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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. STOMACH: no absorption
Liposome has phospholipid bilayer
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

2. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
vitreous humor - retina - fovea
Neurons may perform one of three functions....
Primitive streak - which consists of cells of the MESODERM ****

3. lysosome pH
5
Outermost layer of blood vessel
Primitive streak - which consists of cells of the MESODERM ****
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)

4. What kind of cells make up epithel tiss of stom - then sm intest?
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
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

5. What else do parietals do?
Neurons may perform one of three functions....
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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

6. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Inner lining of circulatory system

7. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Form barrier to extracellular fluid
Has memb - bound organelles - etc...

8. Three stages of the menstrual cycle
Estradiol
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Corpus luteum degrades into corpus albicans
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

9. 'Cell bodies of somatic motor neurons are located in....'
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Conjunction of cell body w/axon
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

10. large intestine E. coli aid absorption of...
Uncontracted: parasymp (eg opoid use)
Vitamin K - b12 - thiamin - riboflavin
Somatic nervous sys - autonomic nervous sys
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

11. when cells hit their limit for prot storage...
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... ...
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Gonadotropin releasing hormone - GnRH
AAs can be burned for energy or converted to fat for storage

12. 3 phases of menstrual cycle
Sympathetic: dilates pupil (for night hunting)
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
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)
- 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

13. What surrounds the hydrophilic heads of the new TAGs
Nitrogen
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
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)
Salivary amylase; both hydrolyze glycosidic linkages

14. How is glucose absorbed in sm intest
Has memb - bound organelles - etc...
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Moves down thru esophageal sphincter
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

15. liver and blood glucose...
Liver is the control center for blood glucose; is fed by portal vein from sm intest
***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
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
Fallopian tubes

16. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Digestion
Glycosaminoglycans - prots - AAs - lipids
***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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

17. 90% digestion - absorption occurs in...
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Estradiol

18. signal transduction occurs only in
Eukaryotes
Glucose = aldose fructose = ketose
Peptides
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

19. overall - fatty - prot - rich food in duod causes
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Micelles; micelles (made of bile) go back and forth between brush border and chyme
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

20. Some PNS nerves are found in brain - spinal cord
Many modern drugs are ligands for GPCRs
Prod of steroid hormones in testes - ovaries
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

21. physiology of gall bladder - liver and pancreatic secretions
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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

22. exocrine types
Direction of differentiation
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Gastrulation occurs: formation of three primary germ layers = differentiation
Conjunction of cell body w/axon

23. FLAT PG: ACTH
In gastric pits; secretions combine into gastric juice
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

24. overview of prot digestion
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
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
Outermost layer of blood vessel
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

25. For focal point that is nearby - what will the lens look like
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Estradiol
Inner lining of blood vessels
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

26. What is secreted into filtrate by cells of the proximal tubule?
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
An endogenous morphine
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

27. Different organs working together
Systems (eg digestive system consists of many organs)
The wall of the body or of a body cavity or hollow structure
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

28. ligands are the messenger compounds that target secondary messenger systems on effectors
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Many modern drugs are ligands for GPCRs
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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

29. After meiosis II...
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

30. Kidney physiology...

31. cAMP - cGMP - calmodulin...
vitreous humor - retina - fovea
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Smooth ER
Digestion

32. The bolus (chewing) is digested to what in the stomach
Thru tight junctions by favorable osmotic gradient
Chyme (by combined activity of exocrine glands)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

33. almost all cells can store Some glycogen - but...
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Only musc and esp ** liver can store large amounts
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

34. The esophageal sphincter is...
Form barrier to extracellular fluid
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
Normally contracted

35. spermatogonia arise from
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... ...
Epithelial tissue near semniferous tubules
Form barrier to extracellular fluid
Chyme (by combined activity of exocrine glands)

36. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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
Creates one ovum (23 N) and three polar bodies

37. medium for paracrine hormones
Membrane - bound - endocytosed bodies
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Interstitial fluid (eg prostaglandins - cytokines)
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

38. sensory (afferent)/interneurons/motor (efferent)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Neurons may perform one of three functions....

39. insulin secreted by
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Beta cells

40. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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

41. only monosaccharides are absorbed
In gastric pits; secretions combine into gastric juice
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

42. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
Estradiol
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

43. Local vs long - distance mediators
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
An endogenous morphine
Paracrine (local) - endocrine (longer distance)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

44. alpha - amylase in the mouth digests what kind of bond
Alpha 1-4 and 1-6 (branching) glycosidic linkages
5
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Increases surface area of food ball (bolus)

45. serous membranes have a viscera - facing layer and a body wall - facing layer
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

46. At post - two weeks ovulation
Within the paravertebral ganglion - running parallel to spinal cord
Corpus luteum degrades into corpus albicans
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Paracrine (local) - endocrine (longer distance)

47. Anterior eye vs. posterior eye
Estradiol
Glands w/ducts: Exocrine glands
Many modern drugs are ligands for GPCRs
Determined by whether in front of or behind the lens

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

49. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Salivary amylase; both hydrolyze glycosidic linkages
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

50. micelles also pick up
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**
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Oxytocin and ADH (aka vasopressin)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)