MCAT Prep - 2

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. What is the net effect of the loop of Henle
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Sympathetic: dilates pupil (for night hunting)
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)


2. smooth ER main function
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Has memb - bound organelles - etc...
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle


3. micelles also pick up
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Many modern drugs are ligands for GPCRs
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate


4. review: parietals secrete intrinsic factor...
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Thru tight junctions by favorable osmotic gradient
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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


5. How does water cross the apical membrane
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Somatic nervous sys - autonomic nervous sys
Thru tight junctions by favorable osmotic gradient
Many modern drugs are ligands for GPCRs


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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Salivary amylase; both hydrolyze glycosidic linkages
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes


7. Where does blood to be filtered by kidney enter the nephron?

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8. Meiosis I Metaphase I
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
5
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation


9. 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
Epithelial tissue near semniferous tubules
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus


10. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Outermost layer of blood vessel
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... ...
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs


11. Neuronal cell bodies have extensions ie
Chylomicrons are much bigger
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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
Processes: axons - dendrites


12. quote on cavities/viscera

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13. Think of spinal cord injury
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Fovea (highest amount of cones)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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


14. thyroid hormones: Not All One Kind of HORM
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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


15. Creating gradients requires what?
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver


16. What is the endothelium?
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Inner lining of circulatory system


17. protein absorption at enterocyte
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Lower blood pH


18. portal vein physiology...

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19. A pinpoint iris is contracted or uncontracted
Uncontracted: parasymp (eg opoid use)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Creates one ovum (23 N) and three polar bodies
Systems (eg digestive system consists of many organs)


20. In IBS - What is defective

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21. 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
Inner lining of blood vessels
Faces the lumen
- 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


22. A group of cell bodies in CNS is nucleus - outside CNS is...
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Ganglion
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH


23. in mammals - gastrulation involves formation of the
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
Primitive streak - which consists of cells of the MESODERM ****
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'


24. inhibin secreted by
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles


25. What force is acting upon chyme to move it forward down sm intestine
Creates one ovum (23 N) and three polar bodies
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides


26. In other words...
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
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Form barrier to extracellular fluid


27. keep in mind that enterocyte is like a regular euk cell
Has memb - bound organelles - etc...
Night vision
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase


28. lysosome main function and derivation
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi


29. golgi body
Most absorption occurs in sm intestine
Lumen (ie continuous w/body cavity) and cytosol
Sorts - modifies - concentrates proteins from the ER
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production


30. What if large intestine isn't working well
HCl; secreted by parietal cells under stim by gastrin
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Inner lining of blood vessels


31. What is a normal blood glucose range
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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
90-140 mg/dl
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase


32. At post - two weeks ovulation
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
It targets liver conc of prothrombin - fibrinogen etc
Corpus luteum degrades into corpus albicans
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity


33. Sensory neuron cell bodies vs. somatic motor cell bodies
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
In mouth - breakdown of starch into polysaccharides
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Buildup of macromolecules in lysosome due to deficient lysosome enzymes


34. in the presence of ADH what happens to movement of water across nephron membr
Water flows from the tubule - concentrating the filtrate - raising BP
Somatic nervous sys - autonomic nervous sys
Pancreatic duct (made of acinar cells?)
Oxytocin and ADH (aka vasopressin)


35. When 'coumadin targets liver enzymes to act as anticoagulant'...
1) by integral ion channels 2) transmitted by second messenger system
It targets liver conc of prothrombin - fibrinogen etc
Needs time for bile - lipase - micelle migration - enterocyte uptake
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


36. mitosis creates somatic cells
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Meiosis creates germ cells
Regulated by gastrointestinal horms
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


37. duodenum must have receptors for fat content - protein because
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity


38. What else do parietals do?
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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


39. Energy from fat - prot - gluc
Ganglion
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Faces the lumen
Smooth ER


40. axon hillock physiology
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Conjunction of cell body w/axon
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor


41. What is an endorphin?
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Needs time for bile - lipase - micelle migration - enterocyte uptake
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.
An endogenous morphine


42. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Somatic nervous sys - autonomic nervous sys
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Membrane - bound - endocytosed bodies


43. components of interstitial fluid
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
Glycosaminoglycans - prots - AAs - lipids
Testosterone and estradiol


44. Kidney physiology...

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45. In effect LH - FSH stimulate
An endogenous morphine
Faces the lumen
The renal corpuscle
Prod of steroid hormones in testes - ovaries


46. Local vs long - distance mediators
Outermost layer of blood vessel
Paracrine (local) - endocrine (longer distance)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'


47. when cells hit their limit for prot storage...
AAs can be burned for energy or converted to fat for storage
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy


48. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Two perpendicular semicircular canals involved in balance - equilibrium
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
Below hypothalamus
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves


49. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
About 7.2
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Ganglion


50. Meiosis I Telophase I
Gonadotropin releasing hormone - GnRH
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots