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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. What is the function of the loop of Henle
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
***nicotinic is ionotropic; muscarinic is GPCR
Increases solute conc and osmotic pressure of the ***medulla
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

2. FLAT PG: hGH aka somatotropin
Digestion
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)
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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

3. How does glycogen compare to starch
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
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

4. at lo blood sugar...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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

5. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Chylomicrons are much bigger

6. What does peroxisome do
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Membrane - bound - endocytosed bodies
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
Low because AAs are immediately used in translation

7. What does lipase attack exactly
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
RBCs - large proteins; What does enter is called the filtrate
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

8. Bile salts and lipase
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
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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
Most absorption occurs in sm intestine

9. What surrounds the hydrophilic heads of the new TAGs
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
An endogenous morphine
Break down TAGs to monoglycerides and free fatty acids
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

10. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Pancreatic duct (made of acinar cells?)

11. signal transduction occurs only in
Eukaryotes
Thru tight junctions by favorable osmotic gradient
Nitrogen
Primitive streak - which consists of cells of the MESODERM ****

12. Mucus - digestive enzymes released thru
Glands w/ducts: Exocrine glands
- 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 (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Form barrier to extracellular fluid

13. Most important nutrients absorbed by large intestine
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Increases blood Calcium
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

14. important pancreatic enzymes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Epithelial tissue near semniferous tubules
Gonadotropin releasing hormone - GnRH

15. Where would materials slated for digestion go?
Determined by whether in front of or behind the lens
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
Gastrulation occurs: formation of three primary germ layers = differentiation

16. Interaction of corpus luteum/placenta
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
An endogenous morphine
Neurons may perform one of three functions....
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

17. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Primitive streak - which consists of cells of the MESODERM ****
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
The wall of the body or of a body cavity or hollow structure

18. In general - parietal=
Albumin increases osmolarity of blood; increases osmotic pressure
The wall of the body or of a body cavity or hollow structure
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

19. parathyroid hormone
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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
Increases blood Calcium
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... ...

20. smooth ER main function
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Albumin increases osmolarity of blood; increases osmotic pressure
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

21. What is a toxic byproduct of gluconeogenesis from proteins
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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)

22. 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)
Only musc and esp ** liver can store large amounts
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Ups bicarbonate secretion by pancreas; raises pH to 6.0

23. The apical side of the villi...
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
Faces the lumen
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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

24. alpha - amylase in the mouth digests what kind of bond
Carry signals to musc OR Gland
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

25. What is a normal blood glucose range
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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
90-140 mg/dl
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

26. How does water cross the apical membrane
Thru tight junctions by favorable osmotic gradient
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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Liver is the control center for blood glucose; is fed by portal vein from sm intest

27. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

28. What are the memb - bound enzymes of the brush border?
Has memb - bound organelles - etc...
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

29. testosterone can be aromatized to...
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Estradiol

30. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Creates one ovum (23 N) and three polar bodies
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste

31. What kind of cells make up epithel tiss of stom - then sm intest?
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

32. 80-90% fat absorbed this way
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Normally contracted
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

33. pancreatic enzymes are zymogens
Facilitated diffusion from hi to lo conc
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
vitreous humor - retina - fovea
An endogenous morphine

34. How is glucose absorbed in sm intest
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Neurons may perform one of three functions....
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

35. What is gastric acid?
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
Two perpendicular semicircular canals involved in balance - equilibrium
HCl; secreted by parietal cells under stim by gastrin
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

36. How do nutrients move?
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Night vision
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Primitive streak - which consists of cells of the MESODERM ****

37. Tight junctions
Form barrier to extracellular fluid
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Abdominal cavity - which is coated in serous fluid

38. Where do pancreatic secretions take effect
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Many modern drugs are ligands for GPCRs

39. Determination is different than differentiation
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

40. PNS is broken down into
Somatic nervous sys - autonomic nervous sys
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

41. portal vein physiology...

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42. Blastocyst
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... ...
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
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

43. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
Facilitated diffusion from hi to lo conc
Uncontracted: parasymp (eg opoid use)
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

44. What is a nerve? (PNS)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Testosterone and estradiol
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

45. liver receives blood from...
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
Fructose is a structural isomer of glucose
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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

46. Beta - oxidation in liver produces...
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
vitreous humor - retina - fovea
Glucose

47. spermatogonia arise from
Many modern drugs are ligands for GPCRs
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Epithelial tissue near semniferous tubules

48. Aldosterone (sodium uptake - potassium secretion)
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
Faces the lumen
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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)

49. Both divisions (somatic - autonomic) of PNS consist of...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Chylomicrons are much bigger
Within the paravertebral ganglion - running parallel to spinal cord
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

50. Some PNS nerves are found in brain - spinal cord
Water flows from the tubule - concentrating the filtrate - raising BP
Inner lining of blood vessels
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Zygotes are diploid