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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 net effect of the distal tubule
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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

2. Embryology
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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
Inner lining of blood vessels

3. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Inner lining of circulatory system
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

4. large intestine E. coli aid absorption of...
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
Vitamin K - b12 - thiamin - riboflavin
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

5. When 'coumadin targets liver enzymes to act as anticoagulant'...
It targets liver conc of prothrombin - fibrinogen etc
HCl; secreted by parietal cells under stim by gastrin
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

6. Blastocyst
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
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
The renal corpuscle

7. Some epithelial cells are... others...
- 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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

8. quote on cavities/viscera

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9. Cell determination begins At what stage of development
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Epithelial tissue near semniferous tubules
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Testosterone upon stim by LH

10. micelles vs liposomes
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Liposome has phospholipid bilayer
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
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'

11. What is gastric acid?
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
HCl; secreted by parietal cells under stim by gastrin
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
vitreous humor - retina - fovea

12. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Meiosis creates germ cells
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... ...
Gonadotropin releasing hormone - GnRH

13. Contrast PNS- Somatic with PNS- Autonomic
Glycosaminoglycans - prots - AAs - lipids
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Direction of differentiation

14. lysosome main function and derivation
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
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

15. keep in mind that enterocyte is like a regular euk cell
Has memb - bound organelles - etc...
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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
Increases blood Calcium

16. Kidney physiology...

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17. sensory (afferent)/interneurons/motor (efferent)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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)
Neurons may perform one of three functions....
Creates one ovum (23 N) and three polar bodies

18. Where do pancreatic secretions take effect
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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)
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

19. Meiosis I Telophase I
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

20. what happens when glycogen stores are saturated and blood sugar remains high?
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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
Primitive streak - which consists of cells of the MESODERM ****

21. medium for paracrine hormones
Interstitial fluid (eg prostaglandins - cytokines)
Salivary amylase; both hydrolyze glycosidic linkages
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

22. euk cell has two principal sides
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Lumen (ie continuous w/body cavity) and cytosol
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
ER

23. sporic life cycle
Peptides
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
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

24. cAMP - cGMP - calmodulin...
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Lumen (ie continuous w/body cavity) and cytosol

25. micelles also pick up
Glucose and ketone bodies (not from glycogen stores)
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Glucose

26. Most important nutrients absorbed by large intestine
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
Lysosome
Testosterone and estradiol
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

27. What does peptic refer to in general
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Digestion

28. extracellular matrix formed mainly of...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Ventrally (picture skeletal vertebrae)
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

29. Beta - oxidation in liver produces...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Prod of steroid hormones in testes - ovaries
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

30. Glucose is a .... sugar; fructose is a .... sugar
The renal corpuscle
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
Glucose = aldose fructose = ketose
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

31. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
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
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
90-140 mg/dl
Creates one ovum (23 N) and three polar bodies

32. What if large intestine isn't working well
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
RBCs - large proteins; What does enter is called the filtrate
Facilitated diffusion from hi to lo conc
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

33. What else do parietals do?
Somatic nervous sys - autonomic nervous sys
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
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

34. Where is bile produced
Membrane - bound - endocytosed bodies
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**
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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

35. What are phagosomes
90-140 mg/dl
Outermost layer of blood vessel
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Membrane - bound - endocytosed bodies

36. FLAT PG: TSH aka thyrotropin
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
Facilitated diffusion: no symport w/ secondary transport
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

37. Three stages of the menstrual cycle
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

38. protein absorption at enterocyte
Amino acid monomers - di - tri absorbed by symport at enterocyte; each AA has slightly diff mechanism; from entero - AAs enter bloodstream where they are taken up by all cells of the body - esp the liver by active or facilitated transport (NEVER PASS
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Ganglion
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

39. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Ventrally (picture skeletal vertebrae)
Oxytocin and ADH (aka vasopressin)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

40. What is a toxic byproduct of gluconeogenesis from proteins
Liposome has phospholipid bilayer
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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
Vitamin K - b12 - thiamin - riboflavin

41. What is endothelium?
Inner lining of blood vessels
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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

42. Both divisions (somatic - autonomic) of PNS consist of...
Glycosaminoglycans - prots - AAs - lipids
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
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

43. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

44. Ovum development is halted At what stage until fertilization...
Neurons may perform one of three functions....
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

45. Meiosis II: EQUATIONAL DIVISION
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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
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
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

46. The apical side of the villi...
Vitamin K - b12 - thiamin - riboflavin
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
The wall of the body or of a body cavity or hollow structure
Faces the lumen

47. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
HCl; secreted by parietal cells under stim by gastrin
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

48. when thinking of proteins - think
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**
Nitrogen
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Eukaryotes

49. Neuronal cell bodies have extensions ie
Processes: axons - dendrites
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

50. testosterone can be aromatized to...
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
All carbs absorbed at enterocytes are carried to liver by portal vein
Two perpendicular semicircular canals involved in balance - equilibrium
Estradiol