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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. Thus inhibiting parietal cells could do What to blood pH
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Lower blood pH
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

2. What is a toxic byproduct of gluconeogenesis from proteins
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Vitamin K - b12 - thiamin - riboflavin

3. light detection via GPCRs
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Below hypothalamus
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
Regulated by gastrointestinal horms

4. How does reabsorption force nutrients across apical membrane of proximal tubule
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
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
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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

5. What is a nerve? (PNS)
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
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Glucose

6. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
Chylomicrons are much bigger
Low because AAs are immediately used in translation
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Fovea (highest amount of cones)

7. liver receives blood from...
Corpus luteum degrades into corpus albicans
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Glucose = aldose fructose = ketose
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

8. Interaction of corpus luteum/placenta
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Neurons may perform one of three functions....
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
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

9. Luteal surge
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Zygotes are diploid
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

10. what happens to bile secretions
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Mostly reabsorbed to liver
An endogenous morphine

11. Cell determination begins At what stage of development
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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)

12. Human chorionic gonadotropin...
Glucose and ketone bodies (not from glycogen stores)
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Interstitial fluid (eg prostaglandins - cytokines)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

13. FLAT PG: TSH aka thyrotropin
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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Fructose is a structural isomer of glucose

14. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Glands w/ducts: Exocrine glands
90-140 mg/dl
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

15. mucus cells line the stomach...
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

16. calcitonin

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17. Liver Functions
HCl; secreted by parietal cells under stim by gastrin
The wall of the body or of a body cavity or hollow structure
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
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

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

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19. Blastocyst
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Lysosome
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

20. Spinal cord horns (thick knobs) point
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
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
Ventrally (picture skeletal vertebrae)
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

21. in the presence of ADH what happens to movement of water across nephron membr
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Many modern drugs are ligands for GPCRs
Water flows from the tubule - concentrating the filtrate - raising BP
Glands w/ducts: Exocrine glands

22. What does lipase attack exactly
ER
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)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

23. What is the path of a sound wave that enters the ear?
ER
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

24. 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
About 7.2
The renal corpuscle
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

25. 80% of end product of carbohydrate metabolism is...
Glucose
Neurons may perform one of three functions....
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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

26. Glycogenolysis/gluconeogenesis
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Ammonia; must be converted to urea by liver and excreted in urine by kidney

27. Meiosis II: EQUATIONAL DIVISION
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
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
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

28. FLAT PG: prolactin
The renal corpuscle
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

29. What is the net effect of the distal tubule
Glucose and ketone bodies (not from glycogen stores)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
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
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

30. Between meals most fats appear in blood as
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Zygotes are diploid
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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

31. Chewing does what?
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Increases surface area of food ball (bolus)
5

32. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
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
Inner lining of blood vessels
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries

33. Where else does ADH act
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)
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
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

34. PNS review: SAME DAVE
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
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
Thru tight junctions by favorable osmotic gradient

35. What does portal vein do
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
All carbs absorbed at enterocytes are carried to liver by portal vein

36. What are phagosomes
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Membrane - bound - endocytosed bodies
The wall of the body or of a body cavity or hollow structure

37. Determination is different than differentiation
Interstitial fluid (eg prostaglandins - cytokines)
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
About 7.2
Conjunction of cell body w/axon

38. peroxisome is derived from this
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

39. 80-90% fat absorbed this way
Many modern drugs are ligands for GPCRs
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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.
Contain capillary network - lymph vessels (lacteals)

40. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Lumen (ie continuous w/body cavity) and cytosol
Organs
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

41. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Outermost layer of blood vessel
- 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
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)

42. 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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Somatic nervous sys - autonomic nervous sys
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

43. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
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)
Cancer; apop can be programmed cell death; mitochon can play important role in apop

44. Alpha - amylase found where
Amino acid monomers - di - tri absorbed by symport at enterocyte; each AA has slightly diff mechanism; from entero - AAs enter bloodstream where they are taken up by all cells of the body - esp the liver by active or facilitated transport (NEVER PASS
Direction of differentiation
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
In mouth - breakdown of starch into polysaccharides

45. Where does the bolus go after mouth chews food
Moves down thru esophageal sphincter
Sorts - modifies - concentrates proteins from the ER
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Peripheral nervous sys

46. Leydig cells produce
Carry signals to musc OR Gland
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Testosterone upon stim by LH

47. interneurons
Chylomicrons are much bigger
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Increases solute conc and osmotic pressure of the ***medulla

48. Seen in lysosomal storage diseases
In gastric pits; secretions combine into gastric juice
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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)
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

49. insulin secreted by
Glycosaminoglycans - prots - AAs - lipids
Smooth ER
Beta cells
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

50. overview of prot digestion
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
Faces the lumen
Glucose and ketone bodies (not from glycogen stores)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine