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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.
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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. Three stages of the menstrual cycle
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Gastrulation occurs: formation of three primary germ layers = differentiation

2. gradual increase in FSH typical of primary follicle development;
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

3. these transport proteins - when concs are high enough...
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Direction of differentiation
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Peptides

4. in the presence of ADH what happens to movement of water across nephron membr
Many modern drugs are ligands for GPCRs
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Water flows from the tubule - concentrating the filtrate - raising BP
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

5. when thinking of proteins - think
Interstitial fluid (eg prostaglandins - cytokines)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
'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
Nitrogen

6. Alpha - amylase found where
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
In mouth - breakdown of starch into polysaccharides

7. Luteal surge
Below hypothalamus
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Glucose and ketone bodies (not from glycogen stores)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

8. duodenum must have receptors for fat content - protein because
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
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
Inner lining of circulatory system

9. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
RBCs - large proteins; What does enter is called the filtrate
Nitrogen
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

10. almost all exocytosed proteins pass through this
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
Smooth ER
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

11. Spinal cord horns (thick knobs) point
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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
Ventrally (picture skeletal vertebrae)

12. Where does fertilization occur
Fallopian tubes
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
Primitive streak - which consists of cells of the MESODERM ****
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

13. PNS is broken down into
Nitrogen
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Somatic nervous sys - autonomic nervous sys
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

14. exocrine types
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Testosterone and estradiol
Fructose is a structural isomer of glucose

15. A contracted iris occurs with what kind of stimulation
RBCs - large proteins; What does enter is called the filtrate
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Sympathetic: dilates pupil (for night hunting)
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

16. 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)
Fallopian tubes
Organs
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

17. amylase acts where on carbs
Normally contracted
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

18. What is a normal blood glucose range
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
90-140 mg/dl
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
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

19. smooth ER main function
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
Lower blood pH

20. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Gastrulation occurs: formation of three primary germ layers = differentiation

21. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

22. Meiosis I Metaphase I
HCl; secreted by parietal cells under stim by gastrin
Micelles; micelles (made of bile) go back and forth between brush border and chyme
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

23. overall - fatty - prot - rich food in duod causes
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
The wall of the body or of a body cavity or hollow structure
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Pancreatic duct (made of acinar cells?)

24. 80% of end product of carbohydrate metabolism is...
Glucose
- 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
Beta cells
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

25. glucagon secreted by
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Systems (eg digestive system consists of many organs)
Prod of steroid hormones in testes - ovaries

26. chylomicron concentration in blood after meal
'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
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
In mouth - breakdown of starch into polysaccharides

27. In IBS - What is defective

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28. How is the follicle developed during oogenesis
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
Two perpendicular semicircular canals involved in balance - equilibrium
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

29. Thus inhibiting parietal cells could do What to blood pH
Lower blood pH
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

30. The bolus (chewing) is digested to what in the stomach
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Regulated by gastrointestinal horms
Chyme (by combined activity of exocrine glands)
***nicotinic is ionotropic; muscarinic is GPCR

31. What surrounds the hydrophilic heads of the new TAGs
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
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
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

32. spermatogonia arise from
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Epithelial tissue near semniferous tubules
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

33. Where do absorbed fats go in the enterocyte
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

34. golgi body
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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)
Sorts - modifies - concentrates proteins from the ER
Outermost layer of blood vessel

35. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Liposome has phospholipid bilayer
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

36. 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)
Has memb - bound organelles - etc...
1) by integral ion channels 2) transmitted by second messenger system
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

37. protein absorption at enterocyte
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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

38. components of interstitial fluid
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Glycosaminoglycans - prots - AAs - lipids
Ventrally (picture skeletal vertebrae)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

39. oxytocin
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Low because AAs are immediately used in translation

40. How is glucose absorbed in sm intest
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
- 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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

41. lysosome main function and derivation
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Fallopian tubes
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

42. Adrenal cortex hormones (STEROIDS)
Glucose and ketone bodies (not from glycogen stores)
Increases blood Calcium
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
90-140 mg/dl

43. Interaction of corpus luteum/placenta
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Water flows from the tubule - concentrating the filtrate - raising BP
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

44. at lo blood sugar...
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Within the paravertebral ganglion - running parallel to spinal cord
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

45. keep in mind that enterocyte is like a regular euk cell
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
Has memb - bound organelles - etc...
Direction of differentiation
Processes: axons - dendrites

46. Induction affects...
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
Direction of differentiation
Lumen (ie continuous w/body cavity) and cytosol
All carbs absorbed at enterocytes are carried to liver by portal vein

47. From that point...
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.
Increases surface area of food ball (bolus)
Vitamin K - b12 - thiamin - riboflavin
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

48. Different organs working together
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Abdominal cavity - which is coated in serous fluid
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
Systems (eg digestive system consists of many organs)

49. What does portal vein do
Fructose is a structural isomer of glucose
All carbs absorbed at enterocytes are carried to liver by portal vein
- 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
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

50. 90% digestion - absorption occurs in...
Fovea (highest amount of cones)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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