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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. insulin secreted by
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Beta cells
- 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

2. gametes are haploid
Mostly reabsorbed to liver
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
Zygotes are diploid
Contain capillary network - lymph vessels (lacteals)

3. Where else does ADH act
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
Chyme (by combined activity of exocrine glands)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Smooth ER

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

5. Different organs working together
Systems (eg digestive system consists of many organs)
Determined by whether in front of or behind the lens
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
Conjunction of cell body w/axon

6. For focal point that is nearby - what will the lens look like
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Break down TAGs to monoglycerides and free fatty acids
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Which is why lactase - maltase - dextrinase - sucrase are on brush border

7. What is the adventitia?
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Form barrier to extracellular fluid
Outermost layer of blood vessel
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

8. How is the follicle developed during oogenesis
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
Neurons may perform one of three functions....
Albumin increases osmolarity of blood; increases osmotic pressure
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

9. cytosol pH
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
About 7.2
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
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

10. When 'coumadin targets liver enzymes to act as anticoagulant'...
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Inner lining of blood vessels
It targets liver conc of prothrombin - fibrinogen etc
Systems (eg digestive system consists of many organs)

11. Contrast PNS- Somatic with PNS- Autonomic
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
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Most absorption occurs in sm intestine

12. Peritoneal refers to...
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Glucose
Abdominal cavity - which is coated in serous fluid
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

13. How long are peptides when absorbed at brush border
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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Night vision
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

14. A pinpoint iris is contracted or uncontracted
The renal corpuscle
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
Epithelial tissue near semniferous tubules
Uncontracted: parasymp (eg opoid use)

15. Embryology
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

16. Meiosis I Metaphase I
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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Testosterone upon stim by LH
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

17. What is feces composed of...
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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

18. Alpha - amylase found where
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
- 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
In mouth - breakdown of starch into polysaccharides
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

19. 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.

20. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Gastrulation occurs: formation of three primary germ layers = differentiation
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

21. testosterone can be aromatized to...
Most absorption occurs in sm intestine
Facilitated diffusion from hi to lo conc
Estradiol
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

22. keep in mind that enterocyte is like a regular euk cell
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Has memb - bound organelles - etc...
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

23. E storage per unit mass
Chyme (by combined activity of exocrine glands)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

24. sensory (afferent)/interneurons/motor (efferent)
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Neurons may perform one of three functions....
Transfer signals from neuron - neuron; 90% of neurons are interneurons

25. sensory (afferent) neurons
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Interstitial fluid (eg prostaglandins - cytokines)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

26. What is the mesentery?
***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
1) by integral ion channels 2) transmitted by second messenger system
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

27. Morula (...totipotent)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Ganglion
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

28. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
Faces the lumen
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

29. Thus - central nervous sys is...
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
All carbs absorbed at enterocytes are carried to liver by portal vein
HCl; secreted by parietal cells under stim by gastrin
It targets liver conc of prothrombin - fibrinogen etc

30. when thinking of proteins - think
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Digestion
Nitrogen

31. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
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
Digestion

32. STOMACH: no absorption
Sympathetic: dilates pupil (for night hunting)
5
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

33. Failure of apoptosis can result in
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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)
Sensory (afferent - dorsal) - motor (efferent - ventral)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

34. In general - parietal=
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
The wall of the body or of a body cavity or hollow structure
Albumin increases osmolarity of blood; increases osmotic pressure

35. What is a normal blood glucose range
Chyme (by combined activity of exocrine glands)
90-140 mg/dl
1) by integral ion channels 2) transmitted by second messenger system
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

36. What does portal vein do
All carbs absorbed at enterocytes are carried to liver by portal vein
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Albumin increases osmolarity of blood; increases osmotic pressure

37. What is somatostatin
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

38. From that point...
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.
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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

39. inhibin secreted by
Glands w/ducts: Exocrine glands
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

40. What is the endothelium?
Gonadotropin releasing hormone - GnRH
Inner lining of circulatory system
In gastric pits; secretions combine into gastric juice
Collection of cell bodies; cell processes project out from both ends of ganglion; synapses with interneuron in spinal cord on one end and sensory receptor on other

41. Creating gradients requires what?
Lots of energy; eg neurons have hi glucose need for 3Na out 2K in ATPase; stomach epithel tiss needs E for parietal cells to pump protons into lumen and bicarbonate into blood
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Vitamin K - b12 - thiamin - riboflavin
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

42. Where does the bolus go after mouth chews food
The renal corpuscle
Moves down thru esophageal sphincter
Membrane - bound - endocytosed bodies
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

43. what happens to bile secretions
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
- 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
Mostly reabsorbed to liver
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

44. Induction affects...
Direction of differentiation
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Lumen (ie continuous w/body cavity) and cytosol

45. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

46. In IBS - What is defective

47. position of AP...
Contain capillary network - lymph vessels (lacteals)
Water flows from the tubule - concentrating the filtrate - raising BP
Below hypothalamus
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

48. PNS review: SAME DAVE
Processes: axons - dendrites
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
ER

49. in the dark is rhodopsin active or inactive?
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Creates one ovum (23 N) and three polar bodies
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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

50. fat digestion is time - intensive
Contain capillary network - lymph vessels (lacteals)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Glands w/ducts: Exocrine glands
Needs time for bile - lipase - micelle migration - enterocyte uptake