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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. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Outermost layer of blood vessel

2. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Peptides
Testosterone upon stim by LH
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

3. Where would materials slated for digestion go?
Lysosome
Regulated by gastrointestinal horms
Testosterone and estradiol
***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

4. In general - parietal=
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
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
- 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
The wall of the body or of a body cavity or hollow structure

5. 3 phases of menstrual cycle
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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)
Estradiol
All carbs absorbed at enterocytes are carried to liver by portal vein

6. physiology of gall bladder - liver and pancreatic secretions
Albumin increases osmolarity of blood; increases osmotic pressure
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
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
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

7. liver and blood glucose...
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)
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest
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

8. A group of cell bodies in CNS is nucleus - outside CNS is...
Neurons may perform one of three functions....
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Ganglion
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

9. How does glycogen compare to starch
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

10. testosterone can be aromatized to...
Estradiol
Increases solute conc and osmotic pressure of the ***medulla
Carry signals to musc OR Gland
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

11. lining of abdominal cavity=
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
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**
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

12. How do parietal cells work ** (involves CO2)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Nitrogen
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

13. Interaction of corpus luteum/placenta
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

14. Meiosis II: EQUATIONAL DIVISION
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
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
In gastric pits; secretions combine into gastric juice
Homologous chromosomes separate - migrate towards opposite poles/centrioles

15. FLAT PG: ACTH
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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)
- 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
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

16. What hormones affect the stomach?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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

17. Where does the bolus go after mouth chews food
Paracrine (local) - endocrine (longer distance)
Moves down thru esophageal sphincter
Somatic nervous sys - autonomic nervous sys
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

18. Thus inhibiting parietal cells could do What to blood pH
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Lower blood pH
Facilitated diffusion from hi to lo conc
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

19. Anatomy of the villi
Contain capillary network - lymph vessels (lacteals)
Within the paravertebral ganglion - running parallel to spinal cord
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Micelles; micelles (made of bile) go back and forth between brush border and chyme

20. euk cell has two principal sides
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Pancreatic duct (made of acinar cells?)
Lumen (ie continuous w/body cavity) and cytosol
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

21. in mammals - gastrulation involves formation of the
Primitive streak - which consists of cells of the MESODERM ****
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

22. What is main difference is signal transmission in nicotinic vs muscarinic?
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
***nicotinic is ionotropic; muscarinic is GPCR
Facilitated diffusion: no symport w/ secondary transport
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

23. light detection via GPCRs
Fallopian tubes
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Conjunction of cell body w/axon
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

24. What controls release of LH - FSH from anterior pituitary
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
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Gonadotropin releasing hormone - GnRH
- 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

25. 80-90% fat absorbed this way
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Gastrulation occurs: formation of three primary germ layers = differentiation
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

26. parathyroid hormones
Gonadotropin releasing hormone - GnRH
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

27. fat digestion is time - intensive
Glycosaminoglycans - prots - AAs - lipids
Needs time for bile - lipase - micelle migration - enterocyte uptake
RBCs - large proteins; What does enter is called the filtrate
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

28. What is feces composed of...
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
HCl; secreted by parietal cells under stim by gastrin
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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

29. A contracted iris occurs with what kind of stimulation
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Sympathetic: dilates pupil (for night hunting)
Inner lining of circulatory system
Oxytocin and ADH (aka vasopressin)

30. The path from blood plasma to urine

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31. How does the body mobilize fat stores
Alpha 1-4 and 1-6 (branching) glycosidic linkages
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
***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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

32. Tight junctions
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Form barrier to extracellular fluid
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

33. gradual increase in FSH typical of primary follicle development;
Chyme (by combined activity of exocrine glands)
Facilitated diffusion from hi to lo conc
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

34. trypsin is secreted by
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.
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Chylomicrons are much bigger

35. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Facilitated diffusion: no symport w/ secondary transport

36. in the dark is rhodopsin active or inactive?
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Somatic nervous sys - autonomic nervous sys
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

37. portal vein physiology...

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38. A pinpoint iris is contracted or uncontracted
Corpus luteum degrades into corpus albicans
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Uncontracted: parasymp (eg opoid use)
'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

39. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
About 7.2
Increases solute conc and osmotic pressure of the ***medulla
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

40. Cell determination begins At what stage of development
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
In gastric pits; secretions combine into gastric juice
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

41. motor (efferent) neurons --> VENTRAL
Eukaryotes
Carry signals to musc OR Gland
AAs can be burned for energy or converted to fat for storage
Digestion

42. lysosome main function and derivation
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

43. What is an endorphin?
An endogenous morphine
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Peptides
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

44. extracellular matrix formed mainly of...
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
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

45. Blastocyst
Lysosome
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

46. What is the endothelium?
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Inner lining of circulatory system
Carbohydrates are highly hydrated: one water mol per carbon mol - fats are anhydrous: contain more reduced carbons per unit mass - altogether fats contain 6X energy per unit mass

47. position of AP...
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Ganglion
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Below hypothalamus

48. Exocrine GlandS: stomach
AAs can be burned for energy or converted to fat for storage
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
- 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

49. Induction affects...
Direction of differentiation
Chyme (by combined activity of exocrine glands)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

50. overall - fatty - prot - rich food in duod causes
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Estradiol
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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility