Module 3

• Cells


  The foundation of all organisms, forming tissues and organ systems
• Proteins


  Large, complex molecules that play critical roles in the body, comprising amino acids
• Carbohydrates


  Provide energy, structural support, and cellular communication
• Plant and fungal cell walls

  Have carbohydrate cell walls, acting as receptors on the outer surface of cell membranes
• Lipids


  Made up of fatty acids, are the basic building blocks for all cells and play various roles
• Nucleic acids


  Have two types: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA)
• Cells develop after large organic molecules formed and surrounded themselves with a protective membrane 3.8 billion years ago
• According to endosymbiotic theory, a large prokaryote created a nucleus about 2 billion years ago
• Domains of Life on Earth

  Classified into Archaea, Bacteria, and Eukarya
• Prokaryotic cells


  • Simpler and lack membrane-bound organelles and nucleus
• Prokaryotic bacteria are the most numerous and prolific group of species on Earth
• Prokaryotic cells


  • Lack membrane-bound organelles and a membrane-bound nucleus
  • Without these organelles, prokaryotic cells cannot perform advanced functions
  • Most of their DNA is in a chromosome-like structure within a nucleoid
  • Additional DNA pieces, called plasmids, reside outside the nucleoid in the cytoplasm
• Organelle


  A subcellular structure that has one or more specific jobs to perform in the cell
• Eukaryotic cells


  • Reproduce sexually through mitosis, a cell division process
• Prokaryotic cells


  • Participate in reproduction through binary fission
  • Replicate asexually, creating an exact parent clone
• Eukaryotic cells


  • Sexually reproduce through meiosis
• Eukaryotic cells


  • Have larger, more complex ribosomes bound by a membrane
• Prokaryotic cells


  • Ribosomes are spread in the cytoplasm and float freely
• Eukaryotic and prokaryotic ribosomes

  Consist of two subunits, with prokaryotes having slightly smaller subunits called 50-S and 30-S
• Similarities between Prokaryotes and Eukaryotes

  • Both cells have DNA for genetic coding, determining living characteristics
  • Both have a plasma/cell membrane, serving as a barrier between the cell and the outside
  • Both cell types have ribosomes, used to synthesize proteins
  • Both cells have cytoplasm, a jelly-like fluid composed of water, salts, and proteins
  • Despite differences, both cells can perform their primary functions
  • Despite differences, humans and bacteria are made of the same molecules: DNA, proteins, sugars, and lipids
• Capsule (in prokaryotic cells)

  The capsule, often gelatinous in appearance, protects the cell and helps it adhere to surfaces
• Cell Wall (in prokaryotic cells)


  The rigid outer structure just inside the capsule provides structural support and protection
• Cell Membrane (in prokaryotic cells)


  This flexible, thin layer beneath the cell wall regulates the entry and exit of substances
• Cytoplasm (in prokaryotic cells)


  The clear, gel-like fluid filling the cell contains all cell components
• Nucleoid (in prokaryotic cells)


  The irregularly shaped, dense region within the cytoplasm is where the cell's DNA is located
• Plasmids (in prokaryotic cells)


  Small loops of DNA, separate from the nucleoid, carry additional genes
• Ribosomes (in prokaryotic cells)


  Small, spherical structures scattered throughout the cytoplasm synthesize proteins
• Flagellum (in prokaryotic cells, if present)


  The long, whip-like structure extending from the cell surface enables movement
• Cell Membrane (in eukaryotic cells)


  The flexible, thin layer surrounding the cell regulates the entry and exit of substances
• Cell Wall (in plant eukaryotic cells)


  The thick, rigid outer layer provides structural support and protection
• Cytoplasm (in eukaryotic cells)

  The clear, gel-like fluid filling the cell contains all cell components
• Nucleus (in eukaryotic cells)

  The large, round structure, often centrally located, contains the cell's DNA and controls its activities
• Nucleolus (in eukaryotic cells)


  The dense, spherical structure inside the nucleus produces ribosomes
• Mitochondria (in eukaryotic cells)


  The bean-shaped structures with inner folded membranes produce energy through respiration
• Ribosomes (in eukaryotic cells)


  Small, spherical structures, either floating in the cytoplasm or attached to the endoplasmic reticulum, synthesize proteins
• Endoplasmic Reticulum (ER) (in eukaryotic cells)


  The network of membranous tubules, with rough ER having ribosomes and smooth ER not, synthesizes and transports proteins and lipids
• Golgi Apparatus (in eukaryotic cells)


  The stacked, flattened membranous sacs modify, sort, and package proteins and lipids
• Lysosomes (in eukaryotic cells)


  Small, spherical vesicles digest waste materials and cellular debris
• Chloroplasts (in plant eukaryotic cells)


  Green, oval structures containing chlorophyll conduct photosynthesis
• Vacuoles (in eukaryotic cells)


  Large central sac in plant cells, or smaller sacs in animal cells, store nutrients, waste products, and other materials