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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. at lo blood sugar...
Chyme (by combined activity of exocrine glands)
Peripheral nervous sys
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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

2. How is glucose absorbed in sm intest
Ammonia; must be converted to urea by liver and excreted in urine by kidney
- 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
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
Lumen (ie continuous w/body cavity) and cytosol

3. What is a nerve? (PNS)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

4. Where does fertilization occur
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
Fallopian tubes
Pancreatic duct (made of acinar cells?)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

5. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Outermost layer of blood vessel
Interstitial fluid (eg prostaglandins - cytokines)
Zygotes are diploid

6. 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
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
- 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
Sorts - modifies - concentrates proteins from the ER

7. What is a toxic byproduct of gluconeogenesis from proteins
Oxytocin and ADH (aka vasopressin)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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

8. these transport proteins - when concs are high enough...
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
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Cancer; apop can be programmed cell death; mitochon can play important role in apop

9. A group of cell bodies in CNS is nucleus - outside CNS is...
Gastrulation occurs: formation of three primary germ layers = differentiation
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
Testosterone and estradiol
Ganglion

10. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Vitamin K - b12 - thiamin - riboflavin
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

11. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Testosterone and estradiol

12. What is endothelium?
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Inner lining of blood vessels

13. How do parietal cells work ** (involves CO2)
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
Systems (eg digestive system consists of many organs)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

14. Path of food entering body...
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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

15. How long are peptides when absorbed at brush border
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
Mostly reabsorbed to liver
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)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

16. What is main difference is signal transmission in nicotinic vs muscarinic?
Normally contracted
Glucose
***nicotinic is ionotropic; muscarinic is GPCR
Meiosis creates germ cells

17. golgi body
Sorts - modifies - concentrates proteins from the ER
Regulated by gastrointestinal horms
Corpus luteum degrades into corpus albicans
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

18. A contracted iris occurs with what kind of stimulation
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
Uncontracted: parasymp (eg opoid use)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Sympathetic: dilates pupil (for night hunting)

19. What is gastric acid?
Peripheral nervous sys
'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
HCl; secreted by parietal cells under stim by gastrin
Smooth ER

20. mucus cells line the stomach...
Peptides
Glands w/ducts: Exocrine glands
Digestion
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

21. gradual increase in FSH typical of primary follicle development;
Has memb - bound organelles - etc...
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

22. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Increases solute conc and osmotic pressure of the ***medulla
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

23. Beta - oxidation in liver produces...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
ER
Neurons may perform one of three functions....

24. At post - two weeks ovulation
Gonadotropin releasing hormone - GnRH
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Corpus luteum degrades into corpus albicans
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

25. How do nutrients move?
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot
Alpha 1-4 and 1-6 (branching) glycosidic linkages
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Glands w/ducts: Exocrine glands

26. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

27. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
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)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

28. Spinal cord horns (thick knobs) point
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Ventrally (picture skeletal vertebrae)
'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.'

29. Ovum development is halted At what stage until fertilization...
Facilitated diffusion from hi to lo conc
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

30. Three stages of the menstrual cycle
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Sensory (afferent - dorsal) - motor (efferent - ventral)

31. Path of urine

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32. Glycogenolysis/gluconeogenesis
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
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
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

33. Cell determination begins At what stage of development
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Sorts - modifies - concentrates proteins from the ER
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

34. duodenum must have receptors for fat content - protein because
Pancreatic duct (made of acinar cells?)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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

35. Where would materials slated for digestion go?
Lysosome
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Lumen (ie continuous w/body cavity) and cytosol
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

36. Where else does ADH act
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Most absorption occurs in sm intestine
Corpus luteum degrades into corpus albicans

37. micelles also pick up
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
Oxytocin and ADH (aka vasopressin)

38. Anterior eye vs. posterior eye
Interstitial fluid (eg prostaglandins - cytokines)
Determined by whether in front of or behind the lens
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
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

39. in mammals - gastrulation involves formation of the
Water flows from the tubule - concentrating the filtrate - raising BP
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
- 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
Primitive streak - which consists of cells of the MESODERM ****

40. in fat and liver cells monoglycerides and ffas are once again
Chylomicrons are much bigger
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Glycosaminoglycans - prots - AAs - lipids
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

41. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Low because AAs are immediately used in translation
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
Gastrulation occurs: formation of three primary germ layers = differentiation
RBCs - large proteins; What does enter is called the filtrate

42. oxytocin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Inner lining of circulatory system
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.

43. lysosome pH
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
5
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
- 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

44. How is the follicle developed during oogenesis
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

45. when thinking of proteins - think
Nitrogen
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
90-140 mg/dl

46. FLAT PG: FSH
Beta cells
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Systems (eg digestive system consists of many organs)

47. almost all exocytosed proteins pass through this
Sympathetic: dilates pupil (for night hunting)
Smooth ER
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Albumin increases osmolarity of blood; increases osmotic pressure

48. The bolus (chewing) is digested to what in the stomach
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)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Chyme (by combined activity of exocrine glands)
Chylomicrons are much bigger

49. keep in mind that enterocyte is like a regular euk cell
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... ...
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Has memb - bound organelles - etc...
Increases blood Calcium

50. important pancreatic enzymes
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)
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss