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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. remaining secondary follicle becomes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
***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
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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

2. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
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
Fovea (highest amount of cones)
Chylomicrons are much bigger
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

3. from thoracic duct - chylomicrons stick to capillary walls...
Facilitated diffusion: no symport w/ secondary transport
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Corpus luteum degrades into corpus albicans

4. What do the glomerulus and Bowman's capsule add up to...
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
Increases blood Calcium
The renal corpuscle
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

5. these transport proteins - when concs are high enough...
Form barrier to extracellular fluid
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

6. serous membranes have a viscera - facing layer and a body wall - facing layer
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
Membrane - bound - endocytosed bodies
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Digestion

7. In effect LH - FSH stimulate
Peptides
Prod of steroid hormones in testes - ovaries
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Transfer signals from neuron - neuron; 90% of neurons are interneurons

8. Induction affects...
Glucose and ketone bodies (not from glycogen stores)
'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
Gastrulation occurs: formation of three primary germ layers = differentiation
Direction of differentiation

9. FLAT PG: ACTH
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Gastrulation occurs: formation of three primary germ layers = differentiation
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)

10. from the loop of henle...
Ventrally (picture skeletal vertebrae)
Water flows from the tubule - concentrating the filtrate - raising BP
- 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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

11. fat digestion is time - intensive
Digestion
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
Needs time for bile - lipase - micelle migration - enterocyte uptake
Within the paravertebral ganglion - running parallel to spinal cord

12. Tight junctions
Form barrier to extracellular fluid
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Glands w/ducts: Exocrine glands

13. oxytocin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

14. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Break down TAGs to monoglycerides and free fatty acids

15. axon hillock physiology
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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
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
Conjunction of cell body w/axon

16. What controls release of LH - FSH from anterior pituitary
Break down TAGs to monoglycerides and free fatty acids
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
Gonadotropin releasing hormone - GnRH
In mouth - breakdown of starch into polysaccharides

17. Mucus - digestive enzymes released thru
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
Glands w/ducts: Exocrine glands

18. Where else does ADH act
Fallopian tubes
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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

19. Polypeptides are formed with what kind of reaction?
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
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Interstitial fluid (eg prostaglandins - cytokines)

20. peroxisome is derived from this
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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
Processes: axons - dendrites
ER

21. A group of cell bodies in CNS is nucleus - outside CNS is...
Ganglion
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Testosterone upon stim by LH
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

22. pancreatic enzymes are zymogens
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
It targets liver conc of prothrombin - fibrinogen etc
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

23. Spinal cord horns (thick knobs) point
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Ventrally (picture skeletal vertebrae)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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... ...

24. when cells hit their limit for prot storage...
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
AAs can be burned for energy or converted to fat for storage
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

25. energy source of neurons
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)
Glucose and ketone bodies (not from glycogen stores)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Interstitial fluid (eg prostaglandins - cytokines)

26. at lo blood sugar...
Increases blood Calcium
Prod of steroid hormones in testes - ovaries
Inner lining of blood vessels
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

27. smooth ER main function
Beta cells
Faces the lumen
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

28. What testosterone released by secondary follicle by LH stim is converted to...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

29. large intestine E. coli aid absorption of...
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
Vitamin K - b12 - thiamin - riboflavin
Nitrogen
Moves down thru esophageal sphincter

30. The apical side of the villi...
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Faces the lumen
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

31. What kind of cells make up epithel tiss of stom - then sm intest?
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
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Liposome has phospholipid bilayer
Neurons may perform one of three functions....

32. Path of food entering body...
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
Corpus luteum degrades into corpus albicans
Fallopian tubes
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

33. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Testosterone upon stim by LH
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.
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... ...

34. 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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Fovea (highest amount of cones)
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
- 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

35. signal transduction occurs by 2 paths
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
1) by integral ion channels 2) transmitted by second messenger system
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

36. How does reabsorption force nutrients across apical membrane of proximal tubule
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

37. micelles also pick up
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

38. extracellular matrix formed mainly of...
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Mostly reabsorbed to liver
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

39. How does glycogen compare to starch
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Nitrogen
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

40. PNS is broken down into
ER
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Somatic nervous sys - autonomic nervous sys
Processes: axons - dendrites

41. Some PNS nerves are found in brain - spinal cord
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
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)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
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

42. Posterior eye
vitreous humor - retina - fovea
Lower blood pH
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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)

43. albumin has What affect on blood osmotic pressure
Albumin increases osmolarity of blood; increases osmotic pressure
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
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
'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. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
An endogenous morphine
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Digestion
Transfer signals from neuron - neuron; 90% of neurons are interneurons

45. pancreas secretes enzymes via
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Mostly reabsorbed to liver
Liposome has phospholipid bilayer
Pancreatic duct (made of acinar cells?)

46. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Chyme (by combined activity of exocrine glands)
In gastric pits; secretions combine into gastric juice
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

47. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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
Testosterone and estradiol
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

48. Where does the bolus go after mouth chews food
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Moves down thru esophageal sphincter
All carbs absorbed at enterocytes are carried to liver by portal vein
Increases surface area of food ball (bolus)

49. SYMP neurons originate in= PARA neurons originate in=
Membrane - bound - endocytosed bodies
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
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

50. How is the follicle developed during oogenesis
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Normally contracted