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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Thus - central nervous sys is...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Uncontracted: parasymp (eg opoid use)
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

2. micelles vs liposomes
Liposome has phospholipid bilayer
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
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

3. What is feces composed of...
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
Somatic nervous sys - autonomic nervous sys
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
5

4. FLAT PG: ACTH
Digestion
Chylomicrons are much bigger
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

5. What surrounds the hydrophilic heads of the new TAGs
Chyme (by combined activity of exocrine glands)
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
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
Peripheral nervous sys

6. cytosol pH
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Needs time for bile - lipase - micelle migration - enterocyte uptake
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
About 7.2

7. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
'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.'
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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

8. Polypeptides are formed with what kind of reaction?
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

9. What does peptic refer to in general
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Inner lining of blood vessels
Normally contracted
Digestion

10. What does portal vein do
All carbs absorbed at enterocytes are carried to liver by portal vein
Processes: axons - dendrites
Ganglion
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

11. FLAT PG: LH
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
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
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

12. Anatomy of the villi
Contain capillary network - lymph vessels (lacteals)
***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
RBCs - large proteins; What does enter is called the filtrate
Inner lining of blood vessels

13. Mucus - digestive enzymes released thru
Glands w/ducts: Exocrine glands
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Estradiol

14. Human chorionic gonadotropin...
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Primitive streak - which consists of cells of the MESODERM ****
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

15. What determines number of chromosomes?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Lysosome
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

16. FLAT PG: FSH
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
***nicotinic is ionotropic; muscarinic is GPCR
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

17. large intestine E. coli aid absorption of...
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Meiosis creates germ cells
Facilitated diffusion: no symport w/ secondary transport
Vitamin K - b12 - thiamin - riboflavin

18. Important of villi (='shaggy hair') More fluid makes contact with the epithelial tissue: thus nutrients in solution have less distance to travel to diffuse into villi.

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19. How does reabsorption force nutrients across apical membrane of proximal tubule
Epithelial tissue near semniferous tubules
Prod of steroid hormones in testes - ovaries
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Ups bicarbonate secretion by pancreas; raises pH to 6.0

20. these transport proteins - when concs are high enough...
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
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

21. what cannot cross the fenestrations of the renal corpuscle
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Zygotes are diploid
RBCs - large proteins; What does enter is called the filtrate

22. spermatogonia arise from
Micelles; micelles transport lipase products to enterocytes for absorption at 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
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
Epithelial tissue near semniferous tubules

23. Glucose is a .... sugar; fructose is a .... sugar
Increases blood Calcium
Gonadotropin releasing hormone - GnRH
Glucose = aldose fructose = ketose
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

24. What is the path of a sound wave that enters the ear?
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
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
Lumen (ie continuous w/body cavity) and cytosol
Increases solute conc and osmotic pressure of the ***medulla

25. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
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)
Creates one ovum (23 N) and three polar bodies
Increases blood Calcium
Epithelial tissue near semniferous tubules

26. In other words...
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

27. In effect LH - FSH stimulate
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)
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
Ganglion
Prod of steroid hormones in testes - ovaries

28. How does glycogen compare to starch
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Fructose is a structural isomer of glucose
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

29. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Chylomicrons are much bigger
Liposome has phospholipid bilayer
Inner lining of blood vessels

30. How is the follicle developed during oogenesis
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

31. Meiosis I Telophase I
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Has memb - bound organelles - etc...
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

32. Alpha - amylase found where
In mouth - breakdown of starch into polysaccharides
Inner lining of blood vessels
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
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

33. Induction affects...
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)
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
Direction of differentiation
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

34. smooth ER main function
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

35. In IBS - What is defective

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36. gametic life cycle
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
ER

37. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Gonadotropin releasing hormone - GnRH
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
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles

38. At post - two weeks ovulation
Meiosis creates germ cells
Corpus luteum degrades into corpus albicans
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Chylomicrons are much bigger

39. gradual increase in FSH typical of primary follicle development;
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining

40. Cell determination begins At what stage of development
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Fructose is a structural isomer of glucose
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Sympathetic: dilates pupil (for night hunting)

41. What is a nerve? (PNS)
Ventrally (picture skeletal vertebrae)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

42. duodenum must have receptors for fat content - protein because
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Thru tight junctions by favorable osmotic gradient
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

43. How does water cross the apical membrane
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Thru tight junctions by favorable osmotic gradient

44. Where does fertilization occur
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Fallopian tubes

45. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
- 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
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

46. trypsin is secreted by
Conjunction of cell body w/axon
Normally contracted
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

47. peroxisome is derived from this
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
ER
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
'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

48. Embryology
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
- 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
Determined by whether in front of or behind the lens

49. How does the body mobilize fat stores
In mouth - breakdown of starch into polysaccharides
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
***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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

50. fat digestion is time - intensive
Needs time for bile - lipase - micelle migration - enterocyte uptake
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
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
Corpus luteum degrades into corpus albicans