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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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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. Meiosis I Anaphase I
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Food is digested from mouth to stomach (denaturation by gastric acid - digested by pepsin) to duodenum (more digestion); then absorption occurs in jejunum and ileum
Organs

2. What else do parietals do?
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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
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

3. What kind of cells make up epithel tiss of stom - then sm intest?
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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

4. A contracted iris occurs with what kind of stimulation
Sympathetic: dilates pupil (for night hunting)
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
Meiosis creates germ cells
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

5. Kidney physiology...

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6. light detection via GPCRs
Most absorption occurs in sm intestine
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Primitive streak - which consists of cells of the MESODERM ****
Thru tight junctions by favorable osmotic gradient

7. How does duod deal with hi HCl from stom
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Lower blood pH
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

8. little by little chyme is squirted out thru pyloric sphincter
Many modern drugs are ligands for GPCRs
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
Inner lining of circulatory system
Regulated by gastrointestinal horms

9. After meiosis I - daughter cells are...

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10. Chewing does what?
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Increases surface area of food ball (bolus)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

11. these transport proteins - when concs are high enough...
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
'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

12. Cell bodies of SYMP postganglionic neurons lie far from effector...
In gastric pits; secretions combine into gastric juice
Within the paravertebral ganglion - running parallel to spinal cord
Faces the lumen
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

13. 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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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... ...
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

14. ADH
Increases blood Calcium
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
Most absorption occurs in sm intestine
Glucose and ketone bodies (not from glycogen stores)

15. cytosol pH
About 7.2
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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

16. calcitonin

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17. Determination is different than differentiation
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
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
Peptides
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

18. Beta - oxidation in liver produces...
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Sympathetic: dilates pupil (for night hunting)
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... ...
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

19. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Low because AAs are immediately used in translation
Creates one ovum (23 N) and three polar bodies
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
'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

20. Meiosis I Metaphase I
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Uncontracted: parasymp (eg opoid use)
Inner lining of blood vessels
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

21. At post - two weeks ovulation
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
An endogenous morphine
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Corpus luteum degrades into corpus albicans

22. small intestine=
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Two perpendicular semicircular canals involved in balance - equilibrium
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

23. How long are peptides when absorbed at brush border
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Cancer; apop can be programmed cell death; mitochon can play important role in apop

24. What does portal vein do
Salivary amylase; both hydrolyze glycosidic linkages
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
All carbs absorbed at enterocytes are carried to liver by portal vein
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

25. what cannot cross the fenestrations of the renal corpuscle
Mostly reabsorbed to liver
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)
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
RBCs - large proteins; What does enter is called the filtrate

26. What is secreted into filtrate by cells of the proximal tubule?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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)
90-140 mg/dl
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)

27. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
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)
Below hypothalamus
Uncontracted: parasymp (eg opoid use)

28. What is a normal blood glucose range
Increases blood Calcium
About 7.2
Pancreatic duct (made of acinar cells?)
90-140 mg/dl

29. almost all cells can store Some glycogen - but...
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Only musc and esp ** liver can store large amounts
All carbs absorbed at enterocytes are carried to liver by portal vein

30. Different tissues working together
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Organs
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

31. alpha - amylase in the mouth digests what kind of bond
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
***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
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

32. How do parietal cells work ** (involves CO2)
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
***nicotinic is ionotropic; muscarinic is GPCR
ER
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

33. What surrounds the hydrophilic heads of the new TAGs
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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
Prod of steroid hormones in testes - ovaries
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

34. Some epithelial cells are... others...
- 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
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Cancer; apop can be programmed cell death; mitochon can play important role in apop

35. What is an endorphin?
Membrane - bound - endocytosed bodies
Glands w/ducts: Exocrine glands
An endogenous morphine
Prod of steroid hormones in testes - ovaries

36. What is feces composed of...
Salivary amylase; both hydrolyze glycosidic linkages
AAs enter bloodstream for uptake by all cells (esp liver). If intracellular prot conc is at max AAs can be converted to fats or glucose via gluconeogenesis. Byproduct of gluconeo is ammonia --->urea.
Sensory (afferent - dorsal) - motor (efferent - ventral)
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

37. albumin has What affect on blood osmotic pressure
- 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
Fructose is a structural isomer of glucose
Albumin increases osmolarity of blood; increases osmotic pressure
Ganglion

38. PNS nerve signal
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
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
Gonadotropin releasing hormone - GnRH
Corpus luteum degrades into corpus albicans

39. in the presence of ADH what happens to movement of water across nephron membr
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... ...
90-140 mg/dl
Water flows from the tubule - concentrating the filtrate - raising BP
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

40. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Vitamin K - b12 - thiamin - riboflavin
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Ganglion
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

41. Where are these exocrine glands located
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
In gastric pits; secretions combine into gastric juice

42. The apical side of the villi...
About 7.2
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Faces the lumen
Break down TAGs to monoglycerides and free fatty acids

43. Think of spinal cord injury
Epithelial tissue near semniferous tubules
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Low because AAs are immediately used in translation

44. In IBS - What is defective

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45. Seen in lysosomal storage diseases
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Albumin increases osmolarity of blood; increases osmotic pressure
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Two perpendicular semicircular canals involved in balance - equilibrium

46. what happens to bile secretions
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Membrane - bound - endocytosed bodies
90-140 mg/dl
Mostly reabsorbed to liver

47. signal transduction occurs by 2 paths
1) by integral ion channels 2) transmitted by second messenger system
Eukaryotes
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

48. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Interstitial fluid (eg prostaglandins - cytokines)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
AAs can be burned for energy or converted to fat for storage

49. What does peroxisome do
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Zygotes are diploid
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
ER

50. What controls release of LH - FSH from anterior pituitary
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Gonadotropin releasing hormone - GnRH