cell ultra structure

• What are the two main types of cells discussed in the study material?

  Prokaryotes and eukaryotes
• What distinguishes eukaryotes from prokaryotes?

  Eukaryotes have a true nucleus and membrane-bound organelles
• What is the term used for the region where DNA is located in prokaryotes?

  Nucleoid
• What is an organelle?

  An organelle is a structure found within a cell that performs a specific function
• What is the composition of the cell wall in prokaryotes?

  The cell wall is made of peptidoglycan
• How do the ribosomes in prokaryotes compare to those in eukaryotes?

  Prokaryotes have smaller ribosomes (18 nm) than eukaryotes
• What is the structure of DNA in prokaryotes?

  DNA is in a single loop called a circular or bacterial chromosome
• What are plasmids in prokaryotes?

  Plasmids are smaller loops of DNA that carry additional genes
• Where does ATP production occur in prokaryotes?

  ATP production occurs in infolded parts of the membrane called mesosomes
• What is the function of flagella in some prokaryotic species?

  Flagella aid in movement
• What is the role of the plasma membrane in animal cells?

  The plasma membrane defines the cell's perimeter and controls what enters and leaves the cell
• What additional structures do plant cells have compared to animal cells?

  Plant cells have a cellulose cell wall, large vacuoles, and chloroplasts
• What is the function of the nucleus in eukaryotic cells?

  The nucleus contains all genetic information in the form of DNA
• What is the structure of the endoplasmic reticulum (ER)?

  The ER is a series of folded membranes that form interconnected sacs or tubes called cisternae
• What is the difference between rough ER and smooth ER?

  Rough ER has ribosomes attached and is involved in protein synthesis, while smooth ER is the site of lipid synthesis
• What is the primary function of ribosomes?

  Ribosomes are the site of protein synthesis in cells
• How do mitochondria contribute to cellular function?

  Mitochondria are the site of respiration where ATP is produced
• What is the structure of lysosomes?

  Lysosomes are spherical sacs bounded by a single membrane
• What is the role of lysosomes in cells?

  Lysosomes contain digestive enzymes for intracellular digestion and help destroy worn-out organelles
• What is the function of centrioles during cell division?

  Centrioles migrate to opposite ends of the cell to form spindle fibers that pull chromosomes to the poles

  
• What is the structure of cilia and undulipodia?

  Both have microtubules arranged in pairs in a 9+2 pattern
• What is the function of the cell wall in plant cells?

  The cell wall provides strength and support and allows water and dissolved molecules to pass through
• What is the role of chloroplasts in plant cells?

  Chloroplasts contain chlorophyll and absorb light energy for photosynthesis
• What is the difference between vesicles and vacuoles?

  Vesicles are small membrane-bound sacs used for transport, while vacuoles are larger and maintain turgor in plant cells
• What are the main features of prokaryotic cells?

  • No nucleus (nucleoid instead)
  • Only one membrane (cell surface)
  • No membrane-bound organelles
  • Cell wall made of peptidoglycan
  • Smaller ribosomes (18 nm)
  • Circular DNA (bacterial chromosome)
  • Naked DNA (not associated with histones)
  • Plasmids carry additional genes
  • ATP production in mesosomes
  • Some have flagella for movement

  
• What are the main organelles found in eukaryotic cells?

  • Nucleus
  • Mitochondria
  • Ribosomes
  • Endoplasmic reticulum (RER and SER)
  • Golgi apparatus
  • Lysosomes
  • Centrioles
  • Cilia and undulipodia
  • Plasma membrane
  • Cell wall (in plants)
  • Chloroplasts (in plants)
  • Vacuoles (in plants)

  
• What are the functions of the Golgi apparatus?

  • Processes proteins made within the cell
  • Packages proteins into excretion vesicles
  • Distributes proteins to various locations
  • Involved in secretion of hormones, enzymes, antibodies, etc.

  
• What are the functions of lysosomes?

  • Intracellular digestion of food materials
  • Help white blood cells destroy bacteria
  • Destroy worn-out organelles
  • Self-destruction of cells (apoptosis)

  
• What are the functions of the cytoskeleton?

  • Provides support and strength to the cell
  • Facilitates transport within the cell
  • Composed of microtubules and microfilaments
• What are the components of the nucleus?

  • Largest organelle
  • Contains genetic information (DNA)
  • Nucleolus for ribosome and RNA production
  • Nuclear envelope with pores for material exchange
• What are the roles of chloroplasts in plant cells?

  • Absorb light energy for photosynthesis
  • Contain chlorophyll and accessory pigments
  • Double membrane structure
  • Grana (thylakoid stacks) and stroma (fluid with enzymes)

  
• What are the roles of vacuoles in plant cells?

  • Store food, water, or waste materials
  • Maintain turgor for support
  • Large and permanent in plant cells
  • Surrounding membrane called tonoplast

  
• What are the roles of vesicles in cells?


  • Small membrane-bound sacs
  • Used for transport within cells
• What are the differences between cilia and undulipodia?

  • Cilia: short, many per cell, found in respiratory tract
  • Undulipodia: long, few per cell
  • Both allow movement and have a similar microtubule structure