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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. Bile salts and lipase
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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
Lumen (ie continuous w/body cavity) and cytosol

2. lysosome main function and derivation
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
Paracrine (local) - endocrine (longer distance)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

3. Determination is different than differentiation
Mostly reabsorbed to liver
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

4. PNS nerve signal
Testosterone and estradiol
All carbs absorbed at enterocytes are carried to liver by portal vein
Fallopian tubes
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

5. FLAT PG: prolactin
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Primitive streak - which consists of cells of the MESODERM ****
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

6. What hormones affect the stomach?
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
In gastric pits; secretions combine into gastric juice
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel

7. ADH
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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
Has memb - bound organelles - etc...

8. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

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9. from thoracic duct - chylomicrons stick to capillary walls...
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

10. 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
Salivary amylase; both hydrolyze glycosidic linkages
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

11. 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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12. Alpha - amylase found where
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
In mouth - breakdown of starch into polysaccharides
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

13. 'Cell bodies of somatic motor neurons are located in....'
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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)
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

14. The EYE
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

15. peroxisome is derived from this
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
ER
Paracrine (local) - endocrine (longer distance)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

16. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

17. FLAT PG: ACTH
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
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Lysosome

18. What is feces composed of...
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
'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
Liver is the control center for blood glucose; is fed by portal vein from sm intest
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

19. Stomach has no lacteals
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
Digestion
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
Most absorption occurs in sm intestine

20. axon hillock physiology
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Outermost layer of blood vessel
Fovea (highest amount of cones)
Conjunction of cell body w/axon

21. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Primitive streak - which consists of cells of the MESODERM ****
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

22. Fructose relates how structurally to glucose
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Fructose is a structural isomer of glucose
- 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
1) by integral ion channels 2) transmitted by second messenger system

23. Three stages of the menstrual cycle
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Micelles; micelles (made of bile) go back and forth between brush border and chyme

24. pancreatic enzymes are zymogens
Paracrine (local) - endocrine (longer distance)
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Fructose is a structural isomer of glucose

25. How do nutrients move?
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Apoproteins attach to outside of globules; these move to Golgi and are released into interstitial fluid via exocytosis as chylomicrons --->most go to lacteal system
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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

26. what happens when glycogen stores are saturated and blood sugar remains high?
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

27. sensory (afferent) neurons
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

28. What does portal vein do
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
All carbs absorbed at enterocytes are carried to liver by portal vein
Ups bicarbonate secretion by pancreas; raises pH to 6.0

29. Between meals most fats appear in blood as
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... ...
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Sorts - modifies - concentrates proteins from the ER

30. motor (efferent) neurons --> VENTRAL
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Carry signals to musc OR Gland
'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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

31. food in duod stims release of gastrointestinal hormones
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
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
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

32. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Zygotes are diploid
Pancreatic duct (made of acinar cells?)
Meiosis creates germ cells

33. Where do absorbed fats go in the enterocyte
Facilitated diffusion from hi to lo conc
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

34. serous membranes have a viscera - facing layer and a body wall - facing layer
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Determined by whether in front of or behind the lens
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

35. Induction affects...
Vitamin K - b12 - thiamin - riboflavin
Direction of differentiation
It targets liver conc of prothrombin - fibrinogen etc
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

36. these transport proteins - when concs are high enough...
All carbs absorbed at enterocytes are carried to liver by portal vein
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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

37. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
Uncontracted: parasymp (eg opoid use)
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

38. FLAT PG: LH
Micelles; micelles (made of bile) go back and forth between brush border and chyme
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
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

39. What does peptic refer to in general
Increases surface area of food ball (bolus)
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
ER
Digestion

40. Glucose is a .... sugar; fructose is a .... sugar
Glucose
Glucose = aldose fructose = ketose
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Within the paravertebral ganglion - running parallel to spinal cord

41. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
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)
Paracrine (local) - endocrine (longer distance)
Fallopian tubes
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

42. What controls release of LH - FSH from anterior pituitary
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Gonadotropin releasing hormone - GnRH
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Glucose and ketone bodies (not from glycogen stores)

43. inhibin secreted by
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

44. Thus inhibiting parietal cells could do What to blood pH
Lower blood pH
Increases blood Calcium
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

45. Gastrin from G cells stims parietal cells...
An endogenous morphine
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

46. Path of food entering body...
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Oxytocin and ADH (aka vasopressin)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

47. What is the endothelium?
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
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Inner lining of circulatory system

48. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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

49. testosterone can be aromatized to...
Beta cells
Estradiol
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
RBCs - large proteins; What does enter is called the filtrate

50. What does peroxisome do
Increases blood Calcium
Night vision
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle