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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Nitrogen

2. testosterone can be aromatized to...
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat
Below hypothalamus
Estradiol
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

3. therefore - How does plasma leave capillary at the renal corpuscle

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4. what happens when glycogen stores are saturated and blood sugar remains high?
Mostly reabsorbed to liver
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Below hypothalamus

5. How does duod deal with hi HCl from stom
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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

6. Local vs long - distance mediators
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Paracrine (local) - endocrine (longer distance)
Processes: axons - dendrites
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

7. Polypeptides are formed with what kind of reaction?
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Glucose = aldose fructose = ketose
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

8. Where do pancreatic secretions take effect
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat
Albumin increases osmolarity of blood; increases osmotic pressure
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

9. Meiosis II: EQUATIONAL DIVISION
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap
Follicular phase: primary - secondary - ovulation (1 week) luteal phase: ovulation - thickening of uterine lining w/corpus luteum secretion - corpus luteum degrades (2 weeks) flow: shedding of uterine lining (4 days)
Chyme (by combined activity of exocrine glands)

10. 80-90% fat absorbed this way
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
Gonadotropin releasing hormone - GnRH
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

11. Contrast PNS- Somatic with PNS- Autonomic
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'
Needs time for bile - lipase - micelle migration - enterocyte uptake

12. What is endothelium?
Sympathetic: dilates pupil (for night hunting)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Vitamin K - b12 - thiamin - riboflavin
Inner lining of blood vessels

13. spermatogonia arise from
Epithelial tissue near semniferous tubules
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach
Meiosis creates germ cells

14. at lo blood sugar...
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

15. Meiosis I Metaphase I
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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

16. ligands are the messenger compounds that target secondary messenger systems on effectors
Chyme (by combined activity of exocrine glands)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
ER
Many modern drugs are ligands for GPCRs

17. Where does the bolus go after mouth chews food
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)
Moves down thru esophageal sphincter
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
Raises BP; causes collecting ducts at end of nephron (kidney) to become permeable to water - which concentrates urine; coffee - beer block ADH and increase urine volume

18. overview of prot digestion
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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
Ganglion
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap

19. bile + fat forms
Glucose = aldose fructose = ketose
Faces the lumen
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Ganglion

20. duodenum must have receptors for fat content - protein because
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

21. Thus inhibiting parietal cells could do What to blood pH
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Lower blood pH
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
In mouth - breakdown of starch into polysaccharides

22. What is main difference is signal transmission in nicotinic vs muscarinic?
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
***nicotinic is ionotropic; muscarinic is GPCR
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
90-140 mg/dl

23. What kind of cells make up epithel tiss of stom - then sm intest?
Glucose and ketone bodies (not from glycogen stores)
Normally contracted
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
ER

24. After meiosis II...
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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

25. What is feces composed of...
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot
Night vision

26. How does water cross the apical membrane
Glucose = aldose fructose = ketose
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap
Thru tight junctions by favorable osmotic gradient
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

27. 80% of end product of carbohydrate metabolism is...
Glucose
Form barrier to extracellular fluid
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

28. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
Pancreatic duct (made of acinar cells?)
Testosterone and estradiol

29. Both divisions (somatic - autonomic) of PNS consist of...
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Sensory (afferent - dorsal) - motor (efferent - ventral)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

30. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

31. Where would materials slated for digestion go?
Zygotes are diploid
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Lysosome
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

32. pancreas secretes enzymes via
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Pancreatic duct (made of acinar cells?)
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

33. physiology of gall bladder - liver and pancreatic secretions
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
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum

34. in fat and liver cells monoglycerides and ffas are once again
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

35. Posterior eye
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Contain capillary network - lymph vessels (lacteals)
vitreous humor - retina - fovea

36. Aldosterone (sodium uptake - potassium secretion)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Gonadotropin releasing hormone - GnRH
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)

37. pancreatic amylase is much stronger than
Increases solute conc and osmotic pressure of the ***medulla
Testosterone upon stim by LH
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'
Salivary amylase; both hydrolyze glycosidic linkages

38. How does blood sugar move into tissues?
Zygotes are diploid
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.
Uncontracted: parasymp (eg opoid use)
Facilitated diffusion from hi to lo conc

39. STOMACH: no absorption
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi
Primitive streak - which consists of cells of the MESODERM ****

40. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
- enterocytes w/ *microvilli brush border*: membrane - bound digestive enzymes for carbs - fats - nucleic acids - goblet cells: secrete mucous - Deep between villi are the intestinal exocrine glands - the crypts of Lieberkuhn - which secrete pH 7.6 i
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Pancreatic duct (made of acinar cells?)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

41. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

42. components of interstitial fluid
It targets liver conc of prothrombin - fibrinogen etc
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Glycosaminoglycans - prots - AAs - lipids
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

43. In other words...
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)
Food is digested from mouth to stomach (denaturation by gastric acid - digested by pepsin) to duodenum (more digestion); then absorption occurs in jejunum and ileum
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

44. Mucus - digestive enzymes released thru
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Salivary amylase; both hydrolyze glycosidic linkages
Glands w/ducts: Exocrine glands

45. albumin has What affect on blood osmotic pressure
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
About 7.2
Albumin increases osmolarity of blood; increases osmotic pressure

46. The EYE
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Below hypothalamus

47. sensory (afferent)/interneurons/motor (efferent)
In mouth - breakdown of starch into polysaccharides
Neurons may perform one of three functions....
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Glucose

48. The bolus (chewing) is digested to what in the stomach
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot
Chyme (by combined activity of exocrine glands)
Peripheral nervous sys
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum

49. micelles also pick up
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
Eukaryotes

50. FSH - LH - HCG - inhibin are...
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Peptides
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule