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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. Where else does ADH act
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Chylomicrons are much bigger
Albumin increases osmolarity of blood; increases osmotic pressure

2. albumin has What affect on blood osmotic pressure
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Water flows from the tubule - concentrating the filtrate - raising BP
Albumin increases osmolarity of blood; increases osmotic pressure

3. Glucose is a .... sugar; fructose is a .... sugar
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Gonadotropin releasing hormone - GnRH
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Glucose = aldose fructose = ketose

4. How do parietal cells work ** (involves CO2)
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
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

5. Some epithelial cells are... others...
Liposome has phospholipid bilayer
- 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
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
In mouth - breakdown of starch into polysaccharides

6. 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)...
Gastrulation occurs: formation of three primary germ layers = differentiation
An endogenous morphine

7. What determines number of chromosomes?
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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Testosterone upon stim by LH
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

8. Three stages of the menstrual cycle
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Increases blood Calcium
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

9. Adrenal cortex hormones (STEROIDS)
***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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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)

10. A group of cell bodies in CNS is nucleus - outside CNS is...
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
It targets liver conc of prothrombin - fibrinogen etc
Regulated by gastrointestinal horms
Ganglion

11. What is secreted into filtrate by cells of the proximal tubule?
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
***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

12. is intracellular AA conc hi or low?
Testosterone upon stim by LH
Low because AAs are immediately used in translation
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Outermost layer of blood vessel

13. energy source of neurons
Inner lining of blood vessels
Facilitated diffusion: no symport w/ secondary transport
Glucose and ketone bodies (not from glycogen stores)
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

14. 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)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Mostly reabsorbed to liver

15. pancreas secretes enzymes via
Corpus luteum degrades into corpus albicans
Pancreatic duct (made of acinar cells?)
Somatic nervous sys - autonomic nervous sys
Inner lining of blood vessels

16. The EYE
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

17. Tight junctions
Chyme (by combined activity of exocrine glands)
Determined by whether in front of or behind the lens
Form barrier to extracellular fluid
Glucose

18. euk cell has two principal sides
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Lumen (ie continuous w/body cavity) and cytosol
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

19. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
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
Night vision
Peripheral nervous sys

21. Adrenal medulla hormones (TYR- DERIVED)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

22. 3 phases of menstrual cycle
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**
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)
Ventrally (picture skeletal vertebrae)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

23. STOMACH: no absorption
Liposome has phospholipid bilayer
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
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)
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

24. Meiosis I Metaphase I
Has memb - bound organelles - etc...
Uncontracted: parasymp (eg opoid use)
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
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

25. calcitonin

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26. position of AP...
Below hypothalamus
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

27. Cell bodies of SYMP postganglionic neurons lie far from effector...
Within the paravertebral ganglion - running parallel to spinal cord
Eukaryotes
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Nitrogen

28. gradual increase in FSH typical of primary follicle development;
vitreous humor - retina - fovea
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Determined by whether in front of or behind the lens
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

29. FLAT PG: hGH aka somatotropin
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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)
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... ...
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

30. sensory (afferent) neurons
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
90-140 mg/dl
Micelles; micelles (made of bile) go back and forth between brush border and chyme

31. Embryology
Form barrier to extracellular fluid
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

32. important pancreatic enzymes
It targets liver conc of prothrombin - fibrinogen etc
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
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

33. Local vs long - distance mediators
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)
Lumen (ie continuous w/body cavity) and cytosol
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Paracrine (local) - endocrine (longer distance)

34. What does portal vein do
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Needs time for bile - lipase - micelle migration - enterocyte uptake
All carbs absorbed at enterocytes are carried to liver by portal vein
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

35. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
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
ER
Cancer; apop can be programmed cell death; mitochon can play important role in apop

36. From that point...
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Normally contracted
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.

37. The bolus (chewing) is digested to what in the stomach
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
Chyme (by combined activity of exocrine glands)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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)

38. axon hillock physiology
Conjunction of cell body w/axon
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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

39. Gland: ovaries
Peripheral nervous sys
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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

40. How does the body mobilize fat stores
***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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

41. After meiosis II - Male

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42. small intestine=
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

43. When 'coumadin targets liver enzymes to act as anticoagulant'...
It targets liver conc of prothrombin - fibrinogen etc
Ganglion
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
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

44. extracellular matrix formed mainly of...
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

45. Where do pancreatic secretions take effect
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

46. golgi body
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Glands w/ducts: Exocrine glands
Sorts - modifies - concentrates proteins from the ER

47. micelles also pick up
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte 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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

48. Path of food entering body...
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Facilitated diffusion: no symport w/ secondary transport
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

49. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
ER
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

50. Where do absorbed fats go in the enterocyte
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms