BS 161 MSU Exam 2 questions with answers.

BS 161 MSU Exam 2 questions with
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answers

Identify the molecules that comprise a lipid - CORRECT ANSWERS
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✔✔Carbon, Hydrogen, Oxygen, Glycerol
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Explain the molecular difference between saturated and
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unsaturated fats - CORRECT ANSWERS ✔✔Saturated fats are |\ |\ |\ |\ |\ |\ |\ |\


solid, have the maximum number of Hydrogen molecules, and no
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double bonds where as Unsaturated fats are liquid at room temp,
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have less than the max number of Hydrogen molecules, and
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contain double bonds |\ |\




Explain why, based on their properties, phospholipids
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spontaneously form a lipid bilayer - CORRECT ANSWERS |\ |\ |\ |\ |\ |\ |\ |\


✔✔Because of their polar hydrophilic heads (which go towards
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outside) and non-polar hydrophobic tails(more interior): they are
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amphipathic


Predict how changes in lipid structure related to the degree of
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saturation and polarity will impact their behavior in biological
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systems - CORRECT ANSWERS ✔✔Increasing amount of double
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bonds (degree of unsaturation) increases the fluidity of the
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membrane because more double bonds means more unsaturated
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and ability to flow
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Increasing the amount of fatty acid saturation decreases the
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fluidity of the membrane |\ |\ |\

,Increasing the temperature increases the likelihood for the
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membrane to flow |\ |\




Describe the fluid mosaic model of a membrane structure -
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CORRECT ANSWERS ✔✔a membrane is a fluid structure with a
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"mosaic" of various proteins embedded in it
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Explain how membrane fluidity is influenced by temperature and
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membrane composition - CORRECT ANSWERS ✔✔The higher the |\ |\ |\ |\ |\ |\ |\ |\


temp the more fluid |\ |\ |\




Explain how cholesterol resists changes in membrane fluidity as
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temps change - CORRECT ANSWERS ✔✔As the temperatures rise
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cholesterol restrains movement, as it lowers it maintains fluidity
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At moderate temps it reduces fluidity by reducing movement at
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low temps it hinders solidification by disrupting regular packing
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of phospholipids
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Integral vs Peripheral Proteins - CORRECT ANSWERS ✔✔Integral
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proteins penetrate the hydrophobic core where as Peripheral bind
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to the surface of the membrane
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The six roles of membrane proteins - CORRECT ANSWERS
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✔✔transporter, enzyme, cell-surface receptor, identity marker, |\ |\ |\ |\ |\ |\


cell-to-cell adhesion, cytoskeleton anchor |\ |\ |\




Explain the role of membrane carbohydrates in cell-cell
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recognition - CORRECT ANSWERS ✔✔The ability of a cell to |\ |\ |\ |\ |\ |\ |\ |\ |\ |\


distinguish other cells based on recognition of membrane |\ |\ |\ |\ |\ |\ |\ |\

, carbohydrates. The glycolipids and glycoproteins attached to the |\ |\ |\ |\ |\ |\ |\ |\


outside of plasma membranes varies.
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Explain how the polarity of a molecule affects how it moved
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across a membrane - CORRECT ANSWERS ✔✔Non polar,
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hydrophobic molecules pass through more easily and vise versa
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bc they are being pulled by non-polar tails
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easiest 1.hydrophobic molecules
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2. small, uncharged polar molecules
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3.large uncharged polar molecules
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hardest 4. ions (charged molecules)
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Distinguish between channel proteins and carrier proteins -
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CORRECT ANSWERS ✔✔channel proteins only transport
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substances through membranes passively, career proteins can
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transport ions and molecules either passively through diffusion or
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actively
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Explain how aquaporins facilitate the passage of water through
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membranes - CORRECT ANSWERS ✔✔Aquaporins allow the |\ |\ |\ |\ |\ |\ |\


transfer of water across a membrane 10x faster bc they have
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polar regions of functional groups that interact with water
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Define diffusion - CORRECT ANSWERS ✔✔the tendency for
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molecules to spread out evenly into the available space
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