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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. interneurons
Transfer signals from neuron - neuron; 90% of neurons are interneurons
'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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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

2. Meiosis I Telophase I
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
An endogenous morphine
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

3. Posterior eye
Conjunction of cell body w/axon
vitreous humor - retina - fovea
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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

4. exocrine types
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
In mouth - breakdown of starch into polysaccharides
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

5. Where are these exocrine glands located
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Fructose is a structural isomer of glucose
In gastric pits; secretions combine into gastric juice
Glands w/ducts: Exocrine glands

6. sporic life cycle
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Form barrier to extracellular fluid
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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

7. How does duod deal with hi HCl from stom
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
AAs can be burned for energy or converted to fat for storage
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

8. Neuronal cell bodies have extensions ie
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Processes: axons - dendrites
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)

9. How does water cross the apical membrane
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)
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Thru tight junctions by favorable osmotic gradient
Sensory (afferent - dorsal) - motor (efferent - ventral)

10. Adrenal medulla hormones (TYR- DERIVED)
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

11. Kidney
Water flows from the tubule - concentrating the filtrate - raising BP
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

12. Blastocyst
Neurons may perform one of three functions....
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

13. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

14. protein absorption at enterocyte
Contain capillary network - lymph vessels (lacteals)
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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

15. FLAT PG: FSH
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Increases solute conc and osmotic pressure of the ***medulla
Membrane - bound - endocytosed bodies
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

16. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Digestion
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
Night vision
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

17. Luteal surge
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

18. SYMP neurons originate in= PARA neurons originate in=
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
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
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Ventrally (picture skeletal vertebrae)

19. How do nutrients move?
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
Organs
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

20. liver receives blood from...
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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
Normally contracted
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... ...

21. In effect LH - FSH stimulate
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
'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
All carbs absorbed at enterocytes are carried to liver by portal vein
Prod of steroid hormones in testes - ovaries

22. in mammals - gastrulation involves formation of the
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
Primitive streak - which consists of cells of the MESODERM ****
Systems (eg digestive system consists of many organs)

23. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Systems (eg digestive system consists of many organs)
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Chylomicrons are much bigger

24. In IBS - What is defective

25. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Sorts - modifies - concentrates proteins from the ER
5
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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... ...

26. Where does blood to be filtered by kidney enter the nephron?

27. extracellular matrix formed mainly of...
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Zygotes are diploid
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

28. insulin secreted by
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Beta cells
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

29. How long are peptides when absorbed at brush border
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
***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

30. FLAT PG: prolactin
Glycosaminoglycans - prots - AAs - lipids
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Glucose = aldose fructose = ketose

31. What is the endothelium?
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Needs time for bile - lipase - micelle migration - enterocyte uptake
Inner lining of circulatory system
Which is why lactase - maltase - dextrinase - sucrase are on brush border

32. microvilli: increase SA of enterocyte; have hi conc of digestive enzymes

33. What does portal vein do
In gastric pits; secretions combine into gastric juice
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
All carbs absorbed at enterocytes are carried to liver by portal vein

34. A contracted iris occurs with what kind of stimulation
Form barrier to extracellular fluid
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Sympathetic: dilates pupil (for night hunting)
Has memb - bound organelles - etc...

35. overall - fatty - prot - rich food in duod causes
Processes: axons - dendrites
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Beta cells

36. motor (efferent) neurons --> VENTRAL
Digestion
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Carry signals to musc OR Gland
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

37. Thus inhibiting parietal cells could do What to blood pH
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
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
Lower blood pH

38. oxytocin
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)
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Peripheral nervous sys
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

39. 3 phases of menstrual cycle
Follicular phase: primary - secondary - ovulation (1 week) luteal phase: ovulation - thickening of uterine lining w/corpus luteum secretion - corpus luteum degrades (2 weeks) flow: shedding of uterine lining (4 days)
***nicotinic is ionotropic; muscarinic is GPCR
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

40. Embryology
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Break down TAGs to monoglycerides and free fatty acids
Normally contracted
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

41. Beta - oxidation in liver produces...
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

42. Human chorionic gonadotropin...
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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Digestion

43. Sensory neuron cell bodies vs. somatic motor cell bodies
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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

44. light detection via GPCRs
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
- 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
Mostly reabsorbed to liver

45. signal transduction occurs only in
RBCs - large proteins; What does enter is called the filtrate
Eukaryotes
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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

46. Alpha - amylase found where
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
In mouth - breakdown of starch into polysaccharides

47. E storage per unit mass
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
Within the paravertebral ganglion - running parallel to spinal cord

48. thyroid hormones: Not All One Kind of HORM
Epithelial tissue near semniferous tubules
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

49. Where else does ADH act
AAs can be burned for energy or converted to fat for storage
Abdominal cavity - which is coated in serous fluid
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

50. almost all exocytosed proteins pass through this
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Estradiol
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Smooth ER