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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. Chewing does what?
Increases surface area of food ball (bolus)
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
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
HCl; secreted by parietal cells under stim by gastrin

2. portal vein physiology...

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3. How do parietal cells work ** (involves CO2)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Corpus luteum degrades into corpus albicans
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Many modern drugs are ligands for GPCRs

4. What are the memb - bound enzymes of the brush border?
Ganglion
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... ...
Glucose
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

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

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6. 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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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
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

7. Kidney physiology...

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8. How long are peptides when absorbed at brush border
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Needs time for bile - lipase - micelle migration - enterocyte uptake

9. What is secreted into filtrate by cells of the proximal tubule?
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
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
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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

10. almost all exocytosed proteins pass through this
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Chyme (by combined activity of exocrine glands)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Smooth ER

11. Where does fertilization occur
Interstitial fluid (eg prostaglandins - cytokines)
Fallopian tubes
Systems (eg digestive system consists of many organs)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

12. Where else does ADH act
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
AAs can be burned for energy or converted to fat for storage
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Only musc and esp ** liver can store large amounts

13. amylase acts where on carbs
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Chyme (by combined activity of exocrine glands)
Mostly reabsorbed to liver

14. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
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... ...
Abdominal cavity - which is coated in serous fluid
vitreous humor - retina - fovea

15. How does birth control work?
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

16. Where are these exocrine glands located
In gastric pits; secretions combine into gastric juice
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

17. Induction affects...
Sorts - modifies - concentrates proteins from the ER
Only musc and esp ** liver can store large amounts
Two perpendicular semicircular canals involved in balance - equilibrium
Direction of differentiation

18. What force is acting upon chyme to move it forward down sm intestine
AAs can be burned for energy or converted to fat for storage
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

19. Aldosterone (sodium uptake - potassium secretion)
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)
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
All carbs absorbed at enterocytes are carried to liver by portal vein
Glands w/ducts: Exocrine glands

20. Leydig cells produce
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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
Testosterone upon stim by LH
Epithelial tissue near semniferous tubules

21. How is the follicle developed during oogenesis
Creates one ovum (23 N) and three polar bodies
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Direction of differentiation

22. Tight junctions
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Form barrier to extracellular fluid

23. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
Eukaryotes
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

24. chylomicron concentration in blood after meal
In gastric pits; secretions combine into gastric juice
Only musc and esp ** liver can store large amounts
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Ganglion

25. How is glucose absorbed in sm intest
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Vitamin K - b12 - thiamin - riboflavin
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

26. fat digestion is time - intensive
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
Beta cells
Needs time for bile - lipase - micelle migration - enterocyte uptake
Interstitial fluid (eg prostaglandins - cytokines)

27. How do monoglycerides and ffas get to brush border?
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Abdominal cavity - which is coated in serous fluid
Epithelial tissue near semniferous tubules
Micelles; micelles (made of bile) go back and forth between brush border and chyme

28. extracellular matrix formed mainly of...
Glucose = aldose fructose = ketose
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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

29. Kidney
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Testosterone and estradiol
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
Mostly reabsorbed to liver

30. How does glycogen compare to starch
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Break down TAGs to monoglycerides and free fatty acids
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve

31. FLAT PG: LH
Determined by whether in front of or behind the lens
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
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
Fructose is a structural isomer of glucose

32. What is an endorphin?
Inner lining of blood vessels
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
An endogenous morphine
Fallopian tubes

33. For focal point that is nearby - what will the lens look like
- 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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Prod of steroid hormones in testes - ovaries
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

34. What is feces composed of...
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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
'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.'
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

35. FLAT PG: ACTH
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

36. After meiosis II...
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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

37. Posterior pituitary hormones (Small Peptides)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Oxytocin and ADH (aka vasopressin)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit

38. FLAT PG: TSH aka thyrotropin
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
Corpus luteum degrades into corpus albicans
Ventrally (picture skeletal vertebrae)
vitreous humor - retina - fovea

39. inhibin secreted by
Within the paravertebral ganglion - running parallel to spinal cord
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

40. FLAT PG: FSH
Facilitated diffusion from hi to lo conc
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Glucose = aldose fructose = ketose
In mouth - breakdown of starch into polysaccharides

41. when thinking of proteins - think
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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
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
Nitrogen

42. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Creates one ovum (23 N) and three polar bodies
90-140 mg/dl
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

43. From that point...
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Abdominal cavity - which is coated in serous fluid
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.
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

44. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit
It targets liver conc of prothrombin - fibrinogen etc
Many modern drugs are ligands for GPCRs
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

45. What is endothelium?
Inner lining of blood vessels
RBCs - large proteins; What does enter is called the filtrate
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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

46. cytosol pH
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Many modern drugs are ligands for GPCRs
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
About 7.2

47. Between meals most fats appear in blood as
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

48. almost all cells can store Some glycogen - but...
1) by integral ion channels 2) transmitted by second messenger system
Only musc and esp ** liver can store large amounts
ER
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

49. Sensory - motor neurons are part of which nervous system
- 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
It targets liver conc of prothrombin - fibrinogen etc
Night vision
Peripheral nervous sys

50. How do nutrients move?
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
Only musc and esp ** liver can store large amounts
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue