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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. How does reabsorption force nutrients across apical membrane of proximal tubule
Creates one ovum (23 N) and three polar bodies
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Facilitated diffusion: no symport w/ secondary transport
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

2. gametic life cycle
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
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
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

3. euk cell has two principal sides
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Lumen (ie continuous w/body cavity) and cytosol
Smooth ER
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

4. What does peptic refer to in general
Digestion
Testosterone and estradiol
Two perpendicular semicircular canals involved in balance - equilibrium
Inner lining of circulatory system

5. duodenum must have receptors for fat content - protein because
Moves down thru esophageal sphincter
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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

6. Tight junctions
Lysosome
Peripheral nervous sys
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
Form barrier to extracellular fluid

7. 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
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Fructose is a structural isomer of glucose
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

8. bundles of collecting ducts are called
Facilitated diffusion: no symport w/ secondary transport
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

9. What are the major carbohydrates
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Ups bicarbonate secretion by pancreas; raises pH to 6.0

10. 'Cell bodies of somatic motor neurons are located in....'
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
'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

11. Some epithelial cells are... others...
Fructose is a structural isomer of glucose
The renal corpuscle
- 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
Which is why lactase - maltase - dextrinase - sucrase are on brush border

12. What if large intestine isn't working well
1) by integral ion channels 2) transmitted by second messenger system
It targets liver conc of prothrombin - fibrinogen etc
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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

13. Anterior eye
Epithelial tissue near semniferous tubules
Oxytocin and ADH (aka vasopressin)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

14. How is glucose absorbed in sm intest
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Glycosaminoglycans - prots - AAs - lipids
Uncontracted: parasymp (eg opoid use)
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

15. What is a normal blood glucose range
90-140 mg/dl
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Membrane - bound - endocytosed bodies
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

16. portal vein physiology...

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17. sporic life cycle
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Somatic nervous sys - autonomic nervous sys

18. little by little chyme is squirted out thru pyloric sphincter
Regulated by gastrointestinal horms
5
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

19. protein absorption at enterocyte
Pancreatic duct (made of acinar cells?)
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
Below hypothalamus
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

20. Kidney physiology...

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21. peroxisome is derived from this
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
RBCs - large proteins; What does enter is called the filtrate
ER
Fructose is a structural isomer of glucose

22. fat digestion is time - intensive
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
Needs time for bile - lipase - micelle migration - enterocyte uptake
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)
Moves down thru esophageal sphincter

23. What is a toxic byproduct of gluconeogenesis from proteins
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Ammonia; must be converted to urea by liver and excreted in urine by kidney
'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
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

24. Some PNS nerves are found in brain - spinal cord
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Estradiol
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
Abdominal cavity - which is coated in serous fluid

25. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
Most absorption occurs in sm intestine
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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

26. what happens when glycogen stores are saturated and blood sugar remains high?
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

27. trypsin is secreted by
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... ...
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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

28. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Testosterone and estradiol
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Creates one ovum (23 N) and three polar bodies

29. How do nutrients move?
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Paracrine (local) - endocrine (longer distance)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

30. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Inner lining of blood vessels
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

31. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Pancreatic duct (made of acinar cells?)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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

32. mitosis creates somatic cells
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
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
Meiosis creates germ cells
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

33. 80-90% fat absorbed this way
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
HCl; secreted by parietal cells under stim by gastrin
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

34. Blastocyst
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Membrane - bound - endocytosed bodies
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
1) by integral ion channels 2) transmitted by second messenger system

35. Spinal cord horns (thick knobs) point
Primitive streak - which consists of cells of the MESODERM ****
Ventrally (picture skeletal vertebrae)
Glands w/ducts: Exocrine glands
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

36. Aldosterone (sodium uptake - potassium secretion)
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)
Organs
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
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

37. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Zygotes are diploid
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

38. thyroid hormones: Not All One Kind of HORM
Within the paravertebral ganglion - running parallel to spinal cord
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

39. Adrenal medulla hormones (TYR- DERIVED)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Homologous chromosomes separate - migrate towards opposite poles/centrioles

40. Polypeptides are formed with what kind of reaction?
Zygotes are diploid
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
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

41. Where would materials slated for digestion go?
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Lysosome

42. Different tissues working together
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
Organs
Gastrulation occurs: formation of three primary germ layers = differentiation
Ganglion

43. What kind of cells make up epithel tiss of stom - then sm intest?
Stores blood: when expanded liver serves as blood reservoir for body - filters blood: Kupfer cells phagocytize bacteria picked up from intestines - destroys bad RBCs: also done by Kupfer cells - detoxifies blood: detoxified chemicals are excreted eit
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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
Increases surface area of food ball (bolus)

44. What is a nerve? (PNS)
Two perpendicular semicircular canals involved in balance - equilibrium
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
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
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

45. lysosome pH
5
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Night vision

46. alpha - amylase in the mouth digests what kind of bond
Inner lining of circulatory system
Only musc and esp ** liver can store large amounts
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

47. In effect LH - FSH stimulate
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Prod of steroid hormones in testes - ovaries
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep

48. medium for paracrine hormones
Interstitial fluid (eg prostaglandins - cytokines)
Glucose = aldose fructose = ketose
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

49. What is the adventitia?
Glucose
Outermost layer of blood vessel
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
Ammonia; must be converted to urea by liver and excreted in urine by kidney

50. Exocrine GlandS: stomach
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum