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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. in fat and liver cells monoglycerides and ffas are once again
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Form barrier to extracellular fluid
AAs can be burned for energy or converted to fat for storage
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

2. After meiosis I - daughter cells are...

3. Human chorionic gonadotropin...
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Lower blood pH

4. in the dark is rhodopsin active or inactive?
***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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Ganglion

5. When 'coumadin targets liver enzymes to act as anticoagulant'...
It targets liver conc of prothrombin - fibrinogen etc
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Smooth ER
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

6. The esophageal sphincter is...
Vitamin K - b12 - thiamin - riboflavin
Form barrier to extracellular fluid
Normally contracted
Break down TAGs to monoglycerides and free fatty acids

7. What else do parietals do?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Testosterone and estradiol

8. pancreas secretes enzymes via
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Estradiol
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
Pancreatic duct (made of acinar cells?)

9. Posterior eye
vitreous humor - retina - fovea
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Inner lining of blood vessels
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

10. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
'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.'
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Outermost layer of blood vessel
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

11. at lo blood sugar...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Normally contracted
Within the paravertebral ganglion - running parallel to spinal cord
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

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

13. Failure of apoptosis can result in
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Thru tight junctions by favorable osmotic gradient
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
5

14. from thoracic duct - chylomicrons stick to capillary walls...
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.
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

15. What is a nerve? (PNS)
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
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
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

16. What is the net effect of the distal tubule
Glands w/ducts: Exocrine glands
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
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

17. smooth ER main function
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Within the paravertebral ganglion - running parallel to spinal cord

18. axon hillock physiology
Conjunction of cell body w/axon
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

19. oxytocin
5
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Conjunction of cell body w/axon
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

20. important pancreatic enzymes
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

21. 3 phases of menstrual cycle
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Increases surface area of food ball (bolus)
Alpha 1-4 and 1-6 (branching) glycosidic linkages
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)

22. bundles of collecting ducts are called
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Neurons may perform one of three functions....
AAs can be burned for energy or converted to fat for storage
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

23. Path of food entering body...
Estradiol
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Somatic nervous sys - autonomic nervous sys
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

24. What do lipases do
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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
Break down TAGs to monoglycerides and free fatty acids

25. medium for paracrine hormones
Interstitial fluid (eg prostaglandins - cytokines)
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

26. serous membranes have a viscera - facing layer and a body wall - facing layer
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Neurons may perform one of three functions....
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Gastrulation occurs: formation of three primary germ layers = differentiation

27. micelles vs liposomes
Testosterone and estradiol
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Liposome has phospholipid bilayer
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

28. Mucus - digestive enzymes released thru
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
Break down TAGs to monoglycerides and free fatty acids
Glands w/ducts: Exocrine glands
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi

29. remaining secondary follicle becomes
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

30. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Glucose = aldose fructose = ketose
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Prod of steroid hormones in testes - ovaries
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

31. What does peptic refer to in general
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Corpus luteum degrades into corpus albicans
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
Digestion

32. overview of prot digestion
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
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
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

33. Cell bodies of SYMP postganglionic neurons lie far from effector...
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Glucose and ketone bodies (not from glycogen stores)
Within the paravertebral ganglion - running parallel to spinal cord
Abdominal cavity - which is coated in serous fluid

34. How does reabsorption force nutrients across apical membrane of proximal tubule
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

35. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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
Break down TAGs to monoglycerides and free fatty acids
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

36. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
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

37. What is the pH at the entrance to the duodenum
Lower blood pH
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

38. Different organs working together
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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
Systems (eg digestive system consists of many organs)
- 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

39. fructose enters enterocyte by
Sensory (afferent - dorsal) - motor (efferent - ventral)
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)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Facilitated diffusion: no symport w/ secondary transport

40. small intestine=
Carry signals to musc OR Gland
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

41. portal vein physiology...

42. After meiosis II - Male

43. FLAT PG: prolactin
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)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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... ...

44. amylase acts where on carbs
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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

45. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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... ...
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

46. Local vs long - distance mediators
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Paracrine (local) - endocrine (longer distance)

47. Creating gradients requires what?
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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
The wall of the body or of a body cavity or hollow structure
Fovea (highest amount of cones)

48. Chewing does what?
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increases surface area of food ball (bolus)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
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

49. protein absorption at enterocyte
Meiosis creates germ cells
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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

50. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
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
***nicotinic is ionotropic; muscarinic is GPCR
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Testosterone and estradiol