Unit 2: cell structure and function

• Lysosomes


  Must maintain an acidic pH in order to dispose of cellular waste
• Peroxisomes


  Carry out chemical reactions caused by oxidation reactions & produce hydrogen peroxide both would damage the cell if they weren't "stored away"
• Ability to maintain different environments inside a single cell allows Eucaryonе cell to carry out complex metabolic reactions
• EUKARYOTIC CELLS HAVE (that prokaryotes don't)

  • Membrane-bound nucleus that houses genetic material
  • Multiple membrane-bound organelles
  • Multiple linear chromosomes as opposed to the single circular chromosome of prokaryol
• Endomembrane system


  Group of membranes & organelles in eukaryotic cells that work together to modify, package, & transport lipids & proteins
• Includes


  • Endoplasmic reticulum
  • Golgi apparatus
  • Nuclear envelope
  • Lysosomes
  • Plasma membrane
• Does not include


  • Mitochondria
  • Chloroplasts
  • Peroxisomes
• Endoplasmic reticulum


  • Synthesis of lipids
  • Plays an important role in the modification of proteins & the
• Endoplasmic reticulum


  • Consists of a network of membranous tubules & scattered sacs
  • Space inside sacs & tubules is called lumen
  • Rough ER has ribosomes that make proteins & feed the newly forming protein chains into the lumen
  • Modified proteins are packaged into vesicles & shipped to the Golgi apparatus
  • Rough ER also makes phospholipids
• the SMOOTH ER can . . .

  • synthesize carbs , lipids , & steroid hormones
  • detoxify medications & poisons
  • store calcium ions
• transitional ER - " smooth " patches on rough ER - exit sites for vesicles budding off from the rough ER
• Golgi apparatus - storing , tagging , packaging , & distribution of lipids & proteins
• Receiving side is called the cis face
• Opposite side is called the trans face
• in the GA , short chains of sugar molecules might be added or removed , phosphate

  groups attached as tags
• • A phospholipid is a lipid made of glycerol, two fatty acid tails, and a phosphate-linked head group.
• Phospholipid bi-layer is a bilayer of phospholipids with a hydrophilic head and a hydrophobic tail
• phospholipid bilayer: two layers of phospholipids with their tails pointing inward
• cholesterol is found in the core of the membrane
• 2 organelles that contain their own DNA separate from the chromosome

  mitochondria and chloroplast
• Plasma membrane 


  selective barrier that allows oxygen, nutrients, and wastes to service the volume of very cell
• ribosomes use the information from the DNA to

  proteins
• Diffusion through protein channels is known as what?

  facilitated diffusion
• site of ribosomal RNA synthesis

  nucleolus
• what happens to a cell plant when placed in pure water (hypertonic solution)?

  it becomes turgid, cell wall protects from bursting
• site of photosynthesis

  chloroplast
• these vacuoles pump excess water out of the cell

  contractile
• this ER lacks ribosomes

  Smooth ER
• what kind of amino acids will anchor proteins into the membrane?

  non-polar
• What is it called when cells are moving molecules against their concentration gradient, from an area of low concentration to an area of high concentration? What does it require to do this?

  • Active transport requires ATP
• site of cellular respiration

  mitochondria
• these types of vacuoles are formed by phagocytosis

  food
• the logistics of carrying out cellular metabolism set a limit on the size of cells. The ____ to ____ ratio of a cell is critical.

  surface area to volume
• both animals and plants have ____ that allow molecules to pass readily across adjacent cells without crossing the plasma membrane

  cell junctions
• what are the 3 main types of membrane receptors?

  • G-protein linked
  • tryosine kinase
  • ion channel
• oxidative organelles

  peroxisomes
• What happens when you put a red blood cell in pure water (hypotonic solution)? why?

  the cell will burst because water rushes into the cell
• The ____ is continuous with the nuclear membrane

  ER membrane
• which part of the phospholipid layer is considered hydrophobic?

  fatty acid tail
• Which part of the phospholipid bilayer is considered hydrophilic?

  phosphate head