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. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Glucose
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
AAs can be burned for energy or converted to fat for storage


2. smooth ER main function
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Conjunction of cell body w/axon
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate


3. when cells hit their limit for prot storage...
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
AAs can be burned for energy or converted to fat for storage
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries


4. From that point...
Night vision
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte 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.
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability


5. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
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
Chylomicrons are much bigger
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


6. Interaction of corpus luteum/placenta
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
RBCs - large proteins; What does enter is called the filtrate
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Estradiol


7. What do the glomerulus and Bowman's capsule add up to...
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
The renal corpuscle
It targets liver conc of prothrombin - fibrinogen etc
Sympathetic: dilates pupil (for night hunting)


8. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
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
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
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)


9. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Estradiol
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver


10. review: parietals secrete intrinsic factor...
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
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
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
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


11. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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


12. Difference between euk and prok flagella
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges


13. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Form barrier to extracellular fluid
RBCs - large proteins; What does enter is called the filtrate
Glycosaminoglycans - prots - AAs - lipids
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves


14. Leydig cells produce
Testosterone upon stim by LH
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Uncontracted: parasymp (eg opoid use)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons


15. In IBS - What is defective

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16. mucus cells line the stomach...
Ventrally (picture skeletal vertebrae)
Form barrier to extracellular fluid
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
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


17. How does blood sugar move into tissues?
Gastrulation occurs: formation of three primary germ layers = differentiation
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Peptides
Facilitated diffusion from hi to lo conc


18. portal vein physiology...

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19. sporic life cycle
Zygotes are diploid
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
The renal corpuscle
Only musc and esp ** liver can store large amounts


20. Four tissues
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
vitreous humor - retina - fovea
Increases surface area of food ball (bolus)


21. sensory (afferent) neurons
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Most absorption occurs in sm intestine


22. ADH
Smooth ER
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle


23. parathyroid hormone
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
Increases blood Calcium
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Carry signals to musc OR Gland


24. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Estradiol
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
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
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP


25. FLAT PG: TSH aka thyrotropin
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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 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
Normally contracted


26. these transport proteins - when concs are high enough...
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Lysosome
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Corpus luteum degrades into corpus albicans


27. During ejaculation - sperm...

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28. Posterior pituitary hormones (Small Peptides)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
In gastric pits; secretions combine into gastric juice
Oxytocin and ADH (aka vasopressin)


29. Anterior eye vs. posterior eye
Determined by whether in front of or behind the lens
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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


30. Embryology
Peripheral nervous sys
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus


31. What is the adventitia?
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Outermost layer of blood vessel
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Oxytocin and ADH (aka vasopressin)


32. when thinking of proteins - think
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Nitrogen
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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


33. quote on cavities/viscera

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34. FLAT PG: FSH
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Estradiol
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete


35. Embryology
Primitive streak - which consists of cells of the MESODERM ****
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.
Interstitial fluid (eg prostaglandins - cytokines)
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


36. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest


37. bile + fat forms
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
RBCs - large proteins; What does enter is called the filtrate
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... ...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border


38. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Peptides
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
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase


39. After meiosis II...
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Peripheral nervous sys


40. How does the body mobilize fat stores
***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
Water flows from the tubule - concentrating the filtrate - raising BP
Determined by whether in front of or behind the lens
Pancreatic duct (made of acinar cells?)


41. PNS review: SAME DAVE
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Fallopian tubes


42. What testosterone released by secondary follicle by LH stim is converted to...
Ups bicarbonate secretion by pancreas; raises pH to 6.0
'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.'
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Liver is the control center for blood glucose; is fed by portal vein from sm intest


43. micelles also pick up
Below hypothalamus
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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


44. Aldosterone (sodium uptake - potassium secretion)
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
Increases blood Calcium
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)
90-140 mg/dl


45. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
- 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


46. What does peroxisome do
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Mostly reabsorbed to liver


47. Blastocyst
Nitrogen
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
About 7.2
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant


48. The path from blood plasma to urine

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49. albumin has What affect on blood osmotic pressure
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
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Albumin increases osmolarity of blood; increases osmotic pressure
It targets liver conc of prothrombin - fibrinogen etc


50. exocrine types
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Membrane - bound - endocytosed bodies