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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. Some PNS nerves are found in brain - spinal cord
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

2. Which fats are not absorbed like this
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Corpus luteum degrades into corpus albicans

3. What are the major carbohydrates
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

4. chylomicron concentration in blood after meal
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

5. In IBS - What is defective

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6. Kidney
1) by integral ion channels 2) transmitted by second messenger system
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
Gastrulation occurs: formation of three primary germ layers = differentiation
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

7. signal transduction occurs by 2 paths
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
1) by integral ion channels 2) transmitted by second messenger system
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

8. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

9. Mucus - digestive enzymes released thru
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Glands w/ducts: Exocrine glands

10. What is an endorphin?
An endogenous morphine
Two perpendicular semicircular canals involved in balance - equilibrium
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Fructose is a structural isomer of glucose

11. What hormones affect the stomach?
Neurons may perform one of three functions....
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
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0

12. lining of abdominal cavity=
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Facilitated diffusion from hi to lo conc
- 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

13. Human chorionic gonadotropin...
Contain capillary network - lymph vessels (lacteals)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by 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

14. from thoracic duct - chylomicrons stick to capillary walls...
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
It targets liver conc of prothrombin - fibrinogen etc
Smooth ER
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

15. Where would materials slated for digestion go?
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
Direction of differentiation
Interstitial fluid (eg prostaglandins - cytokines)
Lysosome

16. What does peptic refer to in general
In mouth - breakdown of starch into polysaccharides
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Digestion

17. Where does the bolus go after mouth chews food
Liposome has phospholipid bilayer
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
Moves down thru esophageal sphincter
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)

18. What is gastric acid?
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border
HCl; secreted by parietal cells under stim by gastrin
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

19. Path of food entering body...
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

20. Different organs working together
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Systems (eg digestive system consists of many organs)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

21. The apical side of the villi...
AAs can be burned for energy or converted to fat for storage
Transfer signals from neuron - neuron; 90% of neurons are interneurons
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Faces the lumen

22. Where do absorbed fats go in the enterocyte
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

23. Exocrine GlandS: stomach
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep
1) by integral ion channels 2) transmitted by second messenger system
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

24. Meiosis I Anaphase I
Nitrogen
Below hypothalamus
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Systems (eg digestive system consists of many organs)

25. Posterior pituitary hormones (Small Peptides)
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
Regulated by gastrointestinal horms
Oxytocin and ADH (aka vasopressin)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

26. What determines number of chromosomes?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
About 7.2
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
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

27. what happens when glycogen stores are saturated and blood sugar remains high?
Corpus luteum degrades into corpus albicans
Oxytocin and ADH (aka vasopressin)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

28. Polypeptides are formed with what kind of reaction?
Epithelial tissue near semniferous tubules
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Sorts - modifies - concentrates proteins from the ER
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

29. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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

30. Meiosis I Telophase I
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)
***nicotinic is ionotropic; muscarinic is GPCR
***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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

31. sporic life cycle
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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Which is why lactase - maltase - dextrinase - sucrase are on brush border

32. From that point...
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Glucose = aldose fructose = ketose
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.

33. The path from blood plasma to urine

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34. PNS is broken down into
Somatic nervous sys - autonomic nervous sys
Sensory (afferent - dorsal) - motor (efferent - ventral)
Normally contracted
Glucose

35. little by little chyme is squirted out thru pyloric sphincter
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Regulated by gastrointestinal horms
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

36. quote on cavities/viscera

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37. Sensory - motor neurons are part of which nervous system
In gastric pits; secretions combine into gastric juice
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
All carbs absorbed at enterocytes are carried to liver by portal vein
Peripheral nervous sys

38. What is somatostatin
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

39. 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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
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

40. 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
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
Chylomicrons are much bigger
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Transfer signals from neuron - neuron; 90% of neurons are interneurons

41. 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
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
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
Low because AAs are immediately used in translation

42. motor (efferent) neurons --> VENTRAL
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Carry signals to musc OR Gland
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)
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

43. In other words...
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
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
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
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

44. Posterior eye
vitreous humor - retina - fovea
Within the paravertebral ganglion - running parallel to spinal cord
Salivary amylase; both hydrolyze glycosidic linkages
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

45. Where is bile produced
Chylomicrons are much bigger
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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**
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

46. important pancreatic enzymes
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Creates one ovum (23 N) and three polar bodies

47. Where are these exocrine glands located
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
In gastric pits; secretions combine into gastric juice

48. Thus - central nervous sys is...
Systems (eg digestive system consists of many organs)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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

49. keep in mind that enterocyte is like a regular euk cell
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Glucose = aldose fructose = ketose
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Has memb - bound organelles - etc...

50. Where else does ADH act
Normally contracted
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Processes: axons - dendrites
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy