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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. Anterior eye vs. posterior eye
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)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Facilitated diffusion: no symport w/ secondary transport
Determined by whether in front of or behind the lens

2. pancreatic enzymes are zymogens
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

3. energy source of neurons
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Somatic nervous sys - autonomic nervous sys
Glucose and ketone bodies (not from glycogen stores)
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

4. 80% of end product of carbohydrate metabolism is...
Most absorption occurs in sm intestine
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Glucose
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

5. Where is bile produced
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
In liver (RBC recycling of heme); stored in gall bladder; released via cystic duct to common bile duct (shared w/liver); common bile duct joins up with panc duct...everything feeds into the sm intest at the ampulla of vater**
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

6. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Below hypothalamus
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
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Zygotes are diploid

7. Both divisions (somatic - autonomic) of PNS consist of...
Chylomicrons are much bigger
Sensory (afferent - dorsal) - motor (efferent - ventral)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
1) by integral ion channels 2) transmitted by second messenger system

8. How does blood sugar move into tissues?
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Outermost layer of blood vessel
Facilitated diffusion from hi to lo conc
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

9. 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)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Thru tight junctions by favorable osmotic gradient
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

10. At post - two weeks ovulation
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
Corpus luteum degrades into corpus albicans
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

11. position of AP...
Below hypothalamus
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

12. FLAT PG: LH
Lumen (ie continuous w/body cavity) and cytosol
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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
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

13. Where would materials slated for digestion go?
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Lysosome
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
vitreous humor - retina - fovea

14. overall - fatty - prot - rich food in duod causes
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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Chyme (by combined activity of exocrine glands)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome

15. medium for paracrine hormones
Has memb - bound organelles - etc...
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Interstitial fluid (eg prostaglandins - cytokines)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

16. keep in mind that enterocyte is like a regular euk cell
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Has memb - bound organelles - etc...

17. How does the body mobilize fat stores
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Most absorption occurs in sm intestine
***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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

18. sporic life cycle
Glycosaminoglycans - prots - AAs - lipids
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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
'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

19. Some epithelial cells are... others...
- 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
Nitrogen
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
- 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

20. 80-90% fat absorbed this way
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
Normally contracted
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

21. What testosterone released by secondary follicle by LH stim is converted to...
Moves down thru esophageal sphincter
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
'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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

22. Gastrulation: ectoderm/mesoderm/endoderm
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Form barrier to extracellular fluid
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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. Failure of apoptosis can result in
Liposome has phospholipid bilayer
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

24. Exocrine GlandS: stomach
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
- parietal cells (**oxyntic= hi oxygen consumption - hi E??): have hi conc mito; need lots of energy to create proton gradient; thus - responsible for extremely harsh pH conditions in stom; denaturing conditions - chief cells (peptic): synthesize pep
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
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

25. physiology of gall bladder - liver and pancreatic secretions
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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

26. The esophageal sphincter is...
Normally contracted
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Glucose

27. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Fallopian tubes
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

28. Induction affects...
Direction of differentiation
Lower blood pH
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)

29. at lo blood sugar...
Low because AAs are immediately used in translation
Lower blood pH
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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

30. E storage per unit mass
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
'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.'
Organs
Which is why lactase - maltase - dextrinase - sucrase are on brush border

31. 'Cell bodies of somatic motor neurons are located in....'
Conjunction of cell body w/axon
'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
The renal corpuscle
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

32. signal transduction occurs by 2 paths
1) by integral ion channels 2) transmitted by second messenger system
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
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

33. Meiosis I Anaphase I
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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
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

34. lysosome main function and derivation
Sympathetic: dilates pupil (for night hunting)
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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)

35. Morula (...totipotent)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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)

36. What is the function of the loop of Henle
Increases solute conc and osmotic pressure of the ***medulla
Sensory (afferent - dorsal) - motor (efferent - ventral)
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

37. sensory (afferent) neurons
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
HCl; secreted by parietal cells under stim by gastrin
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Outermost layer of blood vessel

38. portal vein physiology...

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39. FSH - LH - HCG - inhibin are...
Glands w/ducts: Exocrine glands
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Peptides
1) by integral ion channels 2) transmitted by second messenger system

40. inhibin secreted by
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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

41. How is the follicle developed during oogenesis
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

42. Gland: ovaries
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

43. PNS nerve signal
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Fructose is a structural isomer of glucose
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
Interstitial fluid (eg prostaglandins - cytokines)

44. 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
Peptides
Membrane - bound - endocytosed bodies
In mouth - breakdown of starch into polysaccharides

45. Gastrin from G cells stims parietal cells...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Facilitated diffusion from hi to lo conc
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

46. PNS review: SAME DAVE
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.
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Digestion
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

47. How does birth control work?
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

48. Beta - oxidation in liver produces...
Oxytocin and ADH (aka vasopressin)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
The wall of the body or of a body cavity or hollow structure

49. examples of different cavities... (compartments for viscera)
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Liver is the control center for blood glucose; is fed by portal vein from sm intest
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

50. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Water flows from the tubule - concentrating the filtrate - raising BP
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Creates one ovum (23 N) and three polar bodies