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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. in mammals - gastrulation involves formation of the
Primitive streak - which consists of cells of the MESODERM ****
Within the paravertebral ganglion - running parallel to spinal cord
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

2. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Micelles; micelles (made of bile) go back and forth between brush border and chyme
via symport - secondary transport (ie by pre - established - ATP- intensive) with Na gradient into enterocyte......with no Na gradient (ie without ATP) carbohydrate monomers could not be transported in
Has memb - bound organelles - etc...
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

3. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Work together to emulsify fats: bile works as a detergent to increase SA of the fat; increased SA gives more substrate to lipase for digestion

4. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Determined by whether in front of or behind the lens
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Has memb - bound organelles - etc...

5. Fructose relates how structurally to glucose
Fallopian tubes
ER
Fructose is a structural isomer of glucose
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

6. portal vein physiology...

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7. Aldosterone (sodium uptake - potassium secretion)
In mouth - breakdown of starch into polysaccharides
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)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
All carbs absorbed at enterocytes are carried to liver by portal vein

8. smooth ER main function
Determined by whether in front of or behind the lens
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

9. Anterior eye vs. posterior eye
Two perpendicular semicircular canals involved in balance - equilibrium
'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.'
Normally contracted
Determined by whether in front of or behind the lens

10. A contracted iris occurs with what kind of stimulation
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Sympathetic: dilates pupil (for night hunting)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

11. Seen in lysosomal storage diseases
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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
Uncontracted: parasymp (eg opoid use)

12. thyroid hormones: Not All One Kind of HORM
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
The wall of the body or of a body cavity or hollow structure
Organs
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

13. Most important nutrients absorbed by large intestine
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

14. 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.

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15. What is the path of a sound wave that enters the ear?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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

16. Chewing does what?
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Increases surface area of food ball (bolus)
Facilitated diffusion from hi to lo conc
In mouth - breakdown of starch into polysaccharides

17. main point of fat transport...
Inner lining of blood vessels
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Ventrally (picture skeletal vertebrae)

18. bile + fat forms
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)
Testosterone and estradiol
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

19. What is feces composed of...
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
Inner lining of circulatory system
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

20. PNS review: SAME DAVE
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

21. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
1) by integral ion channels 2) transmitted by second messenger system
Sympathetic: dilates pupil (for night hunting)

22. 80-90% fat absorbed this way
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

23. protein absorption at enterocyte
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

24. 90% digestion - absorption occurs in...
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
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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
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

25. Three stages of the menstrual cycle
Estradiol
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

26. sensory (afferent)/interneurons/motor (efferent)
Lysosome
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Neurons may perform one of three functions....
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

27. Liver Functions
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Stores blood: when expanded liver serves as blood reservoir for body - filters blood: Kupfer cells phagocytize bacteria picked up from intestines - destroys bad RBCs: also done by Kupfer cells - detoxifies blood: detoxified chemicals are excreted eit
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Regulated by gastrointestinal horms

28. keep in mind that enterocyte is like a regular euk cell
Needs time for bile - lipase - micelle migration - enterocyte uptake
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
Has memb - bound organelles - etc...

29. overview of prot digestion
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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

30. food in duod stims release of gastrointestinal hormones
HCl; secreted by parietal cells under stim by gastrin
Meiosis creates germ cells
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Lower blood pH

31. Gastrulation: ectoderm/mesoderm/endoderm
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
Fallopian tubes
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

32. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Creates one ovum (23 N) and three polar bodies

33. mucus cells line the stomach...
Regulated by gastrointestinal horms
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)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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

34. Which fats are not absorbed like this
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Pancreatic duct (made of acinar cells?)
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

35. what cannot cross the fenestrations of the renal corpuscle
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
RBCs - large proteins; What does enter is called the filtrate
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Alpha 1-4 and 1-6 (branching) glycosidic linkages

36. extracellular matrix formed mainly of...
RBCs - large proteins; What does enter is called the filtrate
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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)
Excretes waste products: urea - uric acid - ammonia - phosphate - maintains homeostasis: including body fluid volume (water reabsorption) and solute composition (mineral balance - nutrient reabsorption) - controls *plasma* pH: antiport of Na/K and pr

37. Mucus - digestive enzymes released thru
Digestion
Sympathetic: dilates pupil (for night hunting)
Glands w/ducts: Exocrine glands
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

38. What is the net effect of the distal tubule
Cancer; apop can be programmed cell death; mitochon can play important role in apop
ER
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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

39. serous membranes have a viscera - facing layer and a body wall - facing layer
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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**

40. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

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

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42. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Fovea (highest amount of cones)

43. in the dark is rhodopsin active or inactive?
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Normally contracted
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
1) by integral ion channels 2) transmitted by second messenger system

44. albumin has What affect on blood osmotic pressure
Albumin increases osmolarity of blood; increases osmotic pressure
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Increases surface area of food ball (bolus)

45. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Facilitated diffusion from hi to lo conc
Sorts - modifies - concentrates proteins from the ER
'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.'

46. Where is bile produced
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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**
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

47. Sensory - motor neurons are part of which nervous system
Fovea (highest amount of cones)
Peripheral nervous sys
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

48. Glucose is a .... sugar; fructose is a .... sugar
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Glucose = aldose fructose = ketose
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

49. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0

50. pancreas secretes enzymes via
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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
Pancreatic duct (made of acinar cells?)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection