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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.
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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. Contrast PNS- Somatic with PNS- Autonomic
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Sorts - modifies - concentrates proteins from the ER
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

2. ligands are the messenger compounds that target secondary messenger systems on effectors
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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Many modern drugs are ligands for GPCRs
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

3. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

4. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Testosterone and estradiol
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Beta cells
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

5. What determines number of chromosomes?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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
Night vision

6. overview of prot digestion
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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

7. Failure of apoptosis can result in
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Lumen (ie continuous w/body cavity) and cytosol
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

8. Both divisions (somatic - autonomic) of PNS consist of...
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Sensory (afferent - dorsal) - motor (efferent - ventral)
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

9. What do the glomerulus and Bowman's capsule add up to...
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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
The renal corpuscle

10. The path from blood plasma to urine

11. liver and blood glucose...
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Liver is the control center for blood glucose; is fed by portal vein from sm intest

12. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
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
Many modern drugs are ligands for GPCRs
Interstitial fluid (eg prostaglandins - cytokines)

13. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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
Lysosome
Fovea (highest amount of cones)

14. at lo blood sugar...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Thru tight junctions by favorable osmotic gradient
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Two perpendicular semicircular canals involved in balance - equilibrium

15. serous membranes have a viscera - facing layer and a body wall - facing layer
Low because AAs are immediately used in translation
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

16. What is the function of the loop of Henle
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Increases solute conc and osmotic pressure of the ***medulla
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
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

17. oxytocin
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Paracrine (local) - endocrine (longer distance)
Digestion
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

18. How does glycogen compare to starch
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Gonadotropin releasing hormone - GnRH
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

19. portal vein physiology...

20. Difference between euk and prok flagella
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... ...
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Membrane - bound - endocytosed bodies

21. cytosol pH
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
About 7.2
Creates one ovum (23 N) and three polar bodies

22. smooth ER main function
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Ammonia; must be converted to urea by liver and excreted in urine by kidney

23. these transport proteins - when concs are high enough...
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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
Lysosome

24. What is somatostatin
Form barrier to extracellular fluid
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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

25. position of AP...
Vitamin K - b12 - thiamin - riboflavin
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Below hypothalamus

26. pancreas secretes enzymes via
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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
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
Pancreatic duct (made of acinar cells?)

27. protein absorption at enterocyte
Chyme (by combined activity of exocrine glands)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
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

28. After meiosis II - Male

29. What is gastric acid?
Testosterone upon stim by LH
HCl; secreted by parietal cells under stim by gastrin
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Chyme (by combined activity of exocrine glands)

30. Meiosis I Metaphase I
***nicotinic is ionotropic; muscarinic is GPCR
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

31. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Needs time for bile - lipase - micelle migration - enterocyte uptake
Testosterone and estradiol
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Prod of steroid hormones in testes - ovaries

32. What is the net effect of the loop of Henle
Contain capillary network - lymph vessels (lacteals)
- 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
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)
Ammonia; must be converted to urea by liver and excreted in urine by kidney

33. physiology of gall bladder - liver and pancreatic secretions
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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 main difference is signal transmission in nicotinic vs muscarinic?
In gastric pits; secretions combine into gastric juice
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Normally contracted
***nicotinic is ionotropic; muscarinic is GPCR

35. Beta - oxidation in liver produces...
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Break down TAGs to monoglycerides and free fatty acids
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

36. lysosome pH
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
5
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Normally contracted

37. Meiosis II: EQUATIONAL DIVISION
Night vision
Inner lining of blood vessels
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
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... ...

38. golgi body
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Ganglion
Sorts - modifies - concentrates proteins from the ER
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

39. signal transduction occurs by 2 paths
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
1) by integral ion channels 2) transmitted by second messenger system
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
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

40. 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
Beta cells
Needs time for bile - lipase - micelle migration - enterocyte uptake
Salivary amylase; both hydrolyze glycosidic linkages
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

41. large intestine E. coli aid absorption of...
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
- 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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Vitamin K - b12 - thiamin - riboflavin

42. Gastrulation: ectoderm/mesoderm/endoderm
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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
Epithelial tissue near semniferous tubules
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

43. STOMACH: no absorption
ER
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Prod of steroid hormones in testes - ovaries
Chylomicrons are much bigger

44. What is the mesentery?
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
AAs can be burned for energy or converted to fat for storage
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

45. What is a normal blood glucose range
Transfer signals from neuron - neuron; 90% of neurons are interneurons
90-140 mg/dl
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
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

46. Polypeptides are formed with what kind of reaction?
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

47. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

48. thyroid hormones: Not All One Kind of HORM
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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)
Break down TAGs to monoglycerides and free fatty acids
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

49. Where are these exocrine glands located
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
In gastric pits; secretions combine into gastric juice

50. Most important nutrients absorbed by large intestine
In gastric pits; secretions combine into gastric juice
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Testosterone and estradiol
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach