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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. Four tissues
Lower blood pH
Glucose and ketone bodies (not from glycogen stores)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

2. 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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

3. What controls release of LH - FSH from anterior pituitary
Gonadotropin releasing hormone - GnRH
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Which is why lactase - maltase - dextrinase - sucrase are on brush border
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

4. Sensory - motor neurons are part of which nervous system
Glucose = aldose fructose = ketose
Peptides
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
Peripheral nervous sys

5. Where does the bolus go after mouth chews food
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Increases solute conc and osmotic pressure of the ***medulla
Moves down thru esophageal sphincter
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

6. What does portal vein do
Abdominal cavity - which is coated in serous fluid
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
All carbs absorbed at enterocytes are carried to liver by portal vein
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

7. Gastrin from G cells stims parietal cells...
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
1) by integral ion channels 2) transmitted by second messenger system

8. Meiosis I Telophase I
Paracrine (local) - endocrine (longer distance)
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
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

9. almost all cells can store Some glycogen - but...
Interstitial fluid (eg prostaglandins - cytokines)
Only musc and esp ** liver can store large amounts
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Increases solute conc and osmotic pressure of the ***medulla

10. Kidney
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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
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
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

11. In general - parietal=
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Lower blood pH
The wall of the body or of a body cavity or hollow structure
Micelles; micelles (made of bile) go back and forth between brush border and chyme

12. What is the pH at the entrance to the duodenum
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Break down TAGs to monoglycerides and free fatty acids
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

13. What happens when rod cell is depolarized
Uncontracted: parasymp (eg opoid use)
Night vision
Determined by whether in front of or behind the lens
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

14. cAMP - cGMP - calmodulin...
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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
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
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)

15. interneurons
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Albumin increases osmolarity of blood; increases osmotic pressure

16. little by little chyme is squirted out thru pyloric sphincter
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
Regulated by gastrointestinal horms
'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.'
Thru tight junctions by favorable osmotic gradient

17. How long are peptides when absorbed at brush border
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
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

18. What do villli do
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Gonadotropin releasing hormone - GnRH
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages

19. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Gastrulation occurs: formation of three primary germ layers = differentiation
In mouth - breakdown of starch into polysaccharides
Oxytocin and ADH (aka vasopressin)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

20. Ovum development is halted At what stage until fertilization...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Processes: axons - dendrites
Carry signals to musc OR Gland
Liposome has phospholipid bilayer

21. lining of abdominal cavity=
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Fructose is a structural isomer of glucose
Digestion
Sorts - modifies - concentrates proteins from the ER

22. protein absorption at enterocyte
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
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
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Faces the lumen

23. What is the endothelium?
Organs
Chyme (by combined activity of exocrine glands)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Inner lining of circulatory system

24. from the loop of henle...
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Processes: axons - dendrites
Below hypothalamus
Homologous chromosomes separate - migrate towards opposite poles/centrioles

25. bile + fat forms
Smooth ER
Conjunction of cell body w/axon
Increases blood Calcium
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

26. Chewing does what?
Comes into play in the large intestine - where vitamin b12 is absorbed w/help of E. coli; thus; must travel thru bloodstream to large intestine
Increases surface area of food ball (bolus)
Salivary amylase; both hydrolyze glycosidic linkages
Outermost layer of blood vessel

27. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Creates one ovum (23 N) and three polar bodies
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

28. What does lipase attack exactly
Needs time for bile - lipase - micelle migration - enterocyte uptake
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Ventrally (picture skeletal vertebrae)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

29. What is main difference is signal transmission in nicotinic vs muscarinic?
***nicotinic is ionotropic; muscarinic is GPCR
Smooth ER
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

30. What is the path of a sound wave that enters the ear?
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Lower blood pH
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

31. spermatogonia arise from
***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
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Epithelial tissue near semniferous tubules
Nitrogen

32. Posterior pituitary hormones (Small Peptides)
Oxytocin and ADH (aka vasopressin)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Prod of steroid hormones in testes - ovaries

33. During ejaculation - sperm...

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34. What are phagosomes
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Neurons may perform one of three functions....
Membrane - bound - endocytosed bodies

35. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Increases surface area of food ball (bolus)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

36. Different tissues working together
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Organs
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

37. exocrine types
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Ventrally (picture skeletal vertebrae)
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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

38. Where does fertilization occur
Paracrine (local) - endocrine (longer distance)
Fallopian tubes
Corpus luteum degrades into corpus albicans
Micelles; micelles (made of bile) go back and forth between brush border and chyme

39. what cannot cross the fenestrations of the renal corpuscle
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
Estradiol
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
RBCs - large proteins; What does enter is called the filtrate

40. What are the major carbohydrates
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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
ER
Fructose is a structural isomer of glucose

41. Posterior eye
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
vitreous humor - retina - fovea

42. position of AP...
Below hypothalamus
An endogenous morphine
Interstitial fluid (eg prostaglandins - cytokines)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

43. 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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44. How is glucose absorbed in sm intest
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Testosterone upon stim by LH

45. What is a normal blood glucose range
90-140 mg/dl
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Within the paravertebral ganglion - running parallel to spinal cord
Regulated by gastrointestinal horms

46. What is a toxic byproduct of gluconeogenesis from proteins
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi
***nicotinic is ionotropic; muscarinic is GPCR
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Ammonia; must be converted to urea by liver and excreted in urine by kidney

47. chylomicron concentration in blood after meal
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
In mouth - breakdown of starch into polysaccharides

48. Seen in lysosomal storage diseases
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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... ...
Testosterone and estradiol

49. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Corpus luteum degrades into corpus albicans
Beta cells
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Mostly reabsorbed to liver

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

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