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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. PNS nerve signal
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Chylomicrons are much bigger
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
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

2. examples of different cavities... (compartments for viscera)
Glycosaminoglycans - prots - AAs - lipids
Increases solute conc and osmotic pressure of the ***medulla
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
5

3. FLAT PG: LH
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Gastrulation occurs: formation of three primary germ layers = differentiation
Beta cells
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

4. Glucose is a .... sugar; fructose is a .... sugar
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
Lumen (ie continuous w/body cavity) and cytosol
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
Glucose = aldose fructose = ketose

5. axon hillock physiology
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
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
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Conjunction of cell body w/axon

6. What do lipases do
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Break down TAGs to monoglycerides and free fatty acids
Inner lining of blood vessels
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

7. Human chorionic gonadotropin...
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

8. Meiosis I Telophase I
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Uncontracted: parasymp (eg opoid use)
Meiosis creates germ cells

9. almost all exocytosed proteins pass through this
Testosterone and estradiol
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Sympathetic: dilates pupil (for night hunting)
Smooth ER

10. During ejaculation - sperm...

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

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12. amylase acts where on carbs
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage

13. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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... ...
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
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

14. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Increases solute conc and osmotic pressure of the ***medulla
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)

15. parathyroid hormone
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Increases blood Calcium

16. Ovum development is halted At what stage until fertilization...
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Below hypothalamus
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

17. After meiosis II - Male

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18. 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
Chyme (by combined activity of exocrine glands)
In gastric pits; secretions combine into gastric juice
All carbs absorbed at enterocytes are carried to liver by portal vein

19. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
'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
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

20. Meiosis I Metaphase I
Carry signals to musc OR Gland
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Transfer signals from neuron - neuron; 90% of neurons are interneurons

21. Both divisions (somatic - autonomic) of PNS consist of...
Sensory (afferent - dorsal) - motor (efferent - ventral)
Increases solute conc and osmotic pressure of the ***medulla
Processes: axons - dendrites
Which is why lactase - maltase - dextrinase - sucrase are on brush border

22. overview of prot digestion
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
Two perpendicular semicircular canals involved in balance - equilibrium
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

23. What is the net effect of the loop of Henle
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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)
The wall of the body or of a body cavity or hollow structure
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

24. Spinal cord horns (thick knobs) point
(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
Ventrally (picture skeletal vertebrae)
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**

25. 80% of end product of carbohydrate metabolism is...
Micelles; micelles (made of bile) go back and forth between brush border and chyme
Glucose
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
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids

26. On what surface of the retina is the eye most sensitive
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Fovea (highest amount of cones)
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
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

27. What surrounds the hydrophilic heads of the new TAGs
Peptides
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
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
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

28. The EYE
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Form barrier to extracellular fluid
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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate

29. Kidney
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

30. Contrast PNS- Somatic with PNS- Autonomic
Glucose
Meiosis creates germ cells
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Glands w/ducts: Exocrine glands

31. AP- peptides (FSH - LH - ACTH - TSH - prolactin - hGH); PP- peptides (ADH - oxytocin); thyroid - peptide *and* tyr - derived (T3/T4 - calcitonin); parathyroid - peptide (PTH; raise blood Ca via pathway involving vitamin D)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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
Regulated by gastrointestinal horms
About 7.2

32. energy source of neurons
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Digestion
Glucose and ketone bodies (not from glycogen stores)

33. mitosis creates somatic cells
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Meiosis creates germ cells
Two perpendicular semicircular canals involved in balance - equilibrium
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

34. 'Cell bodies of somatic motor neurons are located in....'
'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.'
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Liposome has phospholipid bilayer
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

35. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
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
Ventrally (picture skeletal vertebrae)

36. glucagon secreted by
HCl; secreted by parietal cells under stim by gastrin
Smooth ER
Most absorption occurs in sm intestine
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

37. these transport proteins - when concs are high enough...
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Glucose
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

38. from thoracic duct - chylomicrons stick to capillary walls...
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
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.
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

39. portal vein physiology...

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40. What hormones affect the stomach?
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
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
Ganglion
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)

41. keep in mind that enterocyte is like a regular euk cell
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
RBCs - large proteins; What does enter is called the filtrate
Has memb - bound organelles - etc...
Glucose

42. What is a nerve? (PNS)
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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
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
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

43. trypsin is secreted by
23 N; 23 chromosomes and haploid (no homologous chromosomes); each chromosome has two sister chromatids Male: primary spermatocyte -->REDUCTIONAL DIVISION (first stim'd at puberty by GnRH - LH-->secondary spermatocyte Female: primary oocyte (arreste
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides
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
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

44. In effect LH - FSH stimulate
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
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Prod of steroid hormones in testes - ovaries

45. Cell bodies of SYMP postganglionic neurons lie far from effector...
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
AAs can be burned for energy or converted to fat for storage
Within the paravertebral ganglion - running parallel to spinal cord
Normally contracted

46. A contracted iris occurs with what kind of stimulation
Epithelial tissue near semniferous tubules
Sympathetic: dilates pupil (for night hunting)
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

47. What if large intestine isn't working well
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Testosterone and estradiol
Outermost layer of blood vessel
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

48. What is the mesentery?
Water flows from the tubule - concentrating the filtrate - raising BP
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
Transfer signals from neuron - neuron; 90% of neurons are interneurons
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

49. What is secreted into filtrate by cells of the proximal tubule?
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

50. At post - two weeks ovulation
Corpus luteum degrades into corpus albicans
Direction of differentiation
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Testosterone and estradiol