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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. What is gastric acid?
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)
Chylomicrons are much bigger
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
HCl; secreted by parietal cells under stim by gastrin

2. inhibin secreted by
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
The wall of the body or of a body cavity or hollow structure
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

3. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

4. What is a toxic byproduct of gluconeogenesis from proteins
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
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

5. Bile salts and lipase
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.
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

6. How long are peptides when absorbed at brush border
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Glucose = aldose fructose = ketose
Increases solute conc and osmotic pressure of the ***medulla
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

7. The apical side of the villi...
Faces the lumen
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
'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
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

8. Mucus - digestive enzymes released thru
Meiosis creates germ cells
Smooth ER
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
Glands w/ducts: Exocrine glands

9. Liver Functions
Inner lining of blood vessels
Chyme (by combined activity of exocrine glands)
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
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

10. The EYE
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

11. energy source of neurons
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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Glucose and ketone bodies (not from glycogen stores)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

12. medium for paracrine hormones
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
Interstitial fluid (eg prostaglandins - cytokines)
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
Eukaryotes

13. lining of abdominal cavity=
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)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

14. peroxisome is derived from this
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
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
ER

15. Between meals most fats appear in blood as
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Smooth ER
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

16. testosterone can be aromatized to...
Inner lining of blood vessels
Estradiol
In gastric pits; secretions combine into gastric juice
Most absorption occurs in sm intestine

17. Determination is different than differentiation
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

18. pancreas secretes enzymes via
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Pancreatic duct (made of acinar cells?)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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

19. What is a dorsal root ganglion?
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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

20. The esophageal sphincter is...
Meiosis creates germ cells
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Normally contracted
Faces the lumen

21. Tight junctions
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
Form barrier to extracellular fluid
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Normally contracted

22. Posterior eye
vitreous humor - retina - fovea
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0

23. zygotic life cycle
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
'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.'
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

24. PNS nerve signal
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
Carry signals to musc OR Gland
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

25. Where does fertilization occur
Fallopian tubes
Glucose
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Lysosome

26. 3 phases of menstrual cycle
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)
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
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Two perpendicular semicircular canals involved in balance - equilibrium

27. What is secreted into filtrate by cells of the proximal tubule?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Thru tight junctions by favorable osmotic gradient
Normally contracted
Night vision

28. In other words...
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... ...
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
'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
Peripheral nervous sys

29. In effect LH - FSH stimulate
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Chylomicrons are much bigger
Prod of steroid hormones in testes - ovaries
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

30. sensory (afferent) neurons
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

31. physiology of gall bladder - liver and pancreatic secretions
Smooth ER
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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

32. Difference between euk and prok flagella
Testosterone and estradiol
Digestion
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

33. Meiosis I Anaphase I
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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
Glucose and ketone bodies (not from glycogen stores)

34. How do parietal cells work ** (involves CO2)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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

35. protein absorption at enterocyte
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
- 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
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum

36. Kidney physiology...

37. At post - two weeks ovulation
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Corpus luteum degrades into corpus albicans
Many modern drugs are ligands for GPCRs
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

38. After meiosis I - daughter cells are...

39. Where else does ADH act
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Night vision
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Uncontracted: parasymp (eg opoid use)

40. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
5

41. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

42. After meiosis II - Male

43. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Water flows from the tubule - concentrating the filtrate - raising BP
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border

44. What force is acting upon chyme to move it forward down sm intestine
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Ganglion
Salivary amylase; both hydrolyze glycosidic linkages

45. FLAT PG: TSH aka thyrotropin
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
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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

46. Most important nutrients absorbed by large intestine
Neurons may perform one of three functions....
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Facilitated diffusion: no symport w/ secondary transport
- 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

47. Creating gradients requires what?
Meiosis creates germ cells
Inner lining of circulatory system
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

48. FLAT PG: LH
5
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
An endogenous morphine
Inner lining of blood vessels

49. What is the net effect of the distal tubule
Carry signals to musc OR Gland
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
Direction of differentiation
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

50. After meiosis II - Female