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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. is intracellular AA conc hi or low?
Thru tight junctions by favorable osmotic gradient
Low because AAs are immediately used in translation
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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

2. from thoracic duct - chylomicrons stick to capillary walls...
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Moves down thru esophageal sphincter
Interstitial fluid (eg prostaglandins - cytokines)
RBCs - large proteins; What does enter is called the filtrate

3. What is the path of a sound wave that enters the ear?
Uncontracted: parasymp (eg opoid use)
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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

4. Contrast PNS- Somatic with PNS- Autonomic
Prod of steroid hormones in testes - ovaries
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

5. bile + fat forms
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)
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat

6. Luteal surge
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
In mouth - breakdown of starch into polysaccharides

7. What is an endorphin?
Below hypothalamus
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
An endogenous morphine
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

8. pancreatic enzymes are zymogens
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Moves down thru esophageal sphincter
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

9. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Oxytocin and ADH (aka vasopressin)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

10. Where would materials slated for digestion go?
Lumen (ie continuous w/body cavity) and cytosol
Lysosome
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

11. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Interstitial fluid (eg prostaglandins - cytokines)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

12. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Moves down thru esophageal sphincter
ER

13. gradual increase in FSH typical of primary follicle development;
Determined by whether in front of or behind the lens
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Increases solute conc and osmotic pressure of the ***medulla
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

14. ADH
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Raises BP; causes collecting ducts at end of nephron (kidney) to become permeable to water - which concentrates urine; coffee - beer block ADH and increase urine volume
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

15. 3 phases of menstrual cycle
Eukaryotes
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)
'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
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

16. sensory (afferent) neurons
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Ventrally (picture skeletal vertebrae)
Ganglion

17. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Fructose is a structural isomer of glucose
Increases blood Calcium
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

18. portal vein physiology...

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19. What do the glomerulus and Bowman's capsule add up to...
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Interstitial fluid (eg prostaglandins - cytokines)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
The renal corpuscle

20. Think of spinal cord injury
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Chylomicrons are much bigger

21. Where do absorbed fats go in the enterocyte
Low because AAs are immediately used in translation
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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

22. Failure of apoptosis can result in
Within the paravertebral ganglion - running parallel to spinal cord
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
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop

23. main point of fat transport...
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
In gastric pits; secretions combine into gastric juice
Corpus luteum degrades into corpus albicans
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

24. keep in mind that enterocyte is like a regular euk cell
Water flows from the tubule - concentrating the filtrate - raising BP
Has memb - bound organelles - etc...
Many modern drugs are ligands for GPCRs
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

25. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Ventrally (picture skeletal vertebrae)

26. The apical side of the villi...
Contain capillary network - lymph vessels (lacteals)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Glucose and ketone bodies (not from glycogen stores)
Faces the lumen

27. Ovum development is halted At what stage until fertilization...
Pancreatic duct (made of acinar cells?)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Neurons may perform one of three functions....
Membrane - bound - endocytosed bodies

28. Embryology
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
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
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

29. What is the function of the loop of Henle
Increases solute conc and osmotic pressure of the ***medulla
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Inner lining of circulatory system

30. FLAT PG: prolactin
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Break down TAGs to monoglycerides and free fatty acids
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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

31. Tight junctions
Form barrier to extracellular fluid
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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
- 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

32. What hormones affect the stomach?
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
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
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Membrane - bound - endocytosed bodies

33. parathyroid hormones
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Liposome has phospholipid bilayer
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

34. micelles also pick up
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Smooth ER
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

35. What is feces composed of...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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
AAs can be burned for energy or converted to fat for storage
Prod of steroid hormones in testes - ovaries

36. The bolus (chewing) is digested to what in the stomach
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Carry signals to musc OR Gland
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Chyme (by combined activity of exocrine glands)

37. What surrounds the hydrophilic heads of the new TAGs
- 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
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
It targets liver conc of prothrombin - fibrinogen etc

38. What are phagosomes
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
Salivary amylase; both hydrolyze glycosidic linkages
About 7.2
Membrane - bound - endocytosed bodies

39. SYMP neurons originate in= PARA neurons originate in=
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
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

40. extracellular matrix formed mainly of...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Sensory (afferent - dorsal) - motor (efferent - ventral)
Testosterone and estradiol
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

41. in the presence of ADH what happens to movement of water across nephron membr
Glycosaminoglycans - prots - AAs - lipids
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Water flows from the tubule - concentrating the filtrate - raising BP
Most absorption occurs in sm intestine

42. What is a nerve? (PNS)
Nitrogen
Organs
Sensory (afferent - dorsal) - motor (efferent - ventral)
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

43. Gastrulation: ectoderm/mesoderm/endoderm
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

44. Beta - oxidation in liver produces...
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)
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Beta cells
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

45. FLAT PG: ACTH
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
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
Regulated by gastrointestinal horms

46. at lo blood sugar...
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

47. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Beta cells
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)
Neurons may perform one of three functions....

48. How do monoglycerides and ffas get to brush border?
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Ventrally (picture skeletal vertebrae)

49. zygotic life cycle
Liver is the control center for blood glucose; is fed by portal vein from sm intest
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Estradiol
Beta cells

50. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Gonadotropin releasing hormone - GnRH
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)