Practice Test 5 Review Flashcards
What is the purpose of the myelin sheath
Myelin is an insulating layer that forms around nerves - The myelin sheath is made of proteins and fatty substances - The myelin sheath allows electrical impulses to transmit quickly and efficiently along the nerve cell
Equation for capacitance of a parallel plate capacitor?
C = € (A/d)
Where C is the capacitance
€ represents the absolute permittivity of the dielectric material being used
A is the area
and d is the distance between the plates
* Voltage gated channels only exist where the cell is unmyelinated *
Voltage gated channels only exist where the cell is unmyelinated
If the distance between two plates increases what happens to the capacitance?
If the disance between two plates increases then the capacitane decreases
What exists at the nodes of Ranvier in a neuron?
The nodes of Ranvier contain additional sodium channels that open to propagate the wave of depolarization - if the additional sodium channels did not exist then the wave of depolarization would die before it reached the terminal axon
What is a sphingolipid?
A sphingolipid is a kind of lipid - Sphingolipids gnenerally contain a sphingosine backbone amide-linked to a fatty acid - Sphingolipids have a significant role as structural components of the cell membrane and they act as signalling molecules in regulatory paths - In sphingolipids sphingosine takes the place of glycerol (because glycerol generally provides the backbone for phospholipids)
When light passes through a diverging lens what happens to it?
When light passes through a diverging lens it spreads out after it passes through
What is the difference between a real and a virtual image?
A real image is formed when light rays converge and a virtual image occurs where light rays diverge - The light rays of a real image will continue on past where the image has formed, this does not happen for a virtual image; the light rays of a virtual image appeat to stop where the image is produced
What is the Gibbs free energy for a spontaneous process?
The Gibbs free energy of a spontaneous process is negative
Entropy
Entropy is the randomness or disorder of a system - If the disorder increases, entropy is positive - When something moves from high to low concentration, the entropy is said to increase
Entropy = S
What is an epimer?
An epimer is one half of a diasteromer - Two epimers have opposite configurations at only one stereogenic center, all of the rest are the same
What is epimerization?
Epimerization is the interconversion of one epimer to the other epimer
What forms when the carbonyl carbon is attacked by the hydroxy group on the 5th carbon?
A hemiacetal will form when the molecule cyclizes
What does a catalyst do?
A catalyst lowers the energy of the transition state (which in turn lowers the activation energy of the reaction) - a catalyst DOES NOT change the energy of the intermediates or the products
What does an IR peak at 3300 cm-1 correspond to?
A hydroxy group (-OH) being present in the compound
What does an IR peak at 2250 cm-1 correspond to?
An IR peak at 2250 indicates the presence of a nitrile (-C triple bond N)
What is the formula for buoyant force?
Fbuoyancy = pVsubmergedg
p = density of liquid
g = gravitational force
Vsub = volume of object submerged
How do you calculate weight?
Fg = force of gravity = weight
Fg = mg
weight = mass * acceleration due to gravity
A good oxidizing agent is going to have a ___ reduction potential
A good oxidizing agent is going to have a more positive reduction potential
A good reducing agent is going to have a ____ reduction potential
A good reducing agent is going to have a more negative reduction potential
What can disrupt a covalent disulfide bond? (what breaks a disulfide bond?)
Only a reducing agent can disrupt a disulfide bond (a disulfide bond is covalent)
What happens to a thiol group in acidic conditions?
In acidic conditions a thiol group would be protonated
- a thiol group is R-SH
Where are disulfide bonds important in the structure of a protein?`
Disulfide bonds are important in the tertiary and quaternary structure of proteins
How are peptide bonds broken?
Peptide bonds are broken via hydrolysis (the addition of water)
What are the formulas for power? (2)
Power = Work/time
Power = current x voltage (P=IV)
If the atoms are in priority order around a chiral carbon and they are clockwise the carbon is in ___ configuration
R configuration is clockwise
If the atoms are in priority order around a chiral carbon and they are counterclockwise the carbon is in ___ configuration
S = counterclockwise
Is acetic acid a strong or weak acid?
Acetic acid is a weak acid
Henry’s law equation
C = kP
C = the concentration of a dissolved gas
k = henrys law constant
P = partial pressure of the gas
What does the mesoderm give rise to?
The mesoderm gives rise to skeletal muscles, smooth muscle, blood vessels, bone, cartilage, joints, connective tissue, endocrine glands, kidney cortex, heart muscles, uterus, fallopian tubes, and testicles
What is special about stem cells?
Stem cells display an indefinite replicative capacity as a result of their continuing ability to produce and use telomerase
What is renin?
Renin is an enzyme that helps control your blood pressure - It is made in the kidneys
What does aldosterone do?
The hormone signals the kidney to reabsorb sodium or increase the amount of potassium released into the urine - The body will increase the amount of re-absorbtion of water with the sodium to increase blood volume
What is a locus?
A locus is the place on a chromosome where alleles for a gene reside
What does the ectoderm give rise to?
The ectoderm gives rise to hair, skin, nails, lens of the eye, epithelia of the digestive tract (because it is considered “outside” the body), and nervous tissue
What is genetic drift?
Genetic drift is variation in the relative frequency of different genotypes in a population
What is gene flow?
Gene flow is the transfer of genetic material from one population to another
What is the structure of DNA?
DNA is a double helix with a negatively charged phosphoribose backbone attached to nitrogenous bases
