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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. large intestine E. coli aid absorption of...
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Night vision
Vitamin K - b12 - thiamin - riboflavin
Alpha 1-4 and 1-6 (branching) glycosidic linkages

2. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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... ...
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

3. What hormones affect the stomach?
Direction of differentiation
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
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
90-140 mg/dl

4. from thoracic duct - chylomicrons stick to capillary walls...
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Mostly reabsorbed to liver
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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... ...

5. 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
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
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
- 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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

6. 90% digestion - absorption occurs in...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Eukaryotes

7. FLAT PG: TSH aka thyrotropin
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
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
Testosterone and estradiol
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti

8. overall - fatty - prot - rich food in duod causes
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Meiosis creates germ cells
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

9. Cell bodies of SYMP postganglionic neurons lie far from effector...
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
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
- 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
Within the paravertebral ganglion - running parallel to spinal cord

10. Where would materials slated for digestion go?
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Lysosome
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

11. Local vs long - distance mediators
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
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
Paracrine (local) - endocrine (longer distance)
Peripheral nervous sys

12. insulin secreted by
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Beta cells
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Increases solute conc and osmotic pressure of the ***medulla

13. What is a plasmalogen?
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Eukaryotes

14. these transport proteins - when concs are high enough...
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

15. On what surface of the retina is the eye most sensitive
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Peptides
Fovea (highest amount of cones)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

16. inhibin secreted by
Testosterone upon stim by LH
Neurons may perform one of three functions....
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Night vision

17. How do parietal cells work ** (involves CO2)
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Glands w/ducts: Exocrine glands

18. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Increases surface area of food ball (bolus)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

19. Bile salts and lipase
***nicotinic is ionotropic; muscarinic is GPCR
Glucose = aldose fructose = ketose
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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

20. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Creates one ovum (23 N) and three polar bodies
Cancer; apop can be programmed cell death; mitochon can play important role in apop
RBCs - large proteins; What does enter is called the filtrate
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

21. 3 phases of menstrual cycle
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)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
'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
Glands w/ducts: Exocrine glands

22. oxytocin
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Which is why lactase - maltase - dextrinase - sucrase are on 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

23. Failure of apoptosis can result in
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
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

24. cytosol pH
Testosterone and estradiol
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
About 7.2
Facilitated diffusion: no symport w/ secondary transport

25. In other words...
'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
Most absorption occurs in sm intestine
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
Micelles; micelles (made of bile) go back and forth between brush border and chyme

26. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Direction of differentiation
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Testosterone and estradiol

27. Think of spinal cord injury
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Salivary amylase; both hydrolyze glycosidic linkages
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

28. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Oxytocin and ADH (aka vasopressin)
In mouth - breakdown of starch into polysaccharides

29. Mucus - digestive enzymes released thru
All carbs absorbed at enterocytes are carried to liver by portal vein
Testosterone upon stim by LH
Glands w/ducts: Exocrine glands
AAs can be burned for energy or converted to fat for storage

30. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
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
Prod of steroid hormones in testes - ovaries
Pancreatic duct (made of acinar cells?)
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

31. Where does blood to be filtered by kidney enter the nephron?

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32. Aldosterone (sodium uptake - potassium secretion)
Determined by whether in front of or behind the lens
Eukaryotes
Liver is the control center for blood glucose; is fed by portal vein from sm intest
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)

33. remaining secondary follicle becomes
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Organs

34. 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
Lower blood pH
Below hypothalamus
Ganglion

35. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
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
Estradiol
Abdominal cavity - which is coated in serous fluid
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

36. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Glands w/ducts: Exocrine glands
About 7.2
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

37. cAMP - cGMP - calmodulin...
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Most absorption occurs in sm intestine
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

38. only monosaccharides are absorbed
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border

39. Glycogenolysis/gluconeogenesis
Regulated by gastrointestinal horms
Ventrally (picture skeletal vertebrae)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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

40. interneurons
Break down TAGs to monoglycerides and free fatty acids
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

41. Gastrulation: ectoderm/mesoderm/endoderm
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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**
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
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... ...

42. Meiosis I Anaphase I
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

43. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
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
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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

44. zygotic life cycle
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Within the paravertebral ganglion - running parallel to spinal cord
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

45. What surrounds the hydrophilic heads of the new TAGs
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Primitive streak - which consists of cells of the MESODERM ****
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti

46. Does bile digest fat?
Membrane - bound - endocytosed bodies
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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

47. Chewing does what?
Epithelial tissue near semniferous tubules
Increases surface area of food ball (bolus)
Systems (eg digestive system consists of many organs)
Thru tight junctions by favorable osmotic gradient

48. What are the memb - bound enzymes of the brush border?
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
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

49. How is the follicle developed during oogenesis
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
***nicotinic is ionotropic; muscarinic is GPCR
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

50. What is the endothelium?
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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Inner lining of circulatory system
Buildup of macromolecules in lysosome due to deficient lysosome enzymes