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. How do monoglycerides and ffas get to brush border?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Eukaryotes
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability


2. E storage per unit mass
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Break down TAGs to monoglycerides and free fatty acids
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
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


3. Blastocyst
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
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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


4. In other words...
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
Determined by whether in front of or behind the lens
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
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


5. Tight junctions
Smooth ER
Form barrier to extracellular fluid
Glycosaminoglycans - prots - AAs - lipids
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt


6. Local vs long - distance mediators
Facilitated diffusion from hi to lo conc
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Paracrine (local) - endocrine (longer distance)
Increases surface area of food ball (bolus)


7. golgi body
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Sorts - modifies - concentrates proteins from the ER
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)


8. FLAT PG: prolactin
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons


9. How does water cross the apical membrane
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Many modern drugs are ligands for GPCRs
Thru tight junctions by favorable osmotic gradient
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


10. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
RBCs - large proteins; What does enter is called the filtrate
Mostly reabsorbed to liver
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
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)


11. What are the major carbohydrates
90-140 mg/dl
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)


12. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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
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


13. sporic life cycle
Glands w/ducts: Exocrine glands
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles


14. Energy from fat - prot - gluc
Determined by whether in front of or behind the lens
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Cancer; apop can be programmed cell death; mitochon can play important role in apop


15. How does birth control work?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
1) by integral ion channels 2) transmitted by second messenger system


16. Failure of apoptosis can result in
Epithelial tissue near semniferous tubules
Digestion
Albumin increases osmolarity of blood; increases osmotic pressure
Cancer; apop can be programmed cell death; mitochon can play important role in apop


17. these transport proteins - when concs are high enough...
Pancreatic duct (made of acinar cells?)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Transfer signals from neuron - neuron; 90% of neurons are interneurons


18. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)


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

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20. Beta - oxidation in liver produces...
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)
Break down TAGs to monoglycerides and free fatty acids
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases


21. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->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
Membrane - bound - endocytosed bodies
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes


22. cytosol pH
Facilitated diffusion from hi to lo conc
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
About 7.2


23. Posterior eye
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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
vitreous humor - retina - fovea
Increases surface area of food ball (bolus)


24. parathyroid hormone
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Within the paravertebral ganglion - running parallel to spinal cord
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Increases blood Calcium


25. Interaction of corpus luteum/placenta
Increases surface area of food ball (bolus)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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


26. How do parietal cells work ** (involves CO2)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
The renal corpuscle


27. Adrenal medulla hormones (TYR- DERIVED)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Faces the lumen
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


28. 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)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)


29. During ejaculation - sperm...

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30. Which fats are not absorbed like this
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)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Testosterone upon stim by LH


31. Meiosis II: EQUATIONAL DIVISION
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Ups bicarbonate secretion by pancreas; raises pH to 6.0
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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


32. A contracted iris occurs with what kind of stimulation
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Lysosome
Glycosaminoglycans - prots - AAs - lipids
Sympathetic: dilates pupil (for night hunting)


33. extracellular matrix formed mainly of...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
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


34. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Glucose
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases


35. 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)
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)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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


36. 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
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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
Systems (eg digestive system consists of many organs)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine


37. PNS is broken down into
Inner lining of blood vessels
Somatic nervous sys - autonomic nervous sys
- 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
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


38. portal vein physiology...

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39. from thoracic duct - chylomicrons stick to capillary walls...
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Meiosis creates germ cells


40. Anterior eye
Liposome has phospholipid bilayer
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Vitamin K - b12 - thiamin - riboflavin


41. lysosome pH
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Corpus luteum degrades into corpus albicans
5


42. testosterone can be aromatized to...
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Estradiol
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)


43. lining of abdominal cavity=
Fallopian tubes
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid


44. duodenum must have receptors for fat content - protein because
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Moves down thru esophageal sphincter
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
Fovea (highest amount of cones)


45. micelles also pick up
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Corpus luteum degrades into corpus albicans


46. quote on cavities/viscera

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47. Neuronal cell bodies have extensions ie
Mostly reabsorbed to liver
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Processes: axons - dendrites


48. The path from blood plasma to urine

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49. overview of prot digestion
Below hypothalamus
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt
Paracrine (local) - endocrine (longer distance)


50. ligands are the messenger compounds that target secondary messenger systems on effectors
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Many modern drugs are ligands for GPCRs