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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. The EYE
Beta cells
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
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

2. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Sympathetic: dilates pupil (for night hunting)
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

3. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Chyme (by combined activity of exocrine glands)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Contain capillary network - lymph vessels (lacteals)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

4. Determination is different than differentiation
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
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Abdominal cavity - which is coated in serous fluid
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate

5. Four tissues
Epithelial tissue near semniferous tubules
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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

6. What is gastric acid?
Corpus luteum degrades into corpus albicans
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
HCl; secreted by parietal cells under stim by gastrin
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

7. what happens when glycogen stores are saturated and blood sugar remains high?
'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.'
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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

8. Glycogenolysis/gluconeogenesis
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
The renal corpuscle
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

9. axon hillock physiology
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Conjunction of cell body w/axon
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

10. gradual increase in FSH typical of primary follicle development;
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Abdominal cavity - which is coated in serous fluid

11. thyroid hormones: Not All One Kind of HORM
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

12. What is a nerve? (PNS)
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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

13. mucus cells line the stomach...
Ventrally (picture skeletal vertebrae)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
1) by integral ion channels 2) transmitted by second messenger system
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

14. quote on cavities/viscera

15. PNS nerve signal
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Moves down thru esophageal sphincter

16. Some epithelial cells are... others...
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
- 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

17. How does the body mobilize fat stores
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
***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
Sensory (afferent - dorsal) - motor (efferent - ventral)

18. cytosol pH
About 7.2
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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

19. calcitonin

20. Gland: ovaries
Chylomicrons are much bigger
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

21. What determines number of chromosomes?
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

22. What surrounds the hydrophilic heads of the new TAGs
Primitive streak - which consists of cells of the MESODERM ****
Membrane - bound - endocytosed bodies
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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

23. In other words...
Pancreatic duct (made of acinar cells?)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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

24. Interaction of corpus luteum/placenta
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Ammonia; must be converted to urea by liver and excreted in urine by kidney
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

25. FLAT PG: prolactin
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

26. pancreas secretes enzymes via
In mouth - breakdown of starch into polysaccharides
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Liposome has phospholipid bilayer
Pancreatic duct (made of acinar cells?)

27. Kidney
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
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Fovea (highest amount of cones)

28. How is glucose absorbed in sm intest
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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.
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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

29. sensory (afferent)/interneurons/motor (efferent)
All carbs absorbed at enterocytes are carried to liver by portal vein
Paracrine (local) - endocrine (longer distance)
Nitrogen
Neurons may perform one of three functions....

30. The path from blood plasma to urine

31. After meiosis II...
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
'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
Uncontracted: parasymp (eg opoid use)

32. ADH
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
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
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
Thru tight junctions by favorable osmotic gradient

33. fructose enters enterocyte by
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
Facilitated diffusion: no symport w/ secondary transport
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

34. Ovum development is halted At what stage until fertilization...
Beta cells
AAs can be burned for energy or converted to fat for storage
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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

35. What does lipase attack exactly
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
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Primitive streak - which consists of cells of the MESODERM ****
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

36. bundles of collecting ducts are called
Gonadotropin releasing hormone - GnRH
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine

37. Morula (...totipotent)
Signal picked up by sensory cell - goes thru dorsal root ganglion to SC - may continue to interneurons in brain or simple reflex arc in SC - brain integrates info and decides (voluntary) response - travels back down SC to appropriate ventral root gan
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

38. cAMP - cGMP - calmodulin...
Chyme (by combined activity of exocrine glands)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Break down TAGs to monoglycerides and free fatty acids
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

39. almost all exocytosed proteins pass through this
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Smooth ER
Ventrally (picture skeletal vertebrae)
Water flows from the tubule - concentrating the filtrate - raising BP

40. What is the net effect of the distal tubule
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

41. Which fats are not absorbed like this
Sympathetic: dilates pupil (for night hunting)
All carbs absorbed at enterocytes are carried to liver by portal vein
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

42. PNS is broken down into
Meiosis creates germ cells
Somatic nervous sys - autonomic nervous sys
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
'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

43. Where would materials slated for digestion go?
Salivary amylase; both hydrolyze glycosidic linkages
Lysosome
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
Testosterone upon stim by LH

44. How does duod deal with hi HCl from stom
Sensory (afferent - dorsal) - motor (efferent - ventral)
In mouth - breakdown of starch into polysaccharides
Primitive streak - which consists of cells of the MESODERM ****
Ups bicarbonate secretion by pancreas; raises pH to 6.0

45. Luteal surge
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
'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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

46. lining of abdominal cavity=
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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
Fovea (highest amount of cones)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

47. Creating gradients requires what?
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Smooth ER
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
Ganglion

48. 'Cell bodies of somatic motor neurons are located in....'
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Moves down thru esophageal sphincter
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

49. What is the net effect of the loop of Henle
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)
- 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
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Gonadotropin releasing hormone - GnRH

50. FLAT PG: FSH
Zygotes are diploid
Inner lining of blood vessels
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Organs