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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. Some PNS nerves are found in brain - spinal cord
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

2. The EYE
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
HCl; secreted by parietal cells under stim by gastrin
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Gastrulation occurs: formation of three primary germ layers = differentiation

3. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Fructose is a structural isomer of glucose

4. Between meals most fats appear in blood as
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Direction of differentiation
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

5. How does water cross the apical membrane
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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
Water flows from the tubule - concentrating the filtrate - raising BP
Thru tight junctions by favorable osmotic gradient

6. 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
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Determined by whether in front of or behind the lens

7. golgi body
***nicotinic is ionotropic; muscarinic is GPCR
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Liposome has phospholipid bilayer
Sorts - modifies - concentrates proteins from the ER

8. How does glycogen compare to starch
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Below hypothalamus
Peptides
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

9. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

10. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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

11. After meiosis II...
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

12. Alpha - amylase found where
In mouth - breakdown of starch into polysaccharides
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Fovea (highest amount of cones)
Has memb - bound organelles - etc...

13. testosterone can be aromatized to...
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
- 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
Estradiol
Glycosaminoglycans - prots - AAs - lipids

14. Four tissues
Most absorption occurs in sm intestine
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

15. What is feces composed of...
Water flows from the tubule - concentrating the filtrate - raising BP
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Lumen (ie continuous w/body cavity) and cytosol
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

16. PNS nerve signal
Regulated by gastrointestinal horms
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

17. Posterior pituitary hormones (Small Peptides)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Oxytocin and ADH (aka vasopressin)
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

18. 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)
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
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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

19. Contrast PNS- Somatic with PNS- Autonomic
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Mostly reabsorbed to liver
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
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

20. liver receives blood from...
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Sorts - modifies - concentrates proteins from the ER
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
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

21. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Two perpendicular semicircular canals involved in balance - equilibrium
Faces the lumen
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
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

22. physiology of gall bladder - liver and pancreatic secretions
Albumin increases osmolarity of blood; increases osmotic pressure
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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
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

23. only monosaccharides are absorbed
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border
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
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

24. Thus inhibiting parietal cells could do What to blood pH
Lower blood pH
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
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
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

25. Seen in lysosomal storage diseases
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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
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
Meiosis creates germ cells

26. What is gastric acid?
Has memb - bound organelles - etc...
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
HCl; secreted by parietal cells under stim by gastrin
Processes: axons - dendrites

27. For focal point that is nearby - what will the lens look like
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Pancreatic duct (made of acinar cells?)
Sympathetic: dilates pupil (for night hunting)
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

28. mucus cells line the stomach...
ER
Salivary amylase; both hydrolyze glycosidic linkages
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach

29. Beta - oxidation in liver produces...
Digestion
Carry signals to musc OR Gland
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

30. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Sympathetic: dilates pupil (for night hunting)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

31. Meiosis II: EQUATIONAL DIVISION
Zygotes are diploid
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Water flows from the tubule - concentrating the filtrate - raising BP
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. 90% digestion - absorption occurs in...
Chyme (by combined activity of exocrine glands)
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
Lumen (ie continuous w/body cavity) and cytosol
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

33. E storage per unit mass
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
In gastric pits; secretions combine into gastric juice
Systems (eg digestive system consists of many organs)
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

34. FLAT PG: FSH
Needs time for bile - lipase - micelle migration - enterocyte uptake
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Epithelial tissue near semniferous tubules

35. Where do absorbed fats go in the enterocyte
Faces the lumen
Has memb - bound organelles - etc...
Increases blood Calcium
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

36. A contracted iris occurs with what kind of stimulation
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Sympathetic: dilates pupil (for night hunting)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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

37. What are the memb - bound enzymes of the brush border?
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Break down TAGs to monoglycerides and free fatty acids
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

38. Embryology
- 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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Sorts - modifies - concentrates proteins from the ER
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

39. What testosterone released by secondary follicle by LH stim is converted to...
It targets liver conc of prothrombin - fibrinogen etc
Testosterone upon stim by LH
Needs time for bile - lipase - micelle migration - enterocyte uptake
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

40. position of AP...
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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
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
Below hypothalamus

41. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

42. 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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43. Different organs working together
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
The wall of the body or of a body cavity or hollow structure
Systems (eg digestive system consists of many organs)

44. when thinking of proteins - think
Only musc and esp ** liver can store large amounts
Nitrogen
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach
Processes: axons - dendrites

45. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
90-140 mg/dl
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Testosterone and estradiol

46. Where is bile produced
Gastrulation occurs: formation of three primary germ layers = differentiation
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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**
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

47. In other words...
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
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)

48. ligands are the messenger compounds that target secondary messenger systems on effectors
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
It targets liver conc of prothrombin - fibrinogen etc
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
Many modern drugs are ligands for GPCRs

49. When 'coumadin targets liver enzymes to act as anticoagulant'...
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
It targets liver conc of prothrombin - fibrinogen etc
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

50. Gland: ovaries
Increases solute conc and osmotic pressure of the ***medulla
AAs can be burned for energy or converted to fat for storage
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane