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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. How long are peptides when absorbed at brush border
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
Meiosis creates germ cells

2. PNS is broken down into
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Glands w/ducts: Exocrine glands
Somatic nervous sys - autonomic nervous sys

3. trypsin is secreted by
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Testosterone upon stim by LH
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Within the paravertebral ganglion - running parallel to spinal cord

4. from thoracic duct - chylomicrons stick to capillary walls...
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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
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
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

5. gradual increase in FSH typical of primary follicle development;
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Chyme (by combined activity of exocrine glands)
Needs time for bile - lipase - micelle migration - enterocyte uptake

6. What is the endothelium?
Inner lining of circulatory system
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Interstitial fluid (eg prostaglandins - cytokines)

7. Human chorionic gonadotropin...
Vitamin K - b12 - thiamin - riboflavin
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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

8. Failure of apoptosis can result in
Membrane - bound - endocytosed bodies
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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

9. insulin secreted by
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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
Beta cells
Fovea (highest amount of cones)

10. testosterone can be aromatized to...
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
Glucose and ketone bodies (not from glycogen stores)
Estradiol
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

11. Morula (...totipotent)
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
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

12. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Glucose and ketone bodies (not from glycogen stores)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

13. How is glucose absorbed in sm intest
via symport - secondary transport (ie by pre - established - ATP- intensive) with Na gradient into enterocyte......with no Na gradient (ie without ATP) carbohydrate monomers could not be transported in
Testosterone upon stim by LH
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Uncontracted: parasymp (eg opoid use)

14. Liver Functions
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
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
Testosterone upon stim by LH

15. components of interstitial fluid
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
The renal corpuscle
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
Glycosaminoglycans - prots - AAs - lipids

16. ADH
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Two perpendicular semicircular canals involved in balance - equilibrium
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
Lower blood pH

17. energy source of neurons
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
RBCs - large proteins; What does enter is called the filtrate
Glucose = aldose fructose = ketose
Glucose and ketone bodies (not from glycogen stores)

18. STOMACH: no absorption
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

19. Adrenal cortex hormones (STEROIDS)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Lysosome
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

20. Where do pancreatic secretions take effect
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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
AAs can be burned for energy or converted to fat for storage

21. in mammals - gastrulation involves formation of the
Primitive streak - which consists of cells of the MESODERM ****
Processes: axons - dendrites
5
Epithelial tissue near semniferous tubules

22. motor (efferent) neurons --> VENTRAL
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
The renal corpuscle
Carry signals to musc OR Gland

23. Where does fertilization occur
Fallopian tubes
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

24. A pinpoint iris is contracted or uncontracted
Uncontracted: parasymp (eg opoid use)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Nitrogen

25. 80% of end product of carbohydrate metabolism is...
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Abdominal cavity - which is coated in serous fluid
- 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
Glucose

26. Difference between euk and prok flagella
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

27. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

28. Some epithelial cells are... others...
Fallopian tubes
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot
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
- 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

29. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
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
Below hypothalamus
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Ganglion

30. Where does the bolus go after mouth chews food
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Moves down thru esophageal sphincter

31. What is feces composed of...
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)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot
Eukaryotes

32. thyroid hormones: Not All One Kind of HORM
Normally contracted
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Glucose = aldose fructose = ketose

33. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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**
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

34. What is the path of a sound wave that enters the ear?
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
- 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
Mostly reabsorbed to liver
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

35. euk cell has two principal sides
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
RBCs - large proteins; What does enter is called the filtrate
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Lumen (ie continuous w/body cavity) and cytosol

36. How does glycogen compare to starch
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
ER
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
- 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

37. overview of prot digestion
Contain rough ER and Golgi to make mucous; mucous is full of **glycoprots (sticky) and electrolytes*; protects epithelial tiss of stomach from low pH and lubricates stomach
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
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
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

38. What does portal vein do
All carbs absorbed at enterocytes are carried to liver by portal vein
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

39. Path of urine

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40. Spinal cord horns (thick knobs) point
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Chylomicrons are much bigger
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
Ventrally (picture skeletal vertebrae)

41. Meiosis I Anaphase I
Outermost layer of blood vessel
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Homologous chromosomes separate - migrate towards opposite poles/centrioles

42. What is endothelium?
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Inner lining of blood vessels
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

43. The EYE
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
In mouth - breakdown of starch into polysaccharides
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

44. Chewing does what?
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Increases surface area of food ball (bolus)
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

45. Fructose relates how structurally to glucose
Normally contracted
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Chylomicrons are much bigger
Fructose is a structural isomer of glucose

46. signal transduction occurs by 2 paths
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
1) by integral ion channels 2) transmitted by second messenger system
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
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

47. axon hillock physiology
Conjunction of cell body w/axon
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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
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

48. gametes are haploid
Zygotes are diploid
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

49. Induction affects...
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Direction of differentiation
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

50. What determines number of chromosomes?
Digestion
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
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
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome