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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. What is the net effect of the loop of Henle
Inner lining of circulatory system
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
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)

2. Fructose relates how structurally to glucose
Fructose is a structural isomer of glucose
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

3. What is the net effect of the distal tubule
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
Neurons may perform one of three functions....
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
Moves down thru esophageal sphincter

4. what happens to bile secretions
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Moves down thru esophageal sphincter
Mostly reabsorbed to liver
Albumin increases osmolarity of blood; increases osmotic pressure

5. Most important nutrients absorbed by large intestine
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
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
Creates one ovum (23 N) and three polar bodies
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

6. axon hillock physiology
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
Conjunction of cell body w/axon
Carry signals to musc OR Gland
Increases solute conc and osmotic pressure of the ***medulla

7. After meiosis I - daughter cells are...

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8. SYMP neurons originate in= PARA neurons originate in=
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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Ventrally (picture skeletal vertebrae)

9. After meiosis II...
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
It targets liver conc of prothrombin - fibrinogen etc
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

10. What is gastric acid?
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
HCl; secreted by parietal cells under stim by gastrin
Glucose
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

11. E storage per unit mass
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
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
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

12. Seen in lysosomal storage diseases
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
90-140 mg/dl
Buildup of macromolecules in lysosome due to deficient lysosome enzymes

13. What is the endothelium?
Inner lining of circulatory system
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Salivary amylase; both hydrolyze glycosidic linkages
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

14. 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
Paracrine (local) - endocrine (longer distance)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

15. What does portal vein do
Glucose
Within the paravertebral ganglion - running parallel to spinal cord
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
All carbs absorbed at enterocytes are carried to liver by portal vein

16. Cell bodies of SYMP postganglionic neurons lie far from effector...
Normally contracted
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
Within the paravertebral ganglion - running parallel to spinal cord
Increases solute conc and osmotic pressure of the ***medulla

17. Sensory neuron cell bodies vs. somatic motor cell bodies
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
Salivary amylase; both hydrolyze glycosidic linkages

18. Polypeptides are formed with what kind of reaction?
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
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
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

19. FLAT PG: FSH
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
Within the paravertebral ganglion - running parallel to spinal cord
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

20. when cells hit their limit for prot storage...
AAs can be burned for energy or converted to fat for storage
HCl; secreted by parietal cells under stim by gastrin
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Conjunction of cell body w/axon

21. 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)
Paracrine (local) - endocrine (longer distance)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Chylomicrons are much bigger

22. Mucus - digestive enzymes released thru
Glands w/ducts: Exocrine glands
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Glucose = aldose fructose = ketose

23. Think of spinal cord injury
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
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
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

24. alpha - amylase in the mouth digests what kind of bond
Testosterone and estradiol
Vitamin K - b12 - thiamin - riboflavin
Abdominal cavity - which is coated in serous fluid
Alpha 1-4 and 1-6 (branching) glycosidic linkages

25. Difference between euk and prok flagella
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

26. What is the pH at the entrance to the duodenum
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Nitrogen
Peptides
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... ...

27. FLAT PG: LH
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
All carbs absorbed at enterocytes are carried to liver by portal vein
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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

28. What do villli do
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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

29. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
***nicotinic is ionotropic; muscarinic is GPCR
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
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

30. 80% of end product of carbohydrate metabolism is...
Mostly reabsorbed to liver
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Sympathetic: dilates pupil (for night hunting)
Glucose

31. PNS review: SAME DAVE
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Chyme (by combined activity of exocrine glands)

32. Posterior pituitary hormones (Small Peptides)
'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
Beta cells
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)
Oxytocin and ADH (aka vasopressin)

33. What is the function of the loop of Henle
Regulated by gastrointestinal horms
Increases solute conc and osmotic pressure of the ***medulla
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

34. when thinking of proteins - think
Nitrogen
Somatic nervous sys - autonomic nervous sys
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

35. Cell determination begins At what stage of development
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Contain capillary network - lymph vessels (lacteals)
Night vision
Inner lining of circulatory system

36. spermatogonia arise from
Epithelial tissue near semniferous tubules
Liposome has phospholipid bilayer
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Only musc and esp ** liver can store large amounts

37. Spinal cord horns (thick knobs) point
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Ventrally (picture skeletal vertebrae)
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

38. Where would materials slated for digestion go?
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Glucose and ketone bodies (not from glycogen stores)
Lysosome

39. Embryology
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Gastrulation occurs: formation of three primary germ layers = differentiation
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

40. 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
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

41. What if large intestine isn't working well
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

42. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
Systems (eg digestive system consists of many organs)
In gastric pits; secretions combine into gastric juice
'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

43. insulin secreted by
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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
Beta cells

44. Human chorionic gonadotropin...
HCl; secreted by parietal cells under stim by gastrin
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Moves down thru esophageal sphincter
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

45. Four tissues
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
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

46. small intestine=
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Beta cells
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

47. ligands are the messenger compounds that target secondary messenger systems on effectors
Vitamin K - b12 - thiamin - riboflavin
Many modern drugs are ligands for GPCRs
Somatic nervous sys - autonomic nervous sys
Oxytocin and ADH (aka vasopressin)

48. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
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
Homologous chromosomes separate - migrate towards opposite poles/centrioles
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
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

49. How is glucose absorbed in sm intest
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
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
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

50. Alpha - amylase found where
Processes: axons - dendrites
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
In mouth - breakdown of starch into polysaccharides