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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. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

2. What is the path of a sound wave that enters the ear?
Glucose = aldose fructose = ketose
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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

3. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Direction of differentiation
In mouth - breakdown of starch into polysaccharides
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

4. fat digestion is time - intensive
Smooth ER
Needs time for bile - lipase - micelle migration - enterocyte uptake
Eukaryotes
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)

5. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
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)
- 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
All carbs absorbed at enterocytes are carried to liver by portal vein

6. peroxisome is derived from this
- 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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
ER

7. is intracellular AA conc hi or low?
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Neurons may perform one of three functions....
Low because AAs are immediately used in translation
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

8. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
It targets liver conc of prothrombin - fibrinogen etc
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

9. Posterior pituitary hormones (Small Peptides)
Increases surface area of food ball (bolus)
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Oxytocin and ADH (aka vasopressin)

10. What is a nerve? (PNS)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
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
Homologous chromosomes line up w/ attachment of spindle fibers/microtubule polymers to centromeres via kinetochores; identical in appearance under light microscope to metaphase of mitosis
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

11. Where do pancreatic secretions take effect
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
'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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Meiosis creates germ cells

12. What is somatostatin
Nitrogen
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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

13. Polypeptides are formed with what kind of reaction?
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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

14. 'Cell bodies of somatic motor neurons are located in....'
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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

15. when thinking of proteins - think
All carbs absorbed at enterocytes are carried to liver by portal vein
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Nitrogen

16. mitosis creates somatic cells
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
Zygotes are diploid
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)
Meiosis creates germ cells

17. Embryology
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Increases surface area of food ball (bolus)
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
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

18. Tight junctions
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Nitrogen
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Form barrier to extracellular fluid

19. Different tissues working together
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increases blood Calcium
Chylomicrons are much bigger
Organs

20. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Increases surface area of food ball (bolus)
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti
Prod of steroid hormones in testes - ovaries

21. golgi body
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
Sorts - modifies - concentrates proteins from the ER
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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

22. Gastrin from G cells stims parietal cells...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Facilitated diffusion from hi to lo conc
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

23. 3 phases of menstrual cycle
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

24. Chewing does what?
Zygotes are diploid
- 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
Increases surface area of food ball (bolus)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

25. At post - two weeks ovulation
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Corpus luteum degrades into corpus albicans
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Break down TAGs to monoglycerides and free fatty acids

26. euk cell has two principal sides
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Ganglion
Sympathetic: dilates pupil (for night hunting)
Lumen (ie continuous w/body cavity) and cytosol

27. How is glucose absorbed in sm intest
'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.'
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
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Low because AAs are immediately used in translation

28. gradual increase in FSH typical of primary follicle development;
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
90-140 mg/dl
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

29. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Systems (eg digestive system consists of many organs)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

30. portal vein physiology...

31. 80% of end product of carbohydrate metabolism is...
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Glucose
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

32. FLAT PG: prolactin
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Determined by whether in front of or behind the lens
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

33. FLAT PG: TSH aka thyrotropin
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
RBCs - large proteins; What does enter is called the filtrate
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Increases surface area of food ball (bolus)

34. In other words...
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
All carbs absorbed at enterocytes are carried to liver by portal vein
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Paracrine (local) - endocrine (longer distance)

35. sensory (afferent)/interneurons/motor (efferent)
Determined by whether in front of or behind the lens
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Neurons may perform one of three functions....
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

36. How do monoglycerides and ffas get to brush border?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Chyme (by combined activity of exocrine glands)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

37. How long are peptides when absorbed at brush border
Somatic nervous sys - autonomic nervous sys
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
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

38. In effect LH - FSH stimulate
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
About 7.2
Prod of steroid hormones in testes - ovaries
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

39. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Gastrulation occurs: formation of three primary germ layers = differentiation
- 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
- 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

40. Mucus - digestive enzymes released thru
Membrane - bound - endocytosed bodies
Glands w/ducts: Exocrine glands
Zygotes are diploid
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

41. How does the body mobilize fat stores
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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)
Abdominal cavity - which is coated in serous fluid
***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

42. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

43. What happens when rod cell is depolarized
Albumin increases osmolarity of blood; increases osmotic pressure
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
Night vision
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

44. After meiosis II - Male

45. Both divisions (somatic - autonomic) of PNS consist of...
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
About 7.2
Peptides
Sensory (afferent - dorsal) - motor (efferent - ventral)

46. Three stages of the menstrual cycle
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

47. position of AP...
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Below hypothalamus
Glucose and ketone bodies (not from glycogen stores)

48. What is a plasmalogen?
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

49. Where does fertilization occur
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
Fallopian tubes
Facilitated diffusion: no symport w/ secondary transport
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

50. E storage per unit mass
- 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
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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