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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. Where would materials slated for digestion go?
All carbs absorbed at enterocytes are carried to liver by portal vein
Lysosome
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
Increases solute conc and osmotic pressure of the ***medulla

2. Exocrine GlandS: stomach
- 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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

3. Where else does ADH act
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Nitrogen

4. Adrenal cortex hormones (STEROIDS)
Carry signals to musc OR Gland
RBCs - large proteins; What does enter is called the filtrate
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

5. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Meiosis creates germ cells
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Primitive streak - which consists of cells of the MESODERM ****

6. Difference between euk and prok flagella
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Form barrier to extracellular fluid
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

7. insulin secreted by
Beta cells
Increases surface area of food ball (bolus)
Carry signals to musc OR Gland
Neurons may perform one of three functions....

8. What do the glomerulus and Bowman's capsule add up to...
The renal corpuscle
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Fovea (highest amount of cones)

9. gametic life cycle
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Liposome has phospholipid bilayer
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

10. What is endothelium?
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
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Inner lining of blood vessels
Glucose = aldose fructose = ketose

11. Spinal cord horns (thick knobs) point
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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
Ventrally (picture skeletal vertebrae)

12. For focal point that is nearby - what will the lens look like
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
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
The renal corpuscle
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

13. How does reabsorption force nutrients across apical membrane of proximal tubule
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Somatic nervous sys - autonomic nervous sys
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

14. 3 phases of menstrual cycle
'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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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)
Membrane - bound - endocytosed bodies

15. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Outermost layer of blood vessel
Testosterone and estradiol
Regulated by gastrointestinal horms
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera

16. What is the net effect of the loop of Henle
vitreous humor - retina - fovea
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)
Sensory (afferent - dorsal) - motor (efferent - ventral)
Normally contracted

17. 'Cell bodies of somatic motor neurons are located in....'
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Ventrally (picture skeletal vertebrae)
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

18. Energy from fat - prot - gluc
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

19. In effect LH - FSH stimulate
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Prod of steroid hormones in testes - ovaries
Eukaryotes
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

20. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Membrane - bound - endocytosed bodies
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

21. What does peroxisome do
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Moves down thru esophageal sphincter

22. What is somatostatin
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
RBCs - large proteins; What does enter is called the filtrate

23. gradual increase in FSH typical of primary follicle development;
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
90-140 mg/dl
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

24. How do parietal cells work ** (involves CO2)
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Peripheral nervous sys
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

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

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26. 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
Beta cells
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Increases solute conc and osmotic pressure of the ***medulla

27. Most important nutrients absorbed by large intestine
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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

28. What testosterone released by secondary follicle by LH stim is converted to...
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Homologous chromosomes separate - migrate towards opposite poles/centrioles
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.
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

29. What does lipase attack exactly
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Within the paravertebral ganglion - running parallel to spinal cord
Contain capillary network - lymph vessels (lacteals)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

30. bile + fat forms
Water flows from the tubule - concentrating the filtrate - raising BP
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
- 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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

31. Meiosis I Telophase I
90-140 mg/dl
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Interstitial fluid (eg prostaglandins - cytokines)

32. Creating gradients requires what?
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
Testosterone and estradiol
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
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

33. FLAT PG: TSH aka thyrotropin
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
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
Systems (eg digestive system consists of many organs)
Testosterone upon stim by LH

34. Seen in lysosomal storage diseases
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Beta cells
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

35. Morula (...totipotent)
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

36. What is the mesentery?
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
- 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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Inner lining of blood vessels

37. Failure of apoptosis can result in
Corpus luteum degrades into corpus albicans
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue

38. How is glucose absorbed in sm intest
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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

39. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Break down TAGs to monoglycerides and free fatty acids
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Direction of differentiation
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

40. In general - parietal=
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Neurons may perform one of three functions....
The wall of the body or of a body cavity or hollow structure
Liposome has phospholipid bilayer

41. Different tissues working together
Organs
Neurons may perform one of three functions....
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Primitive streak - which consists of cells of the MESODERM ****

42. Gastrin from G cells stims parietal cells...
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0

43. pancreatic amylase is much stronger than
Thru tight junctions by favorable osmotic gradient
Salivary amylase; both hydrolyze glycosidic linkages
Mostly reabsorbed to liver
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)

44. portal vein physiology...

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45. Meiosis II: EQUATIONAL DIVISION
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
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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

46. lining of abdominal cavity=
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
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
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
An endogenous morphine

47. Peritoneal refers to...
Primitive streak - which consists of cells of the MESODERM ****
'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
Meiosis creates germ cells
Abdominal cavity - which is coated in serous fluid

48. Blastocyst
Glands w/ducts: Exocrine glands
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

49. energy source of neurons
HCl; secreted by parietal cells under stim by gastrin
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Salivary amylase; both hydrolyze glycosidic linkages
Glucose and ketone bodies (not from glycogen stores)

50. keep in mind that enterocyte is like a regular euk cell
Which is why lactase - maltase - dextrinase - sucrase are on brush border
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Has memb - bound organelles - etc...
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity