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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. On what surface of the retina is the eye most sensitive
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Fovea (highest amount of cones)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

2. What are the major carbohydrates
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Increases solute conc and osmotic pressure of the ***medulla

3. Kidney
***nicotinic is ionotropic; muscarinic is GPCR
Peptides
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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

4. smooth ER main function
In gastric pits; secretions combine into gastric juice
Facilitated diffusion: no symport w/ secondary transport
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

5. Meiosis I Telophase I
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

6. portal vein physiology...

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7. What is the net effect of the distal tubule
Lumen (ie continuous w/body cavity) and cytosol
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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

8. lining of abdominal cavity=
- 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
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
Prod of steroid hormones in testes - ovaries
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

9. How do parietal cells work ** (involves CO2)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

10. E storage per unit mass
Testosterone and estradiol
Meiosis creates germ cells
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass

11. The bolus (chewing) is digested to what in the stomach
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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
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
Chyme (by combined activity of exocrine glands)

12. Where would materials slated for digestion go?
The renal corpuscle
- 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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Lysosome

13. glucagon secreted by
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
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
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

14. Contrast PNS- Somatic with PNS- Autonomic
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Albumin increases osmolarity of blood; increases osmotic pressure

15. Embryology
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
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

16. FLAT PG: ACTH
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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... ...
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

17. Think of spinal cord injury
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)
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Membrane - bound - endocytosed bodies

18. micelles vs liposomes
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
The renal corpuscle
Liposome has phospholipid bilayer

19. when thinking of proteins - think
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)
Nitrogen
Determined by whether in front of or behind the lens
In gastric pits; secretions combine into gastric juice

20. Does bile digest fat?
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
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

21. How do monoglycerides and ffas get to brush border?
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.
Lumen (ie continuous w/body cavity) and cytosol
Micelles; micelles (made of bile) go back and forth between brush border and chyme
***nicotinic is ionotropic; muscarinic is GPCR

22. In other words...
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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
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
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

23. parathyroid hormone
Increases surface area of food ball (bolus)
Increases blood Calcium
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

24. What does portal vein do
Prod of steroid hormones in testes - ovaries
Abdominal cavity - which is coated in serous fluid
All carbs absorbed at enterocytes are carried to liver by portal vein
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

25. Spinal cord horns (thick knobs) point
Ventrally (picture skeletal vertebrae)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Water flows from the tubule - concentrating the filtrate - raising BP

26. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Smooth ER
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Gastrulation occurs: formation of three primary germ layers = differentiation
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

27. physiology of gall bladder - liver and pancreatic secretions
Digestion
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
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

28. components of interstitial fluid
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Glycosaminoglycans - prots - AAs - lipids
Corpus luteum degrades into corpus albicans
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

29. Morula (...totipotent)
An endogenous morphine
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
'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.'
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

30. Gastrin from G cells stims parietal cells...
Increases surface area of food ball (bolus)
It targets liver conc of prothrombin - fibrinogen etc
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
ER

31. amylase acts where on carbs
Eukaryotes
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

32. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Gonadotropin releasing hormone - GnRH
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

33. What is main difference is signal transmission in nicotinic vs muscarinic?
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
AAs can be burned for energy or converted to fat for storage
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
***nicotinic is ionotropic; muscarinic is GPCR

34. from the loop of henle...
Liver is the control center for blood glucose; is fed by portal vein from sm intest
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
1) by integral ion channels 2) transmitted by second messenger system
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

35. what else is located in the inner ear (not directly related to auditory)
RBCs - large proteins; What does enter is called the filtrate
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Two perpendicular semicircular canals involved in balance - equilibrium
Nitrogen

36. Meiosis II: EQUATIONAL DIVISION
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
***nicotinic is ionotropic; muscarinic is GPCR
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

37. What does peroxisome do
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
Zygotes are diploid
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

38. PNS review: SAME DAVE
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Peripheral nervous sys

39. 90% digestion - absorption occurs in...
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
In gastric pits; secretions combine into gastric juice
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

40. Gland: ovaries
Paracrine (local) - endocrine (longer distance)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

41. Peritoneal refers to...
Interstitial fluid (eg prostaglandins - cytokines)
Abdominal cavity - which is coated in serous fluid
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

42. Stomach has no lacteals
Most absorption occurs in sm intestine
vitreous humor - retina - fovea
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

43. almost all cells can store Some glycogen - but...
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
Only musc and esp ** liver can store large amounts
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
'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

44. 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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Glucose
5

45. 80% of end product of carbohydrate metabolism is...
- 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
Glucose
1) by integral ion channels 2) transmitted by second messenger system
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

46. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
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
Conjunction of cell body w/axon

47. thyroid hormones: Not All One Kind of HORM
It targets liver conc of prothrombin - fibrinogen etc
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Ups bicarbonate secretion by pancreas; raises pH to 6.0

48. Where does blood to be filtered by kidney enter the nephron?

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49. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Ganglion
Gastrulation occurs: formation of three primary germ layers = differentiation
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

50. sensory (afferent) neurons
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)