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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. cytosol pH
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
About 7.2
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Testosterone and estradiol

2. Bile salts and lipase
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

3. How do parietal cells work ** (involves CO2)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Gonadotropin releasing hormone - GnRH
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
Within the paravertebral ganglion - running parallel to spinal cord

4. How does the body mobilize fat stores
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs
Ganglion
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

5. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
All carbs absorbed at enterocytes are carried to liver by portal vein

6. Posterior eye
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
vitreous humor - retina - fovea
Lower blood pH
Many modern drugs are ligands for GPCRs

7. What is the adventitia?
Outermost layer of blood vessel
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Regulated by gastrointestinal horms
Lower blood pH

8. Which fats are not absorbed like this
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Faces the lumen
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

9. when cells hit their limit for prot storage...
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
AAs can be burned for energy or converted to fat for storage
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
The wall of the body or of a body cavity or hollow structure

10. Local vs long - distance mediators
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
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
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
Paracrine (local) - endocrine (longer distance)

11. Liver Functions
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

12. Mucus - digestive enzymes released thru
Glands w/ducts: Exocrine glands
Inner lining of circulatory system
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
The wall of the body or of a body cavity or hollow structure

13. inhibin secreted by
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

14. Cell determination begins At what stage of development
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Water flows from the tubule - concentrating the filtrate - raising BP

15. Stomach has no lacteals
Most absorption occurs in sm intestine
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Contain capillary network - lymph vessels (lacteals)
90-140 mg/dl

16. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
- 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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

17. Beta - oxidation in liver produces...
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

18. SYMP neurons originate in= PARA neurons originate in=
RBCs - large proteins; What does enter is called the filtrate
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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
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

19. Aldosterone (sodium uptake - potassium secretion)
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
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
About 7.2
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)

20. 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
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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

21. What is the path of a sound wave that enters the ear?
About 7.2
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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
Abdominal cavity - which is coated in serous fluid

22. Chewing does what?
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Increases surface area of food ball (bolus)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

23. What controls release of LH - FSH from anterior pituitary
Gonadotropin releasing hormone - GnRH
Has memb - bound organelles - etc...
Ventrally (picture skeletal vertebrae)
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

24. sensory (afferent)/interneurons/motor (efferent)
Neurons may perform one of three functions....
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Zygotes are diploid

25. quote on cavities/viscera

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26. insulin secreted by
Normally contracted
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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
Beta cells

27. Adrenal medulla hormones (TYR- DERIVED)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
- 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

28. What are the memb - bound enzymes of the brush border?
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Glucose and ketone bodies (not from glycogen stores)

29. What testosterone released by secondary follicle by LH stim is converted to...
Break down TAGs to monoglycerides and free fatty acids
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

30. position of AP...
Below hypothalamus
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

31. parathyroid hormones
Beta cells
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Oxytocin and ADH (aka vasopressin)

32. thyroid hormones: Not All One Kind of HORM
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
5

33. large intestine E. coli aid absorption of...
Carry signals to musc OR Gland
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Vitamin K - b12 - thiamin - riboflavin

34. 90% digestion - absorption occurs in...
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
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
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
In mouth - breakdown of starch into polysaccharides

35. What is main difference is signal transmission in nicotinic vs muscarinic?
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
***nicotinic is ionotropic; muscarinic is GPCR

36. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Thru tight junctions by favorable osmotic gradient
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

37. What is the function of the loop of Henle
Increases solute conc and osmotic pressure of the ***medulla
The renal corpuscle
Outermost layer of blood vessel
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

38. Gastrin from G cells stims parietal cells...
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Low because AAs are immediately used in translation
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

39. Meiosis II: EQUATIONAL DIVISION
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Carry signals to musc OR Gland
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

40. Fructose relates how structurally to glucose
Moves down thru esophageal sphincter
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Fructose is a structural isomer of glucose
Has memb - bound organelles - etc...

41. The path from blood plasma to urine

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42. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Somatic nervous sys - autonomic nervous sys
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... ...
Water flows from the tubule - concentrating the filtrate - raising BP
Increases solute conc and osmotic pressure of the ***medulla

43. FLAT PG: hGH aka somatotropin
Facilitated diffusion from hi to lo conc
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Most absorption occurs in sm intestine
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)

44. Induction affects...
Direction of differentiation
Systems (eg digestive system consists of many organs)
Eukaryotes
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

45. parathyroid hormone
Increases blood Calcium
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
Facilitated diffusion: no symport w/ secondary transport
Ups bicarbonate secretion by pancreas; raises pH to 6.0

46. Cell bodies of SYMP postganglionic neurons lie far from effector...
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
Chyme (by combined activity of exocrine glands)
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)
Within the paravertebral ganglion - running parallel to spinal cord

47. Tight junctions
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Form barrier to extracellular fluid
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Peripheral nervous sys

48. STOMACH: no absorption
Nitrogen
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Albumin increases osmolarity of blood; increases osmotic pressure

49. What is a plasmalogen?
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Most absorption occurs in sm intestine

50. Human chorionic gonadotropin...
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
The renal corpuscle
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes