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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. Gastrulation: ectoderm/mesoderm/endoderm
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

2. in fat and liver cells monoglycerides and ffas are once again
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

3. alpha - amylase in the mouth digests what kind of bond
Neurons may perform one of three functions....
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

4. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Break down TAGs to monoglycerides and free fatty acids
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
'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

5. cAMP - cGMP - calmodulin...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Uncontracted: parasymp (eg opoid use)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

6. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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... ...
Testosterone and estradiol
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Needs time for bile - lipase - micelle migration - enterocyte uptake

7. Difference between euk and prok flagella
Regulated by gastrointestinal horms
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

8. How is the follicle developed during oogenesis
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
ER
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

9. Three stages of the menstrual cycle
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

10. large intestine E. coli aid absorption of...
Digestion
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Moves down thru esophageal sphincter
Vitamin K - b12 - thiamin - riboflavin

11. 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
An endogenous morphine
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Inner lining of circulatory system
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

12. What do lipases do
Below hypothalamus
Fallopian tubes
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
Break down TAGs to monoglycerides and free fatty acids

13. what happens when glycogen stores are saturated and blood sugar remains high?
Fovea (highest amount of cones)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Sorts - modifies - concentrates proteins from the ER
An endogenous morphine

14. What is a toxic byproduct of gluconeogenesis from proteins
'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
Ammonia; must be converted to urea by liver and excreted in urine by kidney
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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

15. What is the endothelium?
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Inner lining of circulatory system
Water flows from the tubule - concentrating the filtrate - raising BP

16. FLAT PG: hGH aka somatotropin
AAs can be burned for energy or converted to fat for storage
Form barrier to extracellular fluid
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)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

17. when cells hit their limit for prot storage...
AAs can be burned for energy or converted to fat for storage
The renal corpuscle
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Break down TAGs to monoglycerides and free fatty acids

18. interneurons
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Meiosis creates germ cells
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

19. serous membranes have a viscera - facing layer and a body wall - facing layer
Pancreatic duct (made of acinar cells?)
Determined by whether in front of or behind the lens
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

20. golgi body
Pancreatic duct (made of acinar cells?)
Epithelial tissue near semniferous tubules
Inner lining of circulatory system
Sorts - modifies - concentrates proteins from the ER

21. lysosome main function and derivation
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
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

22. Cell determination begins At what stage of development
Oxytocin and ADH (aka vasopressin)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

23. when thinking of proteins - think
Nitrogen
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
An endogenous morphine

24. inhibin secreted by
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

25. SYMP neurons originate in= PARA neurons originate in=
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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
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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

26. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Determined by whether in front of or behind the lens
Inner lining of blood vessels
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Gastrulation occurs: formation of three primary germ layers = differentiation

27. On what surface of the retina is the eye most sensitive
Conjunction of cell body w/axon
Fovea (highest amount of cones)
Beta cells
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui

28. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
ER
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
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

29. pancreatic enzymes are zymogens
Outermost layer of blood vessel
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

30. After meiosis II - Male

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31. What controls release of LH - FSH from anterior pituitary
Fovea (highest amount of cones)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Gonadotropin releasing hormone - GnRH
Neurons may perform one of three functions....

32. liver and blood glucose...
'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
Inner lining of blood vessels
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Chyme (by combined activity of exocrine glands)

33. Different tissues working together
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Organs
Ups bicarbonate secretion by pancreas; raises pH to 6.0

34. gametic life cycle
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Mostly reabsorbed to liver
Primitive streak - which consists of cells of the MESODERM ****

35. How does duod deal with hi HCl from stom
Sympathetic: dilates pupil (for night hunting)
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
Two perpendicular semicircular canals involved in balance - equilibrium
Ups bicarbonate secretion by pancreas; raises pH to 6.0

36. Mucus - digestive enzymes released thru
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Glands w/ducts: Exocrine glands
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

37. FLAT PG: LH
Facilitated diffusion: no symport w/ secondary transport
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
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. A pinpoint iris is contracted or uncontracted
Uncontracted: parasymp (eg opoid use)
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**
Albumin increases osmolarity of blood; increases osmotic pressure
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

39. What do villli do
Sympathetic: dilates pupil (for night hunting)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

40. duodenum must have receptors for fat content - protein because
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
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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

41. 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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

42. How do parietal cells work ** (involves CO2)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Creates one ovum (23 N) and three polar bodies

43. What are the memb - bound enzymes of the brush border?
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Night vision
vitreous humor - retina - fovea
Liver is the control center for blood glucose; is fed by portal vein from sm intest

44. Embryology
***nicotinic is ionotropic; muscarinic is GPCR
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
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
Only musc and esp ** liver can store large amounts

45. almost all cells can store Some glycogen - but...
The wall of the body or of a body cavity or hollow structure
Only musc and esp ** liver can store large amounts
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Salivary amylase; both hydrolyze glycosidic linkages

46. 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
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

47. How does birth control work?
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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
Increases surface area of food ball (bolus)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

48. What determines number of chromosomes?
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Sympathetic: dilates pupil (for night hunting)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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**

49. Where else does ADH act
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

50. lining of abdominal cavity=
Salivary amylase; both hydrolyze glycosidic linkages
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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