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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. cAMP - cGMP - calmodulin...
An endogenous morphine
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

2. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Night vision
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
In gastric pits; secretions combine into gastric juice

3. What is the pH at the entrance to the duodenum
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
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

4. almost all exocytosed proteins pass through this
Smooth ER
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Micelles; micelles (made of bile) go back and forth between brush border and chyme
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

5. Where do absorbed fats go in the enterocyte
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
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
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs

6. What testosterone released by secondary follicle by LH stim is converted to...
Vitamin K - b12 - thiamin - riboflavin
Most absorption occurs in sm intestine
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

7. hypothalamus - AP - ACTH - cortisol release from adrenal cortex
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
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
vitreous humor - retina - fovea
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'

8. gametes are haploid
Zygotes are diploid
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Facilitated diffusion from hi to lo conc

9. What happens when rod cell is depolarized
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
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Night vision
Primitive streak - which consists of cells of the MESODERM ****

10. is intracellular AA conc hi or low?
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Ups bicarbonate secretion by pancreas; raises pH to 6.0
In gastric pits; secretions combine into gastric juice
Low because AAs are immediately used in translation

11. PNS is broken down into
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Somatic nervous sys - autonomic nervous sys
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
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)

12. extracellular matrix formed mainly of...
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
'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
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)
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

13. Meiosis I Anaphase I
Carry signals to musc OR Gland
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)
- 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
Homologous chromosomes separate - migrate towards opposite poles/centrioles

14. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
The renal corpuscle
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)

15. What does peptic refer to in general
Neurons may perform one of three functions....
Digestion
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
Processes: axons - dendrites

16. A group of cell bodies in CNS is nucleus - outside CNS is...
Ganglion
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Nitrogen
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

17. PNS nerve signal
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
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)
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
Eukaryotes

18. important because in meiosis germ - line cells begin as 46 2N w/ 23 pairs of homologous chromosomes which are replicated in S phase of interphase to 23 pairs of sister chromatids = still 46 2N
Fructose is a structural isomer of glucose
Contain capillary network - lymph vessels (lacteals)
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
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

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

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20. Adrenal medulla hormones (TYR- DERIVED)
Prod of steroid hormones in testes - ovaries
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

21. The esophageal sphincter is...
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Gastrulation occurs: formation of three primary germ layers = differentiation
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
Normally contracted

22. Human chorionic gonadotropin...
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)

23. components of interstitial fluid
Contain capillary network - lymph vessels (lacteals)
Glycosaminoglycans - prots - AAs - lipids
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
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves

24. Glycogenolysis/gluconeogenesis
Faces the lumen
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
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
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

25. How is glucose absorbed in sm intest
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
ER
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
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

26. How do nutrients move?
Processes: axons - dendrites
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue

27. How does water cross the apical membrane
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
An endogenous morphine
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
Thru tight junctions by favorable osmotic gradient

28. In IBS - What is defective

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29. Beta - oxidation in liver produces...
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
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Gastrulation occurs: formation of three primary germ layers = differentiation
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

30. Think of spinal cord injury
Glucose = aldose fructose = ketose
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Digestion

31. Tight junctions
Albumin increases osmolarity of blood; increases osmotic pressure
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
Form barrier to extracellular fluid
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine

32. in the dark is rhodopsin active or inactive?
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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)
Needs time for bile - lipase - micelle migration - enterocyte uptake
Break down TAGs to monoglycerides and free fatty acids

33. What are the major carbohydrates
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
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
Glucose = aldose fructose = ketose
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)

34. 3 phases of menstrual cycle
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Glucose = aldose fructose = ketose
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)
Ventrally (picture skeletal vertebrae)

35. micelles vs liposomes
About 7.2
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
Liposome has phospholipid bilayer
Sensory (afferent - dorsal) - motor (efferent - ventral)

36. serous membranes have a viscera - facing layer and a body wall - facing layer
Chylomicrons are much bigger
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Facilitated diffusion from hi to lo conc
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

37. axon hillock physiology
Conjunction of cell body w/axon
Processes: axons - dendrites
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)
Alpha 1-4 and 1-6 (branching) glycosidic linkages

38. How does blood sugar move into tissues?
Facilitated diffusion from hi to lo conc
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
Fructose is a structural isomer of glucose
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**

39. trypsin is secreted by
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
It targets liver conc of prothrombin - fibrinogen etc
Prod of steroid hormones in testes - ovaries
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

40. E storage per unit mass
Meiosis creates germ cells
Glucose and ketone bodies (not from glycogen stores)
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
***nicotinic is ionotropic; muscarinic is GPCR

41. protein absorption at enterocyte
- 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
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
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

42. Neuronal cell bodies have extensions ie
Meiosis creates germ 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
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Processes: axons - dendrites

43. 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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
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)

44. therefore - How does plasma leave capillary at the renal corpuscle

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45. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
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
Mostly reabsorbed to liver
Most absorption occurs in sm intestine
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

46. After meiosis II...
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)
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Many modern drugs are ligands for GPCRs
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

47. food in duod stims release of gastrointestinal hormones
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)
5
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

48. During meiosis I and II in females - rather than creating four chromosomally- equivalent gametes...
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Creates one ovum (23 N) and three polar bodies
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
90-140 mg/dl

49. FLAT PG: TSH aka thyrotropin
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Neurons may perform one of three functions....
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

50. fructose enters enterocyte by
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
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Facilitated diffusion: no symport w/ secondary transport
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)