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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. chylomicron concentration in blood after meal
Conjunction of cell body w/axon
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

2. What determines number of chromosomes?
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
Gonadotropin releasing hormone - GnRH
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

3. Determination is different than differentiation
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Below hypothalamus

4. interneurons
***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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Transfer signals from neuron - neuron; 90% of neurons are interneurons

5. liver receives blood from...
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
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
Fructose is a structural isomer of glucose
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

6. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
***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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

7. What does peroxisome do
Increases surface area of food ball (bolus)
Membrane - bound - endocytosed bodies
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

8. fructose enters enterocyte by
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
Facilitated diffusion: no symport w/ secondary transport
Chyme (by combined activity of exocrine glands)
Increases surface area of food ball (bolus)

9. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
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
Pancreatic duct (made of acinar cells?)
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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

10. What happens when rod cell is depolarized
Night vision
Increases blood Calcium
Mostly reabsorbed to liver
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

11. medium for paracrine hormones
Interstitial fluid (eg prostaglandins - cytokines)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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
Only musc and esp ** liver can store large amounts

12. What is the mesentery?
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
90-140 mg/dl
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP

13. What is a dorsal root ganglion?
Carry signals to musc OR Gland
Most absorption occurs in sm intestine
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop

14. almost all exocytosed proteins pass through this
Smooth ER
Two perpendicular semicircular canals involved in balance - equilibrium
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
The wall of the body or of a body cavity or hollow structure

15. when cells hit their limit for prot storage...
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
AAs can be burned for energy or converted to fat for storage
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

16. What is main difference is signal transmission in nicotinic vs muscarinic?
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
***nicotinic is ionotropic; muscarinic is GPCR
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

17. What do the glomerulus and Bowman's capsule add up to...
The renal corpuscle
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
90-140 mg/dl
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

18. The apical side of the villi...
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Faces the lumen
Eukaryotes

19. only monosaccharides are absorbed
Which is why lactase - maltase - dextrinase - sucrase are on brush border
In mouth - breakdown of starch into polysaccharides
Adrenal gland -- AC: steroids (cortisol - aldosterone); AM: catecholamines (epi - norepi); Islets of langerhans: peptides (insulin/glucagon) ANTAGONISTS: calcitonin (thyroid - peptide lowers Ca in blood); parathyroid hormone - peptide - vitamin D pat
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

20. Chewing does what?
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Increases surface area of food ball (bolus)
Glands w/ducts: Exocrine glands

21. Exocrine GlandS: stomach
Fovea (highest amount of cones)
Prod of steroid hormones in testes - ovaries
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
- 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

22. extracellular matrix formed mainly of...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Glucose and ketone bodies (not from glycogen stores)
Conjunction of cell body w/axon

23. What is the pH at the entrance to the duodenum
Ventrally (picture skeletal vertebrae)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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

24. How is glucose absorbed in sm intest
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
Pancreatic duct (made of acinar cells?)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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

25. little by little chyme is squirted out thru pyloric sphincter
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Regulated by gastrointestinal horms

26. when thinking of proteins - think
Nitrogen
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
Below hypothalamus
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

27. Where would materials slated for digestion go?
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Pancreatic duct (made of acinar cells?)
Lysosome
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

28. What is an endorphin?
An endogenous morphine
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

29. ligands are the messenger compounds that target secondary messenger systems on effectors
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Many modern drugs are ligands for GPCRs
Pepsin - secreted by chief cells in the stomach epithelial lining and active at low pH - breaks down proteins to polypeptides. Protein hydrolysis is aided by the highly acidic environment (hi gastric acid from parietal cells). Polypeptides are squirt

30. Creating gradients requires what?
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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Many modern drugs are ligands for GPCRs

31. examples of different cavities... (compartments for viscera)
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Moves down thru esophageal sphincter
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

32. The bolus (chewing) is digested to what in the stomach
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Chyme (by combined activity of exocrine glands)

33. parathyroid hormones
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
RBCs - large proteins; What does enter is called the filtrate
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

34. How do parietal cells work ** (involves CO2)
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

35. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

36. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Moves down thru esophageal sphincter
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

37. Aldosterone (sodium uptake - potassium secretion)
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)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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
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

38. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

39. What surrounds the hydrophilic heads of the new TAGs
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
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
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)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

40. How does the body mobilize fat stores
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
***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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

41. thyroid hormones: Not All One Kind of HORM
Normally contracted
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
The wall of the body or of a body cavity or hollow structure

42. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Sympathetic: dilates pupil (for night hunting)
Fovea (highest amount of cones)

43. golgi body
Night vision
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Sorts - modifies - concentrates proteins from the ER

44. Where else does ADH act
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Sympathetic: dilates pupil (for night hunting)
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

45. The esophageal sphincter is...
RBCs - large proteins; What does enter is called the filtrate
Sensory (afferent - dorsal) - motor (efferent - ventral)
Normally contracted
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

46. FLAT PG: FSH
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
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

47. trypsin is secreted by
Transfer signals from neuron - neuron; 90% of neurons are interneurons
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

48. FLAT PG: hGH aka somatotropin
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Fallopian tubes
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
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)

49. 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
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

50. inhibin secreted by
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Eukaryotes