Topic 3-Cell structure

• What are the three main parts of a cell?

  Plasma membrane, cytoplasm, nucleus
• How many cells does the body of an average human adult contain?


  Nearly 100 trillion cells
• What is the diameter of the largest cell, a single oocyte?


  About 140 μm
• What is the diameter of a red blood cell?


  8 μm
• How does a cell's shape relate to its function in the body?


  A cell's shape is related to its specific function in the body
• Who first discovered the cell and in what year?

  Robert Hooke in 1665
• What did Robert Hooke observe to discover cells?


  Thin sections of dried cork from plants
• Who described the physical phenomenon of Brownian motion?

  Robert Brown
• What is the first cell theory credited to?

  The work of Theodor Schwann and Matthias Jakob Schleiden in the 1830s
• What does the first cell theory state about cells?


  The cell is the unit of structure, physiology, and organization in living things
• What does modern cell theory state about all known living things?


  All known living things are made up of cells
• What is cytology?


  A branch of biology that studies the structure and function of cells
• What types of microscopy are used to study cell structures?


  Light and electron microscopy
• What is the resolution limit of light microscopy?


  ~200 nm
• What is the maximum magnification of light microscopy?


  x 1000 magnification
• What are the best specimens for light microscopy?


  Stained or naturally pigmented specimens
• What is the main advantage of electron microscopy?


  It can magnify an object up to 500,000 times
• What does a scanning electron microscope (SEM) allow you to see?


  A cell’s three-dimensional shape
• What does a transmission electron microscope (TEM) allow you to see?


  The structures inside a cell
• How do prokaryotic cells differ from eukaryotic cells?


  Prokaryotic cells lack membrane-bound organelles and have a single circular DNA molecule
• What is the function of the cell wall in prokaryotic cells?


  It provides structural support and protection
• What is a plasmid?


  A small circle of additional DNA in bacteria
• What is the role of flagella in prokaryotic cells?


  They enable movement
• What is conjugation in bacteria?


  A process where plasmids are transferred from one cell to another
• What is transformation in bacteria?


  A process where DNA is taken up from the environment by other cells
• What is transduction in bacteria?


  A process where viruses transfer DNA between bacterial cells
• What is the significance of the human microbiome?


  It consists of various bacteria that inhabit different parts of the body
• What distinguishes eukaryotic cells from prokaryotic cells?


  Eukaryotic cells have membrane-bound organelles and a nucleus
• What organelles are present in plant cells but not in animal cells?


  Chloroplasts, cell wall, and central vacuole
• What is the function of chloroplasts in plant cells?


  They are involved in photosynthesis
• What is the role of the central vacuole in plant cells?


  It helps regulate water concentration and contributes to cell expansion
• What is the function of the cytoskeleton?


  It provides structural support and enables cell shape changes
• What is the role of the nuclear membrane in eukaryotic cells?


  It separates transcription and translation processes
• What is endocytosis?


  A process where materials are transported into the cell
• What is exocytosis?


  A process where materials are released from the cell
• What is the endomembrane system in eukaryotic cells?


  • Consists of internal membranes and organelles
  • Modifies, packages, and transports lipids and proteins
  • Includes nuclear envelope, lysosomes, vesicles, endoplasmic reticulum, Golgi apparatus, and plasma membrane
• What do lysosomes contain and what is their function?


  Lysosomes contain digestive enzymes that break down large biomolecules
• What are peroxisomes and their function?


  Peroxisomes are organelles that break down fatty acids and detoxify poisons
• What are the differences between lysosomes, peroxisomes, and proteasomes?

  • Lysosomes: contain digestive enzymes for breaking down biomolecules
  • Peroxisomes: contain oxidases for breaking down fatty acids and detoxifying poisons
  • Proteasomes: destroy unneeded, damaged, or faulty proteins
• What is the rough endoplasmic reticulum (RER)?


  RER is a network of membranes studded with ribosomes that synthesizes proteins