MCAT Prep - 2

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. at lo blood sugar...
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
Conjunction of cell body w/axon
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation


2. cytosol pH
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
The renal corpuscle
About 7.2


3. Chewing does what?
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct
The renal corpuscle
Increases surface area of food ball (bolus)
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue


4. Does bile digest fat?
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase


5. ligands are the messenger compounds that target secondary messenger systems on effectors
Ups bicarbonate secretion by pancreas; raises pH to 6.0
***nicotinic is ionotropic; muscarinic is GPCR
Fructose is a structural isomer of glucose
Many modern drugs are ligands for GPCRs


6. How do nutrients move?
Salivary amylase; both hydrolyze glycosidic linkages
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Estradiol


7. SYMP neurons originate in= PARA neurons originate in=
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons


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

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9. in the presence of ADH what happens to movement of water across nephron membr
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Water flows from the tubule - concentrating the filtrate - raising BP
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra


10. What is a dorsal root ganglion?
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
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production


11. How long are peptides when absorbed at brush border
An endogenous morphine
Estradiol
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Membrane - bound - endocytosed bodies


12. portal vein physiology...

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13. Most important nutrients absorbed by large intestine
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Sensory (afferent - dorsal) - motor (efferent - ventral)


14. The path from blood plasma to urine

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15. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Gonadotropin releasing hormone - GnRH
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
- 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
Inner lining of circulatory system


16. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Estradiol
Thru tight junctions by favorable osmotic gradient


17. In other words...
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Many modern drugs are ligands for GPCRs


18. Polypeptides are formed with what kind of reaction?
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
About 7.2
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)


19. What is a plasmalogen?
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Below hypothalamus
Salivary amylase; both hydrolyze glycosidic linkages
Fovea (highest amount of cones)


20. insulin secreted by
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
Beta cells
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
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


21. gradual increase in FSH typical of primary follicle development;
Corpus luteum degrades into corpus albicans
About 7.2
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)


22. calcitonin

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23. FLAT PG: hGH aka somatotropin
Below hypothalamus
Peptide; stims growth of nearly all cell of body; all other anterior pituitary horms have specific targets; upregulates anabolic pathways; use of fat for energy goes up (fat - burning); increases AA transport across cell membrane (nutrient uptake)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc


24. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Conjunction of cell body w/axon
Stomach - sm intest - spleen - pancreas from the hepatic portal vein...all blood that passes thru liver go thru flattened spaces called the ***hepatic sinusoids -->hepatic vein --->vena cava


25. review: parietals secrete intrinsic factor...
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs


26. After meiosis II - Male

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27. Anterior eye vs. posterior eye
Determined by whether in front of or behind the lens
'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.'
Fructose is a structural isomer of glucose
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles


28. What is the endothelium?
Lumen (ie continuous w/body cavity) and cytosol
Inner lining of circulatory system
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes


29. E storage per unit mass
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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Chyme (by combined activity of exocrine glands)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy


30. overview of prot digestion
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Fructose is a structural isomer of glucose
Paracrine (local) - endocrine (longer distance)
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


31. duodenum must have receptors for fat content - protein because
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
Has memb - bound organelles - etc...
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
Somatic nervous sys - autonomic nervous sys


32. energy source of neurons
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Glucose and ketone bodies (not from glycogen stores)


33. Leydig cells produce
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
Meiosis creates germ cells
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Testosterone upon stim by LH


34. trypsin is secreted by
Two perpendicular semicircular canals involved in balance - equilibrium
Increases surface area of food ball (bolus)
Sympathetic: dilates pupil (for night hunting)
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides


35. Gland: ovaries
ER
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Inner lining of circulatory system
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves


36. Peritoneal refers to...
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
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons
Abdominal cavity - which is coated in serous fluid
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct


37. What is the path of a sound wave that enters the ear?
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
RBCs - large proteins; What does enter is called the filtrate
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
- 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


38. Adrenal cortex hormones (STEROIDS)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
vitreous humor - retina - fovea
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes


39. Anterior eye
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Mostly reabsorbed to liver
Beta cells


40. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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.
Chylomicrons are much bigger


41. important pancreatic enzymes
Sympathetic: dilates pupil (for night hunting)
- 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
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol


42. exocrine types
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
- 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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
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


43. amylase acts where on carbs
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Liposome has phospholipid bilayer
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)


44. What do the glomerulus and Bowman's capsule add up to...
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
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
The renal corpuscle
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch


45. FLAT PG: TSH aka thyrotropin
Systems (eg digestive system consists of many organs)
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
An endogenous morphine
Lumen (ie continuous w/body cavity) and cytosol


46. physiology of gall bladder - liver and pancreatic secretions
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
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
Epithelial tissue near semniferous tubules


47. gametic life cycle
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Many modern drugs are ligands for GPCRs


48. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
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**
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Testosterone and estradiol
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right


49. What are the memb - bound enzymes of the brush border?
Ventrally (picture skeletal vertebrae)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Testosterone upon stim by LH


50. little by little chyme is squirted out thru pyloric sphincter
Regulated by gastrointestinal horms
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum