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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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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. axon hillock physiology
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Conjunction of cell body w/axon

2. Meiosis I Anaphase I
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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
Peptides
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**

3. What is a toxic byproduct of gluconeogenesis from proteins
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Ammonia; must be converted to urea by liver and excreted in urine by kidney
In mouth - breakdown of starch into polysaccharides
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

4. What is a normal blood glucose range
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Ammonia; must be converted to urea by liver and excreted in urine by kidney
90-140 mg/dl
Chyme (by combined activity of exocrine glands)

5. Some epithelial cells are... others...
Moves down thru esophageal sphincter
- 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
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
Increases surface area of food ball (bolus)

6. What is a dorsal root ganglion?
Determined by whether in front of or behind the lens
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Fallopian tubes

7. Gastrin from G cells stims parietal cells...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Fallopian tubes
Prod of steroid hormones in testes - ovaries
Has memb - bound organelles - etc...

8. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Glucose = aldose fructose = ketose
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste

9. What testosterone released by secondary follicle by LH stim is converted to...
- 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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest

10. What is endothelium?
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Inner lining of blood vessels

11. almost all cells can store Some glycogen - but...
Somatic nervous sys - autonomic nervous sys
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Paracrine (local) - endocrine (longer distance)
Only musc and esp ** liver can store large amounts

12. What surrounds the hydrophilic heads of the new TAGs
Testosterone and estradiol
Fructose is a structural isomer of glucose
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
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

13. 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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Below hypothalamus

14. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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

15. sporic life cycle
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
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

16. sensory (afferent) neurons
Inner lining of blood vessels
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Low because AAs are immediately used in translation

17. in the dark is rhodopsin active or inactive?
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

18. During ejaculation - sperm...

19. What does peptic refer to in general
Digestion
Creates one ovum (23 N) and three polar bodies
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
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)

20. Three stages of the menstrual cycle
Primitive streak - which consists of cells of the MESODERM ****
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

21. Gastrulation: ectoderm/mesoderm/endoderm
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

22. energy source of neurons
Carry signals to musc OR Gland
Glucose and ketone bodies (not from glycogen stores)
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

23. The EYE
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
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
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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

24. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
In mouth - breakdown of starch into polysaccharides
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
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

25. E storage per unit mass
Pancreatic duct (made of acinar cells?)
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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
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

26. After meiosis II - Female

27. remaining secondary follicle becomes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
HCl; secreted by parietal cells under stim by gastrin
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
'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

28. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
'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
Creates one ovum (23 N) and three polar bodies
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
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

29. inhibin secreted by
Break down TAGs to monoglycerides and free fatty acids
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Testosterone upon stim by LH
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

30. 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
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
'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.'
90-140 mg/dl

31. examples of different cavities... (compartments for viscera)
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Digestion
- 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

32. Aldosterone (sodium uptake - potassium secretion)
Determined by whether in front of or behind the lens
Fallopian tubes
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
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)

33. mitosis creates somatic cells
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Meiosis creates germ cells
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)
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**

34. in mammals - gastrulation involves formation of the
Only musc and esp ** liver can store large amounts
Primitive streak - which consists of cells of the MESODERM ****
Break down TAGs to monoglycerides and free fatty acids
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

35. Liver Functions
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Stores blood: when expanded liver serves as blood reservoir for body - filters blood: Kupfer cells phagocytize bacteria picked up from intestines - destroys bad RBCs: also done by Kupfer cells - detoxifies blood: detoxified chemicals are excreted eit
Which is why lactase - maltase - dextrinase - sucrase are on brush border
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

36. what cannot cross the fenestrations of the renal corpuscle
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Eukaryotes
RBCs - large proteins; What does enter is called the filtrate
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

37. Mucus - digestive enzymes released thru
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Glands w/ducts: Exocrine glands
Direction of differentiation

38. Alpha - amylase found where
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
In mouth - breakdown of starch into polysaccharides
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
Lumen (ie continuous w/body cavity) and cytosol

39. Determination is different than differentiation
In gastric pits; secretions combine into gastric juice
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Regulated by gastrointestinal horms

40. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Sorts - modifies - concentrates proteins from the ER

41. Where else does ADH act
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

42. large intestine E. coli aid absorption of...
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Vitamin K - b12 - thiamin - riboflavin
Carry signals to musc OR Gland

43. Thus inhibiting parietal cells could do What to blood pH
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
Prod of steroid hormones in testes - ovaries
Lower blood pH
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

44. euk cell has two principal sides
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
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)
Lumen (ie continuous w/body cavity) and cytosol

45. Where are these exocrine glands located
In gastric pits; secretions combine into gastric juice
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Paracrine (local) - endocrine (longer distance)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

46. Anatomy of the villi
Only musc and esp ** liver can store large amounts
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Contain capillary network - lymph vessels (lacteals)
90-140 mg/dl

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

48. Both divisions (somatic - autonomic) of PNS consist of...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Direction of differentiation
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

49. FLAT PG: TSH aka thyrotropin
Moves down thru esophageal sphincter
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
- filtration occurs at the fenestrations of the renal corpuscle - most reabsorption and secretion occur in the proximal tubule - medulla is concentrated in the loop of henle - sodium and calcium are reabsorbed in the distal tubule -->collecting tubul
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

50. On what surface of the retina is the eye most sensitive
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
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Fovea (highest amount of cones)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)