Cell Structure and Organelles Quiz

Cell Structure

• Cells are the fundamental units of life, exhibiting diverse shapes and sizes.
• All cells share core structures: a plasma membrane, cytoplasm, and genetic material.
• Prokaryotic cells (e.g., bacteria) lack a nucleus and membrane-bound organelles.
• Eukaryotic cells (e.g., plant and animal cells) contain a nucleus and various membrane-bound organelles.
• The plasma membrane is a selective barrier, regulating substance passage. Mainly composed of a phospholipid bilayer.
• Cytoplasm encompasses the region between the plasma membrane and the nucleus, including organelles.
• Cytosol is the fluid component of cytoplasm.
• The nucleus houses the cell's genetic material (DNA) and controls cellular activities.
• Ribosomes are protein synthesis sites; they exist freely in the cytoplasm or attached to the endoplasmic reticulum.

Organelles

• Endoplasmic Reticulum (ER): A membrane network for protein and lipid synthesis.
  • Rough ER: Ribosome-studded, involved in protein synthesis and modification.
  • Smooth ER: No ribosomes, crucial for lipid synthesis, detoxification, and calcium storage.
• Golgi Apparatus: Processes, sorts, and packages proteins and lipids for secretion or cellular use.
• Mitochondria: The "powerhouses" of the cell, responsible for cellular respiration and ATP production; contain their own DNA.
• Lysosomes: Contain enzymes for breaking down waste, cellular debris, and foreign substances.
• Vacuoles: Membrane-bound sacs for storage, transport, and maintaining turgor pressure (especially in plant cells).
• Chloroplasts (plant cells only): Sites of photosynthesis, converting light energy to chemical energy.

Cell Processes

• Cellular Respiration: The process of breaking down glucose to release ATP, occurring in mitochondria.
• Photosynthesis: The process by which plants, and some other organisms, convert light energy into glucose in chloroplasts.
• Protein Synthesis: Building proteins from amino acids, involving transcription (DNA to mRNA) and translation (mRNA to protein) stages; crucial role of ribosomes.
• Cell Division: A cell dividing into two daughter cells via mitosis (somatic cells) or meiosis (gametes).
• Cell Transport: Movement of substances across the cell membrane, encompassing passive transport (diffusion, osmosis) and active transport (energy-dependent).
• Endocytosis and Exocytosis: Processes for moving large molecules or bulk materials into or out of the cell, respectively.

Cell Types and Specializations

• Different cell types have unique shapes and structures reflecting their functions. Examples include muscle, nerve, and epithelial cells.
• Plant cells have a cell wall made of cellulose providing support and structure.