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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.
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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. oxytocin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Somatic nervous sys - autonomic nervous sys
Ventrally (picture skeletal vertebrae)

2. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Ventrally (picture skeletal vertebrae)

3. 3 phases of menstrual cycle
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
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
Testosterone and estradiol
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)

4. Chewing does what?
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Corpus luteum degrades into corpus albicans
Increases surface area of food ball (bolus)
Gastrulation occurs: formation of three primary germ layers = differentiation

5. 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)
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
Peripheral nervous sys
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
Break down TAGs to monoglycerides and free fatty acids

6. The EYE
Two perpendicular semicircular canals involved in balance - equilibrium
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)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Interstitial fluid (eg prostaglandins - cytokines)

7. How does birth control work?
Night vision
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

8. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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... ...

9. How does glycogen compare to starch
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Somatic nervous sys - autonomic nervous sys

10. What is a nerve? (PNS)
Many modern drugs are ligands for GPCRs
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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
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

11. In IBS - What is defective

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12. FLAT PG: TSH aka thyrotropin
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Smooth ER
Chyme (by combined activity of exocrine glands)
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

13. Adrenal cortex hormones (STEROIDS)
AAs can be burned for energy or converted to fat for storage
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Determined by whether in front of or behind the lens
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

14. what cannot cross the fenestrations of the renal corpuscle
Somatic nervous sys - autonomic nervous sys
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
The renal corpuscle
RBCs - large proteins; What does enter is called the filtrate

15. What does peroxisome do
Glycosaminoglycans - prots - AAs - lipids
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

16. Think of spinal cord injury
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Glucose = aldose fructose = ketose
Digestion
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

17. Beta - oxidation in liver produces...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
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
Meiosis creates germ cells
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

18. Kidney
Ventrally (picture skeletal vertebrae)
Lower blood pH
- 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
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

19. Different organs working together
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
ER
Systems (eg digestive system consists of many organs)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

20. A pinpoint iris is contracted or uncontracted
Smooth ER
Testosterone upon stim by LH
Uncontracted: parasymp (eg opoid use)
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

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

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22. From that point...
5
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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.
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

23. serous membranes have a viscera - facing layer and a body wall - facing layer
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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
Gastrulation occurs: formation of three primary germ layers = differentiation
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

24. sensory (afferent)/interneurons/motor (efferent)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Liposome has phospholipid bilayer
Neurons may perform one of three functions....
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

25. pancreatic enzymes are zymogens
Many modern drugs are ligands for GPCRs
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

26. review: parietals secrete intrinsic factor...
Neurons may perform one of three functions....
Has memb - bound organelles - etc...
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
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

27. PNS nerve signal
Somatic nervous sys - autonomic nervous sys
Form barrier to extracellular fluid
Needs time for bile - lipase - micelle migration - enterocyte uptake
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

28. micelles also pick up
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Micelles; micelles (made of bile) go back and forth between brush border and chyme

29. Cell determination begins At what stage of development
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Testosterone and estradiol
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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

30. What hormones affect the stomach?
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Beta cells
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
About 7.2

31. what happens when glycogen stores are saturated and blood sugar remains high?
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
HCl; secreted by parietal cells under stim by gastrin
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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

32. spermatogonia arise from
Eukaryotes
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
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Epithelial tissue near semniferous tubules

33. What is a dorsal root ganglion?
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

34. Different tissues working together
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Organs

35. exocrine types
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Lumen (ie continuous w/body cavity) and cytosol
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

36. How does duod deal with hi HCl from stom
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Increases solute conc and osmotic pressure of the ***medulla

37. Where are these exocrine glands located
Eukaryotes
Needs time for bile - lipase - micelle migration - enterocyte uptake
In gastric pits; secretions combine into gastric juice
Glucose = aldose fructose = ketose

38. How do parietal cells work ** (involves CO2)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

39. What do lipases do
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Break down TAGs to monoglycerides and free fatty acids
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

40. PNS review: SAME DAVE
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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

41. almost all exocytosed proteins pass through this
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)
An endogenous morphine
Smooth ER
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

42. large intestine E. coli aid absorption of...
Vitamin K - b12 - thiamin - riboflavin
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Primitive streak - which consists of cells of the MESODERM ****
Facilitated diffusion from hi to lo conc

43. lining of abdominal cavity=
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
An endogenous morphine
1) by integral ion channels 2) transmitted by second messenger system
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

44. E storage per unit mass
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
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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

45. Aldosterone (sodium uptake - potassium secretion)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Ventrally (picture skeletal vertebrae)

46. Gland: ovaries
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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.
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

47. Ovum development is halted At what stage until fertilization...
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.
Below hypothalamus
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

48. FLAT PG: prolactin
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
Nitrogen
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

49. What is a toxic byproduct of gluconeogenesis from proteins
Increases blood Calcium
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Low because AAs are immediately used in translation

50. What is main difference is signal transmission in nicotinic vs muscarinic?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
***nicotinic is ionotropic; muscarinic is GPCR