrane from high to low concentration.
• Facilitated Diffusion: Utilizes protein channels to assist molecules in crossing membranes.

Biological Molecules

• Carbon Bonding: Carbon's tetravalency allows diverse molecular structures crucial for life.
• Carbohydrates: Polymers made of repeating monomers, vital for energy and structural purposes.
• Lipids: Non-polar molecules for energy storage and cellular functions, not formed through polymerization.
• Proteins: Diverse, large macromolecules made of amino acids; perform various biological functions.

Plant Organelles

• Chloroplasts: Site of photosynthesis; contain chlorophyll, which captures light energy.
• Plastids: Involved in food manufacture and storage, contributing to plant metabolism.

Photosynthesis

• Process converting light energy into chemical energy, producing oxygen and organic compounds.
• Light-dependent Reactions: Occur in thylakoid membranes, converting sunlight into chemical energy (NADPH and ATP).

Test your knowledge on the various types of epidermal cells in plants, their functions, and the characteristics of epithelial tissue in animals. Explore the roles of specialized cells like stomatal guard cells and trichomes. This quiz will help reinforce your understanding of plant and animal cell structures.