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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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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. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Gastrulation occurs: formation of three primary germ layers = differentiation
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

2. From that point...
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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.

3. FSH - LH - HCG - inhibin are...
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Prod of steroid hormones in testes - ovaries
Peptides

4. liver receives blood from...
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
In gastric pits; secretions combine into gastric juice

5. liver and blood glucose...
Peptides
5
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

6. light detection via GPCRs
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Facilitated diffusion: no symport w/ secondary transport
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

7. cytosol pH
- 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
About 7.2
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

8. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Testosterone and estradiol
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Conjunction of cell body w/axon
Membrane - bound - endocytosed bodies

9. physiology of gall bladder - liver and pancreatic secretions
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
Peptides
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. What is endothelium?
Inner lining of blood vessels
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Ventrally (picture skeletal vertebrae)
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

11. Where would materials slated for digestion go?
Only musc and esp ** liver can store large amounts
Glucose = aldose fructose = ketose
Lysosome
Most absorption occurs in sm intestine

12. Aldosterone (sodium uptake - potassium secretion)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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)
Normally contracted
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

13. Meiosis II: EQUATIONAL DIVISION
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Glucose and ketone bodies (not from glycogen stores)
Within the paravertebral ganglion - running parallel to spinal cord
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

14. What is the path of a sound wave that enters the ear?
Processes: axons - dendrites
Normally contracted
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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

15. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Needs time for bile - lipase - micelle migration - enterocyte uptake
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Below hypothalamus

16. sensory (afferent)/interneurons/motor (efferent)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
1) by integral ion channels 2) transmitted by second messenger system
Neurons may perform one of three functions....
Eukaryotes

17. During ejaculation - sperm...

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18. axon hillock physiology
Eukaryotes
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Conjunction of cell body w/axon
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

19. Contrast PNS- Somatic with PNS- Autonomic
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

20. 'Cell bodies of somatic motor neurons are located in....'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

21. How long are peptides when absorbed at brush border
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

22. review: parietals secrete intrinsic factor...
Direction of differentiation
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Carry signals to musc OR Gland

23. Glucose is a .... sugar; fructose is a .... sugar
Outermost layer of blood vessel
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Glucose = aldose fructose = ketose
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

24. Fructose relates how structurally to glucose
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Fructose is a structural isomer of glucose
Inner lining of circulatory system

25. How does glycogen compare to starch
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Lysosome

26. position of AP...
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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
Below hypothalamus

27. ADH
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

28. Embryology
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Testosterone and estradiol
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Vitamin K - b12 - thiamin - riboflavin

29. Gastrin from G cells stims parietal cells...
Testosterone upon stim by LH
- 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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

30. insulin secreted by
Beta cells
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Lysosome
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

31. from thoracic duct - chylomicrons stick to capillary walls...
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Outermost layer of blood vessel
Fovea (highest amount of cones)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

32. What if large intestine isn't working well
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Somatic nervous sys - autonomic nervous sys
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

33. What is a nerve? (PNS)
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
Corpus luteum degrades into corpus albicans
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
Liposome has phospholipid bilayer

34. Where do pancreatic secretions take effect
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
'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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

35. small intestine=
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Within the paravertebral ganglion - running parallel to spinal cord
Paracrine (local) - endocrine (longer distance)

36. exocrine types
In gastric pits; secretions combine into gastric juice
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
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

37. only monosaccharides are absorbed
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border

38. PNS is broken down into
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)
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
Glucose = aldose fructose = ketose
Somatic nervous sys - autonomic nervous sys

39. How does birth control work?
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Peripheral nervous sys
90-140 mg/dl

40. What force is acting upon chyme to move it forward down sm intestine
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
vitreous humor - retina - fovea

41. Stomach has no lacteals
Most absorption occurs in sm intestine
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

42. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Regulated by gastrointestinal horms
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
'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
Gastrulation occurs: formation of three primary germ layers = differentiation

43. Induction affects...
Carry signals to musc OR Gland
Below hypothalamus
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Direction of differentiation

44. Polypeptides are formed with what kind of reaction?
Ventrally (picture skeletal vertebrae)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

45. The path from blood plasma to urine

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46. Path of food entering body...
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

47. What testosterone released by secondary follicle by LH stim is converted to...
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
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
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

48. What does portal vein do
All carbs absorbed at enterocytes are carried to liver by portal vein
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
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Increases solute conc and osmotic pressure of the ***medulla

49. Determination is different than differentiation
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

50. After meiosis II...
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Lumen (ie continuous w/body cavity) and cytosol
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes