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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. gametes are haploid
Inner lining of circulatory system
Zygotes are diploid
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
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)

2. medium for paracrine hormones
Interstitial fluid (eg prostaglandins - cytokines)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
It targets liver conc of prothrombin - fibrinogen etc
Ammonia; must be converted to urea by liver and excreted in urine by kidney

3. size of chylomicrons (fat + apoproteins) vs lipoproteins ('cholesterol')
Chylomicrons are much bigger
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Prod of steroid hormones in testes - ovaries
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

4. duodenum must have receptors for fat content - protein because
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop
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
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol

5. FLAT PG: ACTH
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Below hypothalamus
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor

6. Induction affects...
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Normally contracted
Direction of differentiation
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

7. from the loop of henle...
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
- 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

8. micelles vs liposomes
Smooth ER
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Liposome has phospholipid bilayer
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

9. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
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
Water flows from the tubule - concentrating the filtrate - raising BP
Mediate complex cell processes thru eg phosphorylation via secondary messenger (G protein) systems = signal transduction pathway - GPCR (G protein coupled receptor)

10. How does birth control work?
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

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

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12. physiology of gall bladder - liver and pancreatic secretions
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
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
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion

13. So - following blastocyst implantation (4d) - at approx 2 weeks past fertilization
Gastrulation occurs: formation of three primary germ layers = differentiation
Testosterone and estradiol
Neurons may perform one of three functions....
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc

14. What do villli do
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
Glands w/ducts: Exocrine glands
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Increase surface area of sm intestine; this improves digestion (enzymes adsorbed to villi) and absorption

15. FSH - LH - HCG - inhibin are...
Peptides
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Neurons may perform one of three functions....
Lumen (ie continuous w/body cavity) and cytosol

16. Gastrin from G cells stims parietal cells...
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Glycosaminoglycans - prots - AAs - lipids
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

17. Where is bile produced
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Ganglion
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
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**

18. when cells hit their limit for prot storage...
AAs can be burned for energy or converted to fat for storage
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Increases surface area of food ball (bolus)

19. For focal point that is nearby - what will the lens look like
Chyme (by combined activity of exocrine glands)
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

20. Aldosterone (sodium uptake - potassium secretion)
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
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
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)
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

21. Alpha - amylase found where
Glycosaminoglycans - prots - AAs - lipids
***nicotinic is ionotropic; muscarinic is GPCR
In mouth - breakdown of starch into polysaccharides
Vitamin K - b12 - thiamin - riboflavin

22. Embryology
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
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
Night vision
Ganglion

23. liver receives blood from...
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)

24. What is a toxic byproduct of gluconeogenesis from proteins
Corpus luteum degrades into corpus albicans
Ammonia; must be converted to urea by liver and excreted in urine by kidney
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
Only musc and esp ** liver can store large amounts

25. Anterior eye vs. posterior eye
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
Determined by whether in front of or behind the lens
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Gonadotropin releasing hormone - GnRH

26. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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
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
Conjunction of cell body w/axon

27. large intestine E. coli aid absorption of...
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)
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Urine enters kidneys via artery - to arteriole - capillary bed - glomerulus - Bowman's capsule - proximal tubule - loop of henle (concentrates medulla) - distal tubule - collecting tubule - collecting duct (renal pyramids) - renal calyx - renal pelvi
Vitamin K - b12 - thiamin - riboflavin

28. The bolus (chewing) is digested to what in the stomach
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)
Regulated by gastrointestinal horms
Chyme (by combined activity of exocrine glands)
Chylomicrons are much bigger

29. A pinpoint iris is contracted or uncontracted
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
Uncontracted: parasymp (eg opoid use)
Normally contracted
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production

30. A group of cell bodies in CNS is nucleus - outside CNS is...
Testosterone and estradiol
Ganglion
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
90-140 mg/dl

31. overview of prot digestion
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
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
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis
Somatic nervous sys - autonomic nervous sys

32. 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
From lumenal (apical) to enterocyte to basolateral side of epithelial tissue
Only musc and esp ** liver can store large amounts
Most absorption occurs in sm intestine

33. overall - fatty - prot - rich food in duod causes
Many modern drugs are ligands for GPCRs
'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
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Secondary spermatocyte (stim'd by FSH from Sertoli cells -->EQUATIONAL DIVISION-->spermatid - which matures further into spermatozoa; released into semeniferous tubule; transported to epididymis

34. Luteal surge
Low because AAs are immediately used in translation
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Glands w/ducts: Exocrine glands
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. 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
***starting with adipose tiss: FFAs are transported in the blood by albumin (major component of blood plasma); one albumin typically carries three fatty acid molecules but can hold up to 30 FAs
Ammonia; must be converted to urea by liver and excreted in urine by kidney

36. Liver Functions
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
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
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
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

37. What does lipase attack exactly
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
Peripheral nervous sys
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

38. Anterior eye
All carbs absorbed at enterocytes are carried to liver by portal vein
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Glucose = aldose fructose = ketose
Water flows from the tubule - concentrating the filtrate - raising BP

39. Anatomy of the villi
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Albumin increases osmolarity of blood; increases osmotic pressure
Contain capillary network - lymph vessels (lacteals)
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

40. from thoracic duct - chylomicrons stick to capillary walls...
Fructose is a structural isomer of glucose
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
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)
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct

41. energy source of neurons
Ammonia; must be converted to urea by liver and excreted in urine by kidney
***nicotinic is ionotropic; muscarinic is GPCR
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Glucose and ketone bodies (not from glycogen stores)

42. The path from blood plasma to urine

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43. What Changes - Doesn't Change as a result of movement of molecules across membranes in the proximal tubule
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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
Digestion
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

44. signal transduction occurs only in
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
- 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
Eukaryotes
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

45. hypothalamus controls anterior pit - posterior pit release with inhibitory/releasing hormones of its own; these should have fairly self - explanatory names
Moves down thru esophageal sphincter
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
Gastrulation occurs: formation of three primary germ layers = differentiation
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

46. When 'coumadin targets liver enzymes to act as anticoagulant'...
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
It targets liver conc of prothrombin - fibrinogen etc
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

47. Meiosis I Metaphase I
Homologous chromosomes line up w/ attachment of spindle fibers/microtubule polymers to centromeres via kinetochores; identical in appearance under light microscope to metaphase of mitosis
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Glucose and ketone bodies (not from glycogen stores)
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

48. A contracted iris occurs with what kind of stimulation
Albumin increases osmolarity of blood; increases osmotic pressure
Sympathetic: dilates pupil (for night hunting)
Fovea (highest amount of cones)
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.

49. Neuronal cell bodies have extensions ie
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Processes: axons - dendrites

50. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
All carbs absorbed at enterocytes are carried to liver by portal vein
Glucose and ketone bodies (not from glycogen stores)