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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. what cannot cross the fenestrations of the renal corpuscle
RBCs - large proteins; What does enter is called the filtrate
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

2. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Membrane - bound - endocytosed bodies
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
***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

3. SYMP neurons originate in= PARA neurons originate in=
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Gastrulation occurs: formation of three primary germ layers = differentiation
Meiosis creates germ cells
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

4. Stomach has no lacteals
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Faces the lumen
Most absorption occurs in sm intestine
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

5. PNS is broken down into
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Glucose = aldose fructose = ketose
Liposome has phospholipid bilayer
Somatic nervous sys - autonomic nervous sys

6. What hormones affect the stomach?
Organs
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

7. what happens to bile secretions
Mostly reabsorbed to liver
All carbs absorbed at enterocytes are carried to liver by portal vein
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

8. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
- 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
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
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

9. at lo blood sugar...
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Sensory (afferent - dorsal) - motor (efferent - ventral)

10. FLAT PG: LH
Paracrine (local) - endocrine (longer distance)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Processes: axons - dendrites
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

11. is intracellular AA conc hi or low?
Vitamin K - b12 - thiamin - riboflavin
Low because AAs are immediately used in translation
5
Lumen (ie continuous w/body cavity) and cytosol

12. when thinking of proteins - think
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
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.
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Nitrogen

13. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
- 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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
AAs can be burned for energy or converted to fat for storage
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

14. How do monoglycerides and ffas get to brush border?
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Micelles; micelles (made of bile) go back and forth between brush border and chyme

15. Gastrulation: ectoderm/mesoderm/endoderm
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

16. Neuronal cell bodies have extensions ie
It targets liver conc of prothrombin - fibrinogen etc
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Inner lining of blood vessels
Processes: axons - dendrites

17. liver and blood glucose...
Facilitated diffusion: no symport w/ secondary transport
Ammonia; must be converted to urea by liver and excreted in urine by kidney
***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
Liver is the control center for blood glucose; is fed by portal vein from sm intest

18. After meiosis II...
Low because AAs are immediately used in translation
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Zygotes are diploid

19. Some PNS nerves are found in brain - spinal cord
Nitrogen
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Ventrally (picture skeletal vertebrae)

20. duodenum must have receptors for fat content - protein because
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Night vision

21. Gland: ovaries
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Faces the lumen
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

22. Where else does ADH act
Lower blood pH
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Glucose and ketone bodies (not from glycogen stores)
Direction of differentiation

23. Some epithelial cells are... others...
Inner lining of circulatory system
ER
- 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
Testosterone upon stim by LH

24. PNS nerve signal
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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

25. What is main difference is signal transmission in nicotinic vs muscarinic?
Increases surface area of food ball (bolus)
***nicotinic is ionotropic; muscarinic is GPCR
Mostly reabsorbed to liver
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

26. A group of cell bodies in CNS is nucleus - outside CNS is...
Ganglion
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
Epithelial tissue near semniferous tubules
- 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

27. Different organs working together
Glands w/ducts: Exocrine glands
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Systems (eg digestive system consists of many organs)
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

28. What is a dorsal root ganglion?
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
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue

29. 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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

30. What do villli do
Normally contracted
Fructose is a structural isomer of glucose
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

31. gradual increase in FSH typical of primary follicle development;
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
***nicotinic is ionotropic; muscarinic is GPCR
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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

32. STOMACH: no absorption
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

33. PNS review: SAME DAVE
Epithelial tissue near semniferous tubules
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

34. in fat and liver cells monoglycerides and ffas are once again
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Night vision
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

35. What kind of cells make up epithel tiss of stom - then sm intest?
Creates one ovum (23 N) and three polar bodies
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

36. What are phagosomes
Membrane - bound - endocytosed bodies
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Estradiol
Nitrogen

37. cAMP - cGMP - calmodulin...
Carry signals to musc OR Gland
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Ammonia; must be converted to urea by liver and excreted in urine by kidney

38. Exocrine GlandS: stomach
- 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
***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
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
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

39. position of AP...
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
1) by integral ion channels 2) transmitted by second messenger system
Two perpendicular semicircular canals involved in balance - equilibrium
Below hypothalamus

40. For focal point that is nearby - what will the lens look like
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

41. FLAT PG: hGH aka somatotropin
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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)
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Somatic nervous sys - autonomic nervous sys

42. How does glycogen compare to starch
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
'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.'
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Normally contracted

43. What controls release of LH - FSH from anterior pituitary
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
Fructose is a structural isomer of glucose
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)
Gonadotropin releasing hormone - GnRH

44. Interaction of corpus luteum/placenta
Beta cells
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
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)

45. Think of spinal cord injury
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Processes: axons - dendrites
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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

46. 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
Sympathetic: dilates pupil (for night hunting)
Increases solute conc and osmotic pressure of the ***medulla
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

47. exocrine types
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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Creates one ovum (23 N) and three polar bodies
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

48. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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
Fructose is a structural isomer of glucose

49. Anterior eye vs. posterior eye
Interstitial fluid (eg prostaglandins - cytokines)
Only musc and esp ** liver can store large amounts
Determined by whether in front of or behind the lens
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

50. At post - two weeks ovulation
The renal corpuscle
Corpus luteum degrades into corpus albicans
RBCs - large proteins; What does enter is called the filtrate
Glucose and ketone bodies (not from glycogen stores)