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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. Chewing does what?
Increases surface area of food ball (bolus)
Thru tight junctions by favorable osmotic gradient
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

2. How does the body mobilize fat stores
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
***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
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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

3. review: parietals secrete intrinsic factor...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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
Sympathetic: dilates pupil (for night hunting)

4. FSH - LH - HCG - inhibin are...
- 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
Peptides
Below hypothalamus
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

5. How does glycogen compare to starch
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Sorts - modifies - concentrates proteins from the ER
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Ganglion

6. testosterone can be aromatized to...
Estradiol
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

7. What is a normal blood glucose range
Thru tight junctions by favorable osmotic gradient
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
90-140 mg/dl
Cancer; apop can be programmed cell death; mitochon can play important role in apop

8. Some epithelial cells are... others...
Moves down thru esophageal sphincter
Oxytocin and ADH (aka vasopressin)
- 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
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

9. Peritoneal refers to...
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
Form barrier to extracellular fluid
Abdominal cavity - which is coated in serous fluid
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

10. liver and blood glucose...
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

11. important pancreatic enzymes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Oxytocin and ADH (aka vasopressin)
Gastrulation occurs: formation of three primary germ layers = differentiation
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

12. Anterior eye vs. posterior eye
Testosterone upon stim by LH
Determined by whether in front of or behind the lens
Gastrulation occurs: formation of three primary germ layers = differentiation
It targets liver conc of prothrombin - fibrinogen etc

13. Luteal surge
Moves down thru esophageal sphincter
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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**

14. Does bile digest fat?
Interstitial fluid (eg prostaglandins - cytokines)
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

15. Determination is different than differentiation
Faces the lumen
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

16. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Digestion
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Beta cells
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang

17. 80% of end product of carbohydrate metabolism is...
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Glucose
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

18. What happens when rod cell is depolarized
Night vision
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
***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

19. sensory (afferent)/interneurons/motor (efferent)
Neurons may perform one of three functions....
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
Interstitial fluid (eg prostaglandins - cytokines)

20. After meiosis II - Female

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21. Failure of apoptosis can result in
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Estradiol
Cancer; apop can be programmed cell death; mitochon can play important role in apop
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste

22. What do villli do
- 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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

23. What is the adventitia?
Outermost layer of blood vessel
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
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
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

24. cAMP - cGMP - calmodulin...
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Gastrulation occurs: formation of three primary germ layers = differentiation
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Vitamin K - b12 - thiamin - riboflavin

25. What does peroxisome do
Oxytocin and ADH (aka vasopressin)
Paracrine (local) - endocrine (longer distance)
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

26. What testosterone released by secondary follicle by LH stim is converted to...
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Water flows from the tubule - concentrating the filtrate - raising BP

27. Stomach has no lacteals
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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
Most absorption occurs in sm intestine
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

28. What is feces composed of...
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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

29. How is the follicle developed during oogenesis
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Pancreatic duct (made of acinar cells?)
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

30. What is the net effect of the distal tubule
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
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Pancreatic duct (made of acinar cells?)

31. Where does the bolus go after mouth chews food
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Epithelial tissue near semniferous tubules
Moves down thru esophageal sphincter
Below hypothalamus

32. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
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
Salivary amylase; both hydrolyze glycosidic linkages
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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

33. What is a dorsal root ganglion?
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
Membrane - bound - endocytosed bodies
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

34. only monosaccharides are absorbed
'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
Albumin increases osmolarity of blood; increases osmotic pressure
Which is why lactase - maltase - dextrinase - sucrase are on brush border
1) by integral ion channels 2) transmitted by second messenger system

35. Think of spinal cord injury
Below hypothalamus
AAs enter bloodstream for uptake by all cells (esp liver). If intracellular prot conc is at max AAs can be converted to fats or glucose via gluconeogenesis. Byproduct of gluconeo is ammonia --->urea.
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

36. alpha - amylase in the mouth digests what kind of bond
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Lysosome
An endogenous morphine

37. lysosome main function and derivation
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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
Chylomicrons are much bigger
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

38. The apical side of the villi...
Night vision
Faces the lumen
Facilitated diffusion from hi to lo conc
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

39. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Prod of steroid hormones in testes - ovaries
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

40. Contrast PNS- Somatic with PNS- Autonomic
Interstitial fluid (eg prostaglandins - cytokines)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Prod of steroid hormones in testes - ovaries
Micelles; micelles (made of bile) go back and forth between brush border and chyme

41. Path of urine

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42. ADH
Glands w/ducts: Exocrine glands
Normally contracted
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
'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

43. 'Cell bodies of somatic motor neurons are located in....'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Inner lining of circulatory system
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Uncontracted: parasymp (eg opoid use)

44. signal transduction occurs only in
vitreous humor - retina - fovea
Eukaryotes
Facilitated diffusion from hi to lo conc
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

45. What is the mesentery?
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
'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.'
Inner lining of circulatory system
Facilitated diffusion: no symport w/ secondary transport

46. Path of food entering body...
***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
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
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach

47. 90% digestion - absorption occurs in...
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Facilitated diffusion: no symport w/ secondary transport

48. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

49. What are the memb - bound enzymes of the brush border?
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

50. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

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