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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.
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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. After meiosis II - Female

2. gametes are haploid
Zygotes are diploid
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Which is why lactase - maltase - dextrinase - sucrase are on brush border

3. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Processes: axons - dendrites
Below hypothalamus

4. What controls release of LH - FSH from anterior pituitary
Nitrogen
1) by integral ion channels 2) transmitted by second messenger system
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Gonadotropin releasing hormone - GnRH

5. What does lipase attack exactly
Sorts - modifies - concentrates proteins from the ER
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Low because AAs are immediately used in translation
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

6. 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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

7. fructose enters enterocyte by
Facilitated diffusion: no symport w/ secondary transport
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
Contain capillary network - lymph vessels (lacteals)
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

8. Where would materials slated for digestion go?
The wall of the body or of a body cavity or hollow structure
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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
Lysosome

9. From that point...
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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.
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
90-140 mg/dl

10. main point of fat transport...
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Chyme (by combined activity of exocrine glands)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
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

11. How do monoglycerides and ffas get to brush border?
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi
Epithelial tissue near semniferous tubules
Micelles; micelles (made of bile) go back and forth between brush border and chyme

12. What is an endorphin?
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
An endogenous morphine

13. thyroid hormones: Not All One Kind of HORM
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

14. STOMACH: no absorption
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
'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
Fructose is a structural isomer of glucose
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

15. Four tissues
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Water flows from the tubule - concentrating the filtrate - raising BP
Ventrally (picture skeletal vertebrae)

16. FLAT PG: prolactin
90-140 mg/dl
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Water flows from the tubule - concentrating the filtrate - raising BP

17. What is gastric acid?
Abdominal cavity - which is coated in serous fluid
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
HCl; secreted by parietal cells under stim by gastrin

18. What is a normal blood glucose range
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
The wall of the body or of a body cavity or hollow structure
90-140 mg/dl

19. How does blood sugar move into tissues?
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Neurons may perform one of three functions....
Facilitated diffusion from hi to lo conc

20. Leydig cells produce
Testosterone upon stim by LH
Low because AAs are immediately used in translation
Increases solute conc and osmotic pressure of the ***medulla
Lower blood pH

21. In IBS - What is defective

22. physiology of gall bladder - liver and pancreatic secretions
Night vision
Glucose
Combined via conjunction of pancreatic duct and common bile duct; common bile duct originates at **cystic duct where gall bladder and liver secretions combine ..cystic duct+common bile duct+pancreatic duct --->into duodenum
'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

23. What is the net effect of the loop of Henle
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
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
REABSORPTION: draws off water and ions - increases osmolarity of the medulla while slightly lowering osmolarity of the filtrate -->medulla must have hi osmolarity in order to concentrate urine at collecting duct (final step in nephron)

24. what else is located in the inner ear (not directly related to auditory)
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Two perpendicular semicircular canals involved in balance - equilibrium
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Most absorption occurs in sm intestine

25. During ejaculation - sperm...

26. spermatogonia arise from
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
- 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
Epithelial tissue near semniferous tubules
Contain capillary network - lymph vessels (lacteals)

27. PNS nerve signal
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
About 7.2
HCl; secreted by parietal cells under stim by gastrin
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

28. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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

29. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Nitrogen
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

30. 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
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Interstitial fluid (eg prostaglandins - cytokines)

31. when cells hit their limit for prot storage...
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
AAs can be burned for energy or converted to fat for storage
Primitive streak - which consists of cells of the MESODERM ****
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

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

33. Bile salts and lipase
Testosterone upon stim by LH
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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
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... ...

34. 80-90% fat absorbed this way
Lumen (ie continuous w/body cavity) and cytosol
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Epithelial tissue near semniferous tubules
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

35. Fructose relates how structurally to glucose
Below hypothalamus
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Fructose is a structural isomer of glucose

36. What are the memb - bound enzymes of the brush border?
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

37. Exocrine GlandS: stomach
Break down TAGs to monoglycerides and free fatty 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
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
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

38. Energy from fat - prot - gluc
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Break down TAGs to monoglycerides and free fatty acids
Has memb - bound organelles - etc...
Vitamin K - b12 - thiamin - riboflavin

39. PNS review: SAME DAVE
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Membrane - bound - endocytosed bodies

40. 3 phases of 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)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

41. Embryology
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

42. is intracellular AA conc hi or low?
Low because AAs are immediately used in translation
Moves down thru esophageal sphincter
Sorts - modifies - concentrates proteins from the ER
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

43. FLAT PG: FSH
Which is why lactase - maltase - dextrinase - sucrase are on brush border
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Fructose is a structural isomer of glucose
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

44. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

45. Aldosterone (sodium uptake - potassium secretion)
Glands w/ducts: Exocrine glands
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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)
Zygotes are diploid

46. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Creates one ovum (23 N) and three polar bodies
Lumen (ie continuous w/body cavity) and cytosol
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

47. Between meals most fats appear in blood as
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

48. What is feces composed of...
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
Gonadotropin releasing hormone - GnRH
Water flows from the tubule - concentrating the filtrate - raising BP
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

49. What kind of cells make up epithel tiss of stom - then sm intest?
Below hypothalamus
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
Liver Functions pt. 2 - Carb metabolism: blood is sent straight to liver from sm intest thru portal vein; liver is control center for blood glucose; _______________ - fat metabolism: oxidizes fat for energy by beta - oxidation - forms most lipoprotei
Glucose

50. Adrenal medulla hormones (TYR- DERIVED)
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
- 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
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine