Docsity
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Docsity AI
Docsity AI
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search for your university

Find the specific documents for your university's exams

Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

Bioc 3560 - Final Exam questions latest upload, Exams of Advanced Education

Cheyney University of PennsylvaniaAdvanced Education

Bioc 3560 - Final Exam questions latest upload

Typology: Exams

2025/2026

Available from 07/02/2026

tizian-mwangi
tizian-mwangi 🇺🇸

4.1

(8)

29K documents

1 / 28

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
1 / 28
BIOC 3560 - FINAL EXAM QUESTIONS
LATEST UPLOAD
1.
Some
biological
membrane
examples?
(2):
plasma and
organelle
2.
Functions of cellular membranes? (4): 1) permeability
barrier/compartmentalization
2)
communication
-
action
potentials
3)
energy
conversion
-
inner
mito
membrane
4)
surface
recognition
-
A,B,O
blood
3. Composition of typical plasma membrane? (3 percentages): 45%
=
lipid (long acyl
chains+polar head groups)
50% = protein
5% = carbohydrate
4. Membrane lipids are
:
amphipathic
(hydrophobic
and
hydrophilic)
5. Components of membrane lipids? (3): 1)
phospholipids
2)
glycolipids
3)
cholesterol
6.
What
is
a
phospholipid?:
polar
"head"
group
joined
by
phosphodiester
link
7.
Types of phospholipids? (2): 1) Phosphoglycerides
(glycerophospholipids)
2) sphingolipids (named after the Sphinx)
8. What makes up phosphoglycerides?: -
backbone=glycerol
-2
fatty
acids
in
ester
link
-head group derived from alcohol
-CHARGED
and
HYDROPHOBIC
pf3
pf4
pf5
pf8
pf9
pfa
pfd
pfe
pff
pf12
pf13
pf14
pf15
pf16
pf17
pf18
pf19
pf1a
pf1b
pf1c

Partial preview of the text

Download Bioc 3560 - Final Exam questions latest upload and more Exams Advanced Education in PDF only on Docsity!

1 / 28

BIOC 3560 - FINAL EXAM QUESTIONS

LATEST UPLOAD

  1. Some biological membrane examples? (2): plasma and organelle
  2. Functions of cellular membranes? (4): 1) permeability barrier/compartmentalization
  1. communication - action potentials
  2. energy conversion - inner mito membrane
  3. surface recognition - A,B,O blood
  1. Composition of typical plasma membrane? (3 percentages): 45% = lipid (long acyl chains+polar head groups) 50% = protein 5% = carbohydrate
  2. Membrane lipids are : amphipathic (hydrophobic and hydrophilic)
  3. Components of membrane lipids? (3): 1) phospholipids
  1. glycolipids
  2. cholesterol
  1. What is a phospholipid?: polar "head" group joined by phosphodiester link
  2. Types of phospholipids? (2): 1) Phosphoglycerides (glycerophospholipids)
  1. sphingolipids (named after the Sphinx)
  1. What makes up phosphoglycerides?: - backbone=glycerol -2 fatty acids in ester link -head group derived from alcohol -CHARGED and HYDROPHOBIC

2 / 28

  1. What makes up sphingolipids?: - backbone=sphingosine -1 fatty acid in amide link -head group=choline (sphingomyelin)
  2. What makes up glycolipids?: - backbone=sphingosine -1 fatty acid in amide link -carbohydrate "head" group
  3. Cholesterol head group? Nucleus? Side chain?: -major animal cell sterol -planar fused rings + alkyl side chain + OH (polar head group) + steroid nucleus -FLAT, PLANAR, mostly HYDROPHOBIC (fixed rings=stability)
  4. What are storage lipids?: triacylglycerols (neutral)
  5. How do glycerophospholipids gain membrane fluidity?: C=C always cis (kinked)
  6. Sphingolipids are similar in shape to : glycerolipids
  7. are part of the ABO blood type system: glycosphingolipids
  8. Cholesterol is a precursor for : steroid hormones
  9. Chemical properties/forms of lipids in membranes? (3): 1) monolayers
  1. micelles
  2. bilayers/liposomes
  1. What are monolayers?: -are at air-water interface formed by many types of lipids -air is hydrophobic (NP), interacts with hydrophobic acyl chains
  2. What are micelles?: detergents and lipids with one acyl "tail"
  3. What are bilayers/liposomes?: -non polar tails associate in interior

4 / 28 -electrostatic interactions + hydrogen bonds

  1. Annexin is an example of?: adhesion protein
  2. C14 FA function?: signalling for apoptosis
  3. What makes up transmembrane domain? What do they interact with?: -alpha helix -hydrophobic amino acids -interacts with fatty acyl chains
  4. If pH change or chelator removes a membrane protein = : peripheral protein
  5. If detergent or phospholipase removes a membrane protein = : integral protein
  6. What does a chelator do?: removes Ca2+ (which would remove protein)
  7. What is a Hydropathy plot?: -allows for the visualization of hydrophobicity over the length of a peptide sequence -a hydropathy scale which is based on the hydrophobic and hydrophilic properties of the 20 amino acids is used
  8. Example of single-spanning membrane protein?: -glycophorin A -sugars on RBCs keeps them from sticking to capillaries
  9. Example of multi-spanning membrane protein?: - bacterioriorhodopsin -7 transmembrane segments
  10. What do outer membrane proteins do?: (OMP) bind bacteria to our cells
  11. What amino acids at interface in membrane proteins?: Trp and Tyr (polar and NP)

5 / 28

  1. Parts of glycoproteins? (3): 1) N-linked carbohydrate chain
  1. O-linked carbohydrate chain
  2. Sugar groups
  1. Components of N-linked carbohydrate chains?: -Asn side chain (- CO-NH2) -N-acetylglucosamine (GlcNAc)
  2. Components of O-linked carbohydrate chains?: -Ser of The side chain (-OH) -N-acetylgalactosamine (GalNAc)
  3. What do sugar groups of glycoproteins and glycolipids do? (2):
  1. contribute to cell surface recognition
  2. function as receptors
  1. Ways fluid mosaic model shows movement? (2): 1) lateral movement (fast
  • within plane of membrane, 2D)
  1. flipping/flopping/scrambling (slow - needs enzymes)
  1. Membranes change shape without loss of or becoming : integrity, leaky
  2. Membrane dynamics states? (2): 1) Gel Phase
  1. "Liquid" states
  1. What is the gel phase?: motion of bilayer is constrained in a paracrystalline state
  2. What are the liquid states? (2): 1) Liquid-ordered state
  1. Liquid-disordered state (fluid state)
  1. What is the liquid-ordered state?: -intermediate thermal motion of acyl chains and atoms -lateral movement in the plane of the bilayer is allowed

7 / 28

  1. Types of "flipping/flopping/scrambling" translation movements + times? (3): 1) Uncatalyzed transbilayer ("flip-flop") dittusion
      • -very slow (t1/2=days)
  1. Uncatalyzed lateral dittusion
      • -very fast (t1/2=1 μm/s)
  1. Catalyzed transbilayer translocations
      • -unfavorable, needs enzyme
  1. Family of enzymes that facilitates catalyzed transbilayer translocations? (3): 1) Flippase
  1. Floppase
  2. Scramblase (Flip it In, Flop it Out)
  1. What is single particle tracking?: follow a single lipid molecule on a short time scale (sec)
  2. What does single particle tracking show?: -that lipids generally stay within one region and do not leave that region -some proteins are floating around unrestricted in a seas of lipid, others aggregate in patches
  3. Importance of lipid rafts?: ~500A across, up to 50% of membranes, more solid like than regular membrane, can sequester important signalling complexes
  4. Intracellular membrane traffic points (3): -reorganization of membrane- bound compart-ments at synapse -exchange of membrane and "cargo" between compartments (neurotransmitter release)

8 / 28 -internalization/recycling/degradation of material from plasma membrane (Glut4 transporters, endocytosis in diges-tion, antigen recognition)

  1. The complex, multi-stage process of intracellular membrane traffic? (5): 1) budding (fission of vesicles)
  1. transport
  2. tethering/docking at target membrane
  3. priming
  4. fusion (of vesicle and target membranes)
  1. What do caveolae do?: (mini-caves) put curvature into membranes and SNARE proteins help pinch ott caveolae
  2. What are SNARES?: -Soluble N-ethylmaleimide-sensitive factor Attachment protein Receptor -membrane associated proteins -contain 1 or 2 coiled-coil domain(s) (helical domains--approx 60AA-- that interact to form coiled-coil structures)
  3. SNARES regulate membrane fusion during ...? (5): 1) transport between ER and Golgi
  1. insulin secretion
  2. up-regulation of glucose transporters
  3. phagocytosis
  4. neurotransmitter release
  1. What is exocytosis?: a process by which the contents of a cell vacuole are released to the exterior through fusion of the vacuole membrane with the cell membrane
  2. Why does membrane have hydrophobic core?: -prevent charged, polar compounds from entering cells -NP compounds can cross membrane
  3. Why can aspirin be absorbed into the stomach?: enters at low pH, enters as neutral, becomes negative at high pH

10 / 28

  1. Primary active transporter =
  2. Secondary active transport =
  3. ion channel =: 1) drugs
  4. glucose RBS and liver
  5. Ca pumps
  6. Pi pump into mito
  7. K+ valinomycin
  1. Solute transport types across membranes? (2): 1) simple dittusion
  1. transport of hydrophilic solutes
  1. Logic behind simple diffusion: -free energy of solution (ΔG= ΔGo+RTln[c])
  • ΔG when molecule moves from c1 (high) to c2 (low)-- ΔG=RTln[c2]-RTln[c1]=RTln[c2/c1] -if c1>c2, ln(c2/c1) is negative and ΔG is negative -dittusion occurs spontaneously from high to low concentration -c1=c2 at equilibrium -this energy is needed to maintain chemical gradient
  1. Why is transport of hydrophilic solutes slow without transporter? What must be broken?: very few solutes have enough energy to get over the activation barrier; must break solvent-solute bonds
  2. Ways of transporting hydrophilic solutes? (3): 1) membrane channels
  1. Passive transporters
  2. Active transporters
  1. What are membrane channels?: -donut-like pore spans bilayer -compared to transporters, solutes flow through rapidly (dittusion) -rate of transport alpha [substrate] = not saturable

11 / 28 -gated (open and close to stimuli) -highly selective

  1. Membrane channel examples? (4): Na+, K+, Cl-, H2O
  2. What are aquaporins?: -water channels -water transport=very fast -H20 across, not H+ (makes sense bc mito pumps them out, and you can't have passive dittusion of protons)
  3. What is water transport needed for?: RBCs, kidney, saliva, sweat
  4. What prevents H+ from coming in? What gradient is maintained?: + arginine (maintains electrochemical gradient)
  5. What do passive transporters do?: -transport down a concentration gradient (i.e. facilitated dittusion) -highly sensitive (stereospecific) -no continuous pore through membrane -transport one set of molecule(s) at a time
  6. Rate of passive transporters?: regulated; saturable number of binding site(s) for substrate
  7. 2 passive glucose transporter examples?: 1) GLUT1 in erythrocytes imports glucose
  1. GLUT2 in liver, intestine exports glucose
  1. How are the transporters operated?: -substrate binds on one side of the membrane -conformational change takes place -sites opens on other side of membrane -substrate is released

13 / 28

5) H+=

  1. Cl-=: [intracellular] vs [extracellular] (mM)
  2. 10-30 fold increase
  3. 28 fold decrease
  4. 15-30 fold decrease
  5. 2.5-5 fold increase (free ions=1000 fold increase)
  6. equal
  7. 28 fold increase
  1. When a charged molecule is moved across membrane, a results- : charge imbalance
  2. Typical membrane potential (ΔΨ in volts) of plasma membrane?: -60 (+70 in mito)
  3. Membrane potential equation: ΔG=zFΔΨ F=faraday constant z=unit charge
  4. Equation of ΔG for transport of charged species?: ΔG(t)=RTln(c2/c1)+zFΔΨ (=chemical + electro)
  5. What does Na+K+ ATPase do?: -generates gradients of K+ and Na+ -control cell volume (vs osmosis) -drives active transport of other species (like Na+ and glucose)

14 / 28 -render nerve cells electrically excitable (digitals and other cardiac glycosides bind to outside face)

  1. Na+K+ ATPase movement?: -3Na+ OUT, 2K+ IN (hence, inside=negative) -both ions move up concentration gradient -ATP hydrolysis provides energy -net positive charge out (generates membrane potential-critical for neuronal action)
  2. Na+K+ ATPase shape?: alpha2beta2 tetramer
  3. What does ouabain do?: -based on cholesterol -inhibits Na/K ATPase
  4. Transport cycle of Na+K+ ATPase?: -binds 3Na+ from inside cell -transporter phosphorylated on cytosolic side -phosphorylation induces a conformational change -3Na+ release, 2K+ bind -transporter dephosphorylated -binding site now inside, K+ release
  5. ATP reaction in channel for Na+K+ ATPase?: Asp+ATP-->Asp- Phosphate+ADP
  6. What are ion gradients?: a form of stored free energy
  7. What is secondary active transport?: transport of ion DOWN its gradient can drive transport of another solute UP gradient
  8. Example of secondary active transport?: Na+/glucose transporter
  9. Whats the Na+ glucose symporter driven by?: high extracellular [Na+]
  10. What does glucose uniporter GluT2 facilitate?: downstream efflux
  11. Difference between channels and transporters? (3): 1) rate of flux (very fast for channels)
  1. saturability (usually no for channels)

16 / 28

  1. Helice S4 is repelled by because :
  • outside, 4 + Lys or Arg every third position (the repulsion keeps S4 down and channel closed)
  1. controls opening and closing of Na+ channel gate: voltage sensor
  2. hat causes S4 to open up?: neurotransmitter induced depolarization at the cell body decreases repulsion
  3. Na+ channel and the muscle: channel defects result indices where muscles are paralyzed or stitt
  4. Na+ channel in neurons - a "disease"?: -tetrodotoxin produced by putter fish (fugu) -- binds @ Na+ channel, blocks inactivation -binds to Na+ channels for neurons
  5. What is chemiotaxis?: the movement of an organism in response to a chemical stimulus
  6. Where do bacteria cells receive input from?: membrane proteins that act as information centers
  7. What can the signal elicit?: responses (eg. motion toward food, fleeing toxic substances)
  8. What do signals represent?: information that is detected by specific receptors
  9. What are signals converted to?: chemical change (by a signal transduction)
  10. Evolutionary signalling mechanisms (4): 1) specificity
  1. amplification
  2. desensitization/adaptation
  3. integration
  1. What is specificity?: signal molecule fits binding site on its complementary receptor; other signals do not fit
  2. specificity<--> : tightness of binding KD (smaller KD=strong binding)
  3. How do multicellular organisms have additional specificity?: some receptors only present in certain cell types

17 / 28

  1. Interactions with specificity?: noncovalent (H bonds, hydrophobic, electrostatic)
  2. Factors that account for extraordinary sensitivity of signal transducers? (3): 1) high aflnity of receptors for signal molecules
  1. cooperativity in the ligand-recpetor interaction
  2. amplification of the signal by enzyme cascades
  1. What is amplification?: when enzymes activate enzymes, the number of attected molecules increases geometrically in an enzyme cascade --FAST RESPONSE
  2. Amplification example?: kinases that phosphorylate and activate downstream kinases (PKA) ser-ine/threonine are phosphorylated (KINASE CASCADE)
  3. What is desensitization/adaption?: receptor activation triggers a feedback circuit that shuts ott receptor or removes it from the cell surface
  4. How to increase sensitivity again?: when stimulus falls below a certain threshold
  5. What is integration?: when 2 signals have opposite ettects on a metabolic characteristic such as the concentration of a second messenger X, or the membrane potential VM, the regulatory outcome results in the integrated input from both receptors
  6. What kind of response does integration cause?: unified response appropriate to the needs of the cell or organism
  7. Types of signal transducers (6): 1) G-protein coupled receptor
  1. receptor tyrosine kinase
  2. receptor guanylyl cyclase
  3. adhesion receptor (integrin)
  4. gated ion channel
  5. nuclear receptor
  1. What is the G-protein coupled receptor?: external ligand binding to receptor activates intracellular GTP-binding protein, which regulates an enzyme that generates an intracellular second messenger

19 / 28

  1. Transmission of nerve impulse? (2): 1) action potential carries electrical signal down axon
  1. neurotransmitter carries signal to next cell
  1. What triggers opening of cation channels (Na+, etc)? (3): acetylcholine, serotonin, glutamate (neurotransmitters!)
  2. What happens with the Nicotinic acetylcholine receptor (AchR)?: -passage of electrical signal from the motor neurone to muscle fiber at neurotransmitter junction (or synaptic cleft) -acetylcholine released by motor neurone dittuses to plasma membrane of myocyte -- binds AchR -conformational change in AchR opens (inward movement of cations triggers muscle contraction)
  3. Neural transmission:
  1. opens Ach receptors ( channel)**
  2. Na+ flows down gradient ( )
  3. adjacent open: Na+ rushes in, mV & msec**
  4. inactivated; open
  5. K+ flows out ( , mV, msec)**
  6. inactivated, mV, msec**
  7. travels along axon: 1) acetylcholine (Ach), ligand-gated Na+/Ca2+
  8. depolarization
  9. voltage-gated Na+ channels, +30mV, <1msec
  10. Na+ channels, voltage-gated K+ channels
  11. down gradient, -75mV, 2msec
  12. K+ channels, -60mV, 3msec
  13. wave of de-/re-polarization
  1. releases neurotransmitter into synaptic cleft:

2a)

20 / 28 2b) : SNARE-regulated exocytosis

  1. small depolarization 2a) large depolarization (gated Na+ channels) 2b) large repolarization (gated K+ channels)
  1. Achr has subunits with helices each: 5; 4
  2. KD for binding of ACh is nM. binding sites, twist of exposes along the pore for and to move.: ~20nM; 2; alpha2betagamma; negative groups; Na+ and Ca2+
  3. Structural features of plasma membrane receptors?: -ligand- binding domain out-side -catalytic site inside -conformational change on outside activates enzyme inside
  4. Insulin binds to surface of after a meal: glucose transporters, muscle cells
  5. Insulin binds to its receptor, to surface to absorb : Glut4, glucose
  6. Insulin receptor structural points?: -tetramer (alpha2beta2) -insulin binds externally (activates tyrosine kinase activity in intracellular domain) -B chains autophosphorylated -opens up active site
  7. What does auto-phosphorylation of insulin receptor do?: locks in receptor in active conformation
  8. Inactive form of insulin receptor is stabilized by..?: H-bond between Tyr and Asp