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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. Adrenal medulla hormones (TYR- DERIVED)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

2. How is glucose absorbed in sm intest
Mostly reabsorbed to liver
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

3. Kidney
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
Direction of differentiation
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

4. almost all exocytosed proteins pass through this
***nicotinic is ionotropic; muscarinic is GPCR
Smooth ER
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
In gastric pits; secretions combine into gastric juice

5. trypsin is secreted by
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

6. motor (efferent) neurons --> VENTRAL
Vitamin K - b12 - thiamin - riboflavin
In mouth - breakdown of starch into polysaccharides
Carry signals to musc OR Gland
Eukaryotes

7. in the dark is rhodopsin active or inactive?
Low because AAs are immediately used in translation
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

8. How do nutrients move?
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

9. Failure of apoptosis can result in
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Lysosome
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
Testosterone upon stim by LH

10. What is somatostatin
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

11. thyroid hormones: Not All One Kind of HORM
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
RBCs - large proteins; What does enter is called the filtrate
Normally contracted
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

12. Where do pancreatic secretions take effect
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

13. What is secreted into filtrate by cells of the proximal tubule?
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Inner lining of blood vessels

14. What is endothelium?
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
Ganglion
Inner lining of blood vessels
'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

15. 90% digestion - absorption occurs in...
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
Glucose = aldose fructose = ketose
About 7.2
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

16. therefore - How does plasma leave capillary at the renal corpuscle

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17. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

18. Stomach has no lacteals
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Most absorption occurs in sm intestine
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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

19. Cell bodies of SYMP postganglionic neurons lie far from effector...
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Glucose = aldose fructose = ketose
Within the paravertebral ganglion - running parallel to spinal cord
Paracrine (local) - endocrine (longer distance)

20. Local vs long - distance mediators
Facilitated diffusion: no symport w/ secondary transport
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Paracrine (local) - endocrine (longer distance)
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

21. pancreas secretes enzymes via
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Needs time for bile - lipase - micelle migration - enterocyte uptake
Pancreatic duct (made of acinar cells?)

22. amylase acts where on carbs
Lumen (ie continuous w/body cavity) and cytosol
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
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
Inner lining of blood vessels

23. fructose enters enterocyte by
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Break down TAGs to monoglycerides and free fatty acids
- 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
Facilitated diffusion: no symport w/ secondary transport

24. Where would materials slated for digestion go?
Lysosome
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
It targets liver conc of prothrombin - fibrinogen etc
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

25. FLAT PG: FSH
Lower blood pH
***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
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

26. ADH
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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
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

27. micelles also pick up
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Beta cells
Estradiol
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

28. 'Cell bodies of somatic motor neurons are located in....'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Albumin increases osmolarity of blood; increases osmotic pressure
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
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

29. In other words...
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

30. what cannot cross the fenestrations of the renal corpuscle
Vitamin K - b12 - thiamin - riboflavin
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
RBCs - large proteins; What does enter is called the filtrate
Somatic nervous sys - autonomic nervous sys

31. interneurons
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Two perpendicular semicircular canals involved in balance - equilibrium
***nicotinic is ionotropic; muscarinic is GPCR

32. physiology of gall bladder - liver and pancreatic secretions
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Determined by whether in front of or behind the lens
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

33. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
Organs
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Uncontracted: parasymp (eg opoid use)

34. testosterone can be aromatized to...
Estradiol
Glycosaminoglycans - prots - AAs - lipids
Epithelial tissue near semniferous tubules
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

35. What is the net effect of the loop of Henle
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)
The wall of the body or of a body cavity or hollow structure
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Vitamin K - b12 - thiamin - riboflavin

36. exocrine types
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Glucose

37. Liver Functions
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
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
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

38. sporic life cycle
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Peripheral nervous sys
***nicotinic is ionotropic; muscarinic is GPCR
Estradiol

39. signal transduction occurs only in
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)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Eukaryotes
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

40. What is feces composed of...
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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
Salivary amylase; both hydrolyze glycosidic linkages
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

41. What does peroxisome do
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Vitamin K - b12 - thiamin - riboflavin
About 7.2

42. Seen in lysosomal storage diseases
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

43. FLAT PG: hGH aka somatotropin
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)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Oxytocin and ADH (aka vasopressin)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

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

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45. Kidney physiology...

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46. extracellular matrix formed mainly of...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Paracrine (local) - endocrine (longer distance)

47. Determination is different than differentiation
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

48. What does lipase attack exactly
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

49. Where does blood to be filtered by kidney enter the nephron?

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50. Difference between euk and prok flagella
Nitrogen
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
RBCs - large proteins; What does enter is called the filtrate