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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. motor (efferent) neurons --> VENTRAL
Ganglion
Systems (eg digestive system consists of many organs)
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.

2. Gastrulation: ectoderm/mesoderm/endoderm
Oxytocin and ADH (aka vasopressin)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Albumin increases osmolarity of blood; increases osmotic pressure
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

3. cAMP - cGMP - calmodulin...
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Glucose and ketone bodies (not from glycogen stores)
AAs can be burned for energy or converted to fat for storage

4. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Liposome has phospholipid bilayer
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Gastrulation occurs: formation of three primary germ layers = differentiation
Creates one ovum (23 N) and three polar bodies

5. spermatogonia arise from
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Epithelial tissue near semniferous tubules
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
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

6. large intestine E. coli aid absorption of...
Glucose
Vitamin K - b12 - thiamin - riboflavin
Inner lining of circulatory system
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)

7. Thus inhibiting parietal cells could do What to blood pH
HCl; secreted by parietal cells under stim by gastrin
Lower blood pH
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Increases solute conc and osmotic pressure of the ***medulla

8. Think of spinal cord injury
HCl; secreted by parietal cells under stim by gastrin
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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

9. What is endothelium?
Inner lining of blood vessels
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
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Ammonia; must be converted to urea by liver and excreted in urine by kidney

10. in fat and liver cells monoglycerides and ffas are once again
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Ganglion
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
5

11. micelles vs liposomes
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)
Form barrier to extracellular fluid
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Liposome has phospholipid bilayer

12. oxytocin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Glycosaminoglycans - prots - AAs - lipids
Gonadotropin releasing hormone - GnRH
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

13. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
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
Facilitated diffusion from hi to lo conc
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

14. FLAT PG: prolactin
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Thru tight junctions by favorable osmotic gradient
Below hypothalamus
'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

15. calcitonin

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16. almost all exocytosed proteins pass through this
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
Smooth ER
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

17. What does lipase attack exactly
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Testosterone and estradiol
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
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

18. FLAT PG: FSH
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Gastrulation occurs: formation of three primary germ layers = differentiation
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

19. What do lipases do
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Smooth ER
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Break down TAGs to monoglycerides and free fatty acids

20. Human chorionic gonadotropin...
Creates one ovum (23 N) and three polar bodies
Water flows from the tubule - concentrating the filtrate - raising BP
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

21. fructose enters enterocyte by
Systems (eg digestive system consists of many organs)
Facilitated diffusion: no symport w/ secondary transport
Chylomicrons are much bigger
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

22. fat digestion is time - intensive
Needs time for bile - lipase - micelle migration - enterocyte uptake
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Paracrine (local) - endocrine (longer distance)

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

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24. 80-90% fat absorbed this way
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Gonadotropin releasing hormone - GnRH
'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.'
Somatic nervous sys - autonomic nervous sys

25. What kind of cells make up epithel tiss of stom - then sm intest?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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
Micelles; micelles (made of bile) go back and forth between brush border and chyme

26. Where would materials slated for digestion go?
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
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)
Lysosome
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

27. thyroid hormones: Not All One Kind of HORM
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

28. PNS nerve signal
Membrane - bound - endocytosed bodies
Direction of differentiation
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
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

29. in mammals - gastrulation involves formation of the
Two perpendicular semicircular canals involved in balance - equilibrium
Primitive streak - which consists of cells of the MESODERM ****
Eukaryotes
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

30. Between meals most fats appear in blood as
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
'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.'
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

31. What determines number of chromosomes?
Organs
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Corpus luteum degrades into corpus albicans
Processes: axons - dendrites

32. What is main difference is signal transmission in nicotinic vs muscarinic?
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
***nicotinic is ionotropic; muscarinic is GPCR
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Transfer signals from neuron - neuron; 90% of neurons are interneurons

33. What is the endothelium?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Inner lining of circulatory system
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

34. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

35. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Needs time for bile - lipase - micelle migration - enterocyte uptake
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

36. When 'coumadin targets liver enzymes to act as anticoagulant'...
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Within the paravertebral ganglion - running parallel to spinal cord
It targets liver conc of prothrombin - fibrinogen etc
Direction of differentiation

37. What if large intestine isn't working well
The wall of the body or of a body cavity or hollow structure
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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

38. What is the function of the loop of Henle
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
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Increases solute conc and osmotic pressure of the ***medulla
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

39. bundles of collecting ducts are called
Lumen (ie continuous w/body cavity) and cytosol
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Most absorption occurs in sm intestine
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

40. Adrenal medulla hormones (TYR- DERIVED)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Increases solute conc and osmotic pressure of the ***medulla
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

41. peroxisome is derived from this
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
ER
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Fructose is a structural isomer of glucose

42. What hormones affect the stomach?
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

43. Both divisions (somatic - autonomic) of PNS consist of...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Sensory (afferent - dorsal) - motor (efferent - ventral)
Sorts - modifies - concentrates proteins from the ER
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

44. What do villli do
Liposome has phospholipid bilayer
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Prod of steroid hormones in testes - ovaries
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

45. What is a plasmalogen?
'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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

46. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
***nicotinic is ionotropic; muscarinic is GPCR
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Gastrulation occurs: formation of three primary germ layers = differentiation

47. ligands are the messenger compounds that target secondary messenger systems on effectors
Liposome has phospholipid bilayer
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Many modern drugs are ligands for GPCRs

48. Where does the bolus go after mouth chews food
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
The renal corpuscle
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Moves down thru esophageal sphincter

49. How do parietal cells work ** (involves CO2)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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**
- 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

50. protein absorption at enterocyte
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Lysosome