BIOLOGY 123 WEEK 3 EXAM
QUESTIONS AND ANSWERS
The plasma membrane is a phospholipid bilayer with embedded proteins - Correct
Answers -The plasma membrane is a fluid phospholipid bilayer.
A phospholipid molecule has a polar head, which is hydrophilic, and nonpolar tails,
which are
hydrophobic.
Fluid-mosaic model
Proteins embedded in the membrane have a pattern,
which varies.
Cholesterol reduces fluidity and permeability.
Glycolipids and glycoproteins bear
carbohydrate chains on the outer surface.
The plasma membranes of different cells - Correct Answers -organelles have specific
proteins:
Channel proteins
Carrier proteins
Cell recognition proteins
Receptor proteins
Enzymatic proteins
Junction proteins
Diffusion - Correct Answers -A molecule moves from a high concentration to a low
concentration until it is distributed equally.
Concentration gradient
Passive form of transport
Very few molecules can simply diffuse through the
hydrophobic portion of the plasma membrane
3 light dependent reactions - Correct Answers -• Photosystem I...cyclic
photophosphorylation
• Photosystem II...noncyclic
photophosphorylation
• photolysis
,Photosystems Capture Solar Power - Correct Answers -• In thylakoid, chlorophylls and
other pigments organized into photosystems
• Photosystem: pigments surrounding a reaction center chlorophylls
• When pigment absorbs photon, e- gets excited
• Pigments absorb energy, transfer that energy to neighboring pigments
• Eventually, energy transferred to reaction center chlorophyll - electron gets excited
• Reaction center chlorophyll passes the e- Primary Electron Acceptor
Chemiosmosis Powers ATP Synthesis in the Light Reactions - Correct Answers -• ETC
sets up proton (H+) gradient
• Gradient used to phosphorylate ATP (photophosphorylation)
• H+ gradient accumulates in thylakoid space (inner most part of chloroplast)
• ATP produced in stroma
Facilitated diffusion - Correct Answers -Requires a transporter but no energy
Carrier protein or channel protein
Transporter is specific
Osmosis - Correct Answers -is diffusion of water across the plasma
membrane due to concentration differences.
Which way the water moves is dependent on the
solute versus water concentration on both sides of the
membrane.
Isotonic solution - cell neither gains or loses water
Hypotonic solution - cell gains water
Hemolysis
Turgor pressure
Hypertonic solution - cell loses water
Plasmolysis
Active transport - Correct Answers -Molecules or ions move across the plasma
membrane, accumulating on one side of the cell.
Movement of molecules against their concentration
gradients requires both a carrier protein and ATP.
The sodium-potassium pump undergoes a change
in shape when it combines with ATP, allowing it to
combine alternately with sodium ions and potassium
ions.
Bulk transport - Correct Answers -occurs when fluid or particles
are brought:
Into a cell by vacuole formation - endocytosis
Out of a cell by evagination - exocytosis
Phagocytosis occurs when the material taken in is
, large.
Pinocytosis occurs when vesicles form around a
liquid or around very small particles.
In receptor-mediated endocytosis, receptors for
particular substances are found in the plasma
membrane.
Malfunctioning plasma membrane proteins - Correct Answers -Diabetes Type 2 - Insulin
binds to receptor protein, but
the number of carriers sent to the plasma membrane is
not enough
Too much glucose in the blood results in spillover into the urine.
Color Blindness - Usually three types of photopigment
proteins in plasma membrane within photoreceptor cells
Some people lack functional red or green photopigment.
Cystic Fibrosis (CF) - Unregulated passage of chloride
ions through a plasma membrane channel protein
Thick mucus appears in the lungs and pancreas, damaging the
lungs and contributing to an early death.
Plant cells - Correct Answers -All plant cells
have primary
cells walls.
Living plant cells
are connected by
plasmodesmata.
Animal cells - Correct Answers -Anchoring junction - in tissues that stretch
Tight junction - zipper-like
Gap junctions - strength and coordination
Extracellular matrix (ECM)
Varies from flexible to rock solid
Fibers and glycoproteins
HOW LIFE CHANGES
5B Evolution of the Plasma Membrane - Correct Answers -Plasma membrane must
have arisen early in the
evolution of life.
Similar in bacteria and eukaryotic cells
Serves as a barrier while still allowing transport
Phospholipid component forms a boundary.
Evolution of multicellular organisms would have
been impossible without extracellular material.
Energy - Correct Answers -Energy is needed to maintain order in living
QUESTIONS AND ANSWERS
The plasma membrane is a phospholipid bilayer with embedded proteins - Correct
Answers -The plasma membrane is a fluid phospholipid bilayer.
A phospholipid molecule has a polar head, which is hydrophilic, and nonpolar tails,
which are
hydrophobic.
Fluid-mosaic model
Proteins embedded in the membrane have a pattern,
which varies.
Cholesterol reduces fluidity and permeability.
Glycolipids and glycoproteins bear
carbohydrate chains on the outer surface.
The plasma membranes of different cells - Correct Answers -organelles have specific
proteins:
Channel proteins
Carrier proteins
Cell recognition proteins
Receptor proteins
Enzymatic proteins
Junction proteins
Diffusion - Correct Answers -A molecule moves from a high concentration to a low
concentration until it is distributed equally.
Concentration gradient
Passive form of transport
Very few molecules can simply diffuse through the
hydrophobic portion of the plasma membrane
3 light dependent reactions - Correct Answers -• Photosystem I...cyclic
photophosphorylation
• Photosystem II...noncyclic
photophosphorylation
• photolysis
,Photosystems Capture Solar Power - Correct Answers -• In thylakoid, chlorophylls and
other pigments organized into photosystems
• Photosystem: pigments surrounding a reaction center chlorophylls
• When pigment absorbs photon, e- gets excited
• Pigments absorb energy, transfer that energy to neighboring pigments
• Eventually, energy transferred to reaction center chlorophyll - electron gets excited
• Reaction center chlorophyll passes the e- Primary Electron Acceptor
Chemiosmosis Powers ATP Synthesis in the Light Reactions - Correct Answers -• ETC
sets up proton (H+) gradient
• Gradient used to phosphorylate ATP (photophosphorylation)
• H+ gradient accumulates in thylakoid space (inner most part of chloroplast)
• ATP produced in stroma
Facilitated diffusion - Correct Answers -Requires a transporter but no energy
Carrier protein or channel protein
Transporter is specific
Osmosis - Correct Answers -is diffusion of water across the plasma
membrane due to concentration differences.
Which way the water moves is dependent on the
solute versus water concentration on both sides of the
membrane.
Isotonic solution - cell neither gains or loses water
Hypotonic solution - cell gains water
Hemolysis
Turgor pressure
Hypertonic solution - cell loses water
Plasmolysis
Active transport - Correct Answers -Molecules or ions move across the plasma
membrane, accumulating on one side of the cell.
Movement of molecules against their concentration
gradients requires both a carrier protein and ATP.
The sodium-potassium pump undergoes a change
in shape when it combines with ATP, allowing it to
combine alternately with sodium ions and potassium
ions.
Bulk transport - Correct Answers -occurs when fluid or particles
are brought:
Into a cell by vacuole formation - endocytosis
Out of a cell by evagination - exocytosis
Phagocytosis occurs when the material taken in is
, large.
Pinocytosis occurs when vesicles form around a
liquid or around very small particles.
In receptor-mediated endocytosis, receptors for
particular substances are found in the plasma
membrane.
Malfunctioning plasma membrane proteins - Correct Answers -Diabetes Type 2 - Insulin
binds to receptor protein, but
the number of carriers sent to the plasma membrane is
not enough
Too much glucose in the blood results in spillover into the urine.
Color Blindness - Usually three types of photopigment
proteins in plasma membrane within photoreceptor cells
Some people lack functional red or green photopigment.
Cystic Fibrosis (CF) - Unregulated passage of chloride
ions through a plasma membrane channel protein
Thick mucus appears in the lungs and pancreas, damaging the
lungs and contributing to an early death.
Plant cells - Correct Answers -All plant cells
have primary
cells walls.
Living plant cells
are connected by
plasmodesmata.
Animal cells - Correct Answers -Anchoring junction - in tissues that stretch
Tight junction - zipper-like
Gap junctions - strength and coordination
Extracellular matrix (ECM)
Varies from flexible to rock solid
Fibers and glycoproteins
HOW LIFE CHANGES
5B Evolution of the Plasma Membrane - Correct Answers -Plasma membrane must
have arisen early in the
evolution of life.
Similar in bacteria and eukaryotic cells
Serves as a barrier while still allowing transport
Phospholipid component forms a boundary.
Evolution of multicellular organisms would have
been impossible without extracellular material.
Energy - Correct Answers -Energy is needed to maintain order in living
