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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. spermatogonia arise from
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Sorts - modifies - concentrates proteins from the ER
Epithelial tissue near semniferous tubules

2. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Organs
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

3. The EYE
Lumen (ie continuous w/body cavity) and cytosol
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Glucose = aldose fructose = ketose

4. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Facilitated diffusion from hi to lo conc
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Organs

5. Gland: ovaries
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
- 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
Lower blood pH

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

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7. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

8. How does the body mobilize fat stores
Most absorption occurs in sm intestine
***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
Cancer; apop can be programmed cell death; mitochon can play important role in apop
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

9. is intracellular AA conc hi or low?
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Low because AAs are immediately used in translation
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
The renal corpuscle

10. Morula (...totipotent)
All carbs absorbed at enterocytes are carried to liver by portal vein
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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11. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Gastrulation occurs: formation of three primary germ layers = differentiation
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
Night vision
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

12. in the presence of ADH what happens to movement of water across nephron membr
Needs time for bile - lipase - micelle migration - enterocyte uptake
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
Low because AAs are immediately used in translation
Water flows from the tubule - concentrating the filtrate - raising BP

13. important pancreatic enzymes
Gastrulation occurs: formation of three primary germ layers = differentiation
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
Ventrally (picture skeletal vertebrae)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

14. Where does fertilization occur
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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
Fallopian tubes
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

15. Thus inhibiting parietal cells could do What to blood pH
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Lower blood pH
Within the paravertebral ganglion - running parallel to spinal cord

16. remaining secondary follicle becomes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Thru tight junctions by favorable osmotic gradient
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Creates one ovum (23 N) and three polar bodies

17. components of interstitial fluid
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Glycosaminoglycans - prots - AAs - lipids
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

18. FLAT PG: hGH aka somatotropin
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)
Lots of energy; eg neurons have hi glucose need for 3Na out 2K in ATPase; stomach epithel tiss needs E for parietal cells to pump protons into lumen and bicarbonate into blood
Increases surface area of food ball (bolus)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

19. What is somatostatin
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Paracrine (local) - endocrine (longer distance)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

20. Glucose is a .... sugar; fructose is a .... sugar
Glucose = aldose fructose = ketose
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Abdominal cavity - which is coated in serous fluid
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

21. 80% of end product of carbohydrate metabolism is...
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Glucose
vitreous humor - retina - fovea
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

22. extracellular matrix formed mainly of...
Contain capillary network - lymph vessels (lacteals)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

23. What surrounds the hydrophilic heads of the new TAGs
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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

24. 3 phases of menstrual cycle
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Below hypothalamus
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)
Chyme (by combined activity of exocrine glands)

25. In IBS - What is defective

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26. interneurons
Increases surface area of food ball (bolus)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Processes: axons - dendrites
Conjunction of cell body w/axon

27. How is glucose absorbed in sm intest
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
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
In gastric pits; secretions combine into gastric juice

28. thyroid hormones: Not All One Kind of HORM
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
Glucose and ketone bodies (not from glycogen stores)
Gonadotropin releasing hormone - GnRH
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

29. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

30. Thus - central nervous sys is...
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Fallopian tubes
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

31. After meiosis II...
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Within the paravertebral ganglion - running parallel to spinal cord
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
- 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

32. overview of prot digestion
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
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
Facilitated diffusion from hi to lo conc
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

33. Think of spinal cord injury
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Mostly reabsorbed to liver
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

34. Energy from fat - prot - gluc
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

35. What does peptic refer to in general
1) by integral ion channels 2) transmitted by second messenger system
Digestion
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Outermost layer of blood vessel

36. FLAT PG: LH
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Below hypothalamus
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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

37. testosterone can be aromatized to...
Most absorption occurs in sm intestine
Estradiol
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

38. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
Testosterone and estradiol
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

39. Bile salts and lipase
Meiosis creates germ cells
Fallopian tubes
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

40. mitosis creates somatic cells
Thru tight junctions by favorable osmotic gradient
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Ganglion
Meiosis creates germ cells

41. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

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42. Most important nutrients absorbed by large intestine
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

43. What is the pH at the entrance to the duodenum
In gastric pits; secretions combine into gastric juice
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Organs

44. FLAT PG: FSH
ER
Processes: axons - dendrites
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Organs

45. How long are peptides when absorbed at brush border
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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Night vision
Epithelial tissue near semniferous tubules

46. exocrine types
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Sympathetic: dilates pupil (for night hunting)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Beta cells

47. Adrenal cortex hormones (STEROIDS)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

48. Where does the bolus go after mouth chews food
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Moves down thru esophageal sphincter
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

49. glucagon secreted by
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)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
AAs can be burned for energy or converted to fat for storage
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

50. lysosome pH
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
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
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On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins