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. FLAT PG: hGH aka somatotropin
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)
Increases solute conc and osmotic pressure of the ***medulla
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'


2. in the dark is rhodopsin active or inactive?
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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


3. sensory (afferent) neurons
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Eukaryotes
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
In mouth - breakdown of starch into polysaccharides


4. What does lipase attack exactly
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Moves down thru esophageal sphincter


5. when cells hit their limit for prot storage...
AAs can be burned for energy or converted to fat for storage
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Only musc and esp ** liver can store large amounts
Most absorption occurs in sm intestine


6. almost all exocytosed proteins pass through this
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Smooth ER
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)


7. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Glycosaminoglycans - prots - AAs - lipids
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... ...
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle


8. The esophageal sphincter is...
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Normally contracted
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity


9. What if large intestine isn't working well
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase


10. Induction affects...
Beta cells
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Epithelial tissue near semniferous tubules
Direction of differentiation


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

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12. The apical side of the villi...
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Faces the lumen
1) by integral ion channels 2) transmitted by second messenger system
***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


13. What are the major carbohydrates
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Albumin increases osmolarity of blood; increases osmotic pressure


14. For focal point that is nearby - what will the lens look like
Zygotes are diploid
ER
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals


15. quote on cavities/viscera

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16. alpha - amylase in the mouth digests what kind of bond
Fallopian tubes
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Zygotes are diploid
Alpha 1-4 and 1-6 (branching) glycosidic linkages


17. Some epithelial cells are... others...
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
- 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
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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries


18. During ejaculation - sperm...

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19. calcitonin

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20. medium for paracrine hormones
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Interstitial fluid (eg prostaglandins - cytokines)
Systems (eg digestive system consists of many organs)


21. 90% digestion - absorption occurs in...
On the chyme exiting the stomach and entering duodenum thru the 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
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)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes


22. exocrine types
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons


23. Bile salts and lipase
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector


24. STOMACH: no absorption
Chyme (by combined activity of exocrine glands)
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
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)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss


25. 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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26. Fructose relates how structurally to glucose
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
Fructose is a structural isomer of glucose
***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
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


27. chylomicron concentration in blood after meal
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Glands w/ducts: Exocrine glands
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides


28. How is glucose absorbed in sm intest
'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
Facilitated diffusion: no symport w/ secondary transport
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
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)


29. Thus inhibiting parietal cells could do What to blood pH
It targets liver conc of prothrombin - fibrinogen etc
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Lower blood pH


30. How do parietal cells work ** (involves CO2)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Peripheral nervous sys
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases


31. How does reabsorption force nutrients across apical membrane of proximal tubule
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Lysosome
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5


32. What happens when rod cell is depolarized
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
Night vision
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Contain capillary network - lymph vessels (lacteals)


33. Luteal surge
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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae


34. Exocrine GlandS: stomach
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
- 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
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
Membrane - bound - endocytosed bodies


35. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Form barrier to extracellular fluid
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete


36. Glycogenolysis/gluconeogenesis
Facilitated diffusion: no symport w/ secondary transport
Smooth ER
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
vitreous humor - retina - fovea


37. Alpha - amylase found where
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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
In mouth - breakdown of starch into polysaccharides
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...


38. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Sensory (afferent - dorsal) - motor (efferent - ventral)


39. 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
Zygotes are diploid
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
Most absorption occurs in sm intestine


40. On what surface of the retina is the eye most sensitive
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Fovea (highest amount of cones)
ER
Homologous chromosomes separate - migrate towards opposite poles/centrioles


41. What is secreted into filtrate by cells of the proximal tubule?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Faces the lumen
Regulated by gastrointestinal horms
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics


42. Gland: ovaries
***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
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Form barrier to extracellular fluid
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy


43. light detection via GPCRs
Most absorption occurs in sm intestine
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)


44. in the presence of ADH what happens to movement of water across nephron membr
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Water flows from the tubule - concentrating the filtrate - raising BP
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Many modern drugs are ligands for GPCRs


45. spermatogonia arise from
Epithelial tissue near semniferous tubules
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord


46. What does peptic refer to in general
Lower blood pH
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Thru tight junctions by favorable osmotic gradient
Digestion


47. How does birth control work?
- 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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins


48. FLAT PG: ACTH
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
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


49. How does water cross the apical membrane
The renal corpuscle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Albumin increases osmolarity of blood; increases osmotic pressure
Thru tight junctions by favorable osmotic gradient


50. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Moves down thru esophageal sphincter
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Systems (eg digestive system consists of many organs)