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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. Where do absorbed fats go in the enterocyte
Faces the lumen
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Creates one ovum (23 N) and three polar bodies

2. How is glucose absorbed in sm intest
Inner lining of circulatory system
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
Needs time for bile - lipase - micelle migration - enterocyte uptake
Liver is the control center for blood glucose; is fed by portal vein from sm intest

3. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

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

5. large intestine E. coli aid absorption of...
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Inner lining of circulatory system
Vitamin K - b12 - thiamin - riboflavin
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

6. Anterior eye
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
Uncontracted: parasymp (eg opoid use)
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

7. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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

8. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

9. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Monitors filtrate pressure in the distal tubule; has specialized cells (granular cells) that secrete an enzyme (**renin); renin initiates regulatory cascade that produces angiotensin I - II - III that stim adrenal cortex to secrete aldosterone... ...
It targets liver conc of prothrombin - fibrinogen etc
Organs
An endogenous morphine

10. alpha - amylase in the mouth digests what kind of bond
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Which is why lactase - maltase - dextrinase - sucrase are on brush border

11. Mucus - digestive enzymes released thru
Normally contracted
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Glands w/ducts: Exocrine glands
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

12. almost all cells can store Some glycogen - but...
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
Ammonia; must be converted to urea by liver and excreted in urine by kidney
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Only musc and esp ** liver can store large amounts

13. FLAT PG: prolactin
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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)
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

14. Where do pancreatic secretions take effect
Uncontracted: parasymp (eg opoid use)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
All carbs absorbed at enterocytes are carried to liver by portal vein

15. Glucose is a .... sugar; fructose is a .... sugar
Glucose = aldose fructose = ketose
Inner lining of circulatory system
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

16. these transport proteins - when concs are high enough...
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Digestion
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

17. PNS nerve signal
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Digestion
Fallopian tubes

18. pancreas secretes enzymes via
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Determined by whether in front of or behind the lens
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Pancreatic duct (made of acinar cells?)

19. components of interstitial fluid
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Glycosaminoglycans - prots - AAs - lipids
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

20. How do nutrients move?
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Glands w/ducts: Exocrine glands
Primitive streak - which consists of cells of the MESODERM ****
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

21. fat digestion is time - intensive
Needs time for bile - lipase - micelle migration - enterocyte uptake
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

22. The apical side of the villi...
Ganglion
Ammonia; must be converted to urea by liver and excreted in urine by kidney
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Faces the lumen

23. ADH
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)
Vitamin K - b12 - thiamin - riboflavin
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
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

24. What hormones affect the stomach?
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
Somatic nervous sys - autonomic nervous sys
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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

25. How does water cross the apical membrane
Thru tight junctions by favorable osmotic gradient
Vitamin K - b12 - thiamin - riboflavin
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

26. After meiosis II...
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
About 7.2
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Creates one ovum (23 N) and three polar bodies

27. Kidney
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
Ventrally (picture skeletal vertebrae)
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

28. sporic life cycle
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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

29. Embryology
The renal corpuscle
Albumin increases osmolarity of blood; increases osmotic pressure
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
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

30. gradual increase in FSH typical of primary follicle development;
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... ...
Direction of differentiation
Pancreatic duct (made of acinar cells?)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

31. At post - two weeks ovulation
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Corpus luteum degrades into corpus albicans
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

32. Interaction of corpus luteum/placenta
Uncontracted: parasymp (eg opoid use)
Regulated by gastrointestinal horms
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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)

33. On what surface of the retina is the eye most sensitive
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
Salivary amylase; both hydrolyze glycosidic linkages
Fovea (highest amount of cones)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

34. sensory (afferent)/interneurons/motor (efferent)
Neurons may perform one of three functions....
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

35. duodenum must have receptors for fat content - protein because
Presence of fat - prot in duodenum causes release of **gastric inhibitory peptide**; result is slower stomach contraction; slower emptying into duod thru pyloric sphincter (slower chyme secretion); more time to properly digest - absorb nutrients
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Primitive streak - which consists of cells of the MESODERM ****

36. micelles vs liposomes
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Gastrulation occurs: formation of three primary germ layers = differentiation
Liposome has phospholipid bilayer
- 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

37. amylase acts where on carbs
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Epithelial tissue near semniferous tubules
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Ganglion

38. Posterior eye
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
vitreous humor - retina - fovea
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

39. Anatomy of the villi
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Contain capillary network - lymph vessels (lacteals)

40. Meiosis I Telophase I
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Chylomicrons are much bigger
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

41. 3 phases of menstrual cycle
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)
Epithelial tissue near semniferous tubules
Prophase II: no crossing over b/c there are no homologous chromosomes; nuclear envelope dissolves Metaphase II: chromosomes line up at metaphase plate Anaphase II: sister chromatids separate - migrate to opp poles Telophase II: nuclear envelope reap
Water flows from the tubule - concentrating the filtrate - raising BP

42. What is a toxic byproduct of gluconeogenesis from proteins
Conjunction of cell body w/axon
In gastric pits; secretions combine into gastric juice
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Fallopian tubes

43. Four tissues
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

44. Creating gradients requires what?
Has memb - bound organelles - etc...
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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

45. oxytocin
***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
Thru tight junctions by favorable osmotic gradient
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Faces the lumen

46. When 'coumadin targets liver enzymes to act as anticoagulant'...
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
Fallopian tubes
It targets liver conc of prothrombin - fibrinogen etc
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

47. What is a plasmalogen?
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Most absorption occurs in sm intestine
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

48. Does bile digest fat?
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Interstitial fluid (eg prostaglandins - cytokines)
Break down TAGs to monoglycerides and free fatty acids
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

49. Chewing does what?
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)
vitreous humor - retina - fovea
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Increases surface area of food ball (bolus)

50. FLAT PG: TSH aka thyrotropin
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Gonadotropin releasing hormone - GnRH
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