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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. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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... ...
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

2. What is the path of a sound wave that enters the ear?
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Organs
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

3. The esophageal sphincter is...
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Normally contracted
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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

4. these transport proteins - when concs are high enough...
Albumin increases osmolarity of blood; increases osmotic pressure
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border

5. serous membranes have a viscera - facing layer and a body wall - facing layer
Vitamin K - b12 - thiamin - riboflavin
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Form barrier to extracellular fluid
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

6. What kind of cells make up epithel tiss of stom - then sm intest?
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Normally contracted

7. What is a toxic byproduct of gluconeogenesis from proteins
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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
Carry signals to musc OR Gland
Organs

8. What determines number of chromosomes?
An endogenous morphine
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
'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.'
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

9. zygotic life cycle
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Sympathetic: dilates pupil (for night hunting)

10. Glucose is a .... sugar; fructose is a .... sugar
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Glucose = aldose fructose = ketose
Liposome has phospholipid bilayer
HCl; secreted by parietal cells under stim by gastrin

11. almost all exocytosed proteins pass through this
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
Testosterone and estradiol
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Smooth ER

12. important pancreatic enzymes
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

13. Meiosis II: EQUATIONAL DIVISION
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
Interstitial fluid (eg prostaglandins - cytokines)
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
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)

14. Path of urine

15. What hormones affect the stomach?
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
Neurons may perform one of three functions....
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
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

16. oxytocin
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increases solute conc and osmotic pressure of the ***medulla
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

17. What does portal vein do
All carbs absorbed at enterocytes are carried to liver by portal vein
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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

18. energy source of neurons
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Glucose and ketone bodies (not from glycogen stores)

19. How does glycogen compare to starch
Vitamin K - b12 - thiamin - riboflavin
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

20. Glycogenolysis/gluconeogenesis
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
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
ER

21. Different organs working together
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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
Systems (eg digestive system consists of many organs)

22. For focal point that is nearby - what will the lens look like
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
All carbs absorbed at enterocytes are carried to liver by portal vein
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... ...

23. 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)
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
- 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
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

24. Cell determination begins At what stage of development
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
Zygotes are diploid
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
- 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

25. How is glucose absorbed in sm intest
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
Contain capillary network - lymph vessels (lacteals)
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

26. What does peptic refer to in general
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
Zygotes are diploid
Digestion

27. Where does fertilization occur
Fallopian tubes
Homologous chromosomes separate - migrate towards opposite poles/centrioles
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

28. What controls release of LH - FSH from anterior pituitary
Gonadotropin releasing hormone - GnRH
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Eukaryotes
Two perpendicular semicircular canals involved in balance - equilibrium

29. How is the follicle developed during oogenesis
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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
Ventrally (picture skeletal vertebrae)

30. 90% digestion - absorption occurs in...
Many modern drugs are ligands for GPCRs
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
Salivary amylase; both hydrolyze glycosidic linkages
Low because AAs are immediately used in translation

31. small intestine=
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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)

32. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Facilitated diffusion from hi to lo conc
Uncontracted: parasymp (eg opoid use)
Increases blood Calcium
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

33. What are the memb - bound enzymes of the brush border?
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Determined by whether in front of or behind the lens
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

34. main point of fat transport...
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Below hypothalamus
Somatic nervous sys - autonomic nervous sys

35. calcitonin

36. 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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
- 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
Lysosome
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

37. Human chorionic gonadotropin...
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

38. What does peroxisome do
Water flows from the tubule - concentrating the filtrate - raising BP
Uncontracted: parasymp (eg opoid use)
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

39. Adrenal cortex hormones (STEROIDS)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

40. insulin secreted by
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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)
Beta cells
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

41. When 'coumadin targets liver enzymes to act as anticoagulant'...
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
It targets liver conc of prothrombin - fibrinogen etc
Outermost layer of blood vessel
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

42. inhibin secreted by
Glucose and ketone bodies (not from glycogen stores)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

43. golgi body
Sorts - modifies - concentrates proteins from the ER
Abdominal cavity - which is coated in serous fluid
vitreous humor - retina - fovea
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

44. PNS is broken down into
'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
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Somatic nervous sys - autonomic nervous sys
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

45. micelles also pick up
Paracrine (local) - endocrine (longer distance)
Lysosome
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

46. cAMP - cGMP - calmodulin...
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
About 7.2
Liposome has phospholipid bilayer
Needs time for bile - lipase - micelle migration - enterocyte uptake

47. gradual increase in FSH typical of primary follicle development;
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Creates one ovum (23 N) and three polar bodies
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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

48. testosterone can be aromatized to...
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Estradiol
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. components of interstitial fluid
Break down TAGs to monoglycerides and free fatty acids
Water flows from the tubule - concentrating the filtrate - raising BP
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Glycosaminoglycans - prots - AAs - lipids

50. What do villli do
'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.'
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
1) by integral ion channels 2) transmitted by second messenger system
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption