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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. Posterior eye
About 7.2
Ganglion
Facilitated diffusion from hi to lo conc
vitreous humor - retina - fovea

2. What determines number of chromosomes?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
It targets liver conc of prothrombin - fibrinogen etc
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
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter

3. overall - fatty - prot - rich food in duod causes
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
In gastric pits; secretions combine into gastric juice
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

4. FLAT PG: prolactin
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

5. What happens when rod cell is depolarized
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Night vision
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

6. How does duod deal with hi HCl from stom
Processes: axons - dendrites
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Oxytocin and ADH (aka vasopressin)
Direction of differentiation

7. What is gastric acid?
HCl; secreted by parietal cells under stim by gastrin
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Vitamin K - b12 - thiamin - riboflavin

8. Think of spinal cord injury
Increases surface area of food ball (bolus)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

9. Human chorionic gonadotropin...
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
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

10. At post - two weeks ovulation
Thru tight junctions by favorable osmotic gradient
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
Salivary amylase; both hydrolyze glycosidic linkages
Corpus luteum degrades into corpus albicans

11. A contracted iris occurs with what kind of stimulation
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
AAs can be burned for energy or converted to fat for storage
Sympathetic: dilates pupil (for night hunting)
An endogenous morphine

12. duodenum must have receptors for fat content - protein because
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Presence of fat - prot in duodenum causes release of **gastric inhibitory peptide**; result is slower stomach contraction; slower emptying into duod thru pyloric sphincter (slower chyme secretion); more time to properly digest - absorb nutrients
The renal corpuscle
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

13. fructose enters enterocyte by
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
Facilitated diffusion: no symport w/ secondary transport
In gastric pits; secretions combine into gastric juice
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

14. What if large intestine isn't working well
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

15. lining of abdominal cavity=
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
The wall of the body or of a body cavity or hollow structure
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes

16. FLAT PG: FSH
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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
***nicotinic is ionotropic; muscarinic is GPCR
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males

17. testosterone can be aromatized to...
Inner lining of blood vessels
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Regulated by gastrointestinal horms
Estradiol

18. In effect LH - FSH stimulate
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
Peripheral nervous sys
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
Prod of steroid hormones in testes - ovaries

19. What is the path of a sound wave that enters the ear?
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
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity

20. Both divisions (somatic - autonomic) of PNS consist of...
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Abdominal cavity - which is coated in serous fluid

21. What is feces composed of...
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
Salivary amylase; both hydrolyze glycosidic linkages
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
Vitamin K - b12 - thiamin - riboflavin

22. overview of prot digestion
Glucose and ketone bodies (not from glycogen stores)
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
- 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

23. Failure of apoptosis can result in
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
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop

24. in mammals - gastrulation involves formation of the
Primitive streak - which consists of cells of the MESODERM ****
vitreous humor - retina - fovea
Conjunction of cell body w/axon
Moves down thru esophageal sphincter

25. signal transduction occurs only in
Eukaryotes
An endogenous morphine
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
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

26. mitosis creates somatic cells
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
Meiosis creates germ cells
Chyme (by combined activity of exocrine glands)
Sympathetic: dilates pupil (for night hunting)

27. Meiosis I Telophase I
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Glucose and ketone bodies (not from glycogen stores)
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)
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)

28. liver and blood glucose...
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

29. What is the net effect of the distal tubule
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
Chyme (by combined activity of exocrine glands)
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
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

30. Where does fertilization occur
Fallopian tubes
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Zygotes are diploid

31. Determination is different than differentiation
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Digestion
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

32. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Small intestine; duodenum is smallest and does most DIGESTION; jejunum is medium and does most ABSORPTION; ileum is biggest and does most absorption along with jejunum
Ammonia; must be converted to urea by liver and excreted in urine by kidney
- 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

33. ligands are the messenger compounds that target secondary messenger systems on effectors
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
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Glucose = aldose fructose = ketose
Many modern drugs are ligands for GPCRs

34. smooth ER main function
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Water flows from the tubule - concentrating the filtrate - raising BP
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
All carbs absorbed at enterocytes are carried to liver by portal vein

35. FLAT PG: hGH aka somatotropin
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
Paracrine (local) - endocrine (longer distance)
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)
Chyme (by combined activity of exocrine glands)

36. For focal point that is nearby - what will the lens look like
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
Glucose = aldose fructose = ketose
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
vitreous humor - retina - fovea

37. PNS is broken down into
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Somatic nervous sys - autonomic nervous sys
Processes: axons - dendrites
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

38. Where would materials slated for digestion go?
Lysosome
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Contain capillary network - lymph vessels (lacteals)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

39. protein absorption at enterocyte
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
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
Lysosome

40. What are the memb - bound enzymes of the brush border?
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

41. Where does the bolus go after mouth chews food
Smooth ER
Moves down thru esophageal sphincter
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)

42. The esophageal sphincter is...
5
Normally contracted
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

43. Chewing does what?
Increases surface area of food ball (bolus)
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
Peptides
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

44. interneurons
Neurons may perform one of three functions....
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

45. Path of urine

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46. After meiosis II - Female

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47. The EYE
Water flows from the tubule - concentrating the filtrate - raising BP
Facilitated diffusion: no symport w/ secondary transport
Vitamin K - b12 - thiamin - riboflavin
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)

48. How do parietal cells work ** (involves CO2)
Membrane - bound - endocytosed bodies
Abdominal cavity - which is coated in serous fluid
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Processes: axons - dendrites

49. golgi body
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Membrane - bound - endocytosed bodies
Form barrier to extracellular fluid
Sorts - modifies - concentrates proteins from the ER

50. Where is bile produced
Cancer; apop can be programmed cell death; mitochon can play important role in apop
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Gastrulation occurs: formation of three primary germ layers = differentiation
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**