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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. pancreatic enzymes are zymogens
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
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
Salivary amylase; both hydrolyze glycosidic linkages
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

2. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Below hypothalamus

3. medium for paracrine hormones
- 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
Interstitial fluid (eg prostaglandins - cytokines)
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

4. Creating gradients requires what?
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
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Night vision

5. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Glucose and ketone bodies (not from glycogen stores)
Conjunction of cell body w/axon
Primitive streak - which consists of cells of the MESODERM ****

6. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Glycosaminoglycans - prots - AAs - lipids
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Vitamin K - b12 - thiamin - riboflavin
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

7. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
About 7.2
Smooth ER

8. Fructose relates how structurally to glucose
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Fructose is a structural isomer of glucose

9. micelles vs liposomes
Liposome has phospholipid bilayer
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Glucose

10. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Glucose
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

11. Which fats are not absorbed like this
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

12. oxytocin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

13. 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
Inner lining of circulatory system
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Determined by whether in front of or behind the lens

14. 90% digestion - absorption occurs in...
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

15. For focal point that is nearby - what will the lens look like
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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Albumin increases osmolarity of blood; increases osmotic pressure
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

16. insulin secreted by
Beta cells
Peripheral nervous sys
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

17. What is main difference is signal transmission in nicotinic vs muscarinic?
Organs
Determined by whether in front of or behind the lens
***nicotinic is ionotropic; muscarinic is GPCR
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

18. Cell bodies of SYMP postganglionic neurons lie far from effector...
Within the paravertebral ganglion - running parallel to spinal cord
It targets liver conc of prothrombin - fibrinogen etc
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Fructose is a structural isomer of glucose

19. Different tissues working together
Most absorption occurs in sm intestine
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Organs

20. Where does the bolus go after mouth chews food
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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)
Mostly reabsorbed to liver
Moves down thru esophageal sphincter

21. food in duod stims release of gastrointestinal hormones
Chylomicrons are much bigger
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Neurons may perform one of three functions....
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

22. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
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
- 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
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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)

23. portal vein physiology...

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24. Posterior eye
Prod of steroid hormones in testes - ovaries
Glucose and ketone bodies (not from glycogen stores)
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
vitreous humor - retina - fovea

25. What else do parietals do?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

26. Local vs long - distance mediators
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Normally contracted
Paracrine (local) - endocrine (longer distance)
Organs

27. Gland: ovaries
Faces the lumen
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Form barrier to extracellular fluid
- 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. Meiosis I Metaphase I
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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Ventrally (picture skeletal vertebrae)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

29. After meiosis I - daughter cells are...

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30. sporic life cycle
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Normally contracted
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

31. During ejaculation - sperm...

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32. parathyroid hormone
Chyme (by combined activity of exocrine glands)
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
Increases blood Calcium
1) by integral ion channels 2) transmitted by second messenger system

33. What determines number of chromosomes?
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Needs time for bile - lipase - micelle migration - enterocyte uptake
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

34. examples of different cavities... (compartments for viscera)
Digestion
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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

35. little by little chyme is squirted out thru pyloric sphincter
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Regulated by gastrointestinal horms
Corpus luteum degrades into corpus albicans
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

36. STOMACH: no absorption
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

37. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

38. Path of food entering body...
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

39. Morula (...totipotent)
Only musc and esp ** liver can store large amounts
Many modern drugs are ligands for GPCRs
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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)

40. in mammals - gastrulation involves formation of the
Primitive streak - which consists of cells of the MESODERM ****
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
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
Sorts - modifies - concentrates proteins from the ER

41. at lo blood sugar...
Primitive streak - which consists of cells of the MESODERM ****
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

42. Anterior eye
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Ups bicarbonate secretion by pancreas; raises pH to 6.0
AAs can be burned for energy or converted to fat for storage
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

43. extracellular matrix formed mainly of...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Form barrier to extracellular fluid
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

44. Sensory - motor neurons are part of which nervous system
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Peripheral nervous sys
Lysosome

45. How does duod deal with hi HCl from stom
Somatic nervous sys - autonomic nervous sys
Sorts - modifies - concentrates proteins from the ER
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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

46. sensory (afferent)/interneurons/motor (efferent)
Systems (eg digestive system consists of many organs)
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Neurons may perform one of three functions....

47. What is a dorsal root ganglion?
Eukaryotes
Uncontracted: parasymp (eg opoid use)
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
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

48. peroxisome is derived from this
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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)
ER
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

49. What is an endorphin?
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
An endogenous morphine
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

50. euk cell has two principal sides
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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
Lumen (ie continuous w/body cavity) and cytosol
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH