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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. Spinal cord horns (thick knobs) point
Ventrally (picture skeletal vertebrae)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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

2. lysosome pH
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
5
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
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

3. Does bile digest fat?
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Glands w/ducts: Exocrine glands

4. energy source of 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
Glucose and ketone bodies (not from glycogen stores)
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

5. Neuronal cell bodies have extensions ie
Processes: axons - dendrites
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

6. How does duod deal with hi HCl from stom
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
Ups bicarbonate secretion by pancreas; raises pH to 6.0
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Meiosis creates germ cells

7. Different organs working together
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
Estradiol
Systems (eg digestive system consists of many organs)
The wall of the body or of a body cavity or hollow structure

8. Creating gradients requires what?
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
Organs
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Testosterone upon stim by LH

9. bundles of collecting ducts are called
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)
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
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

10. Path of food entering body...
Somatic nervous sys - autonomic nervous sys
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
Most absorption occurs in sm intestine
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

11. Anterior eye
Systems (eg digestive system consists of many organs)
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Low because AAs are immediately used in translation

12. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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... ...
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
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

13. only monosaccharides are absorbed
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
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
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

14. Where do absorbed fats go in the enterocyte
In mouth - breakdown of starch into polysaccharides
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

15. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Smooth ER
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Gastrulation occurs: formation of three primary germ layers = differentiation

16. 90% digestion - absorption occurs in...
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
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
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
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

17. How does glycogen compare to starch
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

18. Induction affects...
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Estradiol
Direction of differentiation
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

19. What is the net effect of the distal tubule
Increases blood Calcium
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
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop

20. On what surface of the retina is the eye most sensitive
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Fovea (highest amount of cones)
Ups bicarbonate secretion by pancreas; raises pH to 6.0
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)

21. How is glucose absorbed in sm intest
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
Two perpendicular semicircular canals involved in balance - equilibrium
Uncontracted: parasymp (eg opoid use)
Form barrier to extracellular fluid

22. What is the pH at the entrance to the duodenum
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Many modern drugs are ligands for GPCRs
Faces the lumen
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

23. signal transduction occurs by 2 paths
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
vitreous humor - retina - fovea
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
1) by integral ion channels 2) transmitted by second messenger system

24. FLAT PG: FSH
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Neurons may perform one of three functions....

25. sporic life cycle
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
'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.'
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles

26. What is somatostatin
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of 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
'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.'
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

27. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

28. Liver Functions
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
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
Primitive streak - which consists of cells of the MESODERM ****

29. Anatomy of the villi
Testosterone upon stim by LH
Estradiol
Prod of steroid hormones in testes - ovaries
Contain capillary network - lymph vessels (lacteals)

30. Where does fertilization occur
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Meiosis creates germ cells
Fallopian tubes

31. sensory (afferent)/interneurons/motor (efferent)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
Neurons may perform one of three functions....
Lower blood pH

32. inhibin secreted by
Zygotes are diploid
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
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. Where would materials slated for digestion go?
Form barrier to extracellular fluid
Lysosome
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
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

34. What determines number of chromosomes?
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
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
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

35. The bolus (chewing) is digested to what in the stomach
Beta cells
Chyme (by combined activity of exocrine glands)
Meiosis creates germ cells
Sorts - modifies - concentrates proteins from the ER

36. Peritoneal refers to...
Abdominal cavity - which is coated in serous fluid
Somatic nervous sys - autonomic nervous sys
Outermost layer of blood vessel
The renal corpuscle

37. 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)
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Eukaryotes
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
Only musc and esp ** liver can store large amounts

38. What surrounds the hydrophilic heads of the new TAGs
1) by integral ion channels 2) transmitted by second messenger system
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
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
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)

39. micelles also pick up
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Peripheral nervous sys
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

40. What is a dorsal root ganglion?
Size of fist; two kidneys; have cortex (steroid hormones) and medulla (catecholamines) - receives about 20% of cardiac output - blood travels down arteries - up veins -'urine is created by the kidney and emptied into the renal pelvis - which is empti
Carry signals to musc OR Gland
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
Sorts - modifies - concentrates proteins from the ER

41. How does blood sugar move into tissues?
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
Glucose
Increases surface area of food ball (bolus)
Facilitated diffusion from hi to lo conc

42. cAMP - cGMP - calmodulin...
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Only musc and esp ** liver can store large amounts
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

43. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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

44. How does water cross the apical membrane
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Thru tight junctions by favorable osmotic gradient
Glucose and ketone bodies (not from glycogen stores)

45. pancreas secretes enzymes via
Pancreatic duct (made of acinar cells?)
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Outermost layer of blood vessel
Homologous chromosomes separate - migrate towards opposite poles/centrioles

46. Embryology
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
Inner lining of circulatory system
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

47. The esophageal sphincter is...
Normally contracted
Lower blood pH
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest

48. How does reabsorption force nutrients across apical membrane of proximal tubule
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Salivary amylase; both hydrolyze glycosidic linkages
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

49. pancreatic enzymes are zymogens
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
Fovea (highest amount of cones)
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

50. Sensory neuron cell bodies vs. somatic motor cell bodies
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Glycosaminoglycans - prots - AAs - lipids