MCAT Prep - 2

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. Different tissues working together
Estradiol
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Organs


2. The EYE
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
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Uncontracted: parasymp (eg opoid use)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis


3. liver and blood glucose...
Two perpendicular semicircular canals involved in balance - equilibrium
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
All carbs absorbed at enterocytes are carried to liver by portal vein


4. What does portal vein do
Needs time for bile - lipase - micelle migration - enterocyte uptake
All carbs absorbed at enterocytes are carried to liver by portal vein
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose


5. Path of urine

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6. Morula (...totipotent)
Fovea (highest amount of cones)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
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
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage


7. review: parietals secrete intrinsic factor...
Uncontracted: parasymp (eg opoid use)
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
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
Outermost layer of blood vessel


8. peroxisome is derived from this
ER
Uncontracted: parasymp (eg opoid use)
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
Facilitated diffusion: no symport w/ secondary transport


9. remaining secondary follicle becomes
Primitive streak - which consists of cells of the MESODERM ****
About 7.2
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production


10. micelles also pick up
Work together to emulsify fats: bile works as a detergent to increase SA of the fat; increased SA gives more substrate to lipase for digestion
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver


11. inhibin secreted by
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Most absorption occurs in sm intestine
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production


12. Three stages of the menstrual cycle
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)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)


13. Does bile digest fat?
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Water flows from the tubule - concentrating the filtrate - raising BP
Conjunction of cell body w/axon
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'


14. What do villli do
Increases blood Calcium
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Increases solute conc and osmotic pressure of the ***medulla
Break down TAGs to monoglycerides and free fatty acids


15. Meiosis I Anaphase I
Two perpendicular semicircular canals involved in balance - equilibrium
- 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
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Facilitated diffusion: no symport w/ secondary transport


16. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity


17. medium for paracrine hormones
Increases surface area of food ball (bolus)
Interstitial fluid (eg prostaglandins - cytokines)
The wall of the body or of a body cavity or hollow structure
Form barrier to extracellular fluid


18. spermatogonia arise from
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Epithelial tissue near semniferous tubules


19. A pinpoint iris is contracted or uncontracted
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Uncontracted: parasymp (eg opoid use)
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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


20. almost all exocytosed proteins pass through this
Water flows from the tubule - concentrating the filtrate - raising BP
Organs
Smooth ER
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles


21. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Gastrulation occurs: formation of three primary germ layers = differentiation
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc


22. portal vein physiology...

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23. What else do parietals do?
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
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)


24. micelles vs liposomes
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Liposome has phospholipid bilayer
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Cancer; apop can be programmed cell death; mitochon can play important role in apop


25. After meiosis II - Male

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26. Some epithelial cells are... others...
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Increases blood Calcium
- 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
ER


27. Different organs working together
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Systems (eg digestive system consists of many organs)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases


28. E storage per unit mass
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae


29. After meiosis II...
Normally contracted
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor


30. What determines number of chromosomes?
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Mostly reabsorbed to liver


31. zygotic life cycle
Fallopian tubes
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Organs


32. After meiosis II - Female

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33. Chewing does what?
Increases surface area of food ball (bolus)
Sympathetic: dilates pupil (for night hunting)
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)


34. FSH - LH - HCG - inhibin are...
Zygotes are diploid
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Peptides
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter


35. What is the net effect of the distal tubule
***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
In mouth - breakdown of starch into polysaccharides
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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


36. The apical side of the villi...
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
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
Faces the lumen
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right


37. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

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38. What are the major carbohydrates
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors


39. Local vs long - distance mediators
The wall of the body or of a body cavity or hollow structure
Paracrine (local) - endocrine (longer distance)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Liver is the control center for blood glucose; is fed by portal vein from sm intest


40. Meiosis II: EQUATIONAL DIVISION
Increases surface area of food ball (bolus)
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Regulated by gastrointestinal horms


41. sensory (afferent)/interneurons/motor (efferent)
Water flows from the tubule - concentrating the filtrate - raising BP
Carry signals to musc OR Gland
Neurons may perform one of three functions....
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine


42. What if large intestine isn't working well
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss


43. Most important nutrients absorbed by large intestine
Prod of steroid hormones in testes - ovaries
Form barrier to extracellular fluid
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)


44. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine


45. What is a plasmalogen?
Systems (eg digestive system consists of many organs)
Somatic nervous sys - autonomic nervous sys
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss


46. albumin has What affect on blood osmotic pressure
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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
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
Albumin increases osmolarity of blood; increases osmotic pressure


47. FLAT PG: hGH aka somatotropin
It targets liver conc of prothrombin - fibrinogen etc
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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.
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)


48. in the dark is rhodopsin active or inactive?
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Inner lining of circulatory system
Peripheral nervous sys
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching


49. light detection via GPCRs
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra


50. PNS nerve signal
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Albumin increases osmolarity of blood; increases osmotic pressure
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu
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