Cell Structure and Function

Structure of a Cell

• A cell is the basic structural and functional unit of living organisms
• Consists of three main parts:
  1. Plasma membrane: a thin, semi-permeable membrane that surrounds the cell
  2. Cytoplasm: a jelly-like substance inside the cell membrane, where metabolic processes take place
  3. Nucleus: a membrane-bound organelle that contains the cell's genetic material (DNA)

Cell Membrane

• Also known as the plasma membrane
• Functions:
  • Regulates what enters and leaves the cell
  • Maintains cell shape
  • Protects the cell from its environment
• Composed of:
  • Phospholipid bilayer: a double layer of lipid molecules with phosphate heads and fatty acid tails
  • Proteins: embedded in the phospholipid bilayer, involved in transport and cell signaling

Cell Organelles

• Nucleus: contains DNA, responsible for cell growth and reproduction
• Mitochondria: generates energy for the cell through cellular respiration
• Endoplasmic reticulum (ER): involved in protein synthesis, transport, and storage
• Ribosomes: site of protein synthesis
• Lysosomes: contain digestive enzymes, responsible for breaking down and recycling cellular waste
• Golgi apparatus: involved in protein modification, sorting, and transport

Cell Functions

• Metabolism: the process of converting energy and nutrients into cellular components
• Growth and development: increase in cell size and number
• Reproduction: production of new cells through cell division (mitosis or meiosis)
• Response to stimuli: ability to react to changes in the environment
• Waste management: removal of cellular waste and recycling of cellular components

Cell Structure and Function

• A cell is the basic structural and functional unit of living organisms
• Consists of three main parts: plasma membrane, cytoplasm, and nucleus

Plasma Membrane

• Semi-permeable membrane that surrounds the cell
• Functions: regulates what enters and leaves the cell, maintains cell shape, and protects the cell from its environment
• Composed of phospholipid bilayer and proteins
  • Phospholipid bilayer: double layer of lipid molecules with phosphate heads and fatty acid tails
  • Proteins: embedded in phospholipid bilayer, involved in transport and cell signaling

Cytoplasm

• Jelly-like substance inside the cell membrane
• Where metabolic processes take place

Nucleus

• Membrane-bound organelle that contains cell's genetic material (DNA)
• Responsible for cell growth and reproduction

Organelles and Their Functions

• Mitochondria: generates energy for the cell through cellular respiration
• Endoplasmic reticulum (ER): involved in protein synthesis, transport, and storage
• Ribosomes: site of protein synthesis
• Lysosomes: contain digestive enzymes, responsible for breaking down and recycling cellular waste
• Golgi apparatus: involved in protein modification, sorting, and transport

Cellular Functions

• Metabolism: converts energy and nutrients into cellular components
• Growth and development: increase in cell size and number
• Reproduction: production of new cells through cell division (mitosis or meiosis)
• Response to stimuli: ability to react to changes in the environment
• Waste management: removal of cellular waste and recycling of cellular components