NS4: BBCF Flashcards
what happens if you inhibit cytochrome c oxidase?
Cytochrome c oxidase is an enzyme responsible for electron transfer in the electron transport chain (ETC), so inhibiting it would slow or stop the ETC. As a result, ATP production would be dramatically reduced.
carbonic anhydrase
enzyme that assists rapid inter-conversion of carbon dioxide and water into carbonic acid, protons and bicarbonate ions
can work in both directions
- forward decreases pH
- backwards increases pH
integrins vs cadherins
Integrins are transmembrane receptors that modulate cell-to-extracellular matrix interactions. Specifically, these proteins often attach the cell to collagen and fibronectin fibers.
Vs. Cadherins are transmembrane proteins which play a primary role in cell-to-cell adhesion (remember that C stands for cell-to-cell), forming adherens junctions to bind cells within tissues together.
how does dna replicate
Dna replicates in a semiconservative manner, meaning that each replicating strand of double-stranded DNA (dsDNA) produces two daughter molecules, each of which contains one parental and one new strand.
calcium functions
- osteoblasts
- osteoclasts
Calcium plays a key role in multiple physiological functions, most notably in bones, neurotransmitter release, muscle contractions, and as a second messenger within the cell.
– levels are regulated by parathyroid hormone and calcitonin to facilitate bone remodeling, or the degradation of older, existing bone and the formation of new bone in its place
osteoblasts are cells that help build bone, and therefore reduce blood calcium levels by “storing” calcium in bone tissue
osteoclasts are cells that break down bone, releasing calcium into the bloodstream
calcitonin
released by C cells of the thyroid and decreases plasma concentrations of Ca2+ stimulates bone formation by increasing osteoblast activity and decreasing osteoclast activity
parathyroid hormone
secreted from the parathyroid in response to low blood calcium levels and elevates blood calcium levels by decreasing bone formation by osteoblasts and increasing bone degradation by osteoclasts
vitamin D
inactive form = CHOLECALCIFEROL, which will turn into the active form CALCITRIOL
Calcitriol has a similar function to PTH in that it increases serum calcium levels, but it does so primarily through a different mechanism: it promotes the absorption of Ca2+ from the gastrointestinal tract.
antibiotics
antibiotic resistance
Antibiotics: compounds designed to kill prokaryotes, generally work by targeting structures specific to prokaryotes, thus not harming eukaryotic host cells
Antibiotic resistance: caused by genes found on plasmids (non-chromosomal bits of circular prokaryotic DNA) and spread through conjugation
types of symbiosis
occurs when two distinct organisms live in close proximity with each other, affecting each other’s life cycle
Parasitism benefits one species at the cost of harm to another.
Competition is when two species compete for access to a limited resource.
Mutualism requires that both species benefit.
Commensalism is when one species benefits but the other species is neither helped nor harmed
sarcomere
fundamental unit of contraction; consists of a band of thick myosin fibers and half of each of the two adjacent bands of thin fibers
divided into I-band, A-band, H-zone, Z-line, and M-line
The M-line defines the middle of the sarcomere, running through the middle of the thick filaments, while the Z-lines define the edges, running through the middle of the thin filaments.
The I-band refers to the region where only thin actin filaments are present, and the A-band is everything else, that is, the entire region where thick filaments are present, including areas of overlap with the thin filaments.
The H-zone refers to the region where only thick filaments are present, making it analogous to the I-band.
During contraction, the M-lines and Z-lines come closer together, the A-band stays the same, and the I-band and H-zone become shorter.
what is the signal for contraction
The signaling for contraction occurs when the neurotransmitter acetylcholine is released into the neuromuscular junction.
Acetylcholine binds to receptors on the cell membrane, which is known as the sarcolemma in muscle cells
Sarcolemma then depolarizes in response. This results in an action potential, and when the action potential reaches the sarcoplasmic reticulum, Ca2+ is released into the sarcoplasm (recall that this is just muscle-speak for the cytoplasm).
Once in the sarcoplasm, Ca2+ can bind to troponin, which allows contraction to take place
what is the basic mechanism of contraction; aka sliding filament model
Striated muscle fibers contain long rod-like myofibrils that are composed of alternating units of thick (myosin) and thin (actin) fibers that overlap with each other.
– contraction allows for the interwoven myosin and actin fibers to slip past each other
During contraction, the actin and myosin filaments slide past each other through what is known as a cross-bridge cycle, in which a cross-bridge is formed between myosin and actin, and a power stroke provides the force of contraction. Immediately after a power stroke, myosin and actin are bound together, and the cycle begins again.
what is the specific binding pathway of skeletal muscle contraction
ATP binds to the myosin head, causing a conformational change that releases it from actin.
Then, a protein called tropomyosin moves back into place to block strong interactions between actin and myosin.
The ATP molecule is then hydrolyzed. This is a strongly exergonic reaction and is used to move the myosin head into the “cocked position,” where it can interact weakly with actin.
Tropomyosin is ultimately removed by Ca2+ through a somewhat complex mechanism. At this point, the myosin head can bind tightly to actin.
The power stroke then occurs via a conformational change that happens when Pi is released, resulting in a force of about 2 pN.
ADP is then released and actin and myosin are essentially stuck together until another ATP binds to myosin so that the process can start again.
mnemonic “More blasting gas, I’m nervous”
outlines the process of morula to blastula to gastrula to neurulation
morula: solid ball of cells that arises after zygote undergoes a series of cleavages
blastula: hollow ball of cells; has two poles (animal and vegetal)
gastrula: cell migration to the interior of the blastula via the blastopore, resulting in the formation of the germ layers
define the following:
- blastocyst
- inner cell mass
- trophoblast
- blastocoel
The blastocyst consists of an inner cell mass (ICM), along with an outer cell layer called the trophoblast, which surrounds both the ICM and blastocoel (fluid filled cavity)
The inner cell mass is the mass of cells within the blastocyst that will eventually give rise to the fetus.
Isoelectric focusing
requires the use of a gel that has a stable pH gradient in order to separate proteins by isoelectric point, which depends on the amino acid composition of the protein
The protein will cease to migrate when it reaches the region of the gel where the pH of the gel equals the pI of the protein. At this point, the protein will stop migrating because the net charge of the protein will be 0, so it will not experience any electric force.
anode v cathode charges
- ief
- galvanic
- electrolytic
In an IEF setup, the cathode is the negatively-charged electrode.
Vs. In a galvanic (voltaic) cell, the anode is considered negative and the cathode is considered positive.
Vs. in an electrolytic cell, the anode is taken to be positive while the cathode is now negative.
stereospecific enzymes
Many of the enzymes used in the body are stereospecific – they will only react with one particular stereoisomer form of a molecule and will only catalyze a reaction that produces a particular isomer of the product. Often drugs are administered as a racemic mixture because the workup in the lab produces such a mixture even though only one of the isomers has any biological effect.
autonomic nervous system
controls involuntary responses in the body
Sympathetic nervous system: fight or flight response
Parasympathetic: rest and digest response
substitutions
aka point mutations; genetic mutations of a single nucleotide
Silent: mutated codon codes for the same AA as the original
Missense: mutated codons codes for a different AA than the original
Conservative: missense AA encoded but has similar functional properties as the original, thus has a smaller effect on functionality of the protein coded for by the gene
Non-conservative: missense AA encoded with dissimilar functional properties as the original, thus leading to malfunctioning or nonsense mutations
Frameshift mutation
caused by insertion of deletion of nucleotides
Deletion: literal deletion of part of a sequence
Insertion: insertion of a sequence
UTR
untranslated region
region of mRNA that is directly upstream from the initiation codon. This region is important for the regulation of translation of a transcript, thus must be transcribed but not necessarily (fully) translated
In the first trial of the PCR procedure, only one primer was added to the mixture. What was the most likely outcome during this trial?
When performing PCR, if only one primer is added to the mixture, then that primer will bind to one of the strands and initiate replication of that strand to produce the complementary strand. For one double-stranded template DNA molecule, after one cycle, we are left with two of the complementary strand while still having only one of the strands where the primer binds. In the next cycle, the primer again binds to the strand to which it is complementary. Therefore, only the complementary strand will be replicated again; this time we have three of the complementary strand.
mature mrna
DNA coiling in order of compactness
A mature mRNA consists of a 5’-cap (one base pair), the 5’ UTR, coding regions, the 3’ UTR, and a poly(A) tail.
In increasing order of compactness: DNA helix > euchromatin > heterochromatin > nucleosome
intermediate filaments vs microtubules
Intermediate filaments such as keratin are directly responsible for structural integrity in skin.
Microtubules are not involved in structural integrity, but in mitosis, meiosis, cell trafficking of vessels, and ciliar/flagellar motion. Microtubules are composed of tubulin protein dimers.
reflex arc
Voluntary muscles may contract involuntarily due to a reflex arc. The classic example is the patellar tendon reflex, in which sudden stretching of the patellar tendon leads to an involuntary contraction of the quadriceps. Such contraction occurs before the signal has even reached the brain.
This arc contains a sensory neuron, which carries sensory information from peripheral receptors toward the spinal cord, and a motor neuron, which carries a signal from the spinal cord to an effector muscle. This particular reflex arc also contains an interneuron, which is a neuron within the spinal cord that synapses on both the sensory and motor neurons, connecting them.
