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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. How does glycogen compare to starch
Processes: axons - dendrites
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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)
Most absorption occurs in sm intestine

2. Thus inhibiting parietal cells could do What to blood pH
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Organs
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Lower blood pH

3. The esophageal sphincter is...
Prod of steroid hormones in testes - ovaries
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Normally contracted
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

4. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Chylomicrons are much bigger
Gastrulation occurs: formation of three primary germ layers = differentiation
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit

5. Tight junctions
Form barrier to extracellular fluid
It targets liver conc of prothrombin - fibrinogen etc
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

6. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Only musc and esp ** liver can store large amounts
vitreous humor - retina - fovea

7. sensory (afferent)/interneurons/motor (efferent)
Neurons may perform one of three functions....
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

8. How is glucose absorbed in sm intest
Needs time for bile - lipase - micelle migration - enterocyte uptake
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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
Corpus luteum degrades into corpus albicans

9. Kidney physiology...

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10. little by little chyme is squirted out thru pyloric sphincter
Regulated by gastrointestinal horms
Most absorption occurs in sm intestine
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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

11. What are phagosomes
Membrane - bound - endocytosed bodies
Chyme (by combined activity of exocrine glands)
Ventrally (picture skeletal vertebrae)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

12. ADH
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
Moves down thru esophageal sphincter
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

13. How do nutrients move?
Testosterone upon stim by LH
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
90-140 mg/dl

14. What do villli do
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Epithelial tissue near semniferous tubules
Carry signals to musc OR Gland
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

15. smooth ER main function
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

16. SYMP neurons originate in= PARA neurons originate in=
Outermost layer of blood vessel
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
Albumin increases osmolarity of blood; increases osmotic pressure

17. What controls release of LH - FSH from anterior pituitary
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Gonadotropin releasing hormone - GnRH
- 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
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

18. 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
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
Below hypothalamus
Pancreatic duct (made of acinar cells?)
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

19. Polypeptides are formed with what kind of reaction?
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Chyme (by combined activity of exocrine glands)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

20. Some PNS nerves are found in brain - spinal cord
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Inner lining of circulatory system

21. What is secreted into filtrate by cells of the proximal tubule?
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Thru tight junctions by favorable osmotic gradient
Conjunction of cell body w/axon

22. Path of food entering body...
Mostly reabsorbed to liver
Inner lining of circulatory system
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

23. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Facilitated diffusion from hi to lo conc
Direction of differentiation
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

24. Blastocyst
HCl; secreted by parietal cells under stim by gastrin
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
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)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

25. at lo blood sugar...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

26. insulin secreted by
Only musc and esp ** liver can store large amounts
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Beta cells
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

27. peroxisome is derived from this
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
ER
Inner lining of circulatory system
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

28. What is a toxic byproduct of gluconeogenesis from proteins
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Fructose is a structural isomer of glucose

29. bile + fat forms
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Liver is the control center for blood glucose; is fed by portal vein from sm intest
***nicotinic is ionotropic; muscarinic is GPCR
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

30. Adrenal cortex hormones (STEROIDS)
Micelles; micelles (made of bile) go back and forth between brush border and chyme
All carbs absorbed at enterocytes are carried to liver by portal vein
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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)

31. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
HCl; secreted by parietal cells under stim by gastrin
Liposome has phospholipid bilayer
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

32. testosterone can be aromatized to...
***nicotinic is ionotropic; muscarinic is GPCR
Estradiol
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Liposome has phospholipid bilayer

33. amylase acts where on carbs
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
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

34. What is a normal blood glucose range
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
90-140 mg/dl
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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

35. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Facilitated diffusion: no symport w/ secondary transport
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

36. FLAT PG: TSH aka thyrotropin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Increases surface area of food ball (bolus)
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
Gonadotropin releasing hormone - GnRH

37. Ovum development is halted At what stage until fertilization...
Testosterone and estradiol
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

38. thyroid hormones: Not All One Kind of HORM
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

39. Anterior eye vs. posterior eye
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Determined by whether in front of or behind the lens
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

40. Fructose relates how structurally to glucose
It targets liver conc of prothrombin - fibrinogen etc
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Fructose is a structural isomer of glucose
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

41. fructose enters enterocyte by
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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.
Facilitated diffusion: no symport w/ secondary transport
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

42. extracellular matrix formed mainly of...
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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

43. How does birth control work?
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.
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
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

44. what happens to bile secretions
Thru tight junctions by favorable osmotic gradient
Peptides
Mostly reabsorbed to liver
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

45. Embryology
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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
Eukaryotes
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

46. Both divisions (somatic - autonomic) of PNS consist of...
Sensory (afferent - dorsal) - motor (efferent - ventral)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
In gastric pits; secretions combine into gastric juice
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

47. liver and blood glucose...
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Increases surface area of food ball (bolus)

48. How is the follicle developed during oogenesis
1) by integral ion channels 2) transmitted by second messenger system
Form barrier to extracellular fluid
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

49. Where does blood to be filtered by kidney enter the nephron?

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50. Meiosis II: EQUATIONAL DIVISION
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
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 hepatic portal vein is not a true vein - because it does not conduct blood directly to the heart. It is a vessel in the abdominal cavity that drains blood from the gastrointestinal tract and spleen to capillary beds in the liver.'