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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 does portal vein do
Has memb - bound organelles - etc...
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
All carbs absorbed at enterocytes are carried to liver by portal vein
Sensory (afferent - dorsal) - motor (efferent - ventral)

2. In IBS - What is defective

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3. parathyroid hormone
Only musc and esp ** liver can store large amounts
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Increases blood Calcium
Fallopian tubes

4. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Break down TAGs to monoglycerides and free fatty acids
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

5. 80-90% fat absorbed this way
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
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... ...
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Glucose and ketone bodies (not from glycogen stores)

6. 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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
Somatic nervous sys - autonomic nervous sys
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

7. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

8. Where do pancreatic secretions take effect
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

9. Where else does ADH act
Only musc and esp ** liver can store large amounts
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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Stomach - sm intest - spleen - pancreas from the hepatic portal vein...all blood that passes thru liver go thru flattened spaces called the ***hepatic sinusoids -->hepatic vein --->vena cava

10. only monosaccharides are absorbed
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

11. gametic life cycle
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Mostly reabsorbed to liver
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

12. What kind of cells make up epithel tiss of stom - then sm intest?
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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
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

13. peroxisome is derived from this
Direction of differentiation
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
ER

14. FLAT PG: prolactin
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
- 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
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

15. 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)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
In mouth - breakdown of starch into polysaccharides
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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

16. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Glands w/ducts: Exocrine glands
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

17. What is gastric acid?
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Carry signals to musc OR Gland
HCl; secreted by parietal cells under stim by gastrin
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

18. Some PNS nerves are found in brain - spinal cord
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
- 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
HCl; secreted by parietal cells under stim by gastrin
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

19. Mucus - digestive enzymes released thru
In mouth - breakdown of starch into polysaccharides
Glands w/ducts: Exocrine glands
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

20. Kidney
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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

21. Thus - central nervous sys is...
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Only musc and esp ** liver can store large amounts
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

22. Posterior eye
vitreous humor - retina - fovea
'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.'
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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

23. What is secreted into filtrate by cells of the proximal tubule?
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

24. What is the pH at the entrance to the duodenum
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages

25. amylase acts where on carbs
Only musc and esp ** liver can store large amounts
Fovea (highest amount of cones)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

26. PNS review: SAME DAVE
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

27. How do monoglycerides and ffas get to brush border?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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
Meiosis creates germ cells

28. smooth ER main function
Membrane - bound - endocytosed bodies
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Direction of 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

29. E storage per unit mass
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
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
Facilitated diffusion from hi to lo conc
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

30. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Neurons may perform one of three functions....
Which is why lactase - maltase - dextrinase - sucrase are on brush border
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)

31. How does the body mobilize fat stores
***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
Has memb - bound organelles - etc...
Needs time for bile - lipase - micelle migration - enterocyte uptake
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

32. pancreatic amylase is much stronger than
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Glucose and ketone bodies (not from glycogen stores)
Salivary amylase; both hydrolyze glycosidic linkages
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

33. position of AP...
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Below hypothalamus

34. For focal point that is nearby - what will the lens look like
Epithelial tissue near semniferous tubules
Membrane - bound - endocytosed bodies
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Outermost layer of blood vessel

35. what happens to bile secretions
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Facilitated diffusion from hi to lo conc
Mostly reabsorbed to liver
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

36. How does birth control work?
Peripheral nervous sys
Somatic nervous sys - autonomic nervous sys
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

37. alpha - amylase in the mouth digests what kind of bond
Salivary amylase; both hydrolyze glycosidic linkages
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Mostly reabsorbed to liver
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

38. inhibin secreted by
Organs
Fovea (highest amount of cones)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

39. PNS is broken down into
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Somatic nervous sys - autonomic nervous sys
Determined by whether in front of or behind the lens
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

40. Cell determination begins At what stage of development
Break down TAGs to monoglycerides and free fatty acids
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

41. What is the net effect of the loop of Henle
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Needs time for bile - lipase - micelle migration - enterocyte uptake
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)
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

42. mucus cells line the stomach...
Fallopian tubes
90-140 mg/dl
Organs
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

43. sensory (afferent) neurons
Liposome has phospholipid bilayer
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
HCl; secreted by parietal cells under stim by gastrin

44. What is the adventitia?
Outermost layer of blood vessel
Inner lining of blood vessels
Increases surface area of food ball (bolus)
Albumin increases osmolarity of blood; increases osmotic pressure

45. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Testosterone and estradiol
Conjunction of cell body w/axon
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Systems (eg digestive system consists of many organs)

46. quote on cavities/viscera

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47. 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
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
The renal corpuscle
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

48. therefore - How does plasma leave capillary at the renal corpuscle

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49. in mammals - gastrulation involves formation of the
Primitive streak - which consists of cells of the MESODERM ****
Beta cells
Corpus luteum degrades into corpus albicans
Membrane - bound - endocytosed bodies

50. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
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**
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges