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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. What do villli do
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
Glucose and ketone bodies (not from glycogen stores)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

2. Kidney
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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
Lysosome
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

3. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

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4. 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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
In mouth - breakdown of starch into polysaccharides
Lower blood pH

5. A group of cell bodies in CNS is nucleus - outside CNS is...
Determined by whether in front of or behind the lens
Ganglion
Within the paravertebral ganglion - running parallel to spinal cord
Homologous chromosomes separate - migrate towards opposite poles/centrioles

6. serous membranes have a viscera - facing layer and a body wall - facing layer
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Peripheral nervous sys

7. What is the net effect of the loop of Henle
- 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
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)
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)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

8. What is an endorphin?
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
An endogenous morphine
The renal corpuscle
Normally contracted

9. 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
Facilitated diffusion from hi to lo conc
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Night vision

10. calcitonin

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11. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Oxytocin and ADH (aka vasopressin)

12. What are phagosomes
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
Night vision
Membrane - bound - endocytosed bodies
- 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

13. 3 phases of menstrual cycle
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits 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)
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass
AAs can be burned for energy or converted to fat for storage

14. exocrine types
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

15. What is the pH at the entrance to the duodenum
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

16. Which fats are not absorbed like this
Increases blood Calcium
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
ER
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

17. Where are these exocrine glands located
In gastric pits; secretions combine into gastric juice
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Determined by whether in front of or behind the lens
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

18. parathyroid hormone
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Increases blood Calcium

19. bundles of collecting ducts are called
Peripheral nervous sys
Salivary amylase; both hydrolyze glycosidic linkages
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Somatic nervous sys - autonomic nervous sys

20. testosterone can be aromatized to...
Thru tight junctions by favorable osmotic gradient
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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
Estradiol

21. What is the net effect of the distal tubule
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
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
Increases solute conc and osmotic pressure of the ***medulla

22. What is main difference is signal transmission in nicotinic vs muscarinic?
***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
Glycosaminoglycans - prots - AAs - lipids
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
***nicotinic is ionotropic; muscarinic is GPCR

23. What are the memb - bound enzymes of the brush border?
Mostly reabsorbed to liver
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

24. Peritoneal refers to...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Abdominal cavity - which is coated in serous fluid
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

25. What is somatostatin
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
- 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

26. Interaction of corpus luteum/placenta
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Fructose is a structural isomer of glucose
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

27. little by little chyme is squirted out thru pyloric sphincter
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
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Regulated by gastrointestinal horms

28. How does glycogen compare to starch
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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

29. keep in mind that enterocyte is like a regular euk cell
***nicotinic is ionotropic; muscarinic is GPCR
Has memb - bound organelles - etc...
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
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

30. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Processes: axons - dendrites
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Many modern drugs are ligands for GPCRs
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... ...

31. inhibin secreted by
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
All carbs absorbed at enterocytes are carried to liver by portal vein

32. almost all cells can store Some glycogen - but...
Thru tight junctions by favorable osmotic gradient
Zygotes are diploid
Only musc and esp ** liver can store large amounts
Sorts - modifies - concentrates proteins from the ER

33. Where is bile produced
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
In gastric pits; secretions combine into gastric juice
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**
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

34. Posterior eye
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
vitreous humor - retina - fovea
Break down TAGs to monoglycerides and free fatty acids
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

35. How do nutrients move?
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

36. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Fovea (highest amount of cones)
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

37. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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

38. Ovum development is halted At what stage until fertilization...
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Fructose is a structural isomer of glucose
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

39. What testosterone released by secondary follicle by LH stim is converted to...
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Low because AAs are immediately used in translation

40. On what surface of the retina is the eye most sensitive
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Fovea (highest amount of cones)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

41. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
All carbs absorbed at enterocytes are carried to liver by portal vein
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

42. review: parietals secrete intrinsic factor...
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

43. gradual increase in FSH typical of primary follicle development;
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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

44. Creating gradients requires what?
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
Regulated by gastrointestinal horms

45. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Moves down thru esophageal sphincter
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Creates one ovum (23 N) and three polar bodies
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

46. In general - parietal=
The wall of the body or of a body cavity or hollow structure
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Beta cells
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

47. Thus - central nervous sys is...
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

48. what cannot cross the fenestrations of the renal corpuscle
Membrane - bound - endocytosed bodies
RBCs - large proteins; What does enter is called the filtrate
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
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

49. Aldosterone (sodium uptake - potassium secretion)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

50. FLAT PG: prolactin
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Direction of differentiation