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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. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Creates one ovum (23 N) and three polar bodies
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

2. Meiosis I Metaphase I
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
Fovea (highest amount of cones)
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
Interstitial fluid (eg prostaglandins - cytokines)

3. What does peptic refer to in general
Epithelial tissue near semniferous tubules
Paracrine (local) - endocrine (longer distance)
Digestion
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

4. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Beta cells
In mouth - breakdown of starch into polysaccharides

5. What is an endorphin?
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Increases surface area of food ball (bolus)
An endogenous morphine
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

6. in fat and liver cells monoglycerides and ffas are once again
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Membrane - bound - endocytosed bodies
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

7. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Uncontracted: parasymp (eg opoid use)
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... ...

8. What is the net effect of the distal tubule
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
Albumin increases osmolarity of blood; increases osmotic pressure
Chylomicrons are much bigger

9. Embryology
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
About 7.2
Membrane - bound - endocytosed bodies

10. peroxisome is derived from 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
Most absorption occurs in sm intestine
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi
ER

11. energy source of neurons
- 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
Glucose and ketone bodies (not from glycogen stores)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Salivary amylase; both hydrolyze glycosidic linkages

12. A contracted iris occurs with what kind of stimulation
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
Sympathetic: dilates pupil (for night hunting)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Faces the lumen

13. at lo blood sugar...
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Interstitial fluid (eg prostaglandins - cytokines)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

14. Exocrine GlandS: stomach
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
- 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

15. Human chorionic gonadotropin...
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
All carbs absorbed at enterocytes are carried to liver by portal vein
Two perpendicular semicircular canals involved in balance - equilibrium
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

16. How does glycogen compare to starch
Mostly reabsorbed to liver
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
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

17. Neuronal cell bodies have extensions ie
Zygotes are diploid
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Processes: axons - dendrites
Neurons may perform one of three functions....

18. How does water cross the apical membrane
Epithelial tissue near semniferous tubules
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi
Thru tight junctions by favorable osmotic gradient
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

19. What is the endothelium?
Within the paravertebral ganglion - running parallel to spinal cord
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... ...
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Inner lining of circulatory system

20. The bolus (chewing) is digested to what in the stomach
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
Chyme (by combined activity of exocrine glands)
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**
Facilitated diffusion from hi to lo conc

21. Chewing does what?
Cancer; apop can be programmed cell death; mitochon can play important role in apop
vitreous humor - retina - fovea
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
Increases surface area of food ball (bolus)

22. Some PNS nerves are found in brain - spinal cord
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi

23. Posterior pituitary hormones (Small Peptides)
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
Oxytocin and ADH (aka vasopressin)
Night vision
Glucose = aldose fructose = ketose

24. What is secreted into filtrate by cells of the proximal tubule?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Moves down thru esophageal sphincter
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

25. spermatogonia arise from
Epithelial tissue near semniferous tubules
Normally contracted
Glands w/ducts: Exocrine glands
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

26. Adrenal medulla hormones (TYR- DERIVED)
Smooth ER
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

27. micelles vs liposomes
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel
Liposome has phospholipid bilayer
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

28. extracellular matrix formed mainly of...
Chylomicrons are much bigger
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

29. only monosaccharides are absorbed
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Which is why lactase - maltase - dextrinase - sucrase are on brush border
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

30. Liver Functions
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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

31. Sensory neuron cell bodies vs. somatic motor cell bodies
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Lysosome

32. gametes are haploid
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Zygotes are diploid
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

33. During ejaculation - sperm...

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34. In other words...
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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
Systems (eg digestive system consists of many organs)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

35. small intestine=
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

36. What controls release of LH - FSH from anterior pituitary
Gonadotropin releasing hormone - GnRH
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
Ganglion
Gastrulation occurs: formation of three primary germ layers = differentiation

37. Anterior eye
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
ER
'The hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

38. axon hillock physiology
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
Conjunction of cell body w/axon
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

39. Where else does ADH act
Outermost layer of blood vessel
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

40. mucus cells line the stomach...
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
Only musc and esp ** liver can store large amounts
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

41. What surrounds the hydrophilic heads of the new TAGs
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Testosterone and estradiol
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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

42. main point of fat transport...
Gastrulation occurs: formation of three primary germ layers = differentiation
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

43. Does bile digest fat?
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
- 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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Regulated by gastrointestinal horms

44. Creating gradients requires what?
Direction of differentiation
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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

45. What does portal vein do
All carbs absorbed at enterocytes are carried to liver by portal vein
Alpha 1-4 and 1-6 (branching) glycosidic linkages
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

46. pancreas secretes enzymes via
It targets liver conc of prothrombin - fibrinogen etc
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
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
Pancreatic duct (made of acinar cells?)

47. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
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
Chylomicrons are much bigger
Below hypothalamus
Processes: axons - dendrites

48. sensory (afferent) neurons
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Gonadotropin releasing hormone - GnRH
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Peptide; stims growth of nearly all cell of body; all other anterior pituitary horms have specific targets; upregulates anabolic pathways; use of fat for energy goes up (fat - burning); increases AA transport across cell membrane (nutrient uptake)

49. Fructose relates how structurally to glucose
Fructose is a structural isomer of glucose
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Contain capillary network - lymph vessels (lacteals)
Micelles; micelles (made of bile) go back and forth between brush border and chyme

50. Meiosis I Telophase I
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Smooth ER
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production