mcat science 5

  1. Decreased insulin sensitivity implies the presence of insulin resistance.

     Therefore, the body has to secrete more insulin to try to compensate for the insensitivity. This leads to _______, which is characterized by excess insulin in the blood.
    hyperinsulinemia
  2. Increased blood vessel elasticity leads to _____

    decreased blood vessel elasticity leads to ____ because blood vessels will be stiff
    hypotension

    hypertension
  3. ______, which is involved in the fight-or-flight response, provides the body more access to glucose. Specifically, epinephrine activates a G protein-coupled signal transduction pathway that activates glycogen phosphorylase (the enzyme involved in glycogen degradation) and inactivates glycogen synthase (the enzyme involved in glycogen synthesis). Even if you were not aware of these specifics, we can still arrive at the correct answer by process of elimination.

     

    ______ is a peptide hormone secreted by beta cells in pancreas. It increases glucose uptake by liver and muscles; it also increases the rate of anabolic processes.




    ______ is a peptide hormone that stimulates secretion of HCl by the parietal cells of the stomach.



    _______ is a peptide hormone secreted by delta cells of the pancreas. It inhibits both insulin and glucagon and its release is triggered by high glucose and amino acid levels.
    Epinephrine

     Insulin

     Gastrin

     Somatostatin
  4. An R2 value of 1 indicates that the regression line is a perfect fit of the data, while an R2 of 0 indicates that there is no correlation among the data. With an R2 of 0.002 in this analysis, the correlation is virtually nonexistent, so we cannot have statistical confidence in a calculation using the equation of the regression line.
  5. The polar C-terminal tail domain will interact well with water, causing a relatively small decrease in entropy (disorder). In contrast, when a largely hydrophobic structure is exposed to water, the H2O molecules must organize themselves around it in an ordered, low-entropy solvation layer to minimize their contact with nonpolar regions. Thus, the nonpolar transmembrane region would promote a larger decrease in total entropy if it were directly placed in aqueous solution.

    C-terminal tail domain is “cytoplasmic.” As such, it is adjacent to the watery (polar) cytoplasm and will likely be rich in polar amino acid residues.
  6. glucagon is a ____ hormone

     Cortisol is a ___ hormone 

     Aldosterone is a _____ hormone 


     Estrogen is a ____ hormone

    B. Insulin 


    C. Gastrin 


    D. Somatostatin

    norepinehprine 

    epinephrine
    peptide

    steroid

    steroid

    peptide

    peptide

    peptide

    steroid

    amino acid hormone

    amino acid hormone
  7. cardiac output = ______ x ______. Decreased blood volume will cause the heart to compensate by increasing heart rate.
    heart rate

    stroke volume
  8. The liver processes blood that reaches it through the hepatic portal vein from the small intestine. This means that the blood containing nutrients and compounds absorbed from the gastrointestinal tract is processed by the liver before entering the systemic circulation.

     

    The liver performs several important metabolic tasks, including (1) detoxifying compounds, either absorbed from the external environment or produced by metabolic processes, (2) metabolizing medications and drugs, (3) storing excess carbohydrates as glycogen or excess fatty acids as triglycerides, and (4) mobilizing lipids into circulation in the form of lipoproteins and breaking down glycogen to release more glucose if necessary. The liver also produces bile, which is then transferred to and stored in the gall bladder, from which it is released into the small intestine. The liver is also noteworthy because it is the main site of gluconeogenesis in the body, and it also possesses a remarkable ability to regenerate after being damaged.

    the question asks about liver complications, we can deduce that the disease can interfere with, among other things, hepatic cholesterol and clotting factor synthesis (choices A and B) as well as bilirubin (the breakdown product of heme) conjugation and excretion (choice C). No digestive enzymes are synthesized in the liver. Bile, which is synthesized in the liver and is involved in lipid digestion, is not a digestive enzyme but an emulsifier.
  9. _____ isomers are compounds that have the same molecular formula and different connectivity

    ______ isomers are molecules that are locked into their spatial positions with respect to one another due to a double bond or a ring structure. cis / trans
    Constitutional

    Geometric
  10. Several factors that can cause strain in a cyclic molecule are: torsional strain, caused by electron clouds of the molecule’s substituents getting too near one another; non-bonded strain, caused by substituents on non-adjacent ring atoms being brought in close proximity (thus causing more electronic repulsion); and angle strain, caused by the bonding electrons of ring atoms being brought closer that is dictated by hybridization and VSEPR theory.
  11. Prosthetic groups are tightly-bound organic molecules, such as vitamins, or inorganic compounds, such as metal ions, that are required for the hormonal or enzymatic function of a molecule. They are not the protein component.


     A cofactor is a non-protein component of a molecule required for the molecule's biological activity. When a cofactor is tightly bound it is often referred to as a prosthetic group.


     The ______ is the biologically active form of an enzyme in which both the protein and necessary non-protein component are present. A protein component alone is referred to as an ______.
    holoenzyme

    apoprotein
  12. small prokaryotic sub-unit

    large prokaryotic sub-umit

    eukaryotic small

    eukaryotic large
    30S

    50S

    40S

    60S
  13. Phosphoenolpyruvate carboxykinase (PEPCK) is an enzyme in ________. It converts ______ into _______ and ________.
    gluconeogenesis

    oxaloacetate

    phosphoenolpyruvate

    carbon dioxide
  14. Both eukaryotic and prokaryotic DNA are supercoiled to save space. Eukaryotes have an additional level of supercoiling achieved through histones to squeeze more DNA into their nuclei.



    B: Only eukaryotic genes include non-coding introns.




    C: Eukaryotic genomes and chromosomes are much larger than prokaryotic chromosomes.




    D: Bacterial chromosomes, owing to their shape and size, have only one origin of replication. Each eukaryotic chromosome has multiple origins of replication to speed up the process of copying all that DNA.
  15. clustered TFE disrupts melittin protein structure. This is most likely due to the ability of TFE to engage in hydrophobic interactions with side chains of nearby residues.   Quaternary structure is due to hydrophobic interactions and bonds between side chains of amino acids on the protein.

    cleave intramolecular amide bonds on melittin.  primary structure would be disrupted, since it mentions amide bonds.

    cleave intermolecular hydrogen bonds on melittin.  the secondary structure would be affected, since it has TFE disrupting H-bonds on the protein
  16. as the number and electronegativity of the halogens present decreases, the polarity of the molecule will decrease as well, and its hydrophobicity will increase.

    Subsequent solvation studies employing other haloalcohols revealed the strongest interaction between Trp19 in monomeric melittin and the hydrophobic component of what solvent molecule? 

    A. 2,2-difluoroethanol 


    B. 2-fluoroethanol 


    C. 2,2-dichloroethanol 


    D. 2-chloroethanol
    D

    A. 2,2-difluoroethanol - most polar


    B. 2-fluoroethanol - 2nd most polar


    C. 2,2-dichloroethanol - 3rd most polar


    D. 2-chloroethanol - 4th most polar and most hydrophobic
  17. - deltaH = exothermic so heating favors reactants
  18. The enhanced acidity of TFE when compared to ethanol is principally due to what factor? 

    A. Greater inductive withdrawal of electron density from the oxygen-hydrogen bond in TFE 

    The addition of electronegative fluorine atoms to ethanol forms TFE. This addition increases the polarity of the molecule, weakening the O-H bond of the ethanol via inductive movement of electron density away from the bond and consequently enhancing the relative acidity of TFE. Another way of viewing this is that the inductive effect stabilizes the negative charge on the deprotonated form of the molecule
  19. _______ hormones interact with nuclear receptor

    ______ hormones interact with membrane bound receptor
    steroid

    peptide (insulin) / amino acid (norepinephrine)
  20. ______ elements are responsible for moving genes around in the eukaryotic genome.

    _____ transfer of non-viral genetic material into eukaryotes

    ____ transfer of DNA from one cell to another
    Transposable

    transfection 

    transformation
  21. Serum albumin is the main carrier of free fatty acids in the blood.




    A: Hemoglobin is the principal metalloprotein involved in oxygen transport. It does not bind fatty acids.




    B: Fibrinogen is a soluble glycoprotein that is converted by thrombin into fibrin. Fibrin in turn cross-links aggregated platelets during secondary hemostasis. Fibrin does not bind fatty acids.




    C: An immunoglobulin is an antibody produced by the immune system to bind to and neutralize antigens.
  22. We are looking for the RNA molecule that is not noncoding (or basically, the RNA molecule that is coding), which means that it is translated into protein. hnRNA is heterogeneous RNA, which is a precursor to mRNA. mRNA is the only coding RNA.




    A: While tRNA is involved with translation, it is not considered coding because it does not get translated into a protein.




    B: snRNA, or small nuclear RNA, is a class of RNA molecules found within the nucleus of eukaryotic cells associated with specific proteins, referred to as snRNPs.




    C: snoRNA, or small nucleolar RNA, are a subset of snRNA and play an essential role in RNA biogenesis and the modifications of rRNA and tRNAs.
  23. Isoelectric focusing requires the use of a gel that has a stable pH gradient. A protein that is in a region of the gel where the pH is below its pI will be positively charged and will migrate towards the negatively-charged plate (the cathode). 

    Consider a mixture of lysine, histidine, and aspartate in a buffered solution at pH 4.0. You perform an isoelectric focusing procedure on these amino acids. What would be the order of the amino acids in terms of migration distance from greatest to smallest? 

    Lysine > Histidine > Aspartate 



    pI of lysine: 9.74

    pI of histidine: 7.59

    pI of aspartate: 2.77
  24. _______ are star-shaped cells found only in the central nervous system. The primary function is to maintain the proper chemical environment for action potential conduction and neuron signaling. are a key component of the integrity of the blood-brain barrier.

    _______ (CNS only) and _______ cells (PNS only) lay down the lipid-rich myelin that wraps around some, but not all, axons. Myelin significantly improves the velocity of action potential conduction.

    _______ cells, included in the figure below, make cerebrospinal fluid.

    Microglial cells are small cells with a similar function to macrophages; however, microglia are limited to the nervous system. Microglial cells are scroungers that remove cellular debris from sites of injury or normal cell turnover. Following neural injury, a rapid increase in the number of microglia in the region is seen, either by proliferation of microglia already in the area, or by the transport of microglia via macrophages that migrate to the injured area from the circulation.
    Astrocytes

    Oligodendrocytes

    Schwann

    Ependymal
  25. In both males and females, follicle-stimulating hormone (FSH) directly stimulates the maturation of germ cells. In females, it does so by stimulating the recruitment and growth of the immature ovarian follicle. In males, FSH stimulates primary spermatocytes to proceed through meiosis.


    B: A rapid rise in level of luteinizing hormone (LH) triggers ovulation and the development of the corpus luteum in women. In males, LH stimulates production of testosterone by Leydig cells.


    C: Gonadotropin-releasing hormone (GnRH) is a hormone released by the hypothalamus in order to regulate the release of FSH and LH from the anterior pituitary.


    D: Excess production of somatotropin (aka growth hormone or GH) is extremely unlikely to cause azoospermia. GH is responsible for cell growth and regeneration and also plays a major role in maintaining the health of the brain and other vital organs.
  26. Vitamin C acts as a cofactor in collagen synthesis. It is required for the hydroxylation of the collagen precursor, procollagen, a step needed for the later formation of the collagen triple helix structure. A deficiency of Vitamin C can result in impaired collagen synthesis and the development of the disease known as scurvy.




    A: Vitamin A refers to a group of unsaturated compounds including retinal, retinol, retinoic acid, and beta-carotene. It is involved in proper immune function, normal growth and development (especially of epithelial cells), and vision.




    B: Vitamin B1, otherwise known as thiamine, is one of the B complex vitamins. Its phosphate derivatives, including thiamine pyrophosphate (TPP), act as coenzymes in the catabolism of sugars and amino acids. Its deficiency can lead to memory dysfunction (Korsakoff syndrome), visual disturbance (optic neuropathy), and cardiovascular and/or neurological problems (beriberi).




    D: Vitamin D refers to a group of fat-soluble steroid hormones responsible for enhancing intestinal absorption of calcium and phosphate. Synthesis of vitamin D (specifically cholecalciferol) in the skin is the principal natural source of this vitamin and depends on exposure to UVB radiation, most typically from sun exposure. Dietary or dermally-synthesized vitamin D must be converted to its active form, calcitriol, by sequential hydroxylation in the liver and kidneys. Deficiency results in impaired bone mineralization and bone damage
  27. During the reduction of a mole of oxygen to water shown in Figure 1, how much charge is transferred? 



    C is correct. First, we need to balance the reaction:




    O2 (g) + 4 H+ → 2 H2O (l)




    This reaction is now balanced in terms of atoms, but as a redox reaction, it must also be balanced with regard to charge. We currently have a +4 charge on the left and a 0 charge on the right. To balance, we must add 4 electrons to the left side of the reaction.




    O2 (g) + 4 H+ + 4 e- → 2 H2O (l)




    Now, we can see that 4 moles of electrons are transferred per mole of O2. Faraday’s constant tells us that approximately 105 coulombs are present per mole of electrons, so:




    4 mol e- x 10^5 C/mol e- = 4 x 10^5 C
  28. current and electrons always flow in opposite directions! 

    so if electrons moving to right then current moving left so then you point your thumb in direction of current (left) and curl your fingers and point out and that points into the page
  29. The purpose of washing the precipitate with deionized water after filtration was to remove any soluble byproducts of the reaction, such as potassium nitrate or ammonium nitrate. Subsequent washing with ethanol helps remove adsorbed water, and since ethanol has a higher vapor pressure than water, it facilitates the drying of the solid
  30. Upon looking at the structure of glycine, you might be tempted to think that the shortest bond would be the double bond between the oxygen and the carbon in the carboxyl group of the amino acid. However, at physiological pH, the carboxyl group is deprotonated, and the negative charge is therefore delocalized by resonance between the two oxygen atoms. As a result, the bond order of the shortest bond in glycine is not 2, but rather 1.5:

    single bond bond order = 1
    double bond = 2
    triple bond = 3
  31. hexane = nonpolar
  32. The rate-limiting step of any reaction is the step that progresses the most slowly. Usually, the greater the activation energy, the slower the reaction rate.
  33. lower activation energy means more kinetic favorable 

    If a reaction's ΔH is positive, and ΔS is negative, the reaction is alwaysthermodynamically disfavored. If ΔH and ΔS are either both negative, or both positive, the thermodynamic favorability of the reaction can depend on the temperature.
  34. cis fats and double bonds

    single bonds and trans fats
    unsaturated

    saturated
  35. The range of human hearing is about 20 Hz to 20,000 Hz. Ultrasound waves have frequencies above about20,000 Hz (which is 20 kHz). As this is above the normal hearing range for humans, we cannot hear ultrasound.
  36. when this angle is equal to 90°, the device (and the ultrasound beam it sends out) is perpendicular with the direction of blood flow. When this happens, no component of the blood’s velocity is traveling either parallel or antiparallel to the beam, so the device will record a reading of 0, wrongly indicating that the blood was not moving at all. Even angles somewhat close to 90° will yield very erroneous readings, since only a small component of the velocity will be recorded. This limitation, as applied to the use of Doppler radar by police to measure drivers while speeding, is shown below. 

    In classic Doppler ultrasound, readings become less accurate as cos θ approaches 0. Remember, cos 90° = 0.
  37. Transverse waves (like electromagnetic waves, including visible light) can travel through a vacuum, but longitudinal waves cannot, as they require a compressible medium to propagate. Sound waves are the classic example of longitudinal waves. Note that the Doppler effect can be observed with light as well as sound waves.
  38. Without the option of UV visualization, paper chromatography will only be effective if there is a visible difference between the substances being separated. Two colorless substances such as benzoic acid and t-butyl alcohol would likely migrate at different speeds, but it would not be possible to identify their positions.
  39. I. migration of different enzymes would depend upon their respective affinities for the solid phase.

    II. migration of different enzymes would depend on their respective size and molecular mass.

    III. migration of different enzymes would depend on whether the enzymes’ primary structures comprise more amino acids versus fewer amino acids.

     affinity chromatography procedure — as its name implies, this technique is based on varying affinities for the stationary phase, as shown below. In such a procedure, the stationary phase often includes antibodies or other specific molecules.



    II: This describes size-exclusion chromatography and is incorrect.




    III: This choice describes electrophoresis, in which shorter chains of amino acids migrate faster than longer ones.
  40. Be careful here — size-exclusion chromatography does not follow the same trend as some other common separation techniques! In size-exclusion chromatography, smaller particles become trapped in the pore system present in the agarose stationary phase, while larger particles pass directly through the column. As a result, small molecules migrate more slowly than larger ones, as shown below. This differs from gel electrophoresis, in which smaller molecules move more rapidly than large ones through the agarose gel.
  41. Mutations to critical residues, such as the catalytic residue in an enzyme, are much more likely to produce a loss of function than a gain of function. For this reason, individuals with these mutations are likely to be significantly less evolutionarily fit than wild-type individuals, and the residues are more likely to be conserved (similar or identical in sequence) across species.
  42. A: Fractional distillation separates substances based upon differences in their volatilities. Because enantiomers share physical properties, including boiling point, this method of separation would be ineffective.




    B: TLC separates substances based upon differences in their polarities. Enantiomers share physical properties, including dipole moment, so this method of separation would also be ineffective.




    D: Recrystallization separates substances based upon differences in their solubility. Enantiomers have identical solubilities (and other physical properties).

    Finally, centrifugation utilizes a rapidly spinning apparatus to separate particles by density. More dense particles, such as cells, gravitate toward the bottom of the spun tube, while less dense substances remain at the top in a liquid termed the supernatant. This liquid can then be poured off, and further separation or analysis can be conducted.
  43. apoptosis inhibition = cancer
  44. aldehyde to carboxylic acid = oxidation
  45. would promote a less negative change in entropy when immersed in water. (more positive)

    hydrophobic = more negative change in entropy when put in water and forms solvation layer
  46. narrow artery and hydrostatic pressure decreases, volume decreases and velocity increases and hydrostatic pressure decreases

    the hydrostatic pressure must decrease to conserve energy. osmotic pressure won't be affected by narrowing
  47. 100 fold = factor of 10 (10^2)

    1000 fold = factor of 100

    A woman is standing two meters away from a speaker. The speaker is turned up to 11 on its dial, and the power of the sound hitting her tympanic membrane increases 100-fold. How far would the woman need to move to reduce the sound back to its original decibel level? 

    Thus, if the woman originally stands two meters away then to maintain the same decibel level, she needs to stand 2 x 10 = 20 m away from the speaker. Standing 2 m away, the woman must move 18 m to reach a total final distance of 20 m
  48. gas solubility decreases at high temp and low pressure
  49. dependent y axis

    independent x-axis
  50. ideal gas

    B. Collisions between gas molecules are elastic. 

     kinetic molecular theory. According to this theory, the average kinetic energy of a sample of gas depends only on the temperature of the sample


    C. There are no attractive and repulsive forces between gas molecules. 


    D. Gas particles have a volume of zero.

    high temp low pressure
  51. In which of the following aqueous carbohydrate solutions would a given vesicle have the greatest buoyancy? 

    A. 0.15 M sucrose

    B. 0.15 M glucose 


    C. 0.20 M fructose 


    D. 0.25 M galactose 





    Buoyancy is the force that results from the displacement of fluid when an object is submerged. The magnitude of the buoyant force is equal to the weight of the fluid displaced. Therefore, the greater the density of the solution, the larger the buoyant force. Glucose, fructose, and galactose are all monosaccharides with the molecular formula C6H12O6, so their relative densities will depend on their concentrations. The most dense of those three choices, then, is choice D. However, choice A is sucrose, a disaccharide with the formula C12H22O11. Since sucrose has a molecular weight almost twice that of galactose, a 0.15 M sucrose solution would have a density approximately equivalent to that of a 0.3 M galactose solution.
    sucrose
  52. Sphingomyelin may be most specifically categorized as what type of biological molecule? 

    A. Phospholipid 


    B. Fatty acid 


    C. Glycerolipid 


    D. Sterol lipid
    A is correct. Sphingolipids are glycosylceramide lipids containing sphingosine, an 18-carbon amino alcohol, bound to a fatty acid head group through an N-acyl linkage. Sphingolipids lacking additional head groups are referred to as ceramides. Sphingomyelin is a complex phosopholipid formed by the ester linkage of ceramide to a molecule of phosphocholine or phosphoethanolamine (choice A).
  53. The mass of an object will never change when it is moved to a different area. This is different than weight, which will change if the gravitational field is altered.
  54. During the synthesis of bile, cholesterol is conjugated by the addition of a carboxylic acid residue. Bile salts are thus able to solubilize lipids in aqueous digestive secretions because bile salts: 

    have a polar region and a nonpolar region, thus increasing the water-solubility of lipids. 

    Bile salts contain both polar elements and a hydrophobic cholesterol core. Because of this amphipathic structure, they contain both polar and nonpolar regions, acting as a detergent and solubilizing lipids in aqueous digestive contents by interacting with both hydrophobic (lipid) and aqueous phases. Sodium cholate, a common bile salt.
  55. high performance liquid chromatography

    HPLC separates compounds based on polarity and solubility in the stationary phase. In regular-phase HPLC, the stationary phase is _____, and the mobile phase is _____ (similar to typical thin-layer chromatography). In reverse-phase HPLC, the stationary phase is ______, and the mobile phase is ______
    polar

    nonpolar

    nonpolar

    polar
  56. higher frequency = higher energy = lower wavelength

    Absorption of radiation corresponding to what portion of the electromagnetic spectrum is most likely to excite Aequorea fluorophore, a green fluorescent protein used in biological experiments? 

    A is correct. Fluorescence is the emission of a lower-energy photon from a fluorophore excited by the prior absorption of a higher-energy photon. With this in mind, the Aequorea fluorophore must be excited by the absorption of a photon of higher energy (and frequency) than that associated with green visible light. Of the choices listed, only ultraviolet light, choice A, is of higher energy than green light. Even if we were not considering the green fluorescence of this organism, we could simply choose the highest-energy radiation as that which is most likely to promote fluorescence in general.


    A. Ultraviolet

    B. Infrared 


    C. Orange 


    D. Microwave
    roygbiv

    rmivuxg
  57. The index of refraction of an optical medium is the ratio of the speed of light in a vacuum (a known quantity, c = 3 x 108 m/s), to the phase velocity of light in the medium. The equation for index of refraction can be found using the simple equation n = c/v.
  58. Tautomers are isomers of a compound which differ only in the position of the protons and electrons. The carbon skeleton of the compound and tis molecular formulas must remain unchanged.
  59. negative ΔG connotes a _____ reaction, while a positive ΔG means the reaction will be _____.
    spontaneous

    nonspontaneous
  60. Which of the following must be true for a biochemical reaction at equilibrium?

    A. ΔGº’ = 0 


    B. ΔG = 0 


    C. Keq = 0 


    D. Q = 0
    B. ΔG = 0 

    B is correct. The Gibbs free energy change (ΔG) is used to predict the spontaneity of a reaction, with negative values indicating that the reaction will proceed in the forward direction (from reactants to products) and positive values indicating that it will proceed in the reverse direction (from products to reactants). When the reaction has reached equilibrium, ΔG is zero, and choice B is the best answer.

    - delta G: The equilibrium constant is greater than 1 because the products are more stable than the reactants.
  61. In contrast to a galvanic cell, an electrolytic cell uses a connected power source to conduct a nonspontaneous redox reaction. While galvanic cells have positive Ecell values (indicating spontaneity), electrolytic cells are characterized by negative Ecell values.
    gals are positive and spontaneous
  62. I = P/V

    Current = Power / Voltage
  63. Copper (II) ions in aqueous solutions cannot be directly extracted into organic solvents without an extractant because the ions: 

    have greater solubility in water than organic solvents unless complexed with extractant. 

     In a typical solvent extraction procedure, an organic solvent and an aqueous solution are added to a separatory funnel, in which they form two immiscible layers. The species to be extracted will be more soluble in one layer than the other, and can thus be separated out. The question stem asks why copper (II) ions cannot be directly extracted into an organic solvent, and the answer is simple: like other ions, positively-charged copper (II) ions will be more soluble in an aqueous (polar) solution than in an organic (hydrophobic) solvent. Unless an extractant is added, the copper ions will not significantly partition into the organic layer.
  64. The hydrotrope sodium benzoate is formed by the reaction of NaOH and benzoic acid. In aqueous solution, this hydrotrope is weakly basic.

    The reaction of NaOH (a strong base) and benzoic acid (a weak acid) will deprotonate the benzoic acid and produce sodium benzoate, a salt. In general, the salt of an acidic species will be weakly basic when dissolved in solution. Since the other product of the reaction is water (which is neutral), the solution as a whole will be weakly basic,
  65. To determine the density of a gas at STP, we can can take the formula mass of the element or compound and divide by the molar volume of any ideal gas at STP (22.4 L/mol). For choice A, H2 = 2 g/mol, so 2/22.4 = a little less than 0.1 g/L (it is actually 0.089 g/L).
  66. Methane gas is nonpolar. What are the possible implications of this?

     Being nonpolar, dipole-dipole forces will not be present.



    Dipole-dipole forces are present only between polar molecules, and methane is nonpolar.
  67. Induced-dipole bonding occurs only when a polar molecule induces a nonpolar molecule to become temporarily polar.
  68. Soaps are formed by the reaction of long-chain fatty acids with lye (NaOH), as shown below. This removes the hydrogen atom from the carboxylic acid group and replaces it with a Na+ ion.

    weak acid with a strong base.
  69. Better nucleophile is worse leaving group so OH- better nucleophile than water but water better leaving group. Negative charge, double triple Bond and lone pair all nucleophile. More electronegativity means worse nucleophile. Steric hinderance decrease nucleophile
  70. Carbon double bond has oxidation state of 2 but carbon double bond to oxygen and single bond to OH has oxidation state of 3
  71. Ozone cleaves double bonds to produce
    Aldehydes
  72. Rna Pol 1

    Rna Pol 2

    Rna Pol 3

    What kind of rna?
    rRNA

    hnRNA

    tRNA
  73. Insulin and ATP stimulate glycogen synthase 

    Epinephrine, AMP , and glucagon and AMP inhibit glycogen synthase

    Opposite for glycogen phosphorylase which is apart of glycogenolysis
  74. 0.1 mol I2 added to 1L of soln containing 1.0mol of precipitated AgI - what will happen?
    All I2 would dissolve but only a portion of AgI would dissolve.
  75. Elemental iron will not react with aqueous bases such as NaOH without oxygen present so if NaOH added to iron without oxygen present, no reaction takes place. Iron can react with HCL (acid) without oxygen present though.
  76. lower reduction potential reacts most vigorously in HCl (stomach conditions)
  77. STP = 0 Celsius or 273 kelvin
  78. pH = -log(H+)

    10^-pH = (H+)
  79. liquid water will always have some ions in soln

    true or false?
    true

    always
  80. gel filtration column - smaller particles get trapped in pores and so larger particles elute first and travel quicker

    so a non-denatured protein will move fastest and elute first as oppose to a denatured one which is in its individual component proteibns
  81. generation of electric fields from biological sources will not be able to form where the resistivity of medium (air) is high. They are limited to areas of high conductivity and low resistivity like aqueous environments
  82. magnitude of electric field decreases with distance
  83. symmetrical - optically inactive

    chiral = optically active
  84. work done by gas relies on change in volume of the container holding the gas so if the volume doesn't change no work it done
  85. Real images occur when objects are placed outside the focal length of a converging lens or outside the focal length of a converging mirror. 
    Object distance greater than focal length = real so image appears behind lens


    Virtual images are formed by diverging lenses or by placing an object inside the focal length of a converging lens
    Object distance less than focal length = virtual so image appears in front of lens

    I = F - O
  86. P = F/A

    A = (sphere) 4(pi)r^2
  87. lenses refract light at an angle that depends on its wavelength whereas mirrors reflect light of all wavelengths at the same angle
  88. CH3COR = Acetyl Group
  89. peptide bonds link primary sequence of amino acid in protein but are never observed when polypeptide bends or folds to form secondary structure or folds to tertiary structure.

    hydrogen bonding intramolecularly causes the alpha helices and beta sheets of secondary structure and stabilize 3d conformation in tertiary structures. hydrophobic interactions play a major role in arrangement of amino acid R groups in aqueous environments effecting shape of protein (tertiary). electrostatic interactions become a factor in tertiary structure when charged amino acid R groups are brought into close contact and interact due to folding of proteins
  90. racemic = chiral 

    Gringnard reagent - CH3MgBr and hydrolysis H3O+ (turns carbonyl oxygen into OH and CH3)
  91. albumins - globular proteins that act as carriers and enzymes


    below are derived from lipids
    -steroids like cholesterol and estrogen 
    - waxes are esters of fatty acids and monohydroxylic alcohols 
    -carotenoids are fatty acid-like carbon chains containing six membered carbon rings at each end (vitamin A)
  92. hydrostatic pressure = density x g x h

    h (depth)

    density water = 1000 kg/m^3
  93. sharp singlet at 9.5ppm =

    upfield singlet at 1 to 2.5 ppm =
    aldehyde

    methyl groups
Author
JAM41MAN
ID
341128
Card Set
mcat science 5
Description
tg
Updated