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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. 3 phases of menstrual cycle
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Sympathetic: dilates pupil (for night hunting)
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)

2. testosterone can be aromatized to...
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Uncontracted: parasymp (eg opoid use)
Estradiol

3. FLAT PG: LH
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Glucose = aldose fructose = ketose

4. gametic life cycle
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
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
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

5. Three stages of the menstrual cycle
Break down TAGs to monoglycerides and free fatty acids
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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

6. amylase acts where on carbs
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Contain capillary network - lymph vessels (lacteals)

7. sporic life cycle
Most absorption occurs in sm intestine
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
HCl; secreted by parietal cells under stim by gastrin

8. Beta - oxidation in liver produces...
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Chyme (by combined activity of exocrine glands)
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

9. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Prod of steroid hormones in testes - ovaries
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

10. Adrenal cortex hormones (STEROIDS)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Ventrally (picture skeletal vertebrae)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

11. micelles also pick up
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Within the paravertebral ganglion - running parallel to spinal cord

12. remaining secondary follicle becomes
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Night vision
Determined by whether in front of or behind the lens
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

13. lysosome main function and derivation
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Facilitated diffusion: no symport w/ secondary transport
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

14. What hormones affect the stomach?
- 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
Lumen (ie continuous w/body cavity) and cytosol
Testosterone and estradiol
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

15. Some epithelial cells are... others...
Glucose and ketone bodies (not from glycogen stores)
- 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
Determined by whether in front of or behind the lens
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)

16. FLAT PG: TSH aka thyrotropin
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
Glycosaminoglycans - prots - AAs - lipids

17. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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)
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... ...
vitreous humor - retina - fovea

18. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

19. In IBS - What is defective

20. What does peroxisome do
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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)
Lysosome
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

21. From that point...
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.
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
'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
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

22. Interaction of corpus luteum/placenta
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
About 7.2
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

23. duodenum must have receptors for fat content - protein because
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

24. After meiosis II - Male

25. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
An endogenous morphine
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
***nicotinic is ionotropic; muscarinic is GPCR

26. in mammals - gastrulation involves formation of the
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
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
Primitive streak - which consists of cells of the MESODERM ****

27. What does lipase attack exactly
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
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

28. trypsin is secreted by
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Inner lining of blood vessels
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

29. What testosterone released by secondary follicle by LH stim is converted to...
Testosterone upon stim by LH
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

30. Mucus - digestive enzymes released thru
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Below hypothalamus
Glands w/ducts: Exocrine glands

31. 90% digestion - absorption occurs in...
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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
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
Two perpendicular semicircular canals involved in balance - equilibrium

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

33. What is gastric acid?
HCl; secreted by parietal cells under stim by gastrin
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
AAs can be burned for energy or converted to fat for storage

34. Cell determination begins At what stage of development
Transfer signals from neuron - neuron; 90% of neurons are interneurons
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Determined by whether in front of or behind the lens
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

35. cAMP - cGMP - calmodulin...
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
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
Salivary amylase; both hydrolyze glycosidic linkages
Eukaryotes

36. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

37. 'Cell bodies of somatic motor neurons are located in....'
Neurons may perform one of three functions....
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
The renal corpuscle
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

38. After meiosis II - Female

39. FSH - LH - HCG - inhibin are...
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)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Peptides
Oxytocin and ADH (aka vasopressin)

40. axon hillock physiology
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Conjunction of cell body w/axon

41. Where else does ADH act
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
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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

42. What do villli do
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Contain capillary network - lymph vessels (lacteals)
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

43. The EYE
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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

44. micelles vs liposomes
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Liposome has phospholipid bilayer
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

45. What is main difference is signal transmission in nicotinic vs muscarinic?
***nicotinic is ionotropic; muscarinic is GPCR
Epithelial tissue near semniferous tubules
Regulated by gastrointestinal horms
Inner lining of blood vessels

46. light detection via GPCRs
Form barrier to extracellular fluid
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Liposome has phospholipid bilayer

47. How does blood sugar move into tissues?
Form barrier to extracellular fluid
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Facilitated diffusion from hi to lo conc
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

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

49. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
Smooth ER
Carry signals to musc OR Gland
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

50. parathyroid hormone
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
Beta cells
Increases blood Calcium
Determined by whether in front of or behind the lens