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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. What is the mesentery?
Within the paravertebral ganglion - running parallel to spinal cord
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

2. What surrounds the hydrophilic heads of the new TAGs
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Gastrulation occurs: formation of three primary germ layers = differentiation
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

3. liver and blood glucose...
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Liposome has phospholipid bilayer

4. gametic life cycle
Primitive streak - which consists of cells of the MESODERM ****
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

5. at lo blood sugar...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Outermost layer of blood vessel

6. inhibin secreted by
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

7. 80% of end product of carbohydrate metabolism is...
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
It targets liver conc of prothrombin - fibrinogen etc
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Glucose

8. Beta - oxidation in liver produces...
Glycosaminoglycans - prots - AAs - lipids
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Sensory (afferent - dorsal) - motor (efferent - ventral)

9. During ejaculation - sperm...

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10. keep in mind that enterocyte is like a regular euk cell
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Has memb - bound organelles - etc...
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

11. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Sympathetic: dilates pupil (for night hunting)
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
Lysosome

12. components of interstitial fluid
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**
Alpha 1-4 and 1-6 (branching) glycosidic linkages
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Glycosaminoglycans - prots - AAs - lipids

13. What is an endorphin?
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
- 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
An endogenous morphine
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

14. Ovum development is halted At what stage until fertilization...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
'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
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
Creates one ovum (23 N) and three polar bodies

15. Where does fertilization occur
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Fallopian tubes
1) by integral ion channels 2) transmitted by second messenger system
Facilitated diffusion: no symport w/ secondary transport

16. What is a toxic byproduct of gluconeogenesis from proteins
AAs can be burned for energy or converted to fat for storage
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
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**
Ammonia; must be converted to urea by liver and excreted in urine by kidney

17. Where do pancreatic secretions take effect
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

18. Between meals most fats appear in blood as
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

19. Embryology
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
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Peptides
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

20. mitosis creates somatic cells
Abdominal cavity - which is coated in serous fluid
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
Meiosis creates germ cells
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

21. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Chylomicrons are much bigger
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
'Increased absorptive area is useful because digested nutrients (including sugars and amino acids) pass into the villi through diffusion - which is effective only at short distances. In other words - **increased surface area (in contact with the flui

22. What hormones affect the stomach?
Eukaryotes
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Has memb - bound organelles - etc...

23. golgi body
Sorts - modifies - concentrates proteins from the ER
Beta cells
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
'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

24. Both divisions (somatic - autonomic) of PNS consist of...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Processes: axons - dendrites

25. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
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
Gastrulation occurs: formation of three primary germ layers = differentiation
Thru tight junctions by favorable osmotic gradient

26. Adrenal medulla hormones (TYR- DERIVED)
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
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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

27. ligands are the messenger compounds that target secondary messenger systems on effectors
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Many modern drugs are ligands for GPCRs
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

28. what happens to bile secretions
Vitamin K - b12 - thiamin - riboflavin
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Mostly reabsorbed to liver
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

29. gametes are haploid
Zygotes are diploid
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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
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

30. remaining secondary follicle becomes
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
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

31. STOMACH: no absorption
Glycosaminoglycans - prots - AAs - lipids
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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

32. Determination is different than differentiation
Systems (eg digestive system consists of many organs)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

33. when cells hit their limit for prot storage...
An endogenous morphine
AAs can be burned for energy or converted to fat for storage
Vitamin K - b12 - thiamin - riboflavin
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

34. Meiosis I Telophase I
Oxytocin and ADH (aka vasopressin)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

35. pancreatic enzymes are zymogens
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Chylomicrons are much bigger

36. 'Cell bodies of somatic motor neurons are located in....'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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
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

37. What is gastric acid?
Increases solute conc and osmotic pressure of the ***medulla
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
HCl; secreted by parietal cells under stim by gastrin

38. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
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
An endogenous morphine
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
- 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

39. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
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
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Testosterone and estradiol
Gonadotropin releasing hormone - GnRH

40. cytosol pH
The wall of the body or of a body cavity or hollow structure
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Within the paravertebral ganglion - running parallel to spinal cord
About 7.2

41. Gland: ovaries
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Beta cells
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

42. insulin secreted by
Beta cells
Systems (eg digestive system consists of many organs)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Inner lining of blood vessels

43. sensory (afferent)/interneurons/motor (efferent)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Neurons may perform one of three functions....
In mouth - breakdown of starch into polysaccharides

44. What is a plasmalogen?
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Carry signals to musc OR Gland
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

45. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Epithelial tissue near semniferous tubules
Creates one ovum (23 N) and three polar bodies

46. bile + fat forms
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)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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

47. How is the follicle developed during oogenesis
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Vitamin K - b12 - thiamin - riboflavin
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

48. What kind of cells make up epithel tiss of stom - then sm intest?
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
About 7.2
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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

49. Anterior eye vs. posterior eye
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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)
Determined by whether in front of or behind the lens

50. parathyroid hormone
Water flows from the tubule - concentrating the filtrate - raising BP
Vitamin K - b12 - thiamin - riboflavin
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Increases blood Calcium