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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. Adrenal medulla hormones (TYR- DERIVED)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
About 7.2
Peripheral nervous sys

2. Four tissues
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

3. Thus - central nervous sys is...
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
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

4. examples of different cavities... (compartments for viscera)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
An endogenous morphine
Increases solute conc and osmotic pressure of the ***medulla
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes

5. in mammals - gastrulation involves formation of the
'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
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
Abdominal cavity - which is coated in serous fluid
Primitive streak - which consists of cells of the MESODERM ****

6. What are phagosomes
Membrane - bound - endocytosed bodies
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

7. Determination is different than differentiation
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Below hypothalamus
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
An endogenous morphine

8. What is endothelium?
Inner lining of blood vessels
Systems (eg digestive system consists of many organs)
All carbs absorbed at enterocytes are carried to liver by portal vein
Cancer; apop can be programmed cell death; mitochon can play important role in apop

9. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Oxytocin and ADH (aka vasopressin)
It targets liver conc of prothrombin - fibrinogen etc

10. euk cell has two principal sides
Lumen (ie continuous w/body cavity) and cytosol
'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
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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

11. What is a plasmalogen?
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
- 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
Fallopian tubes

12. liver receives blood from...
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Zygotes are diploid

13. important pancreatic enzymes
Lysosome
Outermost layer of blood vessel
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Organs

14. Interaction of corpus luteum/placenta
Increases solute conc and osmotic pressure of the ***medulla
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

15. FLAT PG: prolactin
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
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Faces the lumen

16. Does bile digest fat?
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

17. when cells hit their limit for prot storage...
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
AAs can be burned for energy or converted to fat for storage
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

18. 3 phases of menstrual cycle
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
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)
Has memb - bound organelles - etc...

19. bile + fat forms
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Faces the lumen
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

20. Glucose is a .... sugar; fructose is a .... sugar
Glucose = aldose fructose = ketose
Increases surface area of food ball (bolus)
Most absorption occurs in sm intestine
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

21. Where do absorbed fats go in the enterocyte
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
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
Increases surface area of food ball (bolus)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

22. in fat and liver cells monoglycerides and ffas are once again
Eukaryotes
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver

23. Cell bodies of SYMP postganglionic neurons lie far from effector...
Within the paravertebral ganglion - running parallel to spinal cord
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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)

24. The path from blood plasma to urine

25. In IBS - What is defective

26. fructose enters enterocyte by
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Facilitated diffusion: no symport w/ secondary transport

27. large intestine E. coli aid absorption of...
Transfer signals from neuron - neuron; 90% of neurons are interneurons
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
Vitamin K - b12 - thiamin - riboflavin
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

28. parathyroid hormone
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Testosterone and estradiol
Increases blood Calcium

29. Anterior eye vs. posterior eye
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
Determined by whether in front of or behind the lens
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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

30. Chewing does what?
Increases surface area of food ball (bolus)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Liposome has phospholipid bilayer
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

31. pancreatic enzymes are zymogens
Meiosis creates germ cells
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Homologous chromosomes separate - migrate towards opposite poles/centrioles
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

32. interneurons
Gonadotropin releasing hormone - GnRH
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Sorts - modifies - concentrates proteins from the ER

33. FLAT PG: LH
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
Gonadotropin releasing hormone - GnRH
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

34. alpha - amylase in the mouth digests what kind of bond
'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
Alpha 1-4 and 1-6 (branching) glycosidic linkages
- 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
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

35. Energy from fat - prot - gluc
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms

36. What is somatostatin
Regulated by gastrointestinal horms
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Vitamin K - b12 - thiamin - riboflavin
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

37. little by little chyme is squirted out thru pyloric sphincter
Sensory (afferent - dorsal) - motor (efferent - ventral)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Determined by whether in front of or behind the lens
Regulated by gastrointestinal horms

38. A group of cell bodies in CNS is nucleus - outside CNS is...
Ganglion
***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
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

39. what happens to bile secretions
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Mostly reabsorbed to liver
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

40. Glycogenolysis/gluconeogenesis
Normally contracted
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
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
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

41. FSH - LH - HCG - inhibin are...
HCl; secreted by parietal cells under stim by gastrin
Peptides
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
- 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

42. Anterior eye
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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
Within the paravertebral ganglion - running parallel to spinal cord

43. Gastrin from G cells stims parietal cells...
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Zygotes are diploid
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

44. What are the memb - bound enzymes of the brush border?
Testosterone upon stim by LH
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

45. 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
HCl; secreted by parietal cells under stim by gastrin
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
- 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

46. How is the follicle developed during oogenesis
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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
vitreous humor - retina - fovea

47. Seen in lysosomal storage diseases
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Increases solute conc and osmotic pressure of the ***medulla
Facilitated diffusion: no symport w/ secondary transport
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

48. Sensory neuron cell bodies vs. somatic motor cell bodies
Glycosaminoglycans - prots - AAs - lipids
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
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

49. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

50. only monosaccharides are absorbed
Glycosaminoglycans - prots - AAs - lipids
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Peptides
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy