Biology 151 Exam II SDSU Questions And Answers

plasma membrane has selective permeability. what does that mean? - ANS The membrane can "choose" what goes in and out of the cell Phospholipids are amphipathic molecules. what does that mean to be amphipathic? - ANS it means they have a hydrophilic and hydrophobic region What is a fluid mosaic model? - ANS where the membrane is a mosaic of protein molecules bobbing in a fluid bilayer of phospholipids. proteins can move laterally across the membrane What are the 2 proteins in membranes - ANS Integral and peripherial What is an integral protein? - ANS penetrate the hydrophobic interior of the lipid bilayer what is a peripheral protein? - ANS not embedded in the lipid bilayer at all. they are loosely bound to the surface of the membrane What are the six major functions of membrane proteins? - ANS Transport, enzymatic activity, attach to cytoskeleton, cell-cell recognition, intercellular joining, signal transduction what are cell markers? - ANS if other cells dont have correct markers, the immune system (white blood cells) will attack What are glycolipids? - ANS membrane carbohydrates bond to lipids which form What are glycoproteins? - ANS membrane carbohydrates bond to proteins what are transport proteins? - ANS hydrophilic substances can avoid contact with the lipid bilayer by passing through transport proteins what are channel proteins? - ANS transport proteins have a hydrophilic channel that certain molecules or atomic ions use as a tunnel through the membrane What is diffusion? - ANS the tendency for molecules to spread out evenly into available space Molecules in diffusion move from ________ to ______ concentration - ANS high to low - they move down the concentration gradient until equilibrium What is passive transport? - ANS Diffusion of a substance across the membrane does not require energy to make it happen What is osmosis? - ANS water molecules from high to low concentration What do aquaporins do? - ANS speed up osmosis by opening channels What is tonicity? - ANS ability for a surrounding solution to gain or lose water What is isotonic? - ANS solute concentration is the same as the inside of the cell. no water movement across the plasma membrane What is hypertonic? - ANS solute concentration is greater than inside of the cell What is hypotonic? - ANS solute concentration is less concentrated than the inside of the cell What is osmoregulation? - ANS control of water and solute balance What is membrane potential? - ANS voltage across the membrane... difference in the charges what is an electrogenic pump? - ANS produces charges across the membrane What does phagocytosis mean? - ANS cellular eating What does pinocytosis mean? - ANS cellular drinking What is reception during the 3 stages of cell signal? - ANS the target cell's detection of a signal molecule coming from outside the cell What is transduction? - ANS a step or series of steps that converts the signal to a form that can bring about a specific cellular response What does the cell signalling process help? - ANS It helps ensure that crucial activities like these occur in the right cells, at the right time. What does the response phase do in the cell signalling stages? - ANS Basically activates the cell to perform activities The continuity of life is based off of what? - ANS cell reproduction or cell division Most cell division results in distribution of identical genetic information which then produces what? - ANS 2 daughter cells the dna in a cell is called what - ANS the cells genome DNA molecules in the cell are packaged into _______? - ANS chromosomes What is chromatin made up of? - ANS DNA & Protein How many chromosomes do we have? how many pairs? - ANS 46 chromosomes, 23 pairs What are somatic cells? - ANS nonreproductive cells - Have 2 sets of chromosomes What are gametes? - ANS reproductive cells - have only 1 set of chromosomes What do chromosomes look like? - ANS what do sister chromatids look like? - ANS How many chromatids are there for 2 chromosomes? - ANS 4 sister chromatids what is a centromere? - ANS Where the two chromatids are most closely attached Whats mitosis? - ANS the division of the genetic material in the nucleus What is Cytokinesis? - ANS the division of cytoplasm What is included in the Mitotic (M) Phase?? - ANS mitosis and cytokinesis What is interphase? - ANS includes cell growth and copying of chromosomes in preparation for cell division What is the G1 Phase also called? - ANS First gap What is the S phase also known as? A shorter name or something? - ANS Synthesis What is G2 Phase also known as? - ANS Second gap What is the acronym for Mitosis - ANS PpMAT What is the correct order of mitosis from beginning to end? - ANS Prophase , prometaphase, metaphase, anaphase, telophase What is the mitotic spindle? - ANS a structure made of microtubules and associated proteins In animal cells, assembly of spindle microtubules begins in the ____________ , the microtubule organizing center - ANS centrosome what is an aster? - ANS radial array of short microtubules - they extend from each centrosome What are kinetochores? - ANS protein complexes that assemble on sections of DNA at centromeres