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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 if large intestine isn't working well
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Chyme (by combined activity of exocrine glands)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Vitamin K - b12 - thiamin - riboflavin

2. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Creates one ovum (23 N) and three polar bodies

3. Different organs working together
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Systems (eg digestive system consists of many organs)
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
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

4. What does peroxisome do
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
- 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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

5. trypsin is secreted by
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Fructose is a structural isomer of glucose

6. overview of prot digestion
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Determined by whether in front of or behind the lens
Form barrier to extracellular fluid

7. Leydig cells produce
Testosterone upon stim by LH
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

8. How does blood sugar move into tissues?
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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
Prod of steroid hormones in testes - ovaries
Facilitated diffusion from hi to lo conc

9. lysosome main function and derivation
Has memb - bound organelles - etc...
Faces the lumen
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
The renal corpuscle

10. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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... ...
Estradiol
Paracrine (local) - endocrine (longer distance)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

11. Human chorionic gonadotropin...
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Vitamin K - b12 - thiamin - riboflavin

12. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Meiosis creates germ cells

13. Seen in lysosomal storage diseases
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Prod of steroid hormones in testes - ovaries
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

14. Spinal cord horns (thick knobs) point
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
Ventrally (picture skeletal vertebrae)
Glucose
Glucose and ketone bodies (not from glycogen stores)

15. What is somatostatin
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Ventrally (picture skeletal vertebrae)
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

16. gametes are haploid
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
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
Zygotes are diploid
Mostly reabsorbed to liver

17. insulin secreted by
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
Testosterone upon stim by LH
Beta cells
***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

18. quote on cavities/viscera

19. Local vs long - distance mediators
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Paracrine (local) - endocrine (longer distance)
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

20. Meiosis I Anaphase I
HCl; secreted by parietal cells under stim by gastrin
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Meiosis creates germ cells

21. micelles vs liposomes
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Liposome has phospholipid bilayer
AAs can be burned for energy or converted to fat for storage

22. little by little chyme is squirted out thru pyloric sphincter
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
Regulated by gastrointestinal horms
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0

23. The apical side of the villi...
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Nitrogen
Faces the lumen
- 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

24. What is an endorphin?
An endogenous morphine
It targets liver conc of prothrombin - fibrinogen etc
Paracrine (local) - endocrine (longer distance)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

25. Posterior eye
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
Sorts - modifies - concentrates proteins from the ER
vitreous humor - retina - fovea
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

26. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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)

27. What is a plasmalogen?
Sensory (afferent - dorsal) - motor (efferent - ventral)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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

28. What is the adventitia?
Outermost layer of blood vessel
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Corpus luteum degrades into corpus albicans
Processes: axons - dendrites

29. Where else does ADH act
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
Beta cells

30. Peritoneal refers to...
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
Abdominal cavity - which is coated in serous fluid
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
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

31. How do nutrients move?
Sympathetic: dilates pupil (for night hunting)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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**

32. portal vein physiology...

33. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Moves down thru esophageal sphincter
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

34. Where does the bolus go after mouth chews food
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Glands w/ducts: Exocrine glands
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Moves down thru esophageal sphincter

35. when cells hit their limit for prot storage...
AAs can be burned for energy or converted to fat for storage
Form barrier to extracellular fluid
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
Testosterone and estradiol

36. FLAT PG: ACTH
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
In mouth - breakdown of starch into polysaccharides
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Only musc and esp ** liver can store large amounts

37. in the presence of ADH what happens to movement of water across nephron membr
Increases blood Calcium
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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Water flows from the tubule - concentrating the filtrate - raising BP

38. review: parietals secrete intrinsic factor...
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
About 7.2
Prod of steroid hormones in testes - ovaries
Estradiol

39. FSH - LH - HCG - inhibin are...
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
The renal corpuscle
Peptides

40. Some PNS nerves are found in brain - spinal cord
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
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
ER
Prod of steroid hormones in testes - ovaries

41. Gastrulation: ectoderm/mesoderm/endoderm
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Corpus luteum degrades into corpus albicans
Glucose = aldose fructose = ketose

42. parathyroid hormones
Two perpendicular semicircular canals involved in balance - equilibrium
In mouth - breakdown of starch into polysaccharides
Creates one ovum (23 N) and three polar bodies
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

43. small intestine=
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
All carbs absorbed at enterocytes are carried to liver by portal vein
Glucose = aldose fructose = ketose

44. What are the memb - bound enzymes of the brush border?
Abdominal cavity - which is coated in serous fluid
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

45. Some epithelial cells are... others...
- 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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Paracrine (local) - endocrine (longer distance)

46. at lo blood sugar...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

47. Chewing does what?
RBCs - large proteins; What does enter is called the filtrate
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
Increases surface area of food ball (bolus)
90-140 mg/dl

48. What hormones affect the stomach?
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

49. glucagon secreted by
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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... ...
Nitrogen

50. What kind of cells make up epithel tiss of stom - then sm intest?
Creates one ovum (23 N) and three polar bodies
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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded