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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. euk cell has two principal sides
Lumen (ie continuous w/body cavity) and cytosol
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

2. How does the body mobilize fat stores
Below hypothalamus
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
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
***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

3. What is the function of the loop of Henle
Increases solute conc and osmotic pressure of the ***medulla
Within the paravertebral ganglion - running parallel to spinal cord
Below hypothalamus
Needs time for bile - lipase - micelle migration - enterocyte uptake

4. pancreatic enzymes are zymogens
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Within the paravertebral ganglion - running parallel to spinal cord
Facilitated diffusion from hi to lo conc
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

5. Gastrulation: ectoderm/mesoderm/endoderm
'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.'
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

6. Adrenal medulla hormones (TYR- DERIVED)
Organs
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
- 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
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

7. Posterior pituitary hormones (Small Peptides)
'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
Oxytocin and ADH (aka vasopressin)
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)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

8. duodenum must have receptors for fat content - protein because
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum

9. from the loop of henle...
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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

10. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
5
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Within the paravertebral ganglion - running parallel to spinal cord

11. What is the pH at the entrance to the duodenum
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Glycosaminoglycans - prots - AAs - lipids
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum

12. What is endothelium?
Gastrulation occurs: formation of three primary germ layers = differentiation
1) by integral ion channels 2) transmitted by second messenger system
Inner lining of blood vessels
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

13. quote on cavities/viscera

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14. Thus - central nervous sys is...
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
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

15. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
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
Prod of steroid hormones in testes - ovaries

16. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Gastrulation occurs: formation of three primary germ layers = differentiation
Processes: axons - dendrites

17. What is feces composed of...
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

18. calcitonin

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19. components of interstitial fluid
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Glycosaminoglycans - prots - AAs - lipids
Ups bicarbonate secretion by pancreas; raises pH to 6.0
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

20. Kidney
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
Neurons may perform one of three functions....
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu

21. FSH - LH - HCG - inhibin are...
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Peptides
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Smooth ER

22. How is glucose absorbed in sm intest
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
Two perpendicular semicircular canals involved in balance - equilibrium
Chylomicrons are much bigger
Facilitated diffusion: no symport w/ secondary transport

23. What do lipases do
Glands w/ducts: Exocrine glands
Liposome has phospholipid bilayer
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Break down TAGs to monoglycerides and free fatty acids

24. What is somatostatin
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Organs
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

25. Path of urine

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26. therefore - How does plasma leave capillary at the renal corpuscle

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27. Anterior eye
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... ...
Creates one ovum (23 N) and three polar bodies
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)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

28. What is an endorphin?
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Glucose
An endogenous morphine

29. What if large intestine isn't working well
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Facilitated diffusion from hi to lo conc
Facilitated diffusion: no symport w/ secondary transport
Outermost layer of blood vessel

30. What kind of cells make up epithel tiss of stom - then sm intest?
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Chyme (by combined activity of exocrine glands)
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

31. The esophageal sphincter is...
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Normally contracted
Nitrogen
Gastrulation occurs: formation of three primary germ layers = differentiation

32. What is the endothelium?
Meiosis creates germ cells
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Inner lining of circulatory system

33. Where else does ADH act
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

34. when cells hit their limit for prot storage...
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
AAs can be burned for energy or converted to fat for storage
'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
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

35. In effect LH - FSH stimulate
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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
Prod of steroid hormones in testes - ovaries
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

36. On what surface of the retina is the eye most sensitive
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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Fovea (highest amount of cones)
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

37. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Facilitated diffusion from hi to lo conc
Form barrier to extracellular fluid
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

38. Meiosis I Telophase I
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
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
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

39. energy source of neurons
Normally contracted
Glucose and ketone bodies (not from glycogen stores)
Digestion
Glucose = aldose fructose = ketose

40. Sensory - motor neurons are part of which nervous system
Albumin increases osmolarity of blood; increases osmotic pressure
Corpus luteum degrades into corpus albicans
In mouth - breakdown of starch into polysaccharides
Peripheral nervous sys

41. lining of abdominal cavity=
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Interstitial fluid (eg prostaglandins - cytokines)

42. A pinpoint iris is contracted or uncontracted
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Uncontracted: parasymp (eg opoid use)

43. pancreas secretes enzymes via
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Contain capillary network - lymph vessels (lacteals)
Pancreatic duct (made of acinar cells?)

44. FLAT PG: prolactin
Glucose and ketone bodies (not from glycogen stores)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

45. A group of cell bodies in CNS is nucleus - outside CNS is...
Beta cells
Ganglion
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

46. micelles also pick up
Below hypothalamus
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
'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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

47. Where are these exocrine glands located
In gastric pits; secretions combine into gastric juice
Sensory (afferent - dorsal) - motor (efferent - ventral)
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

48. 90% digestion - absorption occurs in...
An endogenous morphine
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
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

49. Where do pancreatic secretions take effect
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Direction of differentiation
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

50. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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
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... ...
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue