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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. What is the path of a sound wave that enters the ear?
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
Low because AAs are immediately used in translation
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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

2. 3 phases of menstrual cycle
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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)
Only musc and esp ** liver can store large amounts

3. trypsin is secreted by
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

4. sporic life cycle
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Corpus luteum degrades into corpus albicans
Glucose

5. extracellular matrix formed mainly of...
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Form barrier to extracellular fluid
Water flows from the tubule - concentrating the filtrate - raising BP
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

6. What surrounds the hydrophilic heads of the new TAGs
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
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
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Smooth ER

7. 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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
5
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

8. parathyroid hormones
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Contain capillary network - lymph vessels (lacteals)

9. Where do absorbed fats go in the enterocyte
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Smooth ER
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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

10. Alpha - amylase found where
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
In mouth - breakdown of starch into polysaccharides
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

11. Energy from fat - prot - gluc
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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

12. keep in mind that enterocyte is like a regular euk cell
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Ganglion
Has memb - bound organelles - etc...
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

13. at lo blood sugar...
Pancreatic duct (made of acinar cells?)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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

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

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15. Exocrine GlandS: stomach
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
- 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
Outermost layer of blood vessel

16. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Albumin increases osmolarity of blood; increases osmotic pressure
Chylomicrons are much bigger
Smooth ER
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

17. is intracellular AA conc hi or low?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Low because AAs are immediately used in translation

18. Different organs working together
Systems (eg digestive system consists of many organs)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

19. Adrenal medulla hormones (TYR- DERIVED)
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Glucose
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

20. in fat and liver cells monoglycerides and ffas are once again
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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

21. Failure of apoptosis can result in
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
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

22. After meiosis II - Female

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23. What are phagosomes
- 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
Membrane - bound - endocytosed bodies
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

24. FSH - LH - HCG - inhibin are...
Membrane - bound - endocytosed bodies
Peptides
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

25. What do villli do
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

26. Contrast PNS- Somatic with PNS- Autonomic
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

27. Does bile digest fat?
Corpus luteum degrades into corpus albicans
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

28. light detection via GPCRs
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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

29. almost all exocytosed proteins pass through this
Smooth ER
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
Neurons may perform one of three functions....
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

30. 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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

31. signal transduction occurs only in
Eukaryotes
- 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
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Outermost layer of blood vessel

32. Anterior eye
The renal corpuscle
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
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

33. Meiosis I Metaphase I
Below hypothalamus
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
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.
Smooth ER

34. little by little chyme is squirted out thru pyloric sphincter
Glands w/ducts: Exocrine glands
Regulated by gastrointestinal horms
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Zygotes are diploid

35. when thinking of proteins - think
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Nitrogen
'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.'
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

36. How does birth control work?
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
It targets liver conc of prothrombin - fibrinogen etc
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Fructose is a structural isomer of glucose

37. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
'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.'
Interstitial fluid (eg prostaglandins - cytokines)
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

38. Both divisions (somatic - autonomic) of PNS consist of...
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.
Sensory (afferent - dorsal) - motor (efferent - ventral)
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
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

39. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Conjunction of cell body w/axon
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Thru tight junctions by favorable osmotic gradient

40. Glucose is a .... sugar; fructose is a .... sugar
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
Glucose = aldose fructose = ketose

41. What testosterone released by secondary follicle by LH stim is converted to...
Prod of steroid hormones in testes - ovaries
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
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)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

42. E storage per unit mass
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
'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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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

43. Leydig cells produce
Abdominal cavity - which is coated in serous fluid
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Testosterone upon stim by LH
In mouth - breakdown of starch into polysaccharides

44. pancreatic amylase is much stronger than
All carbs absorbed at enterocytes are carried to liver by portal vein
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Salivary amylase; both hydrolyze glycosidic linkages
Sensory (afferent - dorsal) - motor (efferent - ventral)

45. Some PNS nerves are found in brain - spinal cord
'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
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

46. How do monoglycerides and ffas get to brush border?
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Secondary oocyte (stim'd by LH stimulation of theca cells causing release of testosterone - converted to estradiol; eventually brings about luteal surge -->EQUATIONAL DIVISION-->ovum released during ovulation into fallopian tube; burst follicle becom
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Testosterone and estradiol

47. Sensory neuron cell bodies vs. somatic motor cell bodies
'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
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
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)

48. food in duod stims release of gastrointestinal hormones
Uncontracted: parasymp (eg opoid use)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
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. spermatogonia arise from
Most absorption occurs in sm intestine
Epithelial tissue near semniferous tubules
Within the paravertebral ganglion - running parallel to spinal cord
Form barrier to extracellular fluid

50. Chewing does what?
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Increases surface area of food ball (bolus)
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males