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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. gametes are haploid
Zygotes are diploid
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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
- 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

2. What is secreted into filtrate by cells of the proximal tubule?
Sympathetic: dilates pupil (for night hunting)
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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

3. Kidney physiology...

4. Neuronal cell bodies have extensions ie
Has memb - bound organelles - etc...
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Processes: axons - dendrites

5. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Organs
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Mostly reabsorbed to liver

6. How do monoglycerides and ffas get to brush border?
Break down TAGs to monoglycerides and free fatty acids
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Peripheral nervous sys

7. 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
Oxytocin and ADH (aka vasopressin)
It targets liver conc of prothrombin - fibrinogen etc
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

8. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Organs
Conjunction of cell body w/axon
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

9. peroxisome is derived from this
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Mostly reabsorbed to liver
An endogenous morphine
ER

10. axon hillock physiology
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Conjunction of cell body w/axon
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
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

11. Glucose is a .... sugar; fructose is a .... sugar
Glucose = aldose fructose = ketose
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Mostly reabsorbed to liver

12. Exocrine GlandS: stomach
Nitrogen
- 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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Peripheral nervous sys

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

14. ligands are the messenger compounds that target secondary messenger systems on effectors
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
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
Many modern drugs are ligands for GPCRs
Salivary amylase; both hydrolyze glycosidic linkages

15. parathyroid hormones
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Sorts - modifies - concentrates proteins from the ER
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

16. cAMP - cGMP - calmodulin...
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Faces the lumen
Meiosis creates germ cells

17. euk cell has two principal sides
Lumen (ie continuous w/body cavity) and cytosol
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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

18. In IBS - What is defective

19. What is the net effect of the loop of Henle
Abdominal cavity - which is coated in serous fluid
Many modern drugs are ligands for GPCRs
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)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

20. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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
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

21. bundles of collecting ducts are called
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Form barrier to extracellular fluid
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

22. 80-90% fat absorbed this way
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Prod of steroid hormones in testes - ovaries
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

23. liver receives blood from...
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Testosterone and estradiol
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
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

24. Gastrulation: ectoderm/mesoderm/endoderm
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Abdominal cavity - which is coated in serous fluid
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

25. micelles also pick up
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Lysosome
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

26. Where is bile produced
Moves down thru esophageal sphincter
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

27. Three stages of the menstrual cycle
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Testosterone and estradiol
Mostly reabsorbed to liver
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

28. Where would materials slated for digestion go?
RBCs - large proteins; What does enter is called the filtrate
Lysosome
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Lower blood pH

29. Fructose relates how structurally to glucose
Lumen (ie continuous w/body cavity) and cytosol
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
The renal corpuscle
Fructose is a structural isomer of glucose

30. SYMP neurons originate in= PARA neurons originate in=
Direction of differentiation
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
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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

31. Different tissues working together
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
'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.'
Organs
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

32. What is feces composed of...
Form barrier to extracellular fluid
Sensory (afferent - dorsal) - motor (efferent - ventral)
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.
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

33. energy source of neurons
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Glucose and ketone bodies (not from glycogen stores)

34. What does peroxisome do
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Glycosaminoglycans - prots - AAs - lipids

35. fructose enters enterocyte by
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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 collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Facilitated diffusion: no symport w/ secondary transport

36. Where do pancreatic secretions take effect
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
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

37. Between meals most fats appear in blood as
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

38. Human chorionic gonadotropin...
vitreous humor - retina - fovea
Contain capillary network - lymph vessels (lacteals)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Faces the lumen

39. portal vein physiology...

40. How long are peptides when absorbed at brush border
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Fovea (highest amount of cones)

41. at lo blood sugar...
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Lumen (ie continuous w/body cavity) and cytosol

42. mitosis creates somatic cells
Meiosis creates germ cells
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Outermost layer of blood vessel
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

43. How do nutrients move?
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

44. The bolus (chewing) is digested to what in the stomach
Liposome has phospholipid bilayer
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
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Chyme (by combined activity of exocrine glands)

45. What surrounds the hydrophilic heads of the new TAGs
The wall of the body or of a body cavity or hollow structure
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
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
- 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. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Glycosaminoglycans - prots - AAs - lipids
Only musc and esp ** liver can store large amounts

47. Sensory - motor neurons are part of which nervous system
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Peripheral nervous sys
1) by integral ion channels 2) transmitted by second messenger system
About 7.2

48. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Facilitated diffusion from hi to lo conc
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose

49. motor (efferent) neurons --> VENTRAL
Carry signals to musc OR Gland
Pancreatic duct (made of acinar cells?)
Paracrine (local) - endocrine (longer distance)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

50. What is a nerve? (PNS)
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
Organs
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions