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 determines number of chromosomes?
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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.
Conjunction of cell body w/axon
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome


2. The EYE
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage


3. What is the path of a sound wave that enters the ear?
Mostly reabsorbed to liver
Increases solute conc and osmotic pressure of the ***medulla
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang


4. In other words...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Interstitial fluid (eg prostaglandins - cytokines)
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
Organs


5. chylomicron concentration in blood after meal
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
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons


6. medium for paracrine hormones
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Interstitial fluid (eg prostaglandins - cytokines)
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle


7. spermatogonia arise from
Digestion
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Epithelial tissue near semniferous tubules
In gastric pits; secretions combine into gastric juice


8. What if large intestine isn't working well
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Facilitated diffusion from hi to lo conc
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Chyme (by combined activity of exocrine glands)


9. Cell determination begins At what stage of development
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Digestion
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen


10. keep in mind that enterocyte is like a regular euk cell
Has memb - bound organelles - etc...
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger


11. Path of urine

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12. What are the major carbohydrates
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
All carbs absorbed at enterocytes are carried to liver by portal vein
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Break down TAGs to monoglycerides and free fatty acids


13. E storage per unit mass
Vitamin K - b12 - thiamin - riboflavin
Paracrine (local) - endocrine (longer distance)
Only musc and esp ** liver can store large amounts
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


14. What is an endorphin?
Fallopian tubes
- 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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
An endogenous morphine


15. What testosterone released by secondary follicle by LH stim is converted to...
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Increases blood Calcium


16. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'
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
Gastrulation occurs: formation of three primary germ layers = differentiation
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor


17. trypsin is secreted by
Ventrally (picture skeletal vertebrae)
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Ammonia; must be converted to urea by liver and excreted in urine by kidney


18. 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
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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


19. calcitonin

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20. What does lipase attack exactly
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
About 7.2
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Below hypothalamus


21. therefore - How does plasma leave capillary at the renal corpuscle

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22. The path from blood plasma to urine

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23. 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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24. What do villli do
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Smooth ER
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Pancreatic duct (made of acinar cells?)


25. What is gastric acid?
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Ups bicarbonate secretion by pancreas; raises pH to 6.0
HCl; secreted by parietal cells under stim by gastrin
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


26. After meiosis I - daughter cells are...

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27. Peritoneal refers to...
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Abdominal cavity - which is coated in serous fluid
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)


28. sensory (afferent)/interneurons/motor (efferent)
Neurons may perform one of three functions....
Peptides
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals


29. Thus inhibiting parietal cells could do What to blood pH
***nicotinic is ionotropic; muscarinic is GPCR
Lower blood pH
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system


30. lining of abdominal cavity=
Glucose and ketone bodies (not from glycogen stores)
Determined by whether in front of or behind the lens
Facilitated diffusion: no symport w/ secondary transport
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid


31. pancreas secretes enzymes via
Primitive streak - which consists of cells of the MESODERM ****
Pancreatic duct (made of acinar cells?)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Chyme (by combined activity of exocrine glands)


32. physiology of gall bladder - liver and pancreatic secretions
Lumen (ie continuous w/body cavity) and cytosol
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
Many modern drugs are ligands for GPCRs
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger


33. sporic life cycle
Liposome has phospholipid bilayer
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Eukaryotes
Zygotes are diploid


34. Anterior eye
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Outermost layer of blood vessel
An endogenous morphine


35. How is glucose absorbed in sm intest
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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


36. Gland: ovaries
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy


37. Both divisions (somatic - autonomic) of PNS consist of...
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Sensory (afferent - dorsal) - motor (efferent - ventral)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Peripheral nervous sys


38. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
1) by integral ion channels 2) transmitted by second messenger system
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes


39. 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)
Has memb - bound organelles - etc...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Increases surface area of food ball (bolus)


40. insulin secreted by
Beta cells
Sympathetic: dilates pupil (for night hunting)
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
Regulated by gastrointestinal horms


41. Ovum development is halted At what stage until fertilization...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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
Gastrulation occurs: formation of three primary germ layers = differentiation


42. 80% of end product of carbohydrate metabolism is...
Glucose
Sympathetic: dilates pupil (for night hunting)
Vitamin K - b12 - thiamin - riboflavin
Paracrine (local) - endocrine (longer distance)


43. testosterone can be aromatized to...
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Estradiol
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


44. What surrounds the hydrophilic heads of the new TAGs
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Only musc and esp ** liver can store large amounts
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system
***nicotinic is ionotropic; muscarinic is GPCR


45. ADH
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
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
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Regulated by gastrointestinal horms


46. important pancreatic enzymes
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Zygotes are diploid


47. ligands are the messenger compounds that target secondary messenger systems on effectors
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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
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
Many modern drugs are ligands for GPCRs


48. these transport proteins - when concs are high enough...
Testosterone upon stim by LH
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
HCl; secreted by parietal cells under stim by gastrin
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)


49. What is a toxic byproduct of gluconeogenesis from proteins
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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


50. Where is bile produced
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**
90-140 mg/dl
Chyme (by combined activity of exocrine glands)
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