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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. How long are peptides when absorbed at brush border
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

2. Beta - oxidation in liver produces...
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Transfer signals from neuron - neuron; 90% of neurons are interneurons

3. Sensory - motor neurons are part of which nervous system
Peripheral nervous sys
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
Sensory (afferent - dorsal) - motor (efferent - ventral)

4. Anterior eye vs. posterior eye
Break down TAGs to monoglycerides and free fatty acids
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
ER
Determined by whether in front of or behind the lens

5. small intestine=
Pancreatic duct (made of acinar cells?)
Vitamin K - b12 - thiamin - riboflavin
Sensory (afferent - dorsal) - motor (efferent - ventral)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

6. calcitonin

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7. What is a normal blood glucose range
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Beta cells
- 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
90-140 mg/dl

8. Anterior eye
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
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

9. Alpha - amylase found where
Increases blood Calcium
Primitive streak - which consists of cells of the MESODERM ****
In mouth - breakdown of starch into polysaccharides
Normally contracted

10. fructose enters enterocyte by
Moves down thru esophageal sphincter
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Needs time for bile - lipase - micelle migration - enterocyte uptake
Facilitated diffusion: no symport w/ secondary transport

11. What is main difference is signal transmission in nicotinic vs muscarinic?
***nicotinic is ionotropic; muscarinic is GPCR
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

12. Where does the bolus go after mouth chews food
Moves down thru esophageal sphincter
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Lower blood pH

13. from thoracic duct - chylomicrons stick to capillary walls...
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Ammonia; must be converted to urea by liver and excreted in urine by kidney

14. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

15. Ovum development is halted At what stage until fertilization...
- 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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

16. position of AP...
Below hypothalamus
Primitive streak - which consists of cells of the MESODERM ****
HCl; secreted by parietal cells under stim by gastrin
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

17. FLAT PG: ACTH
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

18. lysosome main function and derivation
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
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
Normally contracted

19. Where are these exocrine glands located
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
In gastric pits; secretions combine into gastric juice
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

20. Posterior eye
vitreous humor - retina - fovea
90-140 mg/dl
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Corpus luteum degrades into corpus albicans

21. How does birth control work?
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
1) by integral ion channels 2) transmitted by second messenger system

22. Between meals most fats appear in blood as
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Fallopian tubes
Fovea (highest amount of cones)

23. FLAT PG: LH
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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
Vitamin K - b12 - thiamin - riboflavin

24. Aldosterone (sodium uptake - potassium secretion)
Ventrally (picture skeletal vertebrae)
Outermost layer of blood vessel
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)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

25. cAMP - cGMP - calmodulin...
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Vitamin K - b12 - thiamin - riboflavin
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

26. Spinal cord horns (thick knobs) point
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Ventrally (picture skeletal vertebrae)
Fallopian tubes
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

27. What are the major carbohydrates
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

28. FLAT PG: TSH aka thyrotropin
Break down TAGs to monoglycerides and free fatty acids
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)
Glycosaminoglycans - prots - AAs - lipids
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

29. physiology of gall bladder - liver and pancreatic secretions
Contain capillary network - lymph vessels (lacteals)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
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
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

30. 90% digestion - absorption occurs in...
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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
Fructose is a structural isomer of glucose
Meiosis creates germ cells

31. sporic life cycle
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
AAs can be burned for energy or converted to fat for storage
Low because AAs are immediately used in translation

32. overall - fatty - prot - rich food in duod causes
Needs time for bile - lipase - micelle migration - enterocyte uptake
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

33. FLAT PG: FSH
Determined by whether in front of or behind the lens
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Fructose is a structural isomer of glucose
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

34. albumin has What affect on blood osmotic pressure
Lysosome
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
Albumin increases osmolarity of blood; increases osmotic pressure
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

35. What surrounds the hydrophilic heads of the new TAGs
Break down TAGs to monoglycerides and free fatty acids
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
Glucose
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

36. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
RBCs - large proteins; What does enter is called the filtrate
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)
All carbs absorbed at enterocytes are carried to liver by portal vein

37. What do villli do
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Conjunction of cell body w/axon
Processes: axons - dendrites
'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

38. almost all exocytosed proteins pass through this
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Smooth ER
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

39. liver receives blood from...
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increases solute conc and osmotic pressure of the ***medulla
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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

40. What is a plasmalogen?
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)
Estradiol
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

41. Creating gradients requires what?
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
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Fallopian tubes

42. Neuronal cell bodies have extensions ie
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
Processes: axons - dendrites
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

43. What is gastric acid?
Systems (eg digestive system consists of many organs)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
HCl; secreted by parietal cells under stim by gastrin
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

44. fat digestion is time - intensive
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Normally contracted
Needs time for bile - lipase - micelle migration - enterocyte uptake
Outermost layer of blood vessel

45. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Salivary amylase; both hydrolyze glycosidic linkages

46. Adrenal cortex hormones (STEROIDS)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

47. Path of urine

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48. parathyroid hormones
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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
Corpus luteum degrades into corpus albicans
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)

49. Anatomy of the villi
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Contain capillary network - lymph vessels (lacteals)
Glucose = aldose fructose = ketose
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**

50. from the loop of henle...
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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Glycosaminoglycans - prots - AAs - lipids
Gastrulation occurs: formation of three primary germ layers = differentiation