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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. Path of food entering body...
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
AAs can be burned for energy or converted to fat for storage

2. FLAT PG: TSH aka thyrotropin
Faces the lumen
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
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi
Estradiol

3. The bolus (chewing) is digested to what in the stomach
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Lysosome
Chyme (by combined activity of exocrine glands)

4. examples of different cavities... (compartments for viscera)
Moves down thru esophageal sphincter
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

5. PNS nerve signal
Glycosaminoglycans - prots - AAs - lipids
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
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
1) by integral ion channels 2) transmitted by second messenger system

6. When 'coumadin targets liver enzymes to act as anticoagulant'...
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
It targets liver conc of prothrombin - fibrinogen etc
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

7. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Low because AAs are immediately used in translation
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
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

8. Where else does ADH act
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Mostly reabsorbed to liver
Needs time for bile - lipase - micelle migration - enterocyte uptake
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

9. overall - fatty - prot - rich food in duod causes
Nitrogen
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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Fallopian tubes

10. How do parietal cells work ** (involves CO2)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Interstitial fluid (eg prostaglandins - cytokines)
Chyme (by combined activity of exocrine glands)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

11. Posterior pituitary hormones (Small Peptides)
Oxytocin and ADH (aka vasopressin)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
RBCs - large proteins; What does enter is called the filtrate
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

12. Four tissues
Prod of steroid hormones in testes - ovaries
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Fructose is a structural isomer of glucose
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

13. spermatogonia arise from
Somatic nervous sys - autonomic nervous sys
Needs time for bile - lipase - micelle migration - enterocyte uptake
Epithelial tissue near semniferous tubules
Alpha 1-4 and 1-6 (branching) glycosidic linkages

14. What is gastric acid?
Cancer; apop can be programmed cell death; mitochon can play important role in apop
HCl; secreted by parietal cells under stim by gastrin
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Sorts - modifies - concentrates proteins from the ER

15. lysosome main function and derivation
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
90-140 mg/dl
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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

16. What is the net effect of the loop of Henle
Faces the lumen
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
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)
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

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

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18. What is secreted into filtrate by cells of the proximal tubule?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Increases blood Calcium
Fovea (highest amount of cones)

19. What are the memb - bound enzymes of the brush border?
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

20. almost all exocytosed proteins pass through this
Interstitial fluid (eg prostaglandins - cytokines)
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
Smooth ER
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

21. Blastocyst
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
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Glycosaminoglycans - prots - AAs - lipids

22. trypsin is secreted by
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Smooth ER
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
Liposome has phospholipid bilayer

23. gametic life cycle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
AAs can be burned for energy or converted to fat for storage
Sympathetic: dilates pupil (for night hunting)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

24. duodenum must have receptors for fat content - protein because
Corpus luteum degrades into corpus albicans
Glands w/ducts: Exocrine glands
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
- 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

25. What is the pH at the entrance to the duodenum
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Fovea (highest amount of cones)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

26. SYMP neurons originate in= PARA neurons originate in=
Eukaryotes
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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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

27. What is endothelium?
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
In gastric pits; secretions combine into gastric juice
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Inner lining of blood vessels

28. Chewing does what?
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
Increases surface area of food ball (bolus)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Needs time for bile - lipase - micelle migration - enterocyte uptake

29. The apical side of the villi...
Faces the lumen
Fructose is a structural isomer of glucose
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

30. serous membranes have a viscera - facing layer and a body wall - facing layer
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
- 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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

31. Leydig cells produce
Testosterone upon stim by LH
Increases blood Calcium
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
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

32. In other words...
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Facilitated diffusion from hi to lo conc
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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

33. FLAT PG: prolactin
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Ganglion
Water flows from the tubule - concentrating the filtrate - raising BP

34. sensory (afferent)/interneurons/motor (efferent)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Sorts - modifies - concentrates proteins from the ER
Neurons may perform one of three functions....
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

35. Induction affects...
The renal corpuscle
Direction of differentiation
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

36. Meiosis I Anaphase I
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

37. sensory (afferent) neurons
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Carry signals to musc OR Gland

38. 90% digestion - absorption occurs in...
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Fallopian tubes
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
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

39. pancreatic enzymes are zymogens
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Corpus luteum degrades into corpus albicans
'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.'
***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

40. What determines number of chromosomes?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Gastrulation occurs: formation of three primary germ layers = differentiation
Below hypothalamus
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

41. Cell determination begins At what stage of development
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Has memb - bound organelles - etc...
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

42. Morula (...totipotent)
Primitive streak - which consists of cells of the MESODERM ****
Stims release of tyrosine - derived horms T3/T4 (increase basal metabolic rate); TSH increases thyroid cell size - number - rate of T3/T4 synth -----> thus - iodine deficiency causes swollen thyroid due to lack of neg feedback onto TSH in anterior pi
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

43. 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
Has memb - bound organelles - etc...
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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)

44. What force is acting upon chyme to move it forward down sm intestine
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
Thru tight junctions by favorable osmotic gradient
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

45. After meiosis II...
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Ventrally (picture skeletal vertebrae)

46. Spinal cord horns (thick knobs) point
Ventrally (picture skeletal vertebrae)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Lower blood pH
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

47. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

48. sporic life cycle
Somatic nervous sys - autonomic nervous sys
Moves down thru esophageal sphincter
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

49. Gland: ovaries
Smooth ER
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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
Increases blood Calcium

50. What hormones affect the stomach?
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Glycosaminoglycans - prots - AAs - lipids
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
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