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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. Glucose is a .... sugar; fructose is a .... sugar
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Glucose = aldose fructose = ketose

2. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

3. What is feces composed of...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Lysosome

4. FSH - LH - HCG - inhibin are...
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Peptides
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

5. in mammals - gastrulation involves formation of the
Uncontracted: parasymp (eg opoid use)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Primitive streak - which consists of cells of the MESODERM ****
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

6. physiology of gall bladder - liver and pancreatic secretions
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum
Fructose is a structural isomer of glucose
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

7. In other words...
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

8. Thus - central nervous sys is...
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)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

9. Meiosis I Anaphase I
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

10. Contrast PNS- Somatic with PNS- Autonomic
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

11. What are the memb - bound enzymes of the brush border?
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

12. zygotic life cycle
Lysosome
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Interstitial fluid (eg prostaglandins - cytokines)

13. Bile salts and lipase
Thru tight junctions by favorable osmotic gradient
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
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

14. liver receives blood from...
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Only musc and esp ** liver can store large amounts

15. What determines number of chromosomes?
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Alpha 1-4 and 1-6 (branching) glycosidic linkages

16. pancreas secretes enzymes via
Pancreatic duct (made of acinar cells?)
Many modern drugs are ligands for GPCRs
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)
Facilitated diffusion from hi to lo conc

17. What does peptic refer to in general
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum
Digestion
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

18. liver and blood glucose...
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Nitrogen

19. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

20. Path of urine

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21. FLAT PG: FSH
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Increases solute conc and osmotic pressure of the ***medulla
Primitive streak - which consists of cells of the MESODERM ****

22. How does birth control work?
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

23. in the presence of ADH what happens to movement of water across nephron membr
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Water flows from the tubule - concentrating the filtrate - raising BP
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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)

24. What are the major carbohydrates
About 7.2
Low because AAs are immediately used in translation
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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

25. The path from blood plasma to urine

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26. Leydig cells produce
Testosterone upon stim by LH
Glucose and ketone bodies (not from glycogen stores)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

27. signal transduction occurs by 2 paths
Glycosaminoglycans - prots - AAs - lipids
1) by integral ion channels 2) transmitted by second messenger system
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
It targets liver conc of prothrombin - fibrinogen etc

28. The EYE
Glycosaminoglycans - prots - AAs - lipids
Chylomicrons are much bigger
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

29. After meiosis II - Female

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30. ADH
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
ER
***nicotinic is ionotropic; muscarinic is GPCR
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

31. insulin secreted by
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Beta cells
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

32. FLAT PG: LH
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

33. when thinking of proteins - think
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Nitrogen
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
Peripheral nervous sys

34. How is glucose absorbed in sm intest
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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

35. quote on cavities/viscera

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36. peroxisome is derived from this
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Chylomicrons are much bigger
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
ER

37. 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
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

38. Induction affects...
Organs
Direction of differentiation
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Pancreatic duct (made of acinar cells?)

39. How does reabsorption force nutrients across apical membrane of proximal tubule
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

40. What testosterone released by secondary follicle by LH stim is converted to...
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)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Lysosome
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

41. A pinpoint iris is contracted or uncontracted
Uncontracted: parasymp (eg opoid use)
Creates one ovum (23 N) and three polar bodies
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
Paracrine (local) - endocrine (longer distance)

42. What is the adventitia?
Contain capillary network - lymph vessels (lacteals)
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**
Outermost layer of blood vessel
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

43. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
It targets liver conc of prothrombin - fibrinogen etc
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

44. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Liposome has phospholipid bilayer
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

45. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Liposome has phospholipid bilayer

46. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

47. important pancreatic enzymes
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Glucose = aldose fructose = ketose
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

48. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
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)
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
Gastrulation occurs: formation of three primary germ layers = differentiation
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

49. In effect LH - FSH stimulate
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Chylomicrons are much bigger
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)
Prod of steroid hormones in testes - ovaries

50. 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
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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
90-140 mg/dl
- 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