cell

• What is the fundamental unit of life?


  The cell
• How is cell structure related to cellular function?


  Cell structure is correlated to cellular function
• What do all organisms consist of?


  Cells
• What is the simplest collection of matter that can live?

  A cell
• How are all cells related?


  All cells are related by their descent from earlier cells
• What tools do biologists use to study cells?


  Microscopes and the tools of biochemistry
• Why are most cells not visible to the unaided eye?


  Most cells are too small to be seen by the unaided eye
• When was the first cell observed?


  In 1665
• What distinguishes eukaryotic cells from prokaryotic cells?


  Eukaryotic cells have internal membranes that compartmentalize their functions
• What types of cells do Bacteria and Archaea consist of?

  Prokaryotic cells
• Which organisms consist of eukaryotic cells?


  Protists, fungi, animals, and plants
• What are the basic features of all cells?

  • Plasma membrane
  • Semifluid substance called cytosol
  • Chromosomes (carry genes)
  • Ribosomes (make proteins)
• What characterizes prokaryotic cells?


  They have no nucleus and no membrane-bound organelles
• Where is DNA located in prokaryotic cells?


  In an unbound region called the nucleoid
• What is the size comparison between bacteria and eukaryotic cells?


  Bacteria are about 1/10th the size of a eukaryotic cell
• What is the typical diameter of eukaryotic cells?


  10–100 µm
• What is the function of the plasma membrane?


  It is a selective barrier that allows passage of substances
• What is the general structure of a biological membrane?


  A double layer of phospholipids
• What limits the size of cells?

  The logistics of carrying out cellular metabolism
• Why do small cells have a greater surface area relative to volume?


  As a cell grows, its volume increases more than its surface area
• What is the relationship between surface area and volume as cells grow?


  • Surface area increases by a factor of \( n^2 \)
  • Volume increases by a factor of \( n^3 \)
  • Larger cells have a lower surface area to volume ratio
• What do specialized cells and tissues do to optimize material transfer?


  They increase their surface area
• What are the main organelles found in a eukaryotic cell?

  • Endoplasmic reticulum (ER)
  • Golgi apparatus
  • Mitochondrion
  • Lysosome
  • Ribosomes
  • Nucleus
  • Plasma membrane
• What is the function of ribosomes in a cell?


  They carry out protein synthesis
• What is the role of the nucleus in a eukaryotic cell?


  It contains most of the DNA
• What is the nuclear envelope?


  It encloses the nucleus and separates it from the cytoplasm
• What is chromatin?


  DNA organized into discrete units called chromosomes
• What is the function of the nucleolus?


  It is the site of ribosomal RNA (rRNA) synthesis
• Where do ribosomes carry out protein synthesis?


  In the cytosol and on the endoplasmic reticulum
• What are the components of the endomembrane system?


  • Nuclear envelope
  • Endoplasmic reticulum
  • Golgi apparatus
  • Lysosomes
  • Vacuoles
  • Plasma membrane
• What is the function of the endoplasmic reticulum (ER)?


  It is involved in the synthesis and transport of proteins and lipids
• What are the two distinct regions of the endoplasmic reticulum?


  Smooth ER and Rough ER
• What is the function of Smooth ER?


  It synthesizes lipids and detoxifies drugs
• What is the function of Rough ER?


  It has bound ribosomes that secrete glycoproteins
• What is the Golgi apparatus composed of?


  Flattened membranous sacs called cisternae
• What are the functions of the Golgi apparatus?


  It modifies, sorts, and packages materials into transport vesicles
• What is a lysosome?


  A membranous sac of hydrolytic enzymes
• What is the function of lysosomes?


  They digest macromolecules and recycle organelles
• What is phagocytosis?


  It is the process by which cells engulf another cell
• What is the function of vacuoles in plant cells?


  They store food, water, or waste