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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. serous membranes have a viscera - facing layer and a body wall - facing layer
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Needs time for bile - lipase - micelle migration - enterocyte uptake
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

2. What is the pH at the entrance to the duodenum
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Testosterone and estradiol
RBCs - large proteins; What does enter is called the filtrate
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

3. SYMP neurons originate in= PARA neurons originate in=
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
'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

4. Human chorionic gonadotropin...
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

5. Fructose relates how structurally to glucose
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Fructose is a structural isomer of glucose
- 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
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

6. How does glycogen compare to starch
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

7. trypsin is secreted by
Contain capillary network - lymph vessels (lacteals)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Increases solute conc and osmotic pressure of the ***medulla
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

8. in mammals - gastrulation involves formation of the
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Primitive streak - which consists of cells of the MESODERM ****
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
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

9. In effect LH - FSH stimulate
Liposome has phospholipid bilayer
Chylomicrons are much bigger
Digestion
Prod of steroid hormones in testes - ovaries

10. 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
Glucose = aldose fructose = ketose
Glands w/ducts: Exocrine glands
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

11. small intestine=
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Somatic nervous sys - autonomic nervous sys
- 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

12. Sensory neuron cell bodies vs. somatic motor cell bodies
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)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
Gonadotropin releasing hormone - GnRH

13. What is a nerve? (PNS)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
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
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve

14. signal transduction occurs only in
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Eukaryotes
Uncontracted: parasymp (eg opoid use)
Increases blood Calcium

15. gametes are haploid
Zygotes are diploid
Primitive streak - which consists of cells of the MESODERM ****
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

16. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
It targets liver conc of prothrombin - fibrinogen etc
Nitrogen

17. Gastrin from G cells stims parietal cells...
Carry signals to musc OR Gland
Paracrine (local) - endocrine (longer distance)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

18. What is somatostatin
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Interstitial fluid (eg prostaglandins - cytokines)
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

19. fructose enters enterocyte by
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Facilitated diffusion: no symport w/ secondary transport
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Smooth ER

20. portal vein physiology...

21. Embryology
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
Outermost layer of blood vessel
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

22. sporic life cycle
Liposome has phospholipid bilayer
Meiosis creates germ cells
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Gastrulation occurs: formation of three primary germ layers = differentiation

23. pancreatic enzymes are zymogens
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

24. Leydig cells produce
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Testosterone upon stim by LH
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Homologous chromosomes separate - migrate towards opposite poles/centrioles

25. sensory (afferent) neurons
Cancer; apop can be programmed cell death; mitochon can play important role in apop
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Chylomicrons are much bigger

26. Morula (...totipotent)
Low because AAs are immediately used in translation
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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
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

27. what happens when glycogen stores are saturated and blood sugar remains high?
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... ...
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Mostly reabsorbed to liver
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

28. zygotic life cycle
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Alpha 1-4 and 1-6 (branching) glycosidic linkages

29. 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
Thru tight junctions by favorable osmotic gradient
Glucose and ketone bodies (not from glycogen stores)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

30. remaining secondary follicle becomes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Beta cells
Systems (eg digestive system consists of many organs)
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

31. FLAT PG: FSH
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

32. 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)
AAs can be burned for energy or converted to fat for storage
- 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
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

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

34. Liver Functions
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
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)
Contain capillary network - lymph vessels (lacteals)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

35. What determines number of chromosomes?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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
Lysosome
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

36. chylomicron concentration in blood after meal
Inner lining of circulatory system
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Carry signals to musc OR Gland

37. Failure of apoptosis can result in
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Fallopian tubes
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Homologous chromosomes separate - migrate towards opposite poles/centrioles

38. calcitonin

39. thyroid hormones: Not All One Kind of HORM
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... ...
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)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

40. E storage per unit mass
Glucose = aldose fructose = ketose
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
Primitive streak - which consists of cells of the MESODERM ****
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

41. almost all exocytosed proteins pass through this
Smooth ER
Facilitated diffusion: no symport w/ secondary transport
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

42. what cannot cross the fenestrations of the renal corpuscle
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
RBCs - large proteins; What does enter is called the filtrate
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

43. 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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
- 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
Two perpendicular semicircular canals involved in balance - equilibrium

44. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Lysosome
Testosterone and estradiol
Pancreatic duct (made of acinar cells?)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

45. Adrenal medulla hormones (TYR- DERIVED)
Salivary amylase; both hydrolyze glycosidic linkages
Increases blood Calcium
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

46. What is a plasmalogen?
Glucose
***nicotinic is ionotropic; muscarinic is GPCR
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

47. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Below hypothalamus
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

48. What does portal vein do
Chyme (by combined activity of exocrine glands)
Glycosaminoglycans - prots - AAs - lipids
All carbs absorbed at enterocytes are carried to liver by portal vein
Cancer; apop can be programmed cell death; mitochon can play important role in apop

49. PNS review: SAME DAVE
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Lysosome

50. large intestine E. coli aid absorption of...
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Vitamin K - b12 - thiamin - riboflavin
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
ER