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Alex's MCAT Flashcards > Bio-Biochem > Flashcards

Bio-Biochem Flashcards

1
Q

How does histone acetylation effect gene transcription?

A

Histone Acetylation = neutral charge, gene activation, DNA uncoiled.

Histone Deacetylation = positive charge, gene silincing, DNA coiled.

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2
Q

What were the results of the Griffith Experiment? How was Griffith’s conclusion further supported bythe evidence of Avery’s results?

A

Griffith Experiment: R-form (nonpathogenic) bacteria convered to S-form (pathogenic) by some transforming principle

Avery Experiment: Griffith’s transforming principle = DNA. Evidence… - tested (-) on protein detections but (+) on DNA decection tests - ratio of Nitrogen:Phosphorus resembled that of DNA - protein/RNA degrading enzymes —» no effect

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3
Q

Difference between…

  1. Facultative anaerobe
  2. Obligate anaerobe
  3. Aerobe
A
  1. Facultative anaerobe: can function either in presence or abscence of oxygen. (perform aerobic or anaerobic respiration)
  2. Obligate anaerobe: cannot function in the presence of oxygen
  3. Aerobe: can only function in presence of oxygen
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4
Q

Bacteria Characteristics (pneumococcus):

1.

2.

3.

A

Bacteria Characteristics (pneumococcus):

  1. contains organelles (i.e. ribosome, double membrane bound nucleus structure)
  2. cells larger in diameter than eukaryotic cell
  3. translation occurs in mitochondria
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5
Q

Menarche & avg. age of onset

A

Menarche: beggining of menstruation (ages 9-15+)

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6
Q

Klienfelter’s Syndrome:

  1. genotype?
  2. genotypic sex?
A

Klienfelter’s Syndrome:

  1. genotype: XXY
  2. Genotypic Sex: Male—»presence of Y chromosome
  3. Characteristics:
    - infertile
    - female secondary sex characteristics
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7
Q
  1. Aneuploidy
  2. Examples?
A

Aneuploidy: abnormal number of chromosomes -

EX; Monosomy X, Trisomy 21/18/13, XXX/XXY/XYY “

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8
Q

What is an RFLP and what is it used for?

A

Restriction Fragment Length Polymorphisms (RFLPs): used to identify which parent a non-disjoined chromosome comes from.

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9
Q

Assume that ey is X-linked if ey/+ females are crossed with wt males, what are the phenotypes of the progeny?

  • (Y) = Y chromosome
  • (ey) = small or no eyes (depending on sex & genotype_
  • (+) = Normal eyes
A

Male:

A. (Y/+) —» NORMAL

B. (Y/ey) —» no eyes

Female:

A. (ey/+) —» small eyes

B. (+/+) —» NORMAL

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10
Q

Constitutive vs. Substitution Mutations

A

Constitutive: ““always active”” mutation—»increase ‘strength’ of binding for weak GAL4 promotor thereby inc. transcription

Substitution: mutation to unstream activiating sequence (UAS) would only dec. efficiency of GAL4 promoter

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11
Q

Hardy-Weinberg Equation

A

p^2+2pq+q^2=1

p: frequency of wt allele
q: frequency of recessive allele

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12
Q

Is it more practical to compare the entire genome of a wt vs. cancerous cell in order to isolate a mutation? what is a better alternative?

A

naturally occuring mutations would mask cancer-causing mutations, making it an impractical method for attempting to isolate a mutation.

better alternative = transforming human (hDNA) sequence that upregulates replication & a tag sequence into e. coli then adding this DNA to a mouse cell line.

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13
Q

what are the 3 types of sequencing transfers and what molecules are they used to detect?

A

Southern Transfer: detection of DNA sequence in DNA samples

  • combines transfer of electrophoresis-separated DNA fragments to a filter membrane and subsequent fragment detection by probe hybridization

Northern Transfer: detection of RNA fragments

Western Transfer: detection of proteins”

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14
Q

what codon & AA does the initiator tRNA aminoacyl bind to?

A

initiator aminoacyl tRNA binds the start codon and transports the AA formylmethionine

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15
Q

Polysomes (Polycistronic mRNA):

  • cell type?
  • protein translation?
A
  1. polycistronic mRNA found in prokaryotic cells.
  2. contain multiple start codons and proteins are translated separately into many proteins
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16
Q

what organelles are found within a prokaryote?

A

ribosomes, nucleoid, plasmid, cytoplasm, flagella/pilli, cell wall, and plasma membrane

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17
Q

a non-membrane bound form of CD14 stimulates endothelial cells via interactions w/LPS.

Would CD14 be found in the blood/ECF or the cytoplasm of the endothelial cell?

A

CD14 would be found within the blood/ECF b/c LPS is released by bacteria in the ECF, therefor CD14 could only interact if its also in ECF.

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18
Q

How does the nuclear envelope confine translation to the cytosol?

A

Nuclear Envelope: inner (chromosomal DNA & nuclear RNA) & outer (studded w/ribosomes) membrane system

– perforated by nuclear pores (aqueous channel) that are too small for ribosomes (~30nm) to pass through

– pores are capable of expansion if a molecule contains a nuclear import signal

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19
Q

What is the diameter of a nuclear pore, and how does it accomodate the passage of molecules that exceed the size of the pore?

A
  1. nuclear pore = ~9nm diameter
  2. presence of nuclear import signal (containing (+) AA’s) allows nuclear pore to expand to accomodate objects > 9nm
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20
Q

If RNA is injected into a nucleus and later found in the cytosol, and then injected into the cytosol of a 2nd cell, and no RNA was found in the nucleus, where is the receptor most likely located?

A

nuclear export signal would be found on the nucleoplasmic face

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21
Q

What’s the difference between Gram-positive and gram-negative bacteria?

A
  • *Gram (+):**
  • thick peptidoglycan layer
  • no LPS
  • *Gram (-):**
  • Ex: e. coli
  • express LPS—»stimulate inflammatory immune response
  • thin peptidoglycan layer (network forms double membrane w/periplasmic space)
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22
Q

a phosphatidylethanolamine molecule is formed from which components?

A
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23
Q

what is the greatest contributing fator as to why integral membrane proteins do not diffuse transversley accross a membrane?

A

Asymmetric Distribution of Proteins—» integral proteins vary at ECF vs. cytoplasm & hydrophillic regions cannot transverse hydrophobic interior of PM

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24
Q

How many moles of water are required to hydrolyze a peptide bond?

A
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25
Q

Why is the Na+/K+ ATPase pump more essential (most active) in cells of the Loop of Henle vs. cells in the veins, lungs, or bone marrow?

A

while viens, lungs, and bone marrow all rely on ion exchange, the LOH employs this mechanism in order to concentrate urine ∴ the Na+ pump is most important at LOH.

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26
Q

what is the purpose of a signal seuence protein domain?

A

signal sequence domains are required for proteins directed towards secretory pathways

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27
Q

whats the importance of a negative regulator in gene expression?

A

a negative regulator protein blocks the transcription of a gene when bound, generally by preventing a ligand from binding and activating transcription

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28
Q

Spatial regulation of genes

A
  1. type of regulation of gene expression in which a gene is only expressed in a specific location
  2. Ex: seed storage proteins
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29
Q

temporal regulation of genes

A
  1. type of regulation of gene expression in which a gene is only expressed at a specific time in development
  2. Ex: genes that are only expressed in the light or during flower development
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30
Q

why are certain genes capable of both temporal and spatial regulation of target genes?

A

nuclear factors vary in different cell types and ∴ confer both temporal and spatial regulation of target genes

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31
Q

Glutamine

A
  • Abbreviations: Gln | Q
  • polar
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32
Q

how are different isoforms of proteins expressed?

A

different isoforms of a protein expressed from single genes through alternative splicing of exons of the primary transcript

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33
Q

angiogenesis

A

malignant tumors often undergo mutations that propote their growth and the development of blood vessels to feed them

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34
Q

Oncogenesis

A
  • associated w/mutations that occur by randon chance or as a result of mutagenic compounds (i.e. mutagens/carcinogens)

• Ex of Mutagens = UV light, reactive oxygen species, etc.

  • dysregulation of gene expression —» oncogenes promote abnormal growth and proliuferation leading to cencer
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35
Q

could higher levels of pro-apoptotic gene expression potentially slow proliferation?

A

Yes

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36
Q

assuming that a cationic protein is (+) at physiological pH, the primary structure MUST contain…

A. more basic residues than uncharged residues

B. more basic residues than acidic residues

A

(B) more basic residues than acidic residues

  • question asks what MUST be true, ∴ A is incorrrect b/c a protein could have less basic than uncharged residues and still be a cationic protein
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37
Q

For the S156E residue, what AAs are present?

A

S = serine

E = glutamate

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38
Q

Fight or Flight Response

A
  1. activation of the sympathetic nervous system

2. Physiological reactions:

  • pupils dialate
  • inc. HR
  • inc. blood flow to skeletal muscles
    3. Hormonal Regulation
  • Epinephrine/Norepinephrine
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39
Q

Rest & Digest Response

A
  1. Activation of parasympathetic nervous system
  2. Phisiological rxn:
    - inc. blood flow to digestive system
    - dec. HR
    - pupil constriction
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40
Q

Aldostertone

A
  1. hormone synthesized in the adrenal cortex - released in response to low BP
  2. acts on the distal tubule and of the nephron to increase sodium reabsorption in the distal tubule & proximal collecting duct—»favors water reabsorption
    - upregulates the Na+/K+ pumps lining the nephron—»pump 3 Na+ into blood/pump 2K+ into the nephron/cell (away from blood)
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41
Q

what is the most effective way to dispose of agar plates and pipette tips that were used in an experiment involving pathogenic bacteria?

A

place materials into an open metal container and autoclave

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42
Q

Single Crossover

A
  • affect only one arm of each chromosome
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43
Q

Double Crossover

A
  • affect two arms of each chromosome
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44
Q

does lipid synthesis increase or decrease when insulin is released into the bloodstream?

A
  • lipid synthesis would incresae to store incoming glucose
  • also would see increased glycogen synth, inc. esterificaiton of FA, & dec. gluconeogenesis
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45
Q

Reduction

A
  1. gain of an e-
  2. decreased oxidation state
  3. formation of a C-H bond (alkene—»alkane)
  4. loss of a C–O or C–N bond (or any other electronegative atom and carbon)
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46
Q

If i wanted to use a PET scan to compare the metabolic activity of cancer cells relative to normal ones, which compound should i radioactively label to examine these effects?

pyruvate, acetyl-CoA, ATP, or glucose

A

glucose—» it’s the onle molecule that would travel through the blood between normal and cancer cells, the other options are all produced intracellularly

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47
Q

are Fungi eukaryotes or prokaryotes?

A

Eukaryotes

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48
Q

Analogous Structures

A
  1. structures that evolved independently to carry out the same function
  2. Ex: wing of bee and wing of bird
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49
Q

Homologous Strucutres

A
  1. structures that have similar evolutionary history, arising from common anscestor, but have different functions
  2. Ex: wing of a bee and wing of a bat, forelimbs of mammals (human arm, walrus flipper, bat wing)
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50
Q
  1. where are post-transcriptional modifications completed?
  2. what molecules undergo post-transcriptional modification?
A
  1. all post-transcriptional modifications occur in the nucleus
  2. mRNA is modified via post-transcriptional modification (i.e. poly(A) tail, 5’ cap, splicing)
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51
Q

Epimer

A
  1. sugars that differ at only 1 stereocenter
  2. epimers = anomers, diastereomers
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52
Q

Eicosanoids

A
  1. family of lipids derived from arachidonic acid
  2. 20C molecules w/5C ring
  3. Prostaglandins: signaling molecules w/diverse range of effects including modulation of inflammation
  4. Thromboxanes: involved in the clotting cascade

• NSAIDS (i.e. aspirin) anti-inflammatory drugs inhibit COX1 & COX2 enzymes involved in early steps of clotting pathway preventing production of prostaglandins

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53
Q

the disruption of which membrane component results in cellular traffic complications similar to that of gap junction disorders?

  • cholesterol
  • glycoproteins
  • glycolipids
  • phospholipids
A

Glycoproteins:

  • of all membrane components listed, glycoproteins are the only transmembrane proteins that span the length of the whole PM
  • only transmembrane proteins that extrend throughout the entire membrane will play a role in the management of cellular traffic in and out of the cell
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54
Q

What is the average mass of an amino acid residue?

A

~110 Da

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55
Q

siRNA

A
  1. small interfering RNA (siRNA): binds RNA (not DNA or proteins) to interfere w/expression of certain genes (generally dec. expression)
  2. siRNA interferes w/gene after transcription but before translation ∴ it must prevent the translation of mRNA corresponding to the target protein
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56
Q

Western Blot Test

A

used to identify protein sequences

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57
Q

Southern Blot Test

A

used to identify specific DNA sequences

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58
Q

Northern Blot Test

A

used to identify RNA sequences

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59
Q

ELISA

A
  1. Enzyme-linked immunosorbent assay (ELISA): uses a solid-phase imunoassy to detect the presence of an antigen
  2. intensity of signal following the addition of an enzyme’s substrate is related to the quantity of protein antigen present in the original sample
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60
Q
  1. Can amino acids cross the BBB?
  2. can antibodies cross the BBB?
A
  1. Yes
  2. No (too big)
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61
Q
  1. what types of molecules are more likely to diffuse through the BBB: lipid soluble or hydrophilic molecules?
A
  1. lipophilic molecules more readily pass the BBB

EX: by replacing the alcoholic protons with acetyl groups on a molecule is one example of a way to change a drug to make it more soluble within the BBB

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62
Q

Why is folate given as a supplement to pregnant women?

A
  1. Folate prevents neural tube defects
  2. prevents defects b/c it plays a role in ectodermal induction—»folate is important for neurulation (the induction of the ectoderm–from which the CNS is derived–to differentiate into the nervous system)
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63
Q

Uracil is usually found in:

I. tRNA

II. ribosomes

III. ssDNA

A

I & II —» uracil can be found in any structure that is composed of RNA

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64
Q

Suicide Inhibition

A

irreversible inhibition where substrate irreversibly binds to the enzyme

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65
Q

Hyperventilation (Physiological Changes)

A
  1. dec. of CO2 & inc. of O2 in the blood
  2. inc. blood pH
  3. increased Hb O2 affinity
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66
Q

Hypoxia

A

oxygen deprivation

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67
Q

A) What are the structures of…

  1. folic acid
  2. carbonic acid
  3. ascorbic acid
  4. citric acid

B) which isnt an organic acid?

A

(B) Carbonic Acid.

• Organic acids:

  • must contain C & H (and must contain 1+ C-H bond),
  • weak acids,
  • formula R-CO2H (acidic H+ usually bound to O)
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68
Q

What signal is needed to export mRNA from the nucleus to the cytoplasm?

A

polyadenylation (post-transcriptional modification)

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69
Q

Post-Transcriptional Modifications

A

• immediate product of transcription in Euk = heterogenous nuclear RNA (hnRNA)—»post-transcriptional modifications convert hnRNA into mRNA

  1. 3’ poly-A tail: ~250 adenine nucleotides added to 3’ end of hnRNA —» prevent degredation in cytosol of cell
  2. 5’ cap: 7-methylguanylate triphosphate cap added to 5’ end of hnRNA —» prevent cytosol degredation but also preps RNA for export from nucleus
  3. splicing: introns are removed and exons are ligated together
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70
Q

Transduction

A

form of horizontal gene transfer in bacteria —» bacteriophage (bacterial virus) transmits genomic material (viral gene vector)

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71
Q

Transformation

A

direct uptake of genetic material from environment and is not mediated by viruses

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72
Q

Transfection

A

transmission of genetic material (usually a human plasmid) via the mechanism of some chemical (NON-VIRAL METHODS) that generates openings in the pores of the cell

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73
Q

What is the difference between intra-subunit and inter-subunit interactions?

A
  1. Intra-Subunit: interactions between residues occur on the same chain/subunit
  2. Inter-Subunit: interactions between residues occur btwn two different chains/subunits
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74
Q

G0 Phase

A
  1. the state of the cell cycel a cell enters when it does not need to divide
  2. Ex: epithilial cells are rarely found in G0 b/c they’re constantly dividing whereas neurons are almost always in G0
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75
Q

Viruses (Characteristics)

A
  1. obligate intracellular parasite
  2. ssDNA/RNA or dsDNA/RNA (viral vector)
  3. described as “non-living”
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76
Q

Positive-Sense RNA virus

A
  1. ssRNA virus
  2. contains mRNA that’s immidiately translated by the cell
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77
Q

Negative-sense RNA virus

A
  1. ssRNA virus
  2. contain RNA thats complementary to mRNA

• in this case the mRNA is transcribed by the enzyme RNA replicase, which is caried by the viron

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78
Q

Is the ATP generated during B-oxidation of FAs synthesized via glycolysis, ox phos., or both?

A

all atp is generated by oxidative phosphorylation via the ETC

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79
Q

What nucleic acid substitutions are least likely when they result from methylation or deamination?

A

a change from purine to pyrimidine or vice versa, would be least likely b/c modifications via deamination and methylation would not alter the # of rings in the structure and ∴ wouldnt make change btwn nucleotide class

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80
Q
  1. what is the charge on the proteins tested using SDS-PAGE?
  2. why might the molecular weight of the protein run on the SDS-PAGE appear to be lower than the known MW?
A
  1. negative
    2a. if there are alot of (+) charges on the protein, then it will have a smaller overall (–) charge and travel less distance—»indicating that its heavier than anticipated
    2b. if alot of (-) charge on protien, then overall (-) charge inc. and protein travels farther distance—»indicating that its lighter than anticipated
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81
Q

Passive Immunity

A
  1. the transfer of active humoral immunity in the form of ready-made antibodies from one individual to another

•Ex: passage of IgG Ab’s from mom to fetus

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82
Q

Innate (Nonspecific) Immunity

A
  1. innate immune system includes:

A) anatomical barriers: Mechanical = skin/internal epithelial layers, movement of the intestines, and oscillation of bronchopulmonary cilia

B) secretory molecules

C) cellular components: WBCs (leukocytes)—»neutrophils, lymphocytes, monocytes (diff. into macrophages/dendritic cells), eosinophils, basophils, and mast cells

  1. responds generally to threats (doesnt learn to recognize specific pathogens—»adaptive immune system)
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83
Q

Cell-Mediated Immunity

A
  1. immune response that does not involve antibodies, but instead the activation of phagocytes, antigen specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen
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84
Q

Natural Immunity

A
  1. immunity that is present in the individual at birth, prior to exposure to a pathogen

• includes intact skin, salivary enxymes, neutrophils, natural killer cells, etc.

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85
Q

retrovirus

A
  1. have positive-sense RNA genomes (no DNA gemone)
  2. Require reverse transcriptase to synth mRNA from complementary viral RNA
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86
Q

Why have glucocorticoids been implicated in weight-gain?

A
  1. Glucocorticoids: increases blood glucose level (via adipocyte hydrolysis) and decreases protein synthesis -anti-inflammatory
  2. short-term release of glucocorticoids causes a release of glucose and the hydrolysis of fats from adipocytes—»BUT, glucose not used for metabolism & inc. promotes fat storage—»net result = release of glucose from the liver to be converted into lipids in the adipose tissue under insulin stimulation
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87
Q

What are the chances a child inherits a mutation in a somatic, non-germ line?

A

0%

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88
Q

How many fused rings are present in a steroid?

A

4

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89
Q

Where does the filtrate have its highest concentration?

A

In the medullary portion of the collecting duct, toward the middle of the kidney. The cortical portion of the kidney is the outer cortex.

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90
Q

How does the Na/K ATPase function in an action potential?

A

It restores the resting potential by moving the ions against their concentration gradients

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91
Q

What are ABC transporters?

A

They use ATP to actively transport molecules out of the cell

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92
Q

What are lipid rafts?

A

Cholesterol rich domains of a cell membrane

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93
Q

What is the initial step in glomerular filtration?

A

A passive flow due to a pressure difference. Blood pressure forces the fluid out of the glomerulus and into the lumen of Bowman’s capsule

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94
Q

How do enzymes affect the rate of chemical reactions?

A

They lower the activation energy by co-localizing substrates, altering substrate shape, and altering the local pH. Although they may possess proteolytic function, this is not altering the substrate primary structure

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95
Q

If there is increased concentration of a protein, what is also increased in the cell?

A

The concentration of mRNA for said protein

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96
Q

What happens when a hormone stimulates the release of another hormone which is unable to be produced by the body?

A

The body will continue to release the stimulatory hormone in an effort to increase the concentration of the other hormone, although the other hormone which is unable to be produced will never enter circulation

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97
Q

How does insulin affect glucose in the liver?

A

It aids in glucose uptake by decreasing cellular concentration of glucose by stimulating the first step of the glycolytic pathway

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98
Q

How do macrophages trap foreign material?

A

They trap it within a phagosome which fuses with a lysosome to become a phagolysosome

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99
Q

How does ATP inhibit phosphofructokinase-1?

A

Allosterically through negative feedback

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100
Q

What is active transport vs. facilitated diffusion?

A

Active transport pumps molecules against their concentration gradient. Facilitated diffusion uses a protein to guide a molecule with its concentration gradient and therefore is passave and does not require ATP

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101
Q

If a molecule has an isoelectric point of 9, what does this mean?

A

It has a positive charge at physiological pH

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102
Q

What is the end result of ubiquitination?

A

It targets a protein for degredation by a proteasome

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103
Q

How are disulfide bonds formed in proteins?

A

By thiol groups in cysteine residues and the bonds are broken through reduction

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104
Q

What reaction does GAPDH catalyze?

A

The reversible conversion of G-3-P to 1,3-BPG

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105
Q

What are some ways to influence the reactive oxygen species in yeast?

A

engineer them to lack antioxidant enzymes, make them overexpress antioxidant enzymes, grow them in the presence or absence of hydrogen peroxide

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106
Q

What part of the nephron does vasopressin regulate the insertion of aquaporins?

A

In the collecting duct

107
Q

Which cells myelinate the axons of the peripheral nervous system?

A

Schwann cells (oligodendrocytes are in the CNS)

108
Q

How are proteins translated?

A

Their amino end is translated first, the carboxyl end translated last. An insertion mutation in the mRNA will cause the downstream C-terminal amino acid sequence to change

109
Q

What is phosphoenolpyruvate?

A

A product of glycolysis

110
Q

What is avogadros number?

A

6x10^23 molecules per mole

111
Q

How are egg and sperm most similar?

A

In genome size. (If you think that because the x and y chromosome are different lenghts, they are but remember eggs and sperm can have any combination of x or y chromosomes)

112
Q

Where do microtubules originate in a cell?

A

In centrosomes

113
Q

What is the variable region of an antibody?

A

The two tips of the Y

114
Q

Explain rigormortis

A

The myosin heads are stuck to the actin filament because there is no ATP to bind the myosin head to release it

115
Q

How do you make a homodimeric protein move like a 22 kDa protein rather than a 44 kDa protein in SDS-PAGE?

A

Adding a reducing agent will break the disulfide bond of the homodimer

116
Q

General Trasncription Factors

A

bind the operator of a gene to promote transcription

117
Q

Promoter

A
  1. region of DNA upstream of gene that initiates transcription of a gene
  2. binds RNA polymerase for transcription of gene
118
Q

Activator

A
  1. bind promoter to induce RNA polymerase to bind and transcribe the gene
  2. Ex: CAP protein—»activates transcription of lac operon in e. coli when cAMP binds during glucose starvation
119
Q

Repressor

A
  1. binds to the operator region to prevent transcription (unless bound by an inducer)
  2. Ex: lac repressor—»prevents transcription of lac operon

•lactose = inducer molecule—»causes repressor to unbind operator and allow for RNA pol transcription

120
Q

Enhancer

A
  1. sequence of DNA that functions to enhance transcription
  2. can be located far away from the gene it enhances (upstream, even on different chromosome)
  3. bound by activator proteins to interact w/mediator complex that recruits RNA polymerase
121
Q

Silencer

A
  1. regions of DNA bound by repressor proteins in order to silence gene expression
  2. located several bases upstream or downstream of gene
122
Q

Differences between Prokaryotic and Eukaryotic Transcription

A
  1. Prokaryotes:
    - the regulation of transcription needed for cell to respond quickly to ever-changing outer environment
    - heavy reliance on activators, repressors, & enhancers (rarely)
    - simultaneous transcription/translation of gene

2. Eukaryotes:

  • tend to involve combination of transcription factors that allow for more sophisticated response to environmental conditions
  • presence of nuclear envelope prevents simultaneous transcription/translation of gene
123
Q

Glucocorticoids

A
  1. Glucocorticoids: increases blood glucose level (via adipocyte hydrolysis) and decreases protein synthesis
124
Q

if a cancerous mutation is found only within tumor cells, can the mutation be passed on to a progeny?

A

No—»the mutation is a somatic, not a germ line mutation ∴ its not inherited

125
Q

when concentrated urine is being produced, where in the nephron will the glomelular filtrate reach its highest concentration?

A
  1. Medullary Portion of the collecting duct
126
Q

Lipid Rafts

A

-very stable structures w/region of high sphingolipid and Cholesterol density

127
Q

Are enzymes capable of altering local pH?

A

Yes

128
Q

Aldosterone

A
  1. Mineralocorticoid—»produced in the adrenal cortex
  2. maintains ionic balance by conserving Na+ in cell while excreting K+ from cell
  3. at the DCT & collecting ducts—»increases Na+ reabsorption and water retention
129
Q

What are the effects of insulin on the liver?

A
  1. insulin stimulates the glycolytic pathway in the liver—»aids in glucose uptake (∴ dec. cellular concentration of glucose) 2. glucose transporters in the liver dont require insulin for uptake into the cell
130
Q

Endomembrane System

A

secreted proteins are cleaved into mature forms and modified for release into the cell

131
Q

ADH (Vasopressin)

A
  1. produced in hypothalamus & stored/released from posterior pituitary 1. Low Blood volume response—»stimulates water reabsorption in collecting duct (inc. permeability of H2O)
132
Q
A

5/8

133
Q

Na+ K+ ATPase

A
134
Q

Henry’s Law Constant (kH)

A
  1. Henry’s law constant kH relates the solubility of a gas to the pressure of that gas Pg above the solution 2. S = kH • Pg S: solubility of gas | kH: Henry’s Law constant | Pg: partial pressure of gas
135
Q

Ghrelin Secretion

A
  1. secreted by the stomach in response to signals of an impending meal (stimulated by sight, sound, taste, smell) 2. increases appetite and stimulates ecretion of Orexin (further inc. appetite and involved in sleep/wake cycle)
136
Q

Leptin Secretion

A
  1. hormone secreted by fat cells to decrese appetit by suppressing orexin production 2. implicated in obesity—»KO mice unable to produe leptin becomes obesee
137
Q

What are the 3 AA that are phosphorylated in Eukaryotic Cells?

A

Serine, Tyrosine, & Threonine (any AA w/an -OH grp)

138
Q

Barr Bodies

A
  1. the inactive X chromosome in a female somatic cell,[2] rendered inactive in a process called lyonization 2. one of the last chromosomes to replicate in mitosis—»due to intense coiling
139
Q

How is H20 excreted from the body?

A
  1. H20 excreted via the skin & lungs • NOT the kidney/colon —» at these locations water is REABSORBED
140
Q

Microglia

A
  1. Derived from macrophages—»immune cells of the CNS 2. due to the BBB, the brain is not normally accessible to other immune cells / WBCs unless recruited by microglia
141
Q

Astrocytes

A
  1. general-purpose glia of CNS—»forms BBB & involved in neuron metabolism/recycling of NTs
142
Q

Oligodendrocytes

A
  1. produce mylein for CNS
143
Q

Ependymal Cells

A
  1. Make CSF 2. cells line the ventricles and the inside of the spiinal chord
144
Q

Satellite Cells

A
  1. general-purpose glia of PNS—»forms BBB & involved in neuron metabolism/recycling of NTs
145
Q

Schwann Cells

A
  1. produce myelin in the PNS
146
Q

Cardiac Output

A
  1. CO = HR • Stroke Volume • CO = BP/resistance 2.CO: amount of blood ejected by the left ventricle each minute.
147
Q

Blood Pressure (BP)

A
  1. BP = CO • peripheral resistance
148
Q

Stroke Volume

A
  1. the amount of blood pumped out of the left ventricle/beat
149
Q

Log [i.e. # of cells] = 4 # cells = ?

A

10^4 = 10,000 # cells = 10,000

150
Q

Blood-Brain Barrier

A
  1. In blood capillaries, neighboring endothelial cells form tight junctions with one another to restrict the diffusion of harmful substances and large molecules into the interstitial fluid surrounding the brain 2. molecules that are small, non-charged, and lipophilic will easily dfifuse accross the BBB 3. glucose and AAs will also pass BBB, but—»these enter through special transport proteins and dont readily diffuse
151
Q

What are the 3 stop codons?

A
  1. amber (UAG) 2. opal or umber (UGA) 3. ochre (UAA)
152
Q

Nuclear Localization Signal

A
  1. a signal that guides a protein molecule to the nucleus—»This is useful to up/down regulate certain cellular processes and products.
153
Q

Signal Sequence

A
  1. signal that allows the protein to enter the RER—»typically taggrd on proteins that will be secreted into cytoplasm / plasma membrane (i.e. membrane transporters)
154
Q

cDNA

A

Complementary DNA

155
Q

Negative Control

A
  1. control to show what happens in the absence of whatever IV is being applied 2. treatment setup is the exact same as experimental setup BUT no INDEPENDENT VARIABLE
156
Q

What is the negative control of a transfection study?

A
  1. negative control is the cell being transfected with an empty vector (no DNA) 2. i.e. “mock transfected”
157
Q

Phosphate groups replace what atoms on tyrosine residues?

A

OH

158
Q

receptor tyrosine kinase

A
159
Q

Acetyl-CoA—»Malonyl-CoA—»Palmitoyl-CoA

A
160
Q

Malonyl-CoA

A
161
Q

Acetyl-CoA—»Malonyl-CoA—»Palmitoyl-CoA

A
162
Q

Hb Binding Curve:

  1. CO2
  2. pH
  3. Temp
  4. 2,3-DPG
  5. HbF
A
163
Q

Eukaryotic ribosome

A
164
Q

What are the 8 AA with ionizable R-Groups?

  1. What are the pkas of these R-groups
  2. what are the charges at physiological pH
A

Don’t memorize pKa

165
Q

Which AA are charged at physiological pH?

A

DE HRK

166
Q

Native PAGE

A

No denaturant and no reduction, done at close to physiological pH so as to preserve the protein in its natural folded state.

167
Q

Henry’s Law Constant (kH)

A
  1. Henry’s law constant kH relates the solubility of a gas to the pressure of that gas Pg above the solution 2. S = kH • Pg S: solubility of gas | kH: Henry’s Law constant | Pg: partial pressure of gas
168
Q

Ghrelin Secretion

A
  1. secreted by the stomach in response to signals of an impending meal (stimulated by sight, sound, taste, smell) 2. increases appetite and stimulates ecretion of Orexin (further inc. appetite and involved in sleep/wake cycle)
169
Q

Leptin Secretion

A
  1. hormone secreted by fat cells to decrese appetit by suppressing orexin production 2. implicated in obesity—»KO mice unable to produe leptin becomes obesee
170
Q

What are the 3 AA that are phosphorylated in Eukaryotic Cells?

A

Serine, Tyrosine, & Threonine (any AA w/an -OH grp)

171
Q

Barr Bodies

A
  1. the inactive X chromosome in a female somatic cell,[2] rendered inactive in a process called lyonization 2. one of the last chromosomes to replicate in mitosis—»due to intense coiling
172
Q

How is H20 excreted from the body?

A
  1. H20 excreted via the skin & lungs • NOT the kidney/colon —» at these locations water is REABSORBED
173
Q

Microglia

A
  1. Derived from macrophages—»immune cells of the CNS 2. due to the BBB, the brain is not normally accessible to other immune cells / WBCs unless recruited by microglia
174
Q

Astrocytes

A
  1. general-purpose glia of CNS—»forms BBB & involved in neuron metabolism/recycling of NTs
175
Q

Oligodendrocytes

A
  1. produce mylein for CNS
176
Q

Ependymal Cells

A
  1. Make CSF 2. cells line the ventricles and the inside of the spiinal chord
177
Q

Satellite Cells

A
  1. general-purpose glia of PNS—»forms BBB & involved in neuron metabolism/recycling of NTs
178
Q

Schwann Cells

A
  1. produce myelin in the PNS
179
Q

Cardiac Output

A
  1. CO = HR • Stroke Volume • CO = BP/resistance 2.CO: amount of blood ejected by the left ventricle each minute.
180
Q

Blood Pressure (BP)

A
  1. BP = CO • peripheral resistance
181
Q

Stroke Volume

A
  1. the amount of blood pumped out of the left ventricle/beat
182
Q

Log [i.e. # of cells] = 4 # cells = ?

A

10^4 = 10,000 # cells = 10,000

183
Q

Blood-Brain Barrier

A
  1. In blood capillaries, neighboring endothelial cells form tight junctions with one another to restrict the diffusion of harmful substances and large molecules into the interstitial fluid surrounding the brain 2. molecules that are small, non-charged, and lipophilic will easily dfifuse accross the BBB 3. glucose and AAs will also pass BBB, but—»these enter through special transport proteins and dont readily diffuse
184
Q

What are the 3 stop codons?

A
  1. amber (UAG) 2. opal or umber (UGA) 3. ochre (UAA)
185
Q

Nuclear Localization Signal

A
  1. a signal that guides a protein molecule to the nucleus—»This is useful to up/down regulate certain cellular processes and products.
186
Q

Signal Sequence

A
  1. signal that allows the protein to enter the RER—»typically taggrd on proteins that will be secreted into cytoplasm / plasma membrane (i.e. membrane transporters)
187
Q

cDNA

A

Complementary DNA

188
Q

Negative Control

A
  1. control to show what happens in the absence of whatever IV is being applied 2. treatment setup is the exact same as experimental setup BUT no INDEPENDENT VARIABLE
189
Q

What is the negative control of a transfection study?

A
  1. negative control is the cell being transfected with an empty vector (no DNA) 2. i.e. “mock transfected”
190
Q

Missense Mutation

A

point mutation where one of the DNA base pairs is changed

191
Q

Nonsense Mutation

A

point mutation to a single DNA bp, where the change results in the production of a premature stop codon

192
Q

silent mutation

A

a change in the DNA sequence w/out a subsequent change in the AAs or function of the overall protein

193
Q

frameshift mutation

A

occurs when the “addition” or “deletion” mutations result in a change to the gene’s reading frame—»alters the AAs that are encoded downstream of the mutation

194
Q

what types of molecules drain to the liver prior to arrival at the vena cava? what types dont, and where do they drain?

A

• All hydrophilic molecules (i.e. vitamin C, alanine, galactose) will drain to the liver • all lipid soluble lomecules (i.e. vitamin E) are absorbed by the lacteals in the intestines

195
Q

what mechanism of transport does water primarily move through the cell membrane with?

A

facilitated transport—»aquaporins are the main way that water is transported throughout the body

196
Q

what are the granulocytic cells?

A

neutrophils, eosinopils, and basophils

197
Q

SAME DAVE [neuron pneumonic]

A

Sensory Afferent; Motor Efferent | Dorsal Afferent; Ventral Efferent

198
Q

Transformation

A

the genetic alteration of a cell from incorporating outside DNA—»changes DNA fingerprint ∴ not related to analytical process of DNA fingerprinting

199
Q

Directional Selection

A

Directional selection: selects for a trait on one extreme. EX: election for height of canopy trees in a rainforest: trees compete for sunlight, so selection favors trees to become higher and higher.

200
Q

Disruptive Selection

A

Disruptive selection: selects for the extremes. EX: birds occupying a habitat with 2 distinct niches (eating berries for a living and eating seeds for a living): small beaks are selected for eating berries, large beaks are selected for cracking seeds, medium beak is left out.

201
Q

stabilizing selection

A

selects for a trait that is moderate, and selects against the extremes. EX: birthweight: too low birthweight means that the baby is premature, too high birthweight means that the mom will have a hard time delivering, so there’s a “just right” birthweight that is selected for.

202
Q

There are 100 cats in a population that follows Hardy-Weinberg conditions. 4 cats display a recessive white coat color. How many of the cats are heterozygous?

A
  1. 4/100 cats are recessive, which means that q2 = .04 à q = 0.2. p must then be 0.8, and the number of heterozygotes is 2pq x 100.
203
Q

Edward’s Syndrome

A

autosomal non disjunction—»trisomy 18

204
Q

Hayline Cartilage

A

covers the bones at the point of contact in the joints—»prevents surfaces of bones from rubbing against one another

205
Q

how many nuclei do skeletal, smooth, and cardiac muscle have?

A

Cardiac = 1-2 nuclei smooth = one nucleus skeletal = multi-ncleated

206
Q

T/F: cholesterol maintains cell membrane fluidity

A

TRUE

207
Q

Which types of muscle exhibit myogenic activity

A

Cardiac & smooth muscle—»myogenic = does not require nervous system stimulation

208
Q

what is the function of yellow bone marrow?

A

Energy storage—»yellow color due to the high # of fat cells that serve as energy storage sites

209
Q

Cardiac sphincter

A

cardiac sphincter, named for its proximity to the heart, connects the esophagus to the stomach.

210
Q

Pyloric sphincter

A

pyloric sphincter is located at the junction of the stomach and duodenum.

211
Q

Where is bile formed and what is its function?

A

Bile formed in the Liver (but stored in the gallbladder) and it emulsifies fats to aid in digestion

212
Q

Water Soluble Vitamins

A

Vitamin C, B1 (thiamine), B2 (Riboflavin), B3 (Niacin), B6 (pyridoxine), B12 (bocalamin), biotin, & folate

213
Q

Fat Soluble Vitamins

A

Vitamin A- visual pigment, response to light vitamin E- prevents unsaturated fat oxidation vitamin K- aids in blood coagulation vitamin D- stim. Ca2+ abs. from gut and controls Ca2+ deposition

214
Q

what area of the nephron has the highest solute concentrations?

A

inner medulla

215
Q

What happens when a surgeon mistakenly severs a dorsal root ganglion?

A

Loss of sensation is expected—»dorsal side of spinal chord receives sensory inputs

216
Q

Active Immunity

A

Active immunity is when you are exposed to a pathogen, either through vaccination, another person with the disease, or any other means, and your body responds by producing specific antibodies with B-cells to destroy the pathogen.

217
Q

Passive Immunity

A

Passive immunity is acquired from antibody transfer, so the body does not produce its own antibodies.

218
Q

Cell-mediated immunity

A

The cell-mediated immunity is associated with the T-lymphocytes and is responsible for destroying the pathogens or microorganism which have invaded the cells.

219
Q

innate immunity

A

Innate immunity refers to the body’s natural untargeted defenses, such as the cells that would work to repair damage.

220
Q

Humoral Immunity

A

The humoral immunity is associated with the B-lymphocytes and is responsible for destroying the pathogens by producing antibodies against it.

221
Q

A patient on several powerful anticholinergic medications would be expected to experience: a) diarrhea b)vasodilaiton of SI blood vessels c) dry mouth d) pupillary constriction

A

DRY MOUTH—» Parasympathetic innervation is involved in “rest and digest” functions. Logically, blocking such eating-related responses would dry the mouth out by inhibiting salivation.

222
Q

Where is lactase active in the body?

A

Lactase breaks down lactose in the small intestine

223
Q

Aminopeptidase. Site of Production? Site of function? Action?

A

Intestinal Glands. Small Intestine (specifically the duodenum where environment is slightly basic). Hydrolyzes terminal peptide bond at amino teminus.

224
Q

what hormone levels peak just prior to ovulation?

A

LH

225
Q

At what stage of meiosis are ova held at until puberty?

A

Prophase I

226
Q

at what time during development does an embryo become a fetus?

A

9 weeks

227
Q

Thyroid-Stimulating Hormone (TSH)

A

released by anterior pituitary gland—»stimulates release of thyroid hormones (inc. metabolism)

228
Q

Thymus Gland

A

T-lymphocytes differentiate and mature after being produced in the bone marrow. thymus removes pathogens from lymph.

229
Q

the wing of a bird and a human arm are an example of _________ structures?

A

Homologous structures

230
Q

Parthenogenesis

A

when a female can develop a new individual without fertilization occurring

231
Q

Secondary Spermatocyte

A

products of meiosis I—»first time haploid cells are formed

232
Q

What are ACE inhibitors and how do they affect Angiotensin?

A

-ACE inhibitors prevent the conversion of angiotensin I—»angiotensin II -Angiotensin II inc. aldosterone levels ∴ w/ACE inhibitors, aldosterone lvls are lower (inc. K+ reabsorption, dec. Na+ reabsorption)

233
Q

Ectoderm

A
  1. forms out linings of the body: epidermis and hair 2. forms CNS & PNS 3. precursor to mammary glands
234
Q

Endoderm

A
  1. form many of the internal linings of the body: GI tract, lungs, live, pancreas, and upper urogenital tract/female vagina 2. Organs formed: colon, stomach, intestines, lungs, & pancreas
235
Q

Mesoderm

A
  1. give rise to all tissues of the body: dermis of skin, the heart, muscle system, urogenital system, bones & bone marrow, the blood
236
Q

Respiratory Alkalosis

A

medical condition in which increased respiration elevates the blood pH beyond the normal range (7.35–7.45) with a concurrent reduction in arterial levels of carbon dioxide

237
Q

A reversible competitive inhibitor, known as physostigmine, is used to treat glaucoma. Is it possible to reverse the effects of this medication to prevent an overdose, and if so how?

A

competitive inhibition can be overcome by adding additional agonist substrates—»compete w/physostigmine thereby preventing overdose

238
Q

hnRNA

A

-heterogenous nuclear RNA (hnRNA) = pre-mRNA -mRNA before undergoing post-transcriptional modification—»does not pass from nucleus to cytoplasm -conatins introns and a cap at the 5’ end

239
Q

RNA Polymerase I

A

transcribes genes into rRNA

240
Q

Release factors

A

proteins that recognize the stop codons and terminate protein synthesis

241
Q

If the ∆G° for a rxn = 0kJ/mol, what would the Keq for this rxn be?

A

-Keq = 1 -ΔG° = -RTlnKeq —» implies that neither forward/reverse direction are favored

242
Q

Which muscle tissue is most dependent on creatine phosphate and glycogen for fuel?

A

Active Skeletal Muscle—» creatine phosphate and glycogen are energy sources that are most necessary when a tissue is highly metabolically active

243
Q

Function of HMG-CoA reductase?

A

aids in the production of cholesterol by the smooth ER via the mevalonate pathway (cholesterol production process occuring in the liver)

244
Q

How do HDL molecules differ from LDLs

A

HDLs have relatively more protein than LDLs.

245
Q

What is ketolysis and where can it not take place?

A
  1. ketolysis: the breakdown of ketone bodies to provide energy 2. Liver lacks the enzyme required for this process
246
Q

Palmitic Acid

A
  1. excess carbohydrates are converted to palmitic acid—»highly common in animal tissue
247
Q

what are the 2 essential FAs that humans cannot endogenously produce?

A
  1. Linolenic and linoleic acid are essential FAs b/c the only way humans can get them is by ingesting them
248
Q

where does β-oxidation of fatty acids take place?

A

the mitochondria

249
Q

How many protons do complex IV and III add to the H+ gradient of the inner mitochondrial membrane?

A

Complex IV—»pumps 2H+ Complex III—»pumps 4H+

250
Q

insulin causes which type of glucose transporter to translocate to the cell membrane when blood sugar is high?

A

GLUT4

251
Q

Which enzyme catalyzes the rate-limiting step of glycolysis?

A

Phosphofrucktokinase-1

252
Q

What causes hyperpolarization of a neuron?

A

excess K+ efflux out of cell

253
Q

Peptidyl Transferase

A

•Peptidyl transferase carries out the main function of the ribosome: to link amino acids together with an amide linkage (also known as a peptide bond). •made up of rRNA rather than protein.

254
Q

If Protein X has a pI of 3.5 and Protein Y has a pI of 5, at which of these pH values will electrophoretic isolation of Protein X occur most easily? a) 1 b) 2 c) 3 d) 5

A

At a pH of 5, Protein Y will be neutral and stationary (since its isoelectric point is 5). Protein X, however, will be negatively charged and will move toward the anode in an isoelectric focusing procedure.

255
Q

if i digest cake that contains flour, milk, and sucrose–what carbohydrate products are entering my blood?

A
  1. glucose, galactose, & fructose - sucrose = glucose + fructose -lactose = glucose + galactose
256
Q

heterochromatin vs. euchromatin

A

Heterochromatin is tightly packed and therefore not very transcriptionally active. Euchromatin is less dense, which allows for more transcriptional activity.

257
Q

How many possible D isomers of D-ketohexose exist?

A
  • A ketohexose contains 333 chiral centers (C-3, C-4, C-5)
    • 23 = 8 total isomers
  • D-isomers account for half of the total isomers —» ∴ 4 isomers of D-ketohexose.
258
Q

glycosidic linkage forms as a result of a ________ reaction.

A

dehydration rxn

259
Q

DNA Ligase

A
  • DNA Ligase joins fragments of newly synthesized DNA by using ATP to catalyze the formation of phosphodiester bonds in the DNA backbone
  • without DNA ligase, H-bonds would form temporarily but without the phosphodiester backbone the molecule wont ligate
260
Q

What is cDNA? How is it produced?

A
  • cDNA = Complimentary DNA
  • cDNA is produced by reverse transcriptase, which uses mRNA as a template to generate a complimentary DNA strand
261
Q

clinical advantage of DNA microarray?

A

Microarrays are useful b/c the can simultaneously analyze the gene expression profiles of thousands of genes to study certain diseases and treatments

262
Q

is the nucleotide sequence of cDNA identical to the homologou DNA sequence in the genome?

A
  • NO—»cDNA is created based on an mRNA template, which has already undergone post-transcriptional modifications to remove introns from the sequence
  • cDNA = no introns
263
Q

Negative Control

A
  • Negative Control: designed such that no result is expected to occur
    • effective negative controls address the experimental hypothesis
    • EX: if hypothesis concerns UV dependent transcription of a gene an effective negative control would be a gene that was transcribed independent of UV treatment
264
Q
A

Alex's MCAT Flashcards (3 decks)

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