6.2-eukaryotic cells have internal membranes

• define cells

  basic structural & functional units of every organism
• what are the two distinct types of cells?

  prokaryotic + eukaryotic cells
• what organisms of the domains consists of prokaryotic cells?

  Bacteria and Archaea
• what organisms of the domain consist of eukaryotic cells?

  Protists, fungi, plants, and animals
• define protists for eukaryoticprotists

  informal terms referring to a diverse group of mostly unicellular eukaryotes
• what are the basic features of cells?

  plasma (cell) membrane, cytosol, chromosomes, and ribosomes
• what is the cell membrane?

  also known as plasma membrane, it is the selective barrier bounding around all cells
• what is the cytosol?

  semifluid, jellylike substance where subcellular components are suspended
• what are chromosomes?

  carry genes in the form of DNA
• what are ribosomes?

  tiny complexes that make proteins according to instructions from the genes.
• what is the MAJOR difference between prokaryotic and eukaryotic cells?

  location of their DNA
• where is most of the DNA in eukaryotic cells?

  an organelle called the nucleus (bounded by a double membrane)
• where is the DNA in a prokaryotic cell?

  concentrated in a region that is NOT membrane-enclosed, the nucleoid
• what does the greek term of eukaryotic mean?

  "true nucleus"
• the interior of either type of cell is called the cytoplasm
• where is the cytoplasm in eukaryotic cells?

  only to the region between the nucleus and the plasma membrane
• where are various organelles found in eukaryotic cells?

  Within the cytoplasm suspended in cytosol, are a variety of organelles of specialized form and function.
• are organelles found in prokaryotic cells? if not, what do they have instead?

  no: some prokaryotes contain regions surrounded by proteins (not membranes
• which cell is larger? the prokaryotic or eukaryotic?

  eukaryotic is much larger.
• Size is a general feature of cell structure that relates to function.
• The logistics of carrying out cellular metabolism sets limits on cell size.
• at the lower limit of cellular metabolism, what are the smallest cells known as?

  the bacteria called mycoplasma having diameters between 0.1 and 1.0 micrometers. they are the smallest packages with enough DNA to program metabolism and enough enzymes and other cellular equipment to carry out the activities necessary for a cell to sustain itself and reproduce.
• what is the typical bacteria size? what about eukaryotic cells?

  1-5 micrometers

  10-100 micrometers
• at the boundary of every cell, what does the plasma membrane do?

  Cell communication - functions as a selective barrier that allows passage of enough oxygen, nutrients, and wastes to service the entire cell
• why is the ratio of surface area to volume critical?

  for each square micrometer of membrane, only a limited amount of a particular substance can cross per second
• which cell size has a better ratio of surface area to volume?

  Smaller cells: a large surface area accommodates the volume
• larger organisms don't have larger cells than smaller organisms—they simply have more cells
• A sufficiently high ratio of surface area to volume is especially important in cells that exchange a lot of material with their surroundings, such as intestinal cells.
• a eukaryotic cell has extensive, elaborately arranged internal membranes that divide the cell into compartments—the organelles mentioned earlier.
• what do the cell compartments provide?

  different local environments that support specific metabolic functions, so incompatible processes can occur simultaneously in a single cell.
• what other parts in a cell also participate in cellular metabolism?

  plasma membrane and organelle membrane participate directly because many enzymes are built right into the membranes.
• what is the basic fabric of most biological membranes?

  Double-layer phospholipids and other lipids containing inside or on its surface diverse proteins