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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. Anterior eye
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Abdominal cavity - which is coated in serous fluid
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

2. Where does the bolus go after mouth chews food
- 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
Moves down thru esophageal sphincter
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
Pancreatic duct (made of acinar cells?)

3. From that point...
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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
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.
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

4. lysosome 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
5
Membrane - bound - endocytosed bodies
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

5. When 'coumadin targets liver enzymes to act as anticoagulant'...
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
It targets liver conc of prothrombin - fibrinogen etc
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

6. FLAT PG: hGH aka somatotropin
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... ...
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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)

7. 3 phases of menstrual cycle
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Uncontracted: parasymp (eg opoid use)
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)

8. Liver Functions
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
Below hypothalamus
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

9. Anatomy of the villi
Contain capillary network - lymph vessels (lacteals)
Determined by whether in front of or behind the lens
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
All carbs absorbed at enterocytes are carried to liver by portal vein

10. Alpha - amylase found where
Glycosaminoglycans - prots - AAs - lipids
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**
In mouth - breakdown of starch into polysaccharides
Liver is the control center for blood glucose; is fed by portal vein from sm intest

11. FLAT PG: LH
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

12. Local vs long - distance mediators
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
Paracrine (local) - endocrine (longer distance)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Glucose = aldose fructose = ketose

13. 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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14. parathyroid hormones
Contain capillary network - lymph vessels (lacteals)
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
Sensory (afferent - dorsal) - motor (efferent - ventral)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

15. Adrenal medulla hormones (TYR- DERIVED)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Determined by whether in front of or behind the lens
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Lysosome

16. light detection via GPCRs
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Ventrally (picture skeletal vertebrae)
Homologous chromosomes separate - migrate towards opposite poles/centrioles

17. calcitonin

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18. mitosis creates somatic cells
Meiosis creates germ cells
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

19. what else is located in the inner ear (not directly related to auditory)
Interstitial fluid (eg prostaglandins - cytokines)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Two perpendicular semicircular canals involved in balance - equilibrium
Glycosaminoglycans - prots - AAs - lipids

20. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
- 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
Fovea (highest amount of cones)

21. Polypeptides are formed with what kind of reaction?
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
About 7.2
'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
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

22. therefore - How does plasma leave capillary at the renal corpuscle

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23. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Ganglion
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

24. Blastocyst
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

25. in fat and liver cells monoglycerides and ffas are once again
Gonadotropin releasing hormone - GnRH
Organs
Outermost layer of blood vessel
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

26. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
'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.'
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

27. Spinal cord horns (thick knobs) point
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Ventrally (picture skeletal vertebrae)
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

28. What are phagosomes
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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Glucose

29. Meiosis I Anaphase I
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

30. Where do pancreatic secretions take effect
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

31. Kidney
Glycosaminoglycans - prots - AAs - lipids
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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

32. albumin has What affect on blood osmotic pressure
Creates one ovum (23 N) and three polar bodies
Liposome has phospholipid bilayer
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Albumin increases osmolarity of blood; increases osmotic pressure

33. motor (efferent) neurons --> VENTRAL
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)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Carry signals to musc OR Gland
5

34. What if large intestine isn't working well
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
5
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti

35. FLAT PG: prolactin
Interstitial fluid (eg prostaglandins - cytokines)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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)

36. what happens when glycogen stores are saturated and blood sugar remains high?
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Prod of steroid hormones in testes - ovaries
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

37. alpha - amylase in the mouth digests what kind of bond
Albumin increases osmolarity of blood; increases osmotic pressure
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Alpha 1-4 and 1-6 (branching) glycosidic linkages
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)

38. FSH - LH - HCG - inhibin are...
Direction of differentiation
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Peptides

39. ligands are the messenger compounds that target secondary messenger systems on effectors
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
Many modern drugs are ligands for GPCRs
Abdominal cavity - which is coated in serous fluid
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

40. Morula (...totipotent)
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
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
Testosterone upon stim by LH
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

41. Luteal surge
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Water flows from the tubule - concentrating the filtrate - raising BP
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

42. What is the net effect of the distal tubule
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Peptides
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

43. Gastrulation: ectoderm/mesoderm/endoderm
HCl; secreted by parietal cells under stim by gastrin
Processes: axons - dendrites
Normally contracted
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

44. micelles vs liposomes
Below hypothalamus
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Liposome has phospholipid bilayer

45. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Faces the lumen

46. extracellular matrix formed mainly of...
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Facilitated diffusion: no symport w/ secondary transport
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

47. Peritoneal refers to...
Break down TAGs to monoglycerides and free fatty acids
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Abdominal cavity - which is coated in serous fluid

48. What else do parietals do?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Lumen (ie continuous w/body cavity) and cytosol

49. What is the function of the loop of Henle
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**
Increases solute conc and osmotic pressure of the ***medulla
In gastric pits; secretions combine into gastric juice
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

50. gametic life cycle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger