Exam 1 Jeopardy Pathophysiology

Which ion is most important to initiate contraction in smooth muscle?

Ca2+ calcium entering through channels in membrane = most important source of calcium Ca2+ binds to calmodulin --> creates complex Ca-calmodulin-MCLK --> phosphorylates MCL --> allows for myosin head to grab actin (requires ATP)

A typical cell's resting potential is closest to the equilibrium potential for which ion?

K+ K+ by itself = -91 Na+ by itself = +61 K+ has 100:1 ratio of permeability channels causing the resting potential to fall closer to K+ at -70--90

Initial depolarization is driven by which ion increasing conduction rapidly?

Na+ sodium causes depolarization, potassium causes repolarization

Which vital active transport pump uses about 20% of a cells total energy (65% in neurons!)?

Na/K ATPase pump more energy is needed in neurons

What is another name for the equilibrium potential equation?

Nernst equation calculates Vm for one ion Goldman-Hodgkins-Katz predicts resting Vm based on a plethora of ions (uses permeability too = p')

Where are terminal axons containing neurotransmitter in smooth muscle?

Varicosities

Which two proteins produce the cross-bridges in smooth muscle?

actin & myosin myosin heads bind to actin creating a rowing action

A cotransporter moving substances in opposite directions is also called what?

antiporter a symporter moves in the same direction

Another term for programmed cell death.

apoptosis

Which channels allow for osmosis of water into the cell?

aquaporins

What is the feedback reflex that controls blood pressure?

baroreceptor reflex

What type of elements carry nutrients like glucose through the cell membrane?

carrier proteins bind in the lipid bilayer to allow passage of non-permeable things like glucose

What word describes the 3 letter code that matches RNA to specific amino acids?

codon

What is the primary factor driving diffusion?

concentration gradient other non-primary factors include... electrical potential & hydrostatic pressure difference

Thick and thin filaments and microtubules make up what organelle system?

cytoskeleton thin filaments - F-actin; stress fibers in nonmuscle cells thick filaments - myosin; work w actin to support cellular locomotion & sub-cellular transport microtubules - heterodimers of a&b tubulin; make up spindle fibers

What upstream elements in DNA generally increase the chance RNA polymerase will bind to initiate transcription?

enhancer or promoter "vote"

Temporary or permanent changes to DNA's availability for transcription based on environmental factors is called?

epigenetics environmental factors (+ or -) can cause DNA to be tightly wrapped around histones (heterochromatin = not accessible for transcription) or loosely wrapped around histones (euchromatin = accessible for transcription)

True or false? Increasing concentration of a substance will increase its rate of facilitated diffusion.

false facilitated diffusion plateaus off at a constant Vm, no amount of substance will change that Vm to become higher

True or false? All graded potentials generate action potentials.

false have to reach threshold

True or false? Most mutations that occur in DNA change the amino acid sequence of the protein it codes for.

false most mutations are SILENT mutations which change the DNA letter code but NOT the amino acid (a single amino acid can correlate to many different 3 letter codes of DNA) most common mutation = SNP (single nucleotide polymorphism)

What term describes the magnitude of feedback in a system?

gain

Why do red blood cells have a resting potential closer to 0?

more permeable to Na+ unlike most cells, RBC are more permeable to Na+ instead of K+ making their resting membrane potential closer to Na+ (+61)

What is the term used to describe how many mitochondria may be affected vs unaffected in a mitochondrial disorder?

mosaicism mitochondria contain their own DNA so not every mutation causes all mitochondria to be effected (they have their own mosaic)

microRNA typically have what effect on translation of mRNA?

inhibition miRNA have two possible actions on mRNA 1. sequence perfectly matches mRNA = degraded mRNA 2. sequence slightly matches mRNA = inhibition of translation

Which phase of translation begins with the small ribosomal subunit binding to an RNA chain?

initiation binding & finding AUG (start codon)

K+ is actively transported in which direction across the cell membrane?

into the cell K+ is at large quantities inside the cell normally (it is what make the cell negative); so going against the concentration gradient would be bringing in even more K+ into the cell

What property of a molecule would grant it the ability to passively diffuse through the bilayer in the absence of channels or carrier proteins?

lipid solubility rate depends on how soluble the lipid is water-soluble = requires carrier or channel

Which organelles play a key role in autophagy?

lysosomes contain hydrolytic enzymes; fuse w endocytotic vesicles to form digestive vesicles absense of hydrolases leads to lysosomal storage disorder (become engorged w. undigested cells)

Which organelles have an internal matrix where the majority of cellular energy is produced?

mitochondria "powerhouse of the cell"

Which protein coats some axons and causes increased conduction velocity?

myelin sheath is disrupted every 1-3mm

What type of feedback promotes stability in a homeostatic system?

negative feedback most cells in the body operate on negative feedback (maintain homeostasis)

Which term summarizes diffusion movements in a solution across a membrane?

net diffusion

Which organelle contains DNA used for cellular reproduction?

nucleus

What method is used to measure charge in a membrane channel?

patch clamp Small pipette comes into contact with a very small portion of cell membrane... the contact creates a suction that the ions on the channel can only exit into the pipette.

Which organelles help us to break down alcohol?

peroxisomes contain oxidases, formed by self-replication (attack alcohol & LCFA)

Which type of feedback is created by ion changes at the start of an action potential?

positive feedback incorporates the "all or none" aspect of polarization

What type of feedback occurs due to blood loss after severe hemorrhage?

positive feedback promotes change in 1 direction (instable & disease causing)

What branch of science looks at large-scale changes in proteins in samples?

proteomics -omics = large scale

In what period after an action potential can a cell fire again, but only with supernormal stimulus?

relative refractory period absolute refractory period is when no amount of stimulus can fire another action potential (voltage inactivation)

What mechanical outcome comes from stimulation of smooth muscle with epinephrine?

relaxation epinephrine stimulates other muscles like skeletal and cardiac for the "fight or flight response"; smooth muscle is put in relaxed phase as it it not most important in that time

An increase in serum potassium would increase the excitability of cells. How?

resting potential is closer to threshold does not change threshold, but makes the resting potential move to be closer to threshold

Which two words distinguish endoplasmic reticulum with and without ribosomes on the outer membrane surface?

rough & smooth rough = with ribosomes (processing of proteins) smooth = without ribosomes (synthesis lipids --> golgi)

In addition to via membrane ion channels, where else does Ca2+ come from at the onset of contraction?

sarcoplasmic reticulum (the secondary source, not most important, of calcium)

What word describes the property of an ion channel to transport only one type of ion?

specificity

How does a ribosome know where to bind to a mRNA?

start codon AUG, a specific sequence in the mRNA that allows for the small unit of ribosome to bind ----- tRNA will then bind to this section bringing the amino acid along with it.

A merging of smooth muscle cells into a multinucleated mass that acts in unison.

syncytium found in unitary/ visceral smooth muscle

The membrane potential that will evoke the all or none action potential is called what?

threshold

Which process is measured as "gene expression"?

transcription

True or false - in general, rare mutations have larger effect sizes compared to common mutations.

true common mutations are more likely to have less of an effect on the person than a rare mutation

True or false? Protein folding after translation is a key factor in protein function.

true protein folding is the way that proteins come together to create a specific function... other things that are important for protein function = post-translational modifications