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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 (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
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
AAs can be burned for energy or converted to fat for storage
Testosterone and estradiol
Only musc and esp ** liver can store large amounts

2. FLAT PG: prolactin
Faces the lumen
Normally contracted
Glucose = aldose fructose = ketose
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

3. Path of urine

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4. parathyroid hormones
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Excretes waste products: urea - uric acid - ammonia - phosphate - maintains homeostasis: including body fluid volume (water reabsorption) and solute composition (mineral balance - nutrient reabsorption) - controls *plasma* pH: antiport of Na/K and pr
Increases blood Calcium

5. sensory (afferent)/interneurons/motor (efferent)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Neurons may perform one of three functions....
Within the paravertebral ganglion - running parallel to spinal cord
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

6. Most important nutrients absorbed by large intestine
Regulated by gastrointestinal horms
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**
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

7. For focal point that is nearby - what will the lens look like
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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
Sympathetic: dilates pupil (for night hunting)

8. How does glycogen compare to starch
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Sympathetic: dilates pupil (for night hunting)
Ventrally (picture skeletal vertebrae)

9. How does birth control work?
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
RBCs - large proteins; What does enter is called the filtrate
vitreous humor - retina - fovea

10. bile + fat forms
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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

11. extracellular matrix formed mainly of...
Peripheral nervous sys
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

12. What is a dorsal root ganglion?
Liposome has phospholipid bilayer
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Sorts - modifies - concentrates proteins from the ER
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

13. Sensory neuron cell bodies vs. somatic motor cell bodies
***nicotinic is ionotropic; muscarinic is GPCR
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Fallopian tubes

14. 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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
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
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

15. 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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Glucose
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
RBCs - large proteins; What does enter is called the filtrate

16. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Regulated by gastrointestinal horms
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Lower blood pH
Creates one ovum (23 N) and three polar bodies

17. When 'coumadin targets liver enzymes to act as anticoagulant'...
Lower blood pH
Conjunction of cell body w/axon
***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
It targets liver conc of prothrombin - fibrinogen etc

18. position of AP...
Below hypothalamus
Pancreatic duct (made of acinar cells?)
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

19. FSH - LH - HCG - inhibin are...
An endogenous morphine
Low because AAs are immediately used in translation
Peptides
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

20. bundles of collecting ducts are called
Sorts - modifies - concentrates proteins from the ER
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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

21. Adrenal medulla hormones (TYR- DERIVED)
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

22. fructose enters enterocyte by
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Facilitated diffusion: no symport w/ secondary transport
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

23. alpha - amylase in the mouth digests what kind of bond
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

24. lysosome main function and derivation
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

25. Meiosis II: EQUATIONAL DIVISION
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan
The renal corpuscle

26. small intestine=
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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)
Glucose = aldose fructose = ketose
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

27. what happens to bile secretions
AAs can be burned for energy or converted to fat for storage
RBCs - large proteins; What does enter is called the filtrate
Mostly reabsorbed to liver
***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

28. Which fats are not absorbed like this
Oxytocin and ADH (aka vasopressin)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Liposome has phospholipid bilayer

29. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

30. Where does fertilization occur
RBCs - large proteins; What does enter is called the filtrate
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
Facilitated diffusion from hi to lo conc
Fallopian tubes

31. Meiosis I Telophase I
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

32. The bolus (chewing) is digested to what in the stomach
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Gastrulation occurs: formation of three primary germ layers = differentiation
Chyme (by combined activity of exocrine glands)

33. A contracted iris occurs with what kind of stimulation
Sympathetic: dilates pupil (for night hunting)
Corpus luteum degrades into corpus albicans
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

34. How is the follicle developed during oogenesis
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Glycosaminoglycans - prots - AAs - lipids
Direction of differentiation
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

35. How do monoglycerides and ffas get to brush border?
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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
Micelles; micelles (made of bile) go back and forth between brush border and chyme
AAs can be burned for energy or converted to fat for storage

36. signal transduction occurs only in
Interstitial fluid (eg prostaglandins - cytokines)
Gonadotropin releasing hormone - GnRH
Eukaryotes
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

37. What is the mesentery?
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)
Paracrine (local) - endocrine (longer distance)
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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

38. How does duod deal with hi HCl from stom
Albumin increases osmolarity of blood; increases osmotic pressure
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

39. Where would materials slated for digestion go?
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
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
Lysosome

40. Some epithelial cells are... others...
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
- 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
Glucose

41. What is an endorphin?
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Only musc and esp ** liver can store large amounts
An endogenous morphine
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

42. Creating gradients requires what?
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

43. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Below hypothalamus
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Membrane - bound - endocytosed bodies
Lower blood pH

44. energy source of neurons
Glucose and ketone bodies (not from glycogen stores)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Only musc and esp ** liver can store large amounts
Facilitated diffusion: no symport w/ secondary transport

45. Where else does ADH act
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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
'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

46. from the loop of henle...
Albumin increases osmolarity of blood; increases osmotic pressure
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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

47. thyroid hormones: Not All One Kind of HORM
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

48. main point of fat transport...
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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**
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

49. FLAT PG: ACTH
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

50. Between meals most fats appear in blood as
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Primitive streak - which consists of cells of the MESODERM ****