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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. alpha - amylase in the mouth digests what kind of bond
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective 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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

2. oxytocin
Neurons may perform one of three functions....
Interstitial fluid (eg prostaglandins - cytokines)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

3. Anatomy of the villi
vitreous humor - retina - fovea
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
Contain capillary network - lymph vessels (lacteals)
HCl; secreted by parietal cells under stim by gastrin

4. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
Direction of differentiation
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

5. large intestine E. coli aid absorption of...
Vitamin K - b12 - thiamin - riboflavin
Sorts - modifies - concentrates proteins from the ER
Low because AAs are immediately used in translation
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

6. Different organs working together
Systems (eg digestive system consists of many organs)
Direction of differentiation
Many modern drugs are ligands for GPCRs
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

7. From that point...
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.
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Organs
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

8. 80-90% fat absorbed this way
Form barrier to extracellular fluid
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Lysosome
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

9. How do nutrients move?
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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.
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

10. sensory (afferent)/interneurons/motor (efferent)
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Neurons may perform one of three functions....
RBCs - large proteins; What does enter is called the filtrate

11. Thus - central nervous sys is...
Determined by whether in front of or behind the lens
***nicotinic is ionotropic; muscarinic is GPCR
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

12. FLAT PG: TSH aka thyrotropin
Most absorption occurs in sm intestine
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
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

13. What is the function of the loop of Henle
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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
'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.'
Increases solute conc and osmotic pressure of the ***medulla

14. Think of spinal cord injury
***nicotinic is ionotropic; muscarinic is GPCR
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Form barrier to extracellular fluid

15. overall - fatty - prot - rich food in duod causes
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
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
Salivary amylase; both hydrolyze glycosidic linkages

16. parathyroid hormone
Fallopian tubes
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Oxytocin and ADH (aka vasopressin)
Increases blood Calcium

17. What is the endothelium?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Inner lining of circulatory system

18. PNS is broken down into
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Somatic nervous sys - autonomic nervous sys

19. How does duod deal with hi HCl from stom
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Has memb - bound organelles - etc...
Ups bicarbonate secretion by pancreas; raises pH to 6.0

20. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Moves down thru esophageal sphincter
Chylomicrons are much bigger
Conjunction of cell body w/axon
Ganglion

21. interneurons
Thru tight junctions by favorable osmotic gradient
Transfer signals from neuron - neuron; 90% of neurons are interneurons
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Prod of steroid hormones in testes - ovaries

22. food in duod stims release of gastrointestinal hormones
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

23. Glucose is a .... sugar; fructose is a .... sugar
Glucose = aldose fructose = ketose
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Two perpendicular semicircular canals involved in balance - equilibrium
In gastric pits; secretions combine into gastric juice

24. in fat and liver cells monoglycerides and ffas are once again
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Peptides

25. What kind of cells make up epithel tiss of stom - then sm intest?
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
Break down TAGs to monoglycerides and free fatty acids
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

26. lysosome main function and derivation
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Beta cells
Chylomicrons are much bigger
An endogenous morphine

27. duodenum must have receptors for fat content - protein because
Mostly reabsorbed to liver
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

28. How do monoglycerides and ffas get to brush border?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
RBCs - large proteins; What does enter is called the filtrate
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

29. from the loop of henle...
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
In gastric pits; secretions combine into gastric juice
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

30. 90% digestion - absorption occurs in...
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
Regulated by gastrointestinal horms
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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

31. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Organs
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

32. Where are these exocrine glands located
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
Sympathetic: dilates pupil (for night hunting)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
In gastric pits; secretions combine into gastric juice

33. FLAT PG: 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.
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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
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

34. The esophageal sphincter is...
Normally contracted
Needs time for bile - lipase - micelle migration - enterocyte uptake
Lower blood pH
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

35. Kidney physiology...

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36. Spinal cord horns (thick knobs) point
Ventrally (picture skeletal vertebrae)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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
Faces the lumen

37. What is feces composed of...
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Zygotes are diploid
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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

38. On what surface of the retina is the eye most sensitive
Eukaryotes
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
Fovea (highest amount of cones)
Moves down thru esophageal sphincter

39. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Abdominal cavity - which is coated in serous fluid
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

40. Morula (...totipotent)
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)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

41. Aldosterone (sodium uptake - potassium secretion)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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)
1) by integral ion channels 2) transmitted by second messenger system

42. amylase acts where on carbs
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Processes: axons - dendrites
Outermost layer of blood vessel

43. in the dark is rhodopsin active or inactive?
Sorts - modifies - concentrates proteins from the ER
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

44. Fructose relates how structurally to glucose
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Fructose is a structural isomer of glucose
Below hypothalamus
An endogenous morphine

45. Contrast PNS- Somatic with PNS- Autonomic
'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
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

46. lining of abdominal cavity=
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Chyme (by combined activity of exocrine glands)

47. components of interstitial fluid
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
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
Glycosaminoglycans - prots - AAs - lipids
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

48. 3 phases of menstrual cycle
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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

49. Creating gradients requires what?
Thru tight junctions by favorable osmotic gradient
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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

50. What do villli do
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
Ammonia; must be converted to urea by liver and excreted in urine by kidney