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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. Exocrine GlandS: stomach
Lumen (ie continuous w/body cavity) and cytosol
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
- 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

2. glucagon secreted by
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

3. fat digestion is time - intensive
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
Needs time for bile - lipase - micelle migration - enterocyte uptake
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

4. Beta - oxidation in liver produces...
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**
Determined by whether in front of or behind the lens
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

5. FLAT PG: ACTH
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
1) by integral ion channels 2) transmitted by second messenger system
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
- 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

6. Different organs working together
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Systems (eg digestive system consists of many organs)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Below hypothalamus

7. protein absorption at enterocyte
Ventrally (picture skeletal vertebrae)
Systems (eg digestive system consists of many organs)
In gastric pits; secretions combine into gastric juice
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

8. FLAT PG: FSH
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

9. euk cell has two principal sides
Lumen (ie continuous w/body cavity) and cytosol
Sorts - modifies - concentrates proteins from the ER
Carry signals to musc OR Gland
Contain capillary network - lymph vessels (lacteals)

10. amylase acts where on carbs
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
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Below hypothalamus
5

11. cytosol pH
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Alpha 1-4 and 1-6 (branching) glycosidic linkages
***nicotinic is ionotropic; muscarinic is GPCR
About 7.2

12. Gland: ovaries
Salivary amylase; both hydrolyze glycosidic linkages
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Glucose = aldose fructose = ketose
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

13. What is endothelium?
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Inner lining of blood vessels
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

14. What is an endorphin?
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
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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
An endogenous morphine

15. Anterior eye
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Pancreatic duct (made of acinar cells?)
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

16. How does the body mobilize fat stores
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
In gastric pits; secretions combine into gastric juice
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs
ER

17. pancreas secretes enzymes via
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Pancreatic duct (made of acinar cells?)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Cancer; apop can be programmed cell death; mitochon can play important role in apop

18. How long are peptides when absorbed at brush border
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

19. What testosterone released by secondary follicle by LH stim is converted to...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Within the paravertebral ganglion - running parallel to spinal cord
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
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

20. Where does blood to be filtered by kidney enter the nephron?

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21. Seen in lysosomal storage diseases
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Lysosome
Water flows from the tubule - concentrating the filtrate - raising BP
Form barrier to extracellular fluid

22. Contrast PNS- Somatic with PNS- Autonomic
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
- 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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

23. energy source of neurons
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Glucose and ketone bodies (not from glycogen stores)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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

24. After meiosis II - Male

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25. little by little chyme is squirted out thru pyloric sphincter
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Regulated by gastrointestinal horms
Has memb - bound organelles - etc...
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

26. lysosome pH
5
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
***nicotinic is ionotropic; muscarinic is GPCR

27. overview of prot digestion
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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
Low because AAs are immediately used in translation
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

28. During ejaculation - sperm...

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29. 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
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
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

30. overall - fatty - prot - rich food in duod causes
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Break down TAGs to monoglycerides and free fatty acids
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
- 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

31. gametes are haploid
Zygotes are diploid
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

32. What is somatostatin
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

33. How does glycogen compare to starch
5
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Interstitial fluid (eg prostaglandins - cytokines)

34. 90% digestion - absorption occurs in...
Outermost layer of blood vessel
Glucose
Albumin increases osmolarity of blood; increases osmotic pressure
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

35. In general - parietal=
The wall of the body or of a body cavity or hollow structure
Corpus luteum degrades into corpus albicans
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Cancer; apop can be programmed cell death; mitochon can play important role in apop

36. these transport proteins - when concs are high enough...
Lumen (ie continuous w/body cavity) and cytosol
Membrane - bound - endocytosed bodies
RBCs - large proteins; What does enter is called the filtrate
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

37. Tight junctions
Form barrier to extracellular fluid
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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
It targets liver conc of prothrombin - fibrinogen etc

38. ADH
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Eukaryotes
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

39. What does lipase attack exactly
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Oxytocin and ADH (aka vasopressin)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

40. testosterone can be aromatized to...
Membrane - bound - endocytosed bodies
All carbs absorbed at enterocytes are carried to liver by portal vein
Chyme (by combined activity of exocrine glands)
Estradiol

41. zygotic life cycle
Thru tight junctions by favorable osmotic gradient
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
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

42. How is glucose absorbed in sm intest
Many modern drugs are ligands for GPCRs
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
Eukaryotes

43. Where does the bolus go after mouth chews food
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)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Moves down thru esophageal sphincter
In mouth - breakdown of starch into polysaccharides

44. Anterior eye vs. posterior eye
Determined by whether in front of or behind the lens
Regulated by gastrointestinal horms
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
'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.'

45. Aldosterone (sodium uptake - potassium secretion)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
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)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

46. oxytocin
Fructose is a structural isomer of glucose
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
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

47. lysosome main function and derivation
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

48. main point of fat transport...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

49. Some epithelial cells are... others...
Ventrally (picture skeletal vertebrae)
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
Zygotes are diploid
- 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

50. In IBS - What is defective

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