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MCAT Prep - 2

Subjects : mcat, science

Instructions:

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

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

1. liver and blood glucose...
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest

2. Mucus - digestive enzymes released thru
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
Glands w/ducts: Exocrine glands
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Regulated by gastrointestinal horms

3. from the loop of henle...
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

4. Exocrine GlandS: stomach
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Abdominal cavity - which is coated in serous fluid
- 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
Gastrulation occurs: formation of three primary germ layers = differentiation

5. How does reabsorption force nutrients across apical membrane of proximal tubule
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
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

6. euk cell has two principal sides
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Increases blood Calcium
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Lumen (ie continuous w/body cavity) and cytosol

7. How does duod deal with hi HCl from stom
Facilitated diffusion: no symport w/ secondary transport
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Ups bicarbonate secretion by pancreas; raises pH to 6.0

8. Liver Functions
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

9. Blastocyst
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Increases blood Calcium
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
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

10. from thoracic duct - chylomicrons stick to capillary walls...
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

11. Fructose relates how structurally to glucose
Fructose is a structural isomer of glucose
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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

12. Meiosis II: EQUATIONAL DIVISION
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Lower blood pH

13. what happens when glycogen stores are saturated and blood sugar remains high?
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
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
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

14. Induction affects...
Direction of differentiation
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Abdominal cavity - which is coated in serous fluid
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

15. For focal point that is nearby - what will the lens look like
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Eukaryotes
vitreous humor - retina - fovea
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

16. only monosaccharides are absorbed
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Nitrogen

17. What is somatostatin
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
- 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
Outermost layer of blood vessel
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

18. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Carry signals to musc OR Gland

19. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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)
Glycosaminoglycans - prots - AAs - lipids

20. Thus - central nervous sys is...
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
Smooth ER
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

21. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
Most absorption occurs in sm intestine
Form barrier to extracellular fluid
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

22. In other words...
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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

23. From that point...
Prod of steroid hormones in testes - ovaries
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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
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.

24. parathyroid hormone
Increases blood Calcium
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

25. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Nitrogen
Fructose is a structural isomer of glucose
Eukaryotes

26. What happens when rod cell is depolarized
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Night vision
Glycosaminoglycans - prots - AAs - lipids

27. 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)
Normally contracted
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

28. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

29. FSH - LH - HCG - inhibin are...
Eukaryotes
Thru tight junctions by favorable osmotic gradient
Peptides
Carry signals to musc OR Gland

30. What are the major carbohydrates
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Fovea (highest amount of cones)
Peptides

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

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32. What do villli do
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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
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

33. Between meals most fats appear in blood as
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
An endogenous morphine
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

34. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
Vitamin K - b12 - thiamin - riboflavin
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

35. signal transduction occurs only in
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Eukaryotes
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Fovea (highest amount of cones)

36. Where does fertilization occur
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Many modern drugs are ligands for GPCRs
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Fallopian tubes

37. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

38. insulin secreted by
Beta cells
Digestion
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Facilitated diffusion: no symport w/ secondary transport

39. What is endothelium?
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Inner lining of blood vessels
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Fovea (highest amount of cones)

40. thyroid hormones: Not All One Kind of HORM
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

41. Chewing does what?
Facilitated diffusion from hi to lo conc
Increases surface area of food ball (bolus)
Oxytocin and ADH (aka vasopressin)
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

42. pancreatic enzymes are zymogens
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Mostly reabsorbed to liver
Ventrally (picture skeletal vertebrae)

43. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

44. review: parietals secrete intrinsic factor...
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
The wall of the body or of a body cavity or hollow structure
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

45. How do nutrients move?
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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
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)
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. What determines number of chromosomes?
Has memb - bound organelles - etc...
The renal corpuscle
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

47. chylomicron concentration in blood after meal
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

48. What is the adventitia?
Testosterone and estradiol
Salivary amylase; both hydrolyze glycosidic linkages
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
Outermost layer of blood vessel

49. gametic life cycle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Facilitated diffusion from hi to lo conc
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

50. 80% of end product of carbohydrate metabolism is...
RBCs - large proteins; What does enter is called the filtrate
Glucose
5
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves