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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. in the presence of ADH what happens to movement of water across nephron membr
Water flows from the tubule - concentrating the filtrate - raising BP
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

2. Sensory neuron cell bodies vs. somatic motor cell bodies
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Inner lining of circulatory system
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

3. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
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)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

4. Cell bodies of SYMP postganglionic neurons lie far from effector...
Chyme (by combined activity of exocrine glands)
Within the paravertebral ganglion - running parallel to spinal cord
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

5. Where would materials slated for digestion go?
Liposome has phospholipid bilayer
Direction of differentiation
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
Lysosome

6. liver and blood glucose...
Thru tight junctions by favorable osmotic gradient
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Fallopian tubes
Liver is the control center for blood glucose; is fed by portal vein from sm intest

7. Embryology
Low because AAs are immediately used in translation
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
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
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

8. What is secreted into filtrate by cells of the proximal tubule?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Water flows from the tubule - concentrating the filtrate - raising BP

9. How does the body mobilize fat stores
Contain capillary network - lymph vessels (lacteals)
Reconstituted into TAGs at smooth ER; first stop for most digested fat is 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
Peripheral nervous sys

10. What is the adventitia?
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
Outermost layer of blood vessel
Has memb - bound organelles - etc...
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.

11. Tight junctions
Moves down thru esophageal sphincter
Within the paravertebral ganglion - running parallel to spinal cord
Form barrier to extracellular fluid
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

12. In other words...
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
Zygotes are diploid
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

13. what else is located in the inner ear (not directly related to auditory)
Interstitial fluid (eg prostaglandins - cytokines)
Sympathetic: dilates pupil (for night hunting)
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Two perpendicular semicircular canals involved in balance - equilibrium

14. Some PNS nerves are found in brain - spinal cord
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
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
vitreous humor - retina - fovea
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

15. Determination is different than differentiation
Normally contracted
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Digestion
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)

16. Alpha - amylase found where
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
In mouth - breakdown of starch into polysaccharides
Increases solute conc and osmotic pressure of the ***medulla

17. Fructose relates how structurally to glucose
Nitrogen
Fructose is a structural isomer of glucose
Processes: axons - dendrites
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

18. What is the net effect of the loop of Henle
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)
The renal corpuscle
Uncontracted: parasymp (eg opoid use)
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

19. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Organs
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... ...
Sorts - modifies - concentrates proteins from the ER
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

20. what happens to bile secretions
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Mostly reabsorbed to liver
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

21. Spinal cord horns (thick knobs) point
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)
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Ventrally (picture skeletal vertebrae)
Paracrine (local) - endocrine (longer distance)

22. cAMP - cGMP - calmodulin...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Glucose and ketone bodies (not from glycogen stores)

23. 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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24. lining of abdominal cavity=
90-140 mg/dl
Systems (eg digestive system consists of many organs)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

25. Blastocyst
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

26. 3 phases of menstrual cycle
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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)
90-140 mg/dl
Membrane - bound - endocytosed bodies

27. 'Cell bodies of somatic motor neurons are located in....'
***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
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
Inner lining of circulatory system

28. Adrenal medulla hormones (TYR- DERIVED)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Gonadotropin releasing hormone - GnRH
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

29. liver receives blood from...
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
Testosterone and estradiol
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
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

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

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31. these transport proteins - when concs are high enough...
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Direction of differentiation
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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

32. What is the mesentery?
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Facilitated diffusion: no symport w/ secondary transport
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility

33. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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
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
Ventrally (picture skeletal vertebrae)

34. Creating gradients requires what?
Fructose is a structural isomer of 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
Micelles; micelles (made of bile) go back and forth between brush border and chyme
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

35. examples of different cavities... (compartments for viscera)
Creates one ovum (23 N) and three polar bodies
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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

36. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Gastrulation occurs: formation of three primary germ layers = differentiation
Meiosis creates germ cells
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

37. ligands are the messenger compounds that target secondary messenger systems on effectors
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Salivary amylase; both hydrolyze glycosidic linkages
Many modern drugs are ligands for GPCRs
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

38. parathyroid hormones
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

39. What are the memb - bound enzymes of the brush border?
Salivary amylase; both hydrolyze glycosidic linkages
Lysosome
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

40. What is gastric acid?
Membrane - bound - endocytosed bodies
HCl; secreted by parietal cells under stim by gastrin
Mostly reabsorbed to liver
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)

41. Gland: ovaries
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Needs time for bile - lipase - micelle migration - enterocyte uptake
Homologous chromosomes separate - migrate towards opposite poles/centrioles

42. What is main difference is signal transmission in nicotinic vs muscarinic?
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
***nicotinic is ionotropic; muscarinic is GPCR
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
Zygotes are diploid

43. In general - parietal=
Only musc and esp ** liver can store large amounts
The wall of the body or of a body cavity or hollow structure
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
Creates one ovum (23 N) and three polar bodies

44. insulin secreted by
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
Conjunction of cell body w/axon
Beta cells
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

45. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

46. PNS nerve signal
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
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
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
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. Adrenal cortex hormones (STEROIDS)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

48. micelles vs liposomes
Digestion
Liposome has phospholipid bilayer
Lower blood pH
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

49. remaining secondary follicle becomes
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Sympathetic: dilates pupil (for night hunting)
The renal corpuscle
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

50. Posterior eye
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)
RBCs - large proteins; What does enter is called the filtrate
Alpha 1-4 and 1-6 (branching) glycosidic linkages
vitreous humor - retina - fovea