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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. What is the path of a sound wave that enters the ear?
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Low because AAs are immediately used in translation
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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

2. What happens when rod cell is depolarized
Night vision
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
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Peptides

3. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Glands w/ducts: Exocrine glands
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Gastrulation occurs: formation of three primary germ layers = differentiation
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

4. little by little chyme is squirted out thru pyloric sphincter
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Nitrogen
An endogenous morphine
Regulated by gastrointestinal horms

5. energy source of neurons
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Glucose and ketone bodies (not from glycogen stores)
Water flows from the tubule - concentrating the filtrate - raising BP
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

6. Energy from fat - prot - gluc
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
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
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Low because AAs are immediately used in translation

7. Path of food entering body...
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Peptides
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

8. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Peptides
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**

9. Gastrulation: ectoderm/mesoderm/endoderm
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

10. Some PNS nerves are found in brain - spinal cord
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Break down TAGs to monoglycerides and free fatty acids
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

11. euk cell has two principal sides
ER
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Lumen (ie continuous w/body cavity) and cytosol
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

12. remaining secondary follicle becomes
Uncontracted: parasymp (eg opoid use)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
An endogenous morphine
Zygotes are diploid

13. 3 phases of menstrual cycle
All carbs absorbed at enterocytes are carried to liver by portal vein
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)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Glucose and ketone bodies (not from glycogen stores)

14. gametes are haploid
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Zygotes are diploid
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

15. What are phagosomes
Prod of steroid hormones in testes - ovaries
Membrane - bound - endocytosed bodies
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
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

16. A contracted iris occurs with what kind of stimulation
Testosterone upon stim by LH
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Sympathetic: dilates pupil (for night hunting)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

17. overview of prot digestion
Contain capillary network - lymph vessels (lacteals)
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
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
Micelles; micelles (made of bile) go back and forth between brush border and chyme

18. Meiosis II: EQUATIONAL DIVISION
Moves down thru esophageal sphincter
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
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

19. FSH - LH - HCG - inhibin are...
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
Peptides
Thru tight junctions by favorable osmotic gradient
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

20. components of interstitial fluid
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Organs
Glycosaminoglycans - prots - AAs - lipids
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

21. amylase acts where on carbs
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Glucose and ketone bodies (not from glycogen stores)
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

22. glucagon secreted by
Two perpendicular semicircular canals involved in balance - equilibrium
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Below hypothalamus
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

23. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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
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

24. FLAT PG: ACTH
Lysosome
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Creates one ovum (23 N) and three polar bodies

25. 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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)

26. exocrine types
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
- 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

27. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Creates one ovum (23 N) and three polar bodies

28. spermatogonia arise from
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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Epithelial tissue near semniferous tubules
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

29. physiology of gall bladder - liver and pancreatic secretions
Fovea (highest amount of cones)
Meiosis creates germ cells
Ganglion
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

30. 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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Increases surface area of food ball (bolus)
HCl; secreted by parietal cells under stim by gastrin

31. Adrenal cortex hormones (STEROIDS)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Only musc and esp ** liver can store large amounts

32. ADH
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
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
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Only musc and esp ** liver can store large amounts

33. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Interstitial fluid (eg prostaglandins - cytokines)

34. STOMACH: no absorption
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
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

35. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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... ...

36. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
Moves down thru esophageal sphincter
Increases blood Calcium
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

37. Between meals most fats appear in blood as
Most absorption occurs in sm intestine
AAs can be burned for energy or converted to fat for storage
Inner lining of blood vessels
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

38. Where else does ADH act
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Epithelial tissue near semniferous tubules

39. motor (efferent) neurons --> VENTRAL
ER
Carry signals to musc OR Gland
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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)

40. sensory (afferent)/interneurons/motor (efferent)
Smooth ER
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
Neurons may perform one of three functions....
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

41. bile + fat forms
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Somatic nervous sys - autonomic nervous sys
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

42. is intracellular AA conc hi or low?
Low because AAs are immediately used in translation
Testosterone and estradiol
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

43. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Lower blood pH
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

44. trypsin is secreted by
Neurons may perform one of three functions....
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Processes: axons - dendrites

45. liver receives blood from...
Nitrogen
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Eukaryotes

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

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47. Aldosterone (sodium uptake - potassium secretion)
The renal corpuscle
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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)

48. In IBS - What is defective

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49. at lo blood sugar...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Epithelial tissue near semniferous tubules
Salivary amylase; both hydrolyze glycosidic linkages

50. From that point...
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Glucose = aldose fructose = ketose
Mostly reabsorbed to liver
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.