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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. in mammals - gastrulation involves formation of the
Lysosome
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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
Primitive streak - which consists of cells of the MESODERM ****

2. 90% digestion - absorption occurs in...
AAs can be burned for energy or converted to fat for storage
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
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles

3. Spinal cord horns (thick knobs) point
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Ventrally (picture skeletal vertebrae)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

4. Where do pancreatic secretions take effect
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.
Abdominal cavity - which is coated in serous fluid
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

5. Does bile digest fat?
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
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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

6. Neuronal cell bodies have extensions ie
Uncontracted: parasymp (eg opoid use)
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
Two perpendicular semicircular canals involved in balance - equilibrium
Processes: axons - dendrites

7. Thus inhibiting parietal cells could do What to blood pH
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Lower blood pH

8. glucagon secreted by
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Lysosome
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

9. Embryology
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Sympathetic: dilates pupil (for night hunting)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

10. What are phagosomes
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Membrane - bound - endocytosed bodies

11. sensory (afferent) neurons
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Break down TAGs to monoglycerides and free fatty acids
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

12. On what surface of the retina is the eye most sensitive
Albumin increases osmolarity of blood; increases osmotic pressure
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
Testosterone and estradiol
Fovea (highest amount of cones)

13. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Water flows from the tubule - concentrating the filtrate - raising BP
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
RBCs - large proteins; What does enter is called the filtrate

14. liver receives blood from...
Stomach - sm intest - spleen - pancreas from the hepatic portal vein...all blood that passes thru liver go thru flattened spaces called the ***hepatic sinusoids -->hepatic vein --->vena cava
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

15. Glycogenolysis/gluconeogenesis
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Estradiol
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

16. remaining secondary follicle becomes
Corpus luteum degrades into corpus albicans
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Liposome has phospholipid bilayer
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

17. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Beta cells
90-140 mg/dl

18. How is the follicle developed during oogenesis
About 7.2
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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

19. What do villli do
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Glycosaminoglycans - prots - AAs - lipids
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
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

20. How does birth control work?
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

21. The bolus (chewing) is digested to what in the stomach
Inner lining of blood vessels
Abdominal cavity - which is coated in serous fluid
Chyme (by combined activity of exocrine glands)
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

22. bundles of collecting ducts are called
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
1) by integral ion channels 2) transmitted by second messenger system
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
- 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

23. is intracellular AA conc hi or low?
Low because AAs are immediately used in translation
Glucose and ketone bodies (not from glycogen stores)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

24. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Facilitated diffusion from hi to lo conc
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Night vision
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

25. what cannot cross the fenestrations of the renal corpuscle
Stomach - sm intest - spleen - pancreas from the hepatic portal vein...all blood that passes thru liver go thru flattened spaces called the ***hepatic sinusoids -->hepatic vein --->vena cava
Inner lining of circulatory system
RBCs - large proteins; What does enter is called the filtrate
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

26. Gastrulation: ectoderm/mesoderm/endoderm
Fovea (highest amount of cones)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
'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.'
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

27. From that point...
Micelles; micelles (made of bile) go back and forth between brush border and chyme
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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.
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

28. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Ventrally (picture skeletal vertebrae)

29. Kidney
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
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
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
In mouth - breakdown of starch into polysaccharides

30. Gland: ovaries
Ups bicarbonate secretion by pancreas; raises pH to 6.0
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

31. What hormones affect the stomach?
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Break down TAGs to monoglycerides and free fatty acids
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

32. What happens when rod cell is depolarized
Increases solute conc and osmotic pressure of the ***medulla
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Peripheral nervous sys
Night vision

33. Mucus - digestive enzymes released thru
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
***nicotinic is ionotropic; muscarinic is GPCR
Glands w/ducts: Exocrine glands
Zygotes are diploid

34. golgi body
Sorts - modifies - concentrates proteins from the ER
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
Glucose and ketone bodies (not from glycogen stores)
Inner lining of blood vessels

35. After meiosis II - Male

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36. liver and blood glucose...
In mouth - breakdown of starch into polysaccharides
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Neurons may perform one of three functions....
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

37. FSH - LH - HCG - inhibin are...
Paracrine (local) - endocrine (longer distance)
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
Peptides
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

38. How do parietal cells work ** (involves CO2)
Creates one ovum (23 N) and three polar bodies
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Ganglion
- 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

39. Where are these exocrine glands located
In gastric pits; secretions combine into gastric juice
Contain capillary network - lymph vessels (lacteals)
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
Lysosome

40. signal transduction occurs only in
Ventrally (picture skeletal vertebrae)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Mostly reabsorbed to liver
Eukaryotes

41. examples of different cavities... (compartments for viscera)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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
AAs can be burned for energy or converted to fat for storage

42. what else is located in the inner ear (not directly related to auditory)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Facilitated diffusion: no symport w/ secondary transport
Two perpendicular semicircular canals involved in balance - equilibrium
Liposome has phospholipid bilayer

43. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Thru tight junctions by favorable osmotic gradient
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

44. What else do parietals do?
Digestion
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

45. In general - parietal=
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Facilitated diffusion: no symport w/ secondary transport
The wall of the body or of a body cavity or hollow structure
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

46. Exocrine GlandS: stomach
Conjunction of cell body w/axon
- 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
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
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

47. Meiosis I Anaphase I
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles

48. spermatogonia arise from
1) by integral ion channels 2) transmitted by second messenger system
Epithelial tissue near semniferous tubules
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Which is why lactase - maltase - dextrinase - sucrase are on brush border

49. physiology of gall bladder - liver and pancreatic secretions
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
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
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

50. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
Ganglion
Inner lining of blood vessels
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate