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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. What is a nerve? (PNS)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
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
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve

2. What is secreted into filtrate by cells of the proximal tubule?
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Facilitated diffusion: no symport w/ secondary transport
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Stom= G cells (gastrin) - parietal (oxyntic); chief (peptic); mucous cells (hi ER - Golgi to make sticky glycoprots) - sm intest= enterocytes (w/brush border of maltase - sucrase - lactase - dextrinase; peptidase; lipase; nucleases); goblet cells (mu

3. PNS nerve signal
Within the paravertebral ganglion - running parallel to spinal cord
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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

4. Fructose relates how structurally to glucose
Fructose is a structural isomer of glucose
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
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

5. What are phagosomes
Membrane - bound - endocytosed bodies
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
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
Increases blood Calcium

6. when cells hit their limit for prot storage...
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
AAs can be burned for energy or converted to fat for storage
Peptides

7. Alpha - amylase found where
90-140 mg/dl
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
Normally contracted
In mouth - breakdown of starch into polysaccharides

8. 3 phases of menstrual cycle
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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
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)
Form barrier to extracellular fluid

9. What is main difference is signal transmission in nicotinic vs muscarinic?
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
***nicotinic is ionotropic; muscarinic is GPCR
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

10. review: parietals secrete intrinsic factor...
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
In mouth - breakdown of starch into polysaccharides
Sensory (afferent - dorsal) - motor (efferent - ventral)
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

11. How is the follicle developed during oogenesis
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Within the paravertebral ganglion - running parallel to spinal cord
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Water flows from the tubule - concentrating the filtrate - raising BP

12. Embryology
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
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
Abdominal cavity - which is coated in serous fluid
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

13. quote on cavities/viscera

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14. glucagon secreted by
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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.

15. Both divisions (somatic - autonomic) of PNS consist of...
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Sensory (afferent - dorsal) - motor (efferent - ventral)
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule

16. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Digestion
Glycosaminoglycans - prots - AAs - lipids
An endogenous morphine

17. golgi body
Break down TAGs to monoglycerides and free fatty acids
Sorts - modifies - concentrates proteins from the ER
Systems (eg digestive system consists of many organs)
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

18. medium for paracrine hormones
Sensory (afferent - dorsal) - motor (efferent - ventral)
HCl; secreted by parietal cells under stim by gastrin
Interstitial fluid (eg prostaglandins - cytokines)
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit

19. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
Zygotes are diploid
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron

20. How do monoglycerides and ffas get to brush border?
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Zygotes are diploid
Glycosaminoglycans - prots - AAs - lipids
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)

21. 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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
- 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

22. what else is located in the inner ear (not directly related to auditory)
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Two perpendicular semicircular canals involved in balance - equilibrium

23. Some epithelial cells are... others...
Only musc and esp ** liver can store large amounts
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
- 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
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

24. thyroid hormones: Not All One Kind of HORM
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
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
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

25. What does peroxisome do
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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
Water flows from the tubule - concentrating the filtrate - raising BP

26. Thus inhibiting parietal cells could do What to blood pH
Lower blood pH
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Corpus luteum degrades into corpus albicans
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

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

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28. insulin secreted by
Beta cells
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
An endogenous morphine
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

29. On what surface of the retina is the eye most sensitive
Glands w/ducts: Exocrine glands
About 7.2
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Fovea (highest amount of cones)

30. bile + fat forms
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Two perpendicular semicircular canals involved in balance - equilibrium

31. What does peptic refer to in general
Digestion
Vitamin K - b12 - thiamin - riboflavin
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
'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

32. mitosis creates somatic cells
Eukaryotes
75% water/ 25% solid mass: of that solid mass: 10-20% fat = phospholipid bilayer of bacteria - slough - off enterocytes ie stomach lining (must be constantly rebuilt) 10-20% inorganic material 30% roughage = fiber = cellulose (indigestible) 2-3% prot
Meiosis creates germ cells
Peptide; stims growth of nearly all cell of body; all other anterior pituitary horms have specific targets; upregulates anabolic pathways; use of fat for energy goes up (fat - burning); increases AA transport across cell membrane (nutrient uptake)

33. Bile salts and lipase
Needs time for bile - lipase - micelle migration - enterocyte uptake
Estradiol
Ups bicarbonate secretion by pancreas; raises pH to 6.0
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

34. After meiosis I - daughter cells are...

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35. What is a plasmalogen?
Faces the lumen
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss

36. Cell determination begins At what stage of development
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Thru tight junctions by favorable osmotic gradient
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

37. Blastocyst
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
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)

38. Meiosis I Metaphase I
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Normally contracted
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on

39. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
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**

40. examples of different cavities... (compartments for viscera)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

41. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Abdominal cavity - which is coated in serous fluid
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

42. Path of urine

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43. Ovum development is halted At what stage until fertilization...
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
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

44. How does blood sugar move into tissues?
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Facilitated diffusion from hi to lo conc
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

45. Where else does ADH act
Pancreatic duct (made of acinar cells?)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

46. sporic life cycle
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
Two perpendicular semicircular canals involved in balance - equilibrium
It targets liver conc of prothrombin - fibrinogen etc
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

47. oxytocin
Night vision
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

48. sensory (afferent) neurons
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
***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
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

49. Mucus - digestive enzymes released thru
ER
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Glands w/ducts: Exocrine glands
Fructose is a structural isomer of glucose

50. When 'coumadin targets liver enzymes to act as anticoagulant'...
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
It targets liver conc of prothrombin - fibrinogen etc
Called a tract in the CNS; bundling together of axons/dendrites thru which many diff signals pass; many many neurons are bundled together into a single nerve
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion