mcat science 7

you can increase enzyme specificity by increasing ____ bonds ____ bonds and transient covalent bonds

Arteries have ____ smooth muscle than veins

arteries have thick walls compared to veins and are more rigid.

Veins will expand more than arteries
----------------------------

arteries are larger and more muscular than veins and more elastic

arteries: 
- more elastic
- thicker
- more muscular
- more rigid
- more smooth muscle
- larger

Veins:

expand more

formula: Formal Charge = [# of valence electrons on atom] – [non-bonded electrons + number of bonds].

ionic bonds = no sigma bond

small distance between HOMO and LUMO means smaller energy of light absorbed so greater wavelength (explains orange / red color of B-Carotene)

C = (F-32)/1.8

F = (C x 1.8) + 32

Saponification 

_____ hydrolyzes triglycerides to form glycerol and soap

- LH surge induces ovulation

- Ovarian follicles secrete estrogen during proliferative phase of menstrual cycle to have a 2-3 fold increase in thickness of endometrium

- FSH plays an important role in development of ovarian follicles increasing estrogen secretion

Volumetric flow rate (veins/ arteries / blood flow)

A1V1 = A2V2

A = Pi(r^2)

-halve diameter halve radius
- Area decrease by factor of 4 means velocity increase by factor of 4

layrnx - houses vocal cords

larger diameter and shorter length = less resistance

V = IR

1L = 1kg

1 pound = 0.45 kg

1ppm = 1 mg/kg

1ppt = 1 ng/L

To increase reaction rate

____ vmax
_____ km

increase pH / decrease H+ ions to increase electromotive force

spontaneous reactions proceed forward and make more products

fisher projection R v S: order priority then switch sign

amines are ___ nucleophillic than alcohols because _______

electron and molecular geometry of atoms only differ when there is a lone pair on atoms

Vitamin D when activated by parathyroid hormone promotes bone strength although it seems counter intuitive it helps counter the resorption of bone by parathyroid in the first place.

Vapor pressure and boiling point

If the solution has a higher boiling point than the pure solvent then it has a lower vapor pressure than the pure solvent because it has more solute and less water (or solvent) so it vaporize quicker but the more solutes means it takes longer to boil

Add diols to ketone to create ketal to protect it from LiAlH4 reduction

when hydrophobic amino acid or molecule placed in water water molecules must rearrange in order to maximize H-bonding and since hbonds cant be formed with hydrophobic molecules water is more restricted in its freedom of movement and entropy decreases

lewis - electron
bronsted - proton

lewis base - e- donor
lewis acid - e- acceptor
bronsted acid - H+ donor
bronsted base - H+ acceptor

these units can be used to measure heat/energy:

J
m x N
s x W

greater reduction potential = more likely to accept electrons

hardy wein :

- no mutations
- large population size
- no net migration of individuals into or out population
- random mating
- genes in population all equally successful at reproducing

Proline - cyclic imine that introduces a bend in the protein. Found most often at beginning of alpha helices

transporting Na, Cl-, and glucose out of cell requires ATP

Transporting K+ into cell requires ATP also (Na/K+ ATPase)

ADH - Increase aquaporin channels in distal collecting tubule and collecting duct

H2SO4, NaCr2O7

&

H2SO4, CrO3, Acetone

Primary alcohol --> carboxylic acid
secondary alcohol -- > Ketone

PCC

Primary alcohol --- > Aldehyde
Secondary alcohol -- > Ketone

adrenal medulla - ectoderm

adrenal cortex , spleen, lymph vessels- mesoderm

Growth in long bones occurs in the epiphyseal plates

1 mol = ____ molecules

Urea cycle is to safely eliminate toxic ammonia from the body. Converts ammonia to urea for excretion. 

When amino acids are metabolized ammonia builds up in the body.

SEVEN UP

Use H2O to make R S Chiral products from one reactant because it is Polar protic and hydrogen bonds stabilize anion intermediate and favor SN1 mechanism

Ka > 10^-7 = more H+ than HA- ions

Change in electrical potential:

Delta V x q (charge)

myelin sheath acts to decrease capacitance because capacitors in series have a lower net capacitance

hypokalemia - low blood potassium would cause cell hyperpolarization cuz potassium would try to escape through leak channels

Lyase breaks ATP to form cAMP and pyrophosphate WITHOUT use of water.

coordinate covalent = when both e- are contributed by one of the atoms

ex- ammonia + H+ = ammonium

Polar covalent bond- shared electrons but large difference in electronegativity

brain does not use ketones primarily until starving state not fasting state

presence of chyme in duodenum causes release of brush-order enzymes like dissacharidases and peptidases

maltase- maltose -> glucose + glucose 
sucrase - sucrose -> glucose + fructose
lactase - lactose -> glucose + galactose
enteropeptidase -  Enteropeptidase converts trypsinogen (a zymogen) into its active form trypsin

lower atomic radii for an atom means when bound to itself it would have a shorter and stronger bond than something with a greater atomic radii

Nitrogen has more protons than carbon so its atomic radii is smaller and N-N bond shorter than C-C bond cuz atoms would be closer together.

6 member rings are more stable than 5 member rings due to less angle strain

alpha anomer more stable than beta anomer because of less steric hinderance with adjacent OH group. beta anomer OH group is in cis with adjacent OH

Q > keq = deltaG > 0

so reverse reaction is favored

Downfield The Nucleus feels stronger magnetic field. Deshielding is the opposite of shielding. When we say that an atom is deshielded, we mean that “A nucleus whose chemical shift has been increased due to removal of electron density, magnetic induction, or other effects.”

so on ethylbromide the deshielded H would be near the electronegative Br- and that would be downfield

n + 1 rule (neighbor + 1)

downfield is closer to 10 to left and upfield is closer to 1 to right

only palm of hand and sole of feet have stratium lucidum epidermal layer

any other area of body cut would penetrate 4 layers if cut all the way through to muscle

aldol formation - enolate functions as nucleophile

H+ extracted first from OH and enolate forms to be nucleophile

retro aldol - enolate functions as a leaving group

break down products of lipids ___ ___ ____

no break down of lipids means more cholesterol in blood

embedded proteins - on exterior or interior of cell and involved in transcriptional changes

peripheral proteins do not have pro-transcriptional function, exist on membrane surfaces

Gq receptor increase activity of phospholipase C, which cleaves PIP2 into diacylglycerol & IP3.

IP3 production leads to release of intracellular Ca2+ stores.

chronic effects of high level of cortisol can lead to weight gain and hypertension

Stable quiescent cells - only divide when needed and spend most of time in G0 (liver cells, endocrine gland, proximal tubules of kidney)

- Vascular endothelial cells
- Parenchymal cells of solid organs (e.g., liver, kidney, pancreas)
- Mesenchymal cells (e.g., fibroblasts, smooth muscle)
----------------------------------------

Permanent G0 - brain cells, neurons, heart cells, skeletal muscle cells, red blood cells (RBC precusor in bone marrow can divide).

- Neurons of CNS
- Cardiac and skeletal muscle

-----------------------------

Labile cells:

- Epithelial cells (basal cells of skin; endometrium; mucosa lining GI, respiratory, and biliary tracts; etc.)
- Hematopoietic cells (e.g., bone marrow stem cells)

_____ cells secrete calcitonin in response to elevated calcium in blood

semilumar valves comprise the aortic and pulmonic valve which prevent backflow from aorta and pulmonary arteries

bicuspid valve prevents backflow from left ventricles to left atrium''

tricuspid valve prevents backflow from right ventricle to right atrium

LAB RAT

double concentration of both base and acid in titration _____ buffering capacity and _____ pH

these studies begin by identifying subjects with a particular outcome and restrospectively assessing risk factors

RNA Pol 1- synthesize ____ to make new ribosomes.

RNA Pol 2- DNA - > _____

RNA Pol 3- DNA - > _____

axial skeleton - skull, vetebral column, rib cage, hyoid bone

appendicular skeleton - majority (the rest)

destruction of RBC occur mostly in ____ but also occurs in liver and old RBC are phagocytized by ______

concentration goes up by factor of 2 and reaction rate goes up by factor of 4 means ____ order

General adaptation syndrome:
Hormone primary in each phase

Alarm -
Resistance -

decrease products shift right

decrease reactants shift left

Indicators measure a pH change within one unit of its pKa so if you want to use an indicator to measure deviations from normal physiological pH you can use 

ka 2 x 10^-8
pKa = 7.8 (physiological pH = 7.4)

G Cells -> parietal cells - > HCl

chief cells -> pepsinogen

mucous cells -> alkaline mucous

UV spec- more light absorbed = less transmittance cuz less light reaches detector

greater concentrations means more light absorbed

to absorb light at 3 different wavelengths there must be 3 different sets of pi orbitals like in benzene

400 cm^-1 is finger print region used to distinguish between similar species. this region is unique to each molecule, complex vibrations

HNMR 10.5 - 12 = CARboxylic acid
9 - 10 : aldehyde
1- 5.5: proton in OH group
0.9 - 1 - methyl group

spin-spin coupling - two non equivalent protons near each other

smaller gap between LUMO and HOMO means less energy needed to be excited, so longer wavelength absorbed with less energy carrying

vaccuum filtration - when desired product in solid state

gravity filtration- when desired product in liquid state

vacuum distillation- preferred with molecules with high Bp 

simple distillation- molecules below 150C DEGREES but large difference in Bp

fractional distillation- molecules small difference in Bp and below 150C degrees

TLC- .6 relative retardation vs .7 relative retardation means .7 was performed at higher temp cuz it moved farther

highest peak in reaction profile = slow step

equilibrium constant and rate constant change with temperature

monosustituent alkene- kinetic product

disubstituent alkene- thermodynamic product

low temp- favors kinetic product when both reaction irreversible

exothermic- activation energy of reverse greater than activation energy of forward

specific rotation = observed rotation / c x l

1dm = 10cm

2 mol A <-----> 1 mol B

what change in pressure gets you to B?

low Kp = reverse reaction heavily favored

homogeneous mixture- all gases or all aqueous in reaction

ice less dense than water so to get ice to melt in closed container you increase the pressure because increase in pressure moves things to more dense

Keq and deltaG inversely related

increase temp and pOH lower (OH- greater)

Kp = KcRT^n

products favored = keq > 1
reactants favored = keq <1

products favored = deltaG -
reactants favored = deltaG +

changing temp changes equilibrium constant

more solutes lower vapor pressure and lower the triple point on phase diagram

work done by climber - mgh

cooling rate = heat loss/ per unit time

deltaQ / deltaT

ion product smaller than solubility product = more of it dissolves

to lower temperature without freezing to occur you increase amount of solutes to decrease freezing point 



At the freezing point of any solution the rates of melting and freezing are exactly balanced, allowing both phases to coexist in a thermodynamically stable state. The introduction of a solute reduces the activity of the liquid phase solvent, thereby reducing the rate of freezing.

You can think of this reduction in activity as solute molecules "getting in the way" of solvent molecules from attaining the correct alignment for freezing at the surface. On the other hand, the rate of melting is unaffected by the presence of solute because this is simply the rate of liberation from the frozen surface into the liquid phase.

In the presence of solute, it is necessary to lower the temperature to slow down the rate of melting so that it once again matches the rate of freezing. This is why the freezing point is lowered, or depressed, by the presence of solute in the liquid phase.