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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. thyroid hormones: Not All One Kind of HORM
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Nitrogen
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

2. Embryology
Glands w/ducts: Exocrine glands
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
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
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs

3. SYMP neurons originate in= PARA neurons originate in=
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
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
Interstitial fluid (eg prostaglandins - cytokines)
Peripheral nervous sys

4. What is an endorphin?
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
Form barrier to extracellular fluid
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
An endogenous morphine

5. From that point...
Creates one ovum (23 N) and three polar bodies
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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.
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

6. What is gastric acid?
Zygotes are diploid
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
HCl; secreted by parietal cells under stim by gastrin
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs

7. Leydig cells produce
Contain capillary network - lymph vessels (lacteals)
Thru tight junctions by favorable osmotic gradient
Testosterone upon stim by LH
Oxytocin and ADH (aka vasopressin)

8. review: parietals secrete intrinsic factor...
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Mostly reabsorbed to liver
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)

9. FSH - LH - HCG - inhibin are...
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Peptides

10. PNS is broken down into
In mouth - breakdown of starch into polysaccharides
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
Somatic nervous sys - autonomic nervous sys
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

11. Some epithelial cells are... others...
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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)
- 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
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons

12. light detection via GPCRs
Most absorption occurs in sm intestine
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

13. Local vs long - distance mediators
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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
Paracrine (local) - endocrine (longer distance)
Prod of steroid hormones in testes - ovaries

14. in fat and liver cells monoglycerides and ffas are once again
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

15. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

16. almost all exocytosed proteins pass through this
Fructose is a structural isomer of glucose
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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)
Smooth ER

17. Bile salts and lipase
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Increases surface area of food ball (bolus)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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

18. at lo blood sugar...
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

19. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Beta cells
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

20. Seen in lysosomal storage diseases
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

21. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
- 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
The renal corpuscle

22. What is a dorsal root ganglion?
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Collection of cell bodies; cell processes project out from both ends of ganglion; synapses with interneuron in spinal cord on one end and sensory receptor on other
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

23. Think of spinal cord injury
Corpus luteum degrades into corpus albicans
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Primitive streak - which consists of cells of the MESODERM ****
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

24. Beta - oxidation in liver produces...
Meiosis creates germ cells
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Fructose is a structural isomer of glucose

25. Liver Functions
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
Neurons may perform one of three functions....
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

26. How does birth control work?
vitreous humor - retina - fovea
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
ER
Homologous chromosomes separate - migrate towards opposite poles/centrioles

27. A pinpoint iris is contracted or uncontracted
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Uncontracted: parasymp (eg opoid use)
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

28. Where does fertilization occur
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Fallopian tubes
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
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

29. Where do pancreatic secretions take effect
Systems (eg digestive system consists of many organs)
1) by integral ion channels 2) transmitted by second messenger system
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

30. fructose enters enterocyte by
Facilitated diffusion: no symport w/ secondary transport
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Thru tight junctions by favorable osmotic gradient
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

31. The EYE
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

32. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
AAs can be burned for energy or converted to fat for storage
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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

33. Where would materials slated for digestion go?
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Lysosome
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

34. Anterior eye
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Faces the lumen

35. What is a toxic byproduct of gluconeogenesis from proteins
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Ammonia; must be converted to urea by liver and excreted in urine by kidney

36. smooth ER main function
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Gonadotropin releasing hormone - GnRH
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

37. gametic life cycle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Estradiol
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

38. zygotic life cycle
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Micelles; micelles (made of bile) go back and forth between brush border and chyme
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

39. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Lysosome
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

40. What kind of cells make up epithel tiss of stom - then sm intest?
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Moves down thru esophageal sphincter
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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

41. What is the endothelium?
5
All carbs absorbed at enterocytes are carried to liver by portal vein
Contain capillary network - lymph vessels (lacteals)
Inner lining of circulatory system

42. How does duod deal with hi HCl from stom
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Primitive streak - which consists of cells of the MESODERM ****
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

43. serous membranes have a viscera - facing layer and a body wall - facing layer
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

44. What does peptic refer to in general
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Presence of fat - prot in duodenum causes release of **gastric inhibitory peptide**; result is slower stomach contraction; slower emptying into duod thru pyloric sphincter (slower chyme secretion); more time to properly digest - absorb nutrients
Digestion
In gastric pits; secretions combine into gastric juice

45. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Conjunction of cell body w/axon
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

46. What determines number of chromosomes?
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Night vision
Lower blood pH

47. lysosome pH
Meiosis creates germ cells
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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
5

48. Adrenal cortex hormones (STEROIDS)
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
The renal corpuscle
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

49. liver receives blood from...
'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.'
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
Regulated by gastrointestinal horms
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

50. After meiosis II...
Fallopian tubes
An endogenous morphine
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes