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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. Different organs working together
Systems (eg digestive system consists of many organs)
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul

2. PNS nerve signal
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
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

3. gradual increase in FSH typical of primary follicle development;
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Break down TAGs to monoglycerides and free fatty acids
Water flows from the tubule - concentrating the filtrate - raising BP

4. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Creates one ovum (23 N) and three polar bodies
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
Outermost layer of blood vessel
Zygotes are diploid

5. examples of different cavities... (compartments for viscera)
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul
Chylomicrons are much bigger
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

6. mitosis creates somatic cells
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Glucose = aldose fructose = ketose
Testosterone upon stim by LH
Meiosis creates germ cells

7. What is main difference is signal transmission in nicotinic vs muscarinic?
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
***nicotinic is ionotropic; muscarinic is GPCR

8. smooth ER main function
Estradiol
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Contain capillary network - lymph vessels (lacteals)
- 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

9. Kidney physiology...

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10. 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)
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
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
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

11. What is the path of a sound wave that enters the ear?
Needs time for bile - lipase - micelle migration - enterocyte uptake
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
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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

12. when thinking of proteins - think
vitreous humor - retina - fovea
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Nitrogen
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

13. duodenum must have receptors for fat content - protein because
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)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
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

14. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
'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
***nicotinic is ionotropic; muscarinic is GPCR
AAs can be burned for energy or converted to fat for storage
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

15. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Testosterone and estradiol
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

16. signal transduction occurs by 2 paths
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
1) by integral ion channels 2) transmitted by second messenger system
Fructose is a structural isomer of glucose

17. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
In mouth - breakdown of starch into polysaccharides
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

18. Four tissues
Digestion
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Processes: axons - dendrites

19. What is a normal blood glucose range
Abdominal cavity - which is coated in serous fluid
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
90-140 mg/dl
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)

20. parathyroid hormone
Increases blood Calcium
Abdominal cavity - which is coated in serous fluid
Follicular phase: primary - secondary - ovulation (1 week) luteal phase: ovulation - thickening of uterine lining w/corpus luteum secretion - corpus luteum degrades (2 weeks) flow: shedding of uterine lining (4 days)
About 7.2

21. 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)
Neurons may perform one of three functions....
Regulated by gastrointestinal horms
Albumin increases osmolarity of blood; increases osmotic pressure

22. Spinal cord horns (thick knobs) point
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Ventrally (picture skeletal vertebrae)
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**
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

23. Embryology
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Conjunction of cell body w/axon
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

24. protein absorption at enterocyte
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
***nicotinic is ionotropic; muscarinic is GPCR
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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

25. glucagon secreted by
Testosterone upon stim by LH
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
Two perpendicular semicircular canals involved in balance - equilibrium

26. what else is located in the inner ear (not directly related to auditory)
Smooth ER
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Two perpendicular semicircular canals involved in balance - equilibrium
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

27. Between meals most fats appear in blood as
Below hypothalamus
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Increases blood Calcium
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

28. in mammals - gastrulation involves formation of the
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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Primitive streak - which consists of cells of the MESODERM ****
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

29. albumin has What affect on blood osmotic pressure
Albumin increases osmolarity of blood; increases osmotic pressure
Fovea (highest amount of cones)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

30. testosterone can be aromatized to...
Organs
Estradiol
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

31. What are phagosomes
AAs can be burned for energy or converted to fat for storage
Membrane - bound - endocytosed bodies
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

32. After meiosis II - Female

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33. What hormones affect the stomach?
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
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
Lower blood pH

34. Which fats are not absorbed like this
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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

35. in fat and liver cells monoglycerides and ffas are once again
Sensory (afferent - dorsal) - motor (efferent - ventral)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Water flows from the tubule - concentrating the filtrate - raising BP
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

36. 80% of end product of carbohydrate metabolism is...
Glucose
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Glycosaminoglycans - prots - AAs - lipids

37. Cell determination begins At what stage of development
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Lower blood pH
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

38. PNS is broken down into
All carbs absorbed at enterocytes are carried to liver by portal vein
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Ventrally (picture skeletal vertebrae)
Somatic nervous sys - autonomic nervous sys

39. 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
Ganglion
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

40. What is secreted into filtrate by cells of the proximal tubule?
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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
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)

41. signal transduction occurs only in
Two perpendicular semicircular canals involved in balance - equilibrium
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Eukaryotes

42. Aldosterone (sodium uptake - potassium secretion)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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
Thru tight junctions by favorable osmotic gradient
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)

43. Where are these exocrine glands located
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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
In gastric pits; secretions combine into gastric juice
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

44. A contracted iris occurs with what kind of stimulation
Lumen (ie continuous w/body cavity) and cytosol
Mostly reabsorbed to liver
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... ...
Sympathetic: dilates pupil (for night hunting)

45. bile + fat forms
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
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
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

46. A pinpoint iris is contracted or uncontracted
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Uncontracted: parasymp (eg opoid use)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

47. sensory (afferent)/interneurons/motor (efferent)
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
Uncontracted: parasymp (eg opoid use)
Neurons may perform one of three functions....
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

48. Alpha - amylase found where
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
The wall of the body or of a body cavity or hollow structure
In mouth - breakdown of starch into polysaccharides
ER

49. Some PNS nerves are found in brain - spinal cord
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
'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.'
Paracrine (local) - endocrine (longer distance)

50. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
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
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