Cell Structure and Function Quiz

Cell Structure and Function

• Cell Membrane: Controls substances entering and leaving the cell; partially permeable.
• Cytoplasm: Jelly-like substance; matrix where all organelles reside; site of cellular activities.
• Nucleus: Contains organism's genetic information (DNA) in the form of chromatin; controls cell activities, including cell division.
• Rough Endoplasmic Reticulum (RER): Complex membrane system; connected to the nuclear envelope; ribosomes attached to its surface; synthesizes proteins (intended for transport out of the cell).
• Smooth Endoplasmic Reticulum (SER): Tube-like structure; connected to the RER; no ribosomes; synthesizes substances like fats and steroids (e.g., sex hormones); detoxifies harmful substances.
• Ribosomes: Found freely throughout the cytoplasm (free ribosomes – synthesize proteins used within the cell) or attached to RER (synthesize proteins transported out of the cell).
• Golgi Body: Chemically modifies substances produced by the RER; packages them in vesicles for secretion.
• Mitochondria: Performs aerobic respiration; oxidizes glucose to release energy (often called the powerhouse of the cell); sausage/oval shape.
• Vacuole: Protects the cell from bursting; maintains cell shape.
• Cell Wall (Plant Cells): Provides structural support; rigid cell shape.
• Chloroplast (Plant Cells): Contains chlorophyll, absorbing light for photosynthesis to produce glucose.

Protein Secretion Pathway

• Protein Synthesis & Packaging:
  • Substances synthesized by RER are packaged into vesicles.
  • Vesicles transport from RER.
  • Vesicles fuse with the Golgi apparatus.
  • Substances are modified and sorted into vesicles within the Golgi apparatus.
• Secretion:
  • Modified substances are secreted from the Golgi apparatus into secretory vesicles.
  • Secretory vesicles move towards the cell membrane.
  • Secretory vesicles fuse with the cell membrane, releasing contents outside the cell.