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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. from thoracic duct - chylomicrons stick to capillary walls...
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Sensory (afferent - dorsal) - motor (efferent - ventral)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

2. pancreatic enzymes are zymogens
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Gastrulation occurs: formation of three primary germ layers = differentiation
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel

3. examples of different cavities... (compartments for viscera)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Ups bicarbonate secretion by pancreas; raises pH to 6.0

4. Where do absorbed fats go in the enterocyte
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Break down TAGs to monoglycerides and free fatty acids
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt

5. cAMP - cGMP - calmodulin...
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Organs
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

6. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Needs time for bile - lipase - micelle migration - enterocyte uptake

7. micelles also pick up
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Estradiol

8. FLAT PG: TSH aka thyrotropin
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Glucose and ketone bodies (not from glycogen stores)
Break down TAGs to monoglycerides and free fatty acids

9. Adrenal cortex hormones (STEROIDS)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Organs
In mouth - breakdown of starch into polysaccharides
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

10. What does peptic refer to in general
Digestion
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang

11. exocrine types
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

12. Anterior eye vs. posterior eye
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Determined by whether in front of or behind the lens
Albumin increases osmolarity of blood; increases osmotic pressure
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons

13. Gland: ovaries
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Vitamin K - b12 - thiamin - riboflavin
Neurons may perform one of three functions....

14. The path from blood plasma to urine

15. Where is bile produced
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Lots of energy; eg neurons have hi glucose need for 3Na out 2K in ATPase; stomach epithel tiss needs E for parietal cells to pump protons into lumen and bicarbonate into blood
Conjunction of cell body w/axon
Chylomicrons are much bigger

16. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Amino acid monomers - di - tri absorbed by symport at enterocyte; each AA has slightly diff mechanism; from entero - AAs enter bloodstream where they are taken up by all cells of the body - esp the liver by active or facilitated transport (NEVER PASS
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

17. micelles vs liposomes
An endogenous morphine
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Liposome has phospholipid bilayer
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

18. mitosis creates somatic cells
It targets liver conc of prothrombin - fibrinogen etc
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Meiosis creates germ cells

19. What do lipases do
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Break down TAGs to monoglycerides and free fatty acids
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

20. at lo blood sugar...
Prod of steroid hormones in testes - ovaries
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

21. Spinal cord horns (thick knobs) point
Ventrally (picture skeletal vertebrae)
Creates one ovum (23 N) and three polar bodies
Epithelial tissue near semniferous tubules
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

22. PNS review: SAME DAVE
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Lysosome
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

23. During ejaculation - sperm...

24. gradual increase in FSH typical of primary follicle development;
Prod of steroid hormones in testes - ovaries
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

25. In IBS - What is defective

26. How do parietal cells work ** (involves CO2)
Facilitated diffusion from hi to lo conc
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

27. quote on cavities/viscera

28. 80-90% fat absorbed this way
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Glands w/ducts: Exocrine glands

29. extracellular matrix formed mainly of...
Collection of cell bodies; cell processes project out from both ends of ganglion; synapses with interneuron in spinal cord on one end and sensory receptor on other
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Outermost layer of blood vessel

30. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Form barrier to extracellular fluid
Monitors filtrate pressure in the distal tubule; has specialized cells (granular cells) that secrete an enzyme (**renin); renin initiates regulatory cascade that produces angiotensin I - II - III that stim adrenal cortex to secrete aldosterone... ...

31. Contrast PNS- Somatic with PNS- Autonomic
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Has memb - bound organelles - etc...
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom

32. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

33. The apical side of the villi...
AAs enter bloodstream for uptake by all cells (esp liver). If intracellular prot conc is at max AAs can be converted to fats or glucose via gluconeogenesis. Byproduct of gluconeo is ammonia --->urea.
Faces the lumen
Lower blood pH
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

34. pancreas secretes enzymes via
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Testosterone upon stim by LH
Gonadotropin releasing hormone - GnRH
Pancreatic duct (made of acinar cells?)

35. E storage per unit mass
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit

36. in fat and liver cells monoglycerides and ffas are once again
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Presence of fat - prot in duodenum causes release of **gastric inhibitory peptide**; result is slower stomach contraction; slower emptying into duod thru pyloric sphincter (slower chyme secretion); more time to properly digest - absorb nutrients
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

37. What is somatostatin
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Membrane - bound - endocytosed bodies
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Faces the lumen

38. large intestine E. coli aid absorption of...
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Vitamin K - b12 - thiamin - riboflavin
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

39. signal transduction occurs only in
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Eukaryotes
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

40. what happens when glycogen stores are saturated and blood sugar remains high?
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

41. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Homologous chromosomes line up w/ attachment of spindle fibers/microtubule polymers to centromeres via kinetochores; identical in appearance under light microscope to metaphase of mitosis
Moves down thru esophageal sphincter
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Fovea (highest amount of cones)

42. golgi body
Sorts - modifies - concentrates proteins from the ER
Nitrogen
Liposome has phospholipid bilayer
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

43. What is the path of a sound wave that enters the ear?
Needs time for bile - lipase - micelle migration - enterocyte uptake
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

44. Embryology
Ammonia; must be converted to urea by liver and excreted in urine by kidney
About 7.2
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
Paracrine (local) - endocrine (longer distance)

45. what else is located in the inner ear (not directly related to auditory)
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
Two perpendicular semicircular canals involved in balance - equilibrium
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

46. What are the major carbohydrates
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Abdominal cavity - which is coated in serous fluid
Smooth ER

47. Kidney physiology...

48. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Increases solute conc and osmotic pressure of the ***medulla
Most absorption occurs in sm intestine
Creates one ovum (23 N) and three polar bodies
Nitrogen

49. Failure of apoptosis can result in
Glucose = aldose fructose = ketose
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Sorts - modifies - concentrates proteins from the ER
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

50. Ovum development is halted At what stage until fertilization...
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms