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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. pancreatic enzymes are zymogens
Water flows from the tubule - concentrating the filtrate - raising BP
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

2. How does birth control work?
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Chyme (by combined activity of exocrine glands)
Peripheral nervous sys
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

3. 80-90% fat absorbed this way
Fovea (highest amount of cones)
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

4. How does reabsorption force nutrients across apical membrane of proximal tubule
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
The renal corpuscle
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

5. examples of different cavities... (compartments for viscera)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
5
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Outermost layer of blood vessel

6. Meiosis I Anaphase I
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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

7. How does glycogen compare to starch
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

8. How does the body mobilize fat stores
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
***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
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

9. Cell bodies of SYMP postganglionic neurons lie far from effector...
Fallopian tubes
Neurons may perform one of three functions....
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Within the paravertebral ganglion - running parallel to spinal cord

10. When 'coumadin targets liver enzymes to act as anticoagulant'...
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
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
It targets liver conc of prothrombin - fibrinogen etc

11. Thus - central nervous sys is...
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Zygotes are diploid
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
ER

12. What is a plasmalogen?
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

13. What is a dorsal root ganglion?
Inner lining of blood vessels
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

14. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
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
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Only musc and esp ** liver can store large amounts

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

16. duodenum must have receptors for fat content - protein because
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Interstitial fluid (eg prostaglandins - cytokines)
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

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

18. Different tissues working together
Ganglion
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Organs

19. sporic life cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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)
All carbs absorbed at enterocytes are carried to liver by portal vein

20. Sensory - motor neurons are part of which nervous system
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
Peripheral nervous sys
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

21. Local vs long - distance mediators
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
Paracrine (local) - endocrine (longer distance)
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
Peptides

22. oxytocin
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

23. The EYE
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
AAs can be burned for energy or converted to fat for storage
Outermost layer of blood vessel
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

24. Path of urine

25. What do villli do
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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

26. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
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
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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

27. what happens when glycogen stores are saturated and blood sugar remains high?
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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
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)
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

28. gradual increase in FSH typical of primary follicle development;
Thru tight junctions by favorable osmotic gradient
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages

29. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Regulated by gastrointestinal horms

30. Glucose is a .... sugar; fructose is a .... sugar
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
Night vision
Glucose = aldose fructose = ketose
Processes: axons - dendrites

31. Kidney physiology...

32. How is glucose absorbed in sm intest
Estradiol
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Thru tight junctions by favorable osmotic gradient

33. serous membranes have a viscera - facing layer and a body wall - facing layer
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Pancreatic duct (made of acinar cells?)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Corpus luteum degrades into corpus albicans

34. 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.

35. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
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**

36. On what surface of the retina is the eye most sensitive
Regulated by gastrointestinal horms
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Fovea (highest amount of cones)

37. sensory (afferent) neurons
Water flows from the tubule - concentrating the filtrate - raising BP
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

38. Some epithelial cells are... others...
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Alpha 1-4 and 1-6 (branching) glycosidic linkages
- 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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

39. Most important nutrients absorbed by large intestine
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
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
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)

40. Chewing does what?
Faces the lumen
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Fovea (highest amount of cones)
Increases surface area of food ball (bolus)

41. FLAT PG: prolactin
In gastric pits; secretions combine into gastric juice
Eukaryotes
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

42. Liver Functions
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Zygotes are diploid
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
Needs time for bile - lipase - micelle migration - enterocyte uptake

43. micelles also pick up
Inner lining of blood vessels
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Corpus luteum degrades into corpus albicans

44. Different organs working together
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
Systems (eg digestive system consists of many organs)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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

45. Kidney
- 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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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
Fovea (highest amount of cones)

46. mucus cells line the stomach...
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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

47. Luteal surge
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Inner lining of circulatory system
Epithelial tissue near semniferous tubules
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

48. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
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
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)

49. FLAT PG: ACTH
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
ER
'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.'

50. FSH - LH - HCG - inhibin are...
Break down TAGs to monoglycerides and free fatty acids
Testosterone upon stim by LH
Peptides
Regulated by gastrointestinal horms