The Cell Study Guide Flashcards
What are the 3 tenets of cell theory?
- the cell is the basic unit of life
- all cells come from preexisting cells
- all organisms are made of cells
Do all your human cells look the same? Function the same? Contain the same genetic material?
No (over 250 diff types of human cells)
List 5 different types of cells in the human body. Think of an example where 1 of those cell types might have more of a particular type of organelle than the others because of it’s function.
- nerve cells
- sperm cells
- fat cells
- epithelial cells
- cardiac (muscle) cells (more mitochondria because it requires more energy production)
Be able to list the 3 types of extracellular material – and the 3 types of extracellular fluid!
Extracellular material:
- Extracellular fluid
- cellular secretions
- extracellular matrix
Extracellular fluid:
- interstitial fluid
- blood plasma
- cerebrospinal fluid
What is glycocalyx? What is its function?
- sugars (carbohydrates) sticking out of cell surface, sometimes attached to lipids or proteins
- functions as cell-to-cell recognition and allows immune system to tell if that cell is a friend or foe
- mutated cells evade immune system by changing their glycocalyx often
What type of lipid is most common in a plasma membrane?
phospholipids
Compare/contrast integral vs peripheral proteins.
Integral proteins:
- transport proteins (channels and carriers), enzymes, or receptors
Peripheral proteins
- loosely attached to integral proteins
- function as enzymes, motor proteins for shape change during motor contraction or cell division, cell-to-cell connections
What are the 3 types of cell junctions? What is the structure + function of each type? Give an example of where you might find each different type.
- tight junctions
- integral proteins on adjacent cells that do not allow fluids and most molecules to move in between cells
- found in lining of digestive tract - desmosomes
- anchoring junction that acts like velcro
- some give between cells to reduce possibility of tearing under tension
- found in heart and skin muscle - gap junctions
- transmembrane proteins form tunnels that allow small molecules to pass from cell-cell
- allow electrical signals to pass from one cell to the next
What does it mean to be “selectively permeable”?
some molecules pass through easily, some do not
What is the main difference in active vs passive transport?
active transport requires energy (ATP) while passive does not
What’s a concentration gradient? How do molecules typically move?
the difference in the concentrations
- molecules move down their concentration gradient
(from higher to lower concentration)
Define diffusion. Differentiate simple vs facilitated diffusion.
diffusion: movement of molecules through the plasma membrane to lower concentrations from higher ones
simple diffusion: movement of hydrophobic particles from high to low concentration without a protein
facilitated (active) diffusion: carrier or channel mediated
What’s the difference between carrier and channel media facilitated diffusion?
carrier mediated: substances bind to specific transmembrane protein carriers (saturation-binding limited by the # of carriers present)
channel-mediated: substances move through water-filled channels
Define osmosis, osmolarity, and equilibrium.
osmosis: diffusion of a solvent (often water) across a selectively permeable membrane by channel (aquaporin) or lipid bilayer 9occurs when concentration of water is different on 2 sides of membrane
- osmolarity: total concentration of all solute particles in a solution
Eqilibrium: state of same concentration of solute and water molecules on both sides (volume may or may not be equal)
Be ready to state what will happen to cells placed into hypotonic, hypertonic, and isotonic solutions.
Hypertonic: cell will shrivel
Hypotonic: cell will swell and possibly undergo lysis (explode)
Isotonic: cell will remain at normal size
