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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. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

2. How does reabsorption force nutrients across apical membrane of proximal tubule
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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

3. 80-90% fat absorbed this way
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Faces the lumen
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

4. Adrenal cortex hormones (STEROIDS)
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
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.

5. When 'coumadin targets liver enzymes to act as anticoagulant'...
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
It targets liver conc of prothrombin - fibrinogen etc
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

6. How does the body mobilize fat stores
HCl; secreted by parietal cells under stim by gastrin
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
***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

7. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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)

8. For focal point that is nearby - what will the lens look like
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Increases solute conc and osmotic pressure of the ***medulla
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

9. How does blood sugar move into tissues?
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Facilitated diffusion from hi to lo conc
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

10. 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
Increases blood Calcium
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Gastrulation occurs: formation of three primary germ layers = differentiation

11. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Growth 1 (G1) phase: STRUCTURAL ProteinS - ENZYMES; This is a very active period - where the cell synthesizes its vast array of proteins - including the enzymes and structural proteins it will need for growth. In G1 stage each of the chromosomes cons
Uncontracted: parasymp (eg opoid use)

12. Posterior pituitary hormones (Small Peptides)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Oxytocin and ADH (aka vasopressin)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

13. The EYE
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

14. On what surface of the retina is the eye most sensitive
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
Interstitial fluid (eg prostaglandins - cytokines)
Fovea (highest amount of cones)
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

15. What is the path of a sound wave that enters the ear?
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
Conjunction of cell body w/axon
The wall of the body or of a body cavity or hollow structure
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

16. What determines number of chromosomes?
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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. Where else does ADH act
Uncontracted: parasymp (eg opoid use)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
Meiosis creates germ cells

18. 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
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
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
- 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
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

19. euk cell has two principal sides
Ventrally (picture skeletal vertebrae)
Lumen (ie continuous w/body cavity) and cytosol
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

20. How do monoglycerides and ffas get to brush border?
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Peripheral nervous sys
Many modern drugs are ligands for GPCRs

21. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Break down TAGs to monoglycerides and free fatty acids
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

22. How long are peptides when absorbed at brush border
Water flows from the tubule - concentrating the filtrate - raising BP
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Primitive streak - which consists of cells of the MESODERM ****
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

23. Where does fertilization occur
Lumen (ie continuous w/body cavity) and cytosol
Ganglion
Digestion
Fallopian tubes

24. portal vein physiology...

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25. Meiosis II: EQUATIONAL DIVISION
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Form barrier to extracellular fluid
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
The renal corpuscle

26. Difference between euk and prok flagella
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Processes: axons - dendrites
Zygotes are diploid

27. Path of urine

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28. Anterior eye vs. posterior eye
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Determined by whether in front of or behind the lens
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

29. What force is acting upon chyme to move it forward down sm intestine
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Direction of differentiation
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

30. Which fats are not absorbed like this
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Lower blood pH
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

31. FSH - LH - HCG - inhibin are...
Peptides
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
About 7.2
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

32. E storage per unit mass
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
Below hypothalamus
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
Facilitated diffusion: no symport w/ secondary transport

33. position of AP...
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Below hypothalamus
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

34. gametic life cycle
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

35. in the presence of ADH what happens to movement of water across nephron membr
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Abdominal cavity - which is coated in serous fluid
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
Water flows from the tubule - concentrating the filtrate - raising BP

36. ligands are the messenger compounds that target secondary messenger systems on effectors
Needs time for bile - lipase - micelle migration - enterocyte uptake
Moves down thru esophageal sphincter
Many modern drugs are ligands for GPCRs
Direction of differentiation

37. mitosis creates somatic cells
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
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
Meiosis creates germ cells
Lumen (ie continuous w/body cavity) and cytosol

38. in fat and liver cells monoglycerides and ffas are once again
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Uncontracted: parasymp (eg opoid use)

39. alpha - amylase in the mouth digests what kind of bond
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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

40. What is a plasmalogen?
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Lower blood pH
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
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. Where would materials slated for digestion go?
Lysosome
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Alpha 1-4 and 1-6 (branching) glycosidic linkages

42. cAMP - cGMP - calmodulin...
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

43. cytosol pH
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
About 7.2
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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

44. What if large intestine isn't working well
Uncontracted: parasymp (eg opoid use)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

45. FLAT PG: hGH aka somatotropin
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Systems (eg digestive system consists of many organs)
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)
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

46. trypsin is secreted by
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Increases solute conc and osmotic pressure of the ***medulla
Ventrally (picture skeletal vertebrae)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

47. thyroid hormones: Not All One Kind of HORM
Most absorption occurs in sm intestine
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Pancreatic duct (made of acinar cells?)
All carbs absorbed at enterocytes are carried to liver by portal vein

48. pancreatic amylase is much stronger than
Faces the lumen
ER
Normally contracted
Salivary amylase; both hydrolyze glycosidic linkages

49. Glycogenolysis/gluconeogenesis
Steroid; target tissue is distal convoluted tubule of nephron and collecting duct; increases blood mineral concentration; potassium - protons secreted (blood pH increases); sodium - chloride reabsorbed (BP increases)
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
Outermost layer of blood vessel
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

50. Bile salts and lipase
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
RBCs - large proteins; What does enter is called the filtrate
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
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