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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 happens when rod cell is depolarized
Night vision
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Prod of steroid hormones in testes - ovaries
'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

2. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Eukaryotes
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
Has memb - bound organelles - etc...
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

3. Aldosterone (sodium uptake - potassium secretion)
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
- 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
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

4. amylase acts where on carbs
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

5. what happens to bile secretions
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
Vitamin K - b12 - thiamin - riboflavin
Mostly reabsorbed to liver
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

6. What is the endothelium?
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Lower blood pH
90-140 mg/dl
Inner lining of circulatory system

7. What are the major carbohydrates
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
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

8. portal vein physiology...

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9. Peritoneal refers to...
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Abdominal cavity - which is coated in serous fluid

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

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11. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
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
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Oxytocin and ADH (aka vasopressin)
Fallopian tubes

12. Where do absorbed fats go in the enterocyte
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Normally contracted
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

13. What controls release of LH - FSH from anterior pituitary
Gonadotropin releasing hormone - GnRH
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

14. What if large intestine isn't working well
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

15. 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
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
Most absorption occurs in sm intestine
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

16. STOMACH: no absorption
Inner lining of blood vessels
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

17. pancreatic amylase is much stronger than
Chyme (by combined activity of exocrine glands)
Salivary amylase; both hydrolyze glycosidic linkages
vitreous humor - retina - fovea
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

18. FLAT PG: prolactin
Liver is the control center for blood glucose; is fed by portal vein from sm intest
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
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

19. After meiosis II - Male

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20. fructose enters enterocyte by
Pancreatic duct (made of acinar cells?)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Sympathetic: dilates pupil (for night hunting)
Facilitated diffusion: no symport w/ secondary transport

21. How does water cross the apical membrane
Thru tight junctions by favorable osmotic gradient
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

22. from the loop of henle...
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
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

23. 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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Paracrine (local) - endocrine (longer distance)

24. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

25. ligands are the messenger compounds that target secondary messenger systems on effectors
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Increases solute conc and osmotic pressure of the ***medulla
Determined by whether in front of or behind the lens
Many modern drugs are ligands for GPCRs

26. Gastrin from G cells stims parietal cells...
Glucose
Many modern drugs are ligands for GPCRs
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

27. lining of abdominal cavity=
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Glucose = aldose fructose = ketose
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
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

28. Tight junctions
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
All carbs absorbed at enterocytes are carried to liver by portal vein
Form barrier to extracellular fluid
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

29. cAMP - cGMP - calmodulin...
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
1) by integral ion channels 2) transmitted by second messenger system
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

30. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Testosterone and estradiol
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
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

31. alpha - amylase in the mouth digests what kind of bond
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Peptides
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
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

32. How does birth control work?
About 7.2
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
90-140 mg/dl
Lower blood pH

33. exocrine types
Pancreatic duct (made of acinar cells?)
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Prod of steroid hormones in testes - ovaries
Beta cells

34. Mucus - digestive enzymes released thru
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
Glands w/ducts: Exocrine glands
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

35. How do parietal cells work ** (involves CO2)
The wall of the body or of a body cavity or hollow structure
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

36. What force is acting upon chyme to move it forward down sm intestine
Ganglion
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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

37. Glycogenolysis/gluconeogenesis
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
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

38. quote on cavities/viscera

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39. Embryology
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
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
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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

40. Gland: ovaries
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Fallopian tubes
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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

41. albumin has What affect on blood osmotic pressure
Most absorption occurs in sm intestine
Albumin increases osmolarity of blood; increases osmotic pressure
Increases surface area of food ball (bolus)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

42. Where else does ADH act
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 the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Peripheral nervous sys

43. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Ganglion
Fovea (highest amount of cones)
An endogenous morphine
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... ...

44. review: parietals secrete intrinsic factor...
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

45. testosterone can be aromatized to...
Many modern drugs are ligands for GPCRs
Zygotes are diploid
Estradiol
Lumen (ie continuous w/body cavity) and cytosol

46. Posterior eye
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
Sorts - modifies - concentrates proteins from the ER
vitreous humor - retina - fovea
Estradiol

47. lysosome pH
Break down TAGs to monoglycerides and free fatty acids
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
5

48. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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
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

49. 90% digestion - absorption occurs in...
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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

50. food in duod stims release of gastrointestinal hormones
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate