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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 are phagosomes
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Form barrier to extracellular fluid
Membrane - bound - endocytosed bodies
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

2. Alpha - amylase found where
In mouth - breakdown of starch into polysaccharides
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Liver is the control center for blood glucose; is fed by portal vein from sm intest

3. Meiosis I Anaphase I
Gastrulation occurs: formation of three primary germ layers = differentiation
Normally contracted
Facilitated diffusion from hi to lo conc
Homologous chromosomes separate - migrate towards opposite poles/centrioles

4. Glycogenolysis/gluconeogenesis
Glucose and ketone bodies (not from glycogen stores)
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
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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

5. STOMACH: no absorption
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Only musc and esp ** liver can store large amounts
Lower blood pH
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

6. How do nutrients move?
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
5
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

7. Where does fertilization occur
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Fallopian tubes
Increases blood Calcium
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

8. trypsin is secreted by
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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

9. What determines number of chromosomes?
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Faces the lumen
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

10. What hormones affect the stomach?
Inner lining of circulatory system
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Smooth ER
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

11. Polypeptides are formed with what kind of reaction?
Direction of differentiation
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Water flows from the tubule - concentrating the filtrate - raising BP
Form barrier to extracellular fluid

12. protein absorption at enterocyte
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
- 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
Nitrogen
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

13. fat digestion is time - intensive
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Ventrally (picture skeletal vertebrae)
Needs time for bile - lipase - micelle migration - enterocyte uptake

14. sporic life cycle
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
90-140 mg/dl

15. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Glucose and ketone bodies (not from glycogen stores)
Sorts - modifies - concentrates proteins from the ER
- 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
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

16. What is the path of a sound wave that enters the ear?
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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
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
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

17. How is glucose absorbed in sm intest
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
Fallopian tubes
All carbs absorbed at enterocytes are carried to liver by portal vein
Increases surface area of food ball (bolus)

18. What is the function of the loop of Henle
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Increases solute conc and osmotic pressure of the ***medulla
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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

19. therefore - How does plasma leave capillary at the renal corpuscle

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20. Where is bile produced
Lower blood pH
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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**
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

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

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22. FLAT PG: hGH aka somatotropin
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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)
Smooth ER

23. pancreatic enzymes are zymogens
It targets liver conc of prothrombin - fibrinogen etc
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
'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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

24. mucus cells line the stomach...
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
In mouth - breakdown of starch into polysaccharides
Increases surface area of food ball (bolus)
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

25. Where does the bolus go after mouth chews food
Moves down thru esophageal sphincter
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Liver is the control center for blood glucose; is fed by portal vein from sm intest

26. Cell determination begins At what stage of development
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Water flows from the tubule - concentrating the filtrate - raising BP
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

27. What is an endorphin?
An endogenous morphine
Vitamin K - b12 - thiamin - riboflavin
Membrane - bound - endocytosed bodies
Most absorption occurs in sm intestine

28. Where do absorbed fats go in the enterocyte
Fallopian tubes
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
- 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
Direction of differentiation

29. During ejaculation - sperm...

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30. Meiosis I Telophase I
Salivary amylase; both hydrolyze glycosidic linkages
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
- 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
AAs can be burned for energy or converted to fat for storage

31. When 'coumadin targets liver enzymes to act as anticoagulant'...
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
It targets liver conc of prothrombin - fibrinogen etc
Two perpendicular semicircular canals involved in balance - equilibrium
Night vision

32. FLAT PG: TSH aka thyrotropin
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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

33. Luteal surge
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

34. How long are peptides when absorbed at brush border
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Beta cells
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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

35. Spinal cord horns (thick knobs) point
Increases surface area of food ball (bolus)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Ventrally (picture skeletal vertebrae)

36. ligands are the messenger compounds that target secondary messenger systems on effectors
Sorts - modifies - concentrates proteins from the ER
Eukaryotes
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Many modern drugs are ligands for GPCRs

37. Four tissues
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Peripheral nervous sys

38. What is the net effect of the loop of Henle
Chylomicrons are much bigger
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)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

39. The apical side of the villi...
Faces the lumen
Fovea (highest amount of cones)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
It targets liver conc of prothrombin - fibrinogen etc

40. What else do parietals do?
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Sensory (afferent - dorsal) - motor (efferent - ventral)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

41. What do lipases do
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Break down TAGs to monoglycerides and free fatty acids
An endogenous morphine
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

42. After meiosis II...
HCl; secreted by parietal cells under stim by gastrin
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

43. spermatogonia arise from
Epithelial tissue near semniferous tubules
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
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

44. Some PNS nerves are found in brain - spinal cord
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Beta cells
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

45. Posterior eye
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
vitreous humor - retina - fovea
Liver is the control center for blood glucose; is fed by portal vein from sm intest

46. in the dark is rhodopsin active or inactive?
The renal corpuscle
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Ganglion
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

47. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Peptides
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

48. From that point...
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
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.
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

49. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

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50. exocrine types
1) by integral ion channels 2) transmitted by second messenger system
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Glucose = aldose fructose = ketose
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal