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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. Where does fertilization occur
Fallopian tubes
Nitrogen
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Transfer signals from neuron - neuron; 90% of neurons are interneurons

2. only monosaccharides are absorbed
Lysosome
1) by integral ion channels 2) transmitted by second messenger system
Zygotes are diploid
Which is why lactase - maltase - dextrinase - sucrase are on brush border

3. at lo blood sugar...
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Facilitated diffusion from hi to lo conc
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

4. motor (efferent) neurons --> VENTRAL
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Carry signals to musc OR Gland
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.
Chylomicrons are much bigger

5. Between meals most fats appear in blood as
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

6. important pancreatic enzymes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Sensory (afferent - dorsal) - motor (efferent - ventral)
Inner lining of blood vessels
Break down TAGs to monoglycerides and free fatty acids

7. quote on cavities/viscera

8. PNS review: SAME DAVE
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

9. Anatomy of the villi
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
Neurons may perform one of three functions....
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
Contain capillary network - lymph vessels (lacteals)

10. lysosome pH
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
5
Peripheral nervous sys
vitreous humor - retina - fovea

11. A group of cell bodies in CNS is nucleus - outside CNS is...
Below hypothalamus
Ganglion
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

12. micelles also pick up
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Digestion
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
90-140 mg/dl

13. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Estradiol
Sorts - modifies - concentrates proteins from the ER
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

14. cAMP - cGMP - calmodulin...
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Epithelial tissue near semniferous tubules
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

15. How does the body mobilize fat stores
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
***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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

16. testosterone can be aromatized to...
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Estradiol
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

17. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

18. 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.

19. What is a toxic byproduct of gluconeogenesis from proteins
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
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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

20. energy source of neurons
Glucose and ketone bodies (not from glycogen stores)
Oxytocin and ADH (aka vasopressin)
The renal corpuscle
Beta cells

21. Polypeptides are formed with what kind of reaction?
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Testosterone upon stim by LH

22. What are the memb - bound enzymes of the brush border?
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Form barrier to extracellular fluid

23. fat digestion is time - intensive
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
90-140 mg/dl
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Needs time for bile - lipase - micelle migration - enterocyte uptake

24. From that point...
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
Determined by whether in front of or behind the lens
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
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.

25. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Many modern drugs are ligands for GPCRs
Contain capillary network - lymph vessels (lacteals)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

26. in mammals - gastrulation involves formation of the
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Primitive streak - which consists of cells of the MESODERM ****
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

27. For focal point that is nearby - what will the lens look like
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Eukaryotes
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

28. bundles of collecting ducts are called
Night vision
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Organs

29. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
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)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

30. small intestine=
Low because AAs are immediately used in translation
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Membrane - bound - endocytosed bodies
- 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

31. trypsin is secreted by
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

32. when thinking of proteins - think
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Nitrogen
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Liposome has phospholipid bilayer

33. ADH
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
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
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
Vitamin K - b12 - thiamin - riboflavin

34. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
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... ...
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Facilitated diffusion from hi to lo conc

35. Kidney physiology...

36. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
An endogenous morphine

37. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
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
It targets liver conc of prothrombin - fibrinogen etc
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

38. signal transduction occurs only in
Eukaryotes
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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
Creates one ovum (23 N) and three polar bodies

39. Exocrine GlandS: stomach
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
- 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
Uncontracted: parasymp (eg opoid use)
Peripheral nervous sys

40. 80% of end product of carbohydrate metabolism is...
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
Prod of steroid hormones in testes - ovaries
Glucose
Chyme (by combined activity of exocrine glands)

41. Posterior eye
All carbs absorbed at enterocytes are carried to liver by portal vein
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
vitreous humor - retina - fovea

42. Ovum development is halted At what stage until fertilization...
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Epithelial tissue near semniferous tubules
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

43. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Increases surface area of food ball (bolus)
- 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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

44. What do villli do
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Facilitated diffusion from hi to lo conc

45. physiology of gall bladder - liver and pancreatic secretions
- 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
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
Smooth ER
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

46. Leydig cells produce
Testosterone upon stim by LH
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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
Gastrulation occurs: formation of three primary germ layers = differentiation

47. When 'coumadin targets liver enzymes to act as anticoagulant'...
Vitamin K - b12 - thiamin - riboflavin
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
It targets liver conc of prothrombin - fibrinogen etc
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

48. thyroid hormones: Not All One Kind of HORM
The wall of the body or of a body cavity or hollow structure
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Faces the lumen

49. Aldosterone (sodium uptake - potassium secretion)
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)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

50. Some PNS nerves are found in brain - spinal cord
Sorts - modifies - concentrates proteins from the ER
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
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle