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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
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. Glycogenolysis/gluconeogenesis
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
- 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
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
- 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

2. Creating gradients requires what?
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

3. Chewing does what?
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Glands w/ducts: Exocrine glands
Increases surface area of food ball (bolus)
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

4. therefore - How does plasma leave capillary at the renal corpuscle

5. How does reabsorption force nutrients across apical membrane of proximal tubule
Sorts - modifies - concentrates proteins from the ER
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

6. How does the body mobilize fat stores
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Gonadotropin releasing hormone - GnRH
***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
Increases solute conc and osmotic pressure of the ***medulla

7. 90% digestion - absorption occurs in...
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
Gastrulation occurs: formation of three primary germ layers = differentiation
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Neurons may perform one of three functions....

8. What kind of cells make up epithel tiss of stom - then sm intest?
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
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
Fallopian tubes

9. components of interstitial fluid
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Regulated by gastrointestinal horms
Glycosaminoglycans - prots - AAs - lipids
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

10. When 'coumadin targets liver enzymes to act as anticoagulant'...
Somatic nervous sys - autonomic nervous sys
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
It targets liver conc of prothrombin - fibrinogen etc
Lysosome

11. from thoracic duct - chylomicrons stick to capillary walls...
Increases surface area of food ball (bolus)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct

12. Posterior eye
'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
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
vitreous humor - retina - fovea
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

13. pancreas secretes enzymes via
Facilitated diffusion: no symport w/ secondary transport
Pancreatic duct (made of acinar cells?)
Two perpendicular semicircular canals involved in balance - equilibrium
***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

14. smooth ER main function
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

15. micelles vs liposomes
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
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Moves down thru esophageal sphincter
Liposome has phospholipid bilayer

16. exocrine types
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

17. What is gastric acid?
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
HCl; secreted by parietal cells under stim by gastrin
Has memb - bound organelles - etc...
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

18. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
Salivary amylase; both hydrolyze glycosidic linkages
Pancreatic duct (made of acinar cells?)
1) by integral ion channels 2) transmitted by second messenger system
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

19. what happens to bile secretions
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Mostly reabsorbed to liver
vitreous humor - retina - fovea
5

20. when thinking of proteins - think
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Nitrogen
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

21. Gland: ovaries
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Digestion

22. gametes are haploid
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Oxytocin and ADH (aka vasopressin)
Zygotes are diploid
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

23. What is endothelium?
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
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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
Inner lining of blood vessels

24. Mucus - digestive enzymes released thru
Glands w/ducts: Exocrine glands
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
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
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

25. What is the adventitia?
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Outermost layer of blood vessel
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

26. lysosome pH
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
5
Inner lining of blood vessels
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

27. only monosaccharides are absorbed
Which is why lactase - maltase - dextrinase - sucrase are on brush border
HCl; secreted by parietal cells under stim by gastrin
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

28. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Inner lining of circulatory system

29. What is the net effect of the loop of Henle
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)
Normally contracted
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Lower blood pH

30. Sensory neuron cell bodies vs. somatic motor cell bodies
Peptides
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Facilitated diffusion: no symport w/ secondary transport

31. Three stages of the menstrual 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
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
90-140 mg/dl
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

32. Where do pancreatic secretions take effect
Digestion
RBCs - large proteins; What does enter is called the filtrate
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Sorts - modifies - concentrates proteins from the ER

33. What testosterone released by secondary follicle by LH stim is converted to...
Pancreatic duct (made of acinar 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)
Interstitial fluid (eg prostaglandins - cytokines)
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

34. How does blood sugar move into tissues?
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Facilitated diffusion from hi to lo conc
- 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

35. How does water cross the apical membrane
Liposome has phospholipid bilayer
Thru tight junctions by favorable osmotic gradient
Normally contracted
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

36. What are the major carbohydrates
Gonadotropin releasing hormone - GnRH
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Paracrine (local) - endocrine (longer distance)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

37. Where does fertilization occur
Fallopian tubes
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
ER
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

38. fructose enters enterocyte by
Salivary amylase; both hydrolyze glycosidic linkages
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Facilitated diffusion: no symport w/ secondary transport
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

39. Beta - oxidation in liver produces...
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

40. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
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 line up w/ attachment of spindle fibers/microtubule polymers to centromeres via kinetochores; identical in appearance under light microscope to metaphase of mitosis
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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

41. PNS nerve signal
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
Glucose = aldose fructose = ketose
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

42. What force is acting upon chyme to move it forward down sm intestine
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons

43. mucus cells line the stomach...
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Conjunction of cell body w/axon

44. What hormones affect the stomach?
5
Fructose is a structural isomer of glucose
Micelles; micelles (made of bile) go back and forth between brush border and chyme
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

45. Alpha - amylase found where
Fallopian tubes
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
In mouth - breakdown of starch into polysaccharides
Meiosis creates germ cells

46. Human chorionic gonadotropin...
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Eukaryotes
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

47. what else is located in the inner ear (not directly related to auditory)
Two perpendicular semicircular canals involved in balance - equilibrium
Mostly reabsorbed to liver
Membrane - bound - endocytosed bodies
Liver is the control center for blood glucose; is fed by portal vein from sm intest

48. Think of spinal cord injury
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Systems (eg digestive system consists of many organs)
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
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

49. At post - two weeks ovulation
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Sorts - modifies - concentrates proteins from the ER
Corpus luteum degrades into corpus albicans
Below hypothalamus

50. Gastrulation: ectoderm/mesoderm/endoderm
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Glucose and ketone bodies (not from glycogen stores)
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Has memb - bound organelles - etc...