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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. Three stages of the menstrual cycle
Only musc and esp ** liver can store large amounts
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
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
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

2. when thinking of proteins - think
HCl; secreted by parietal cells under stim by gastrin
Nitrogen
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Night vision

3. PNS nerve signal
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
Primitive streak - which consists of cells of the MESODERM ****
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)

4. Peritoneal refers to...
Membrane - bound - endocytosed bodies
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)
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

5. Gland: ovaries
Transfer signals from neuron - neuron; 90% of neurons are interneurons
- 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
Travels vas deferens - urethra; mixes with prostate fluids - seminal vesicles - couper's gland - etc
Estrogen: steroid; stims LH in luteal surge; causes growth of female sex organs progesterone: prepares/maintains uterus for pregnancy

6. Creating gradients requires what?
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Testosterone and estradiol
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
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

7. Which fats are not absorbed like this
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
***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

8. A group of cell bodies in CNS is nucleus - outside CNS is...
Ganglion
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
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
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

9. sensory (afferent) neurons
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Nuclear envelope reassembled in daughter cells; cytokinesis occurs; nucleoli reappear (site of rRNA synthesis)
Contain capillary network - lymph vessels (lacteals)
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

10. signal transduction occurs by 2 paths
1) by integral ion channels 2) transmitted by second messenger system
Lysosome
In gastric pits; secretions combine into gastric juice
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

11. Cell determination begins At what stage of development
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Estradiol
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

12. PNS review: SAME DAVE
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Chyme (by combined activity of exocrine glands)
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

13. What kind of cells make up epithel tiss of stom - then sm intest?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch
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
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen

14. Where else does ADH act
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
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
Alpha 1-4 and 1-6 (branching) glycosidic linkages

15. amylase acts where on carbs
5
'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.'
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

16. Chewing does what?
The wall of the body or of a body cavity or hollow structure
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Increases surface area of food ball (bolus)
Homologous chromosomes separate - migrate towards opposite poles/centrioles

17. ligands are the messenger compounds that target secondary messenger systems on effectors
Beta cells
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle
Many modern drugs are ligands for GPCRs

18. Thus - central nervous sys is...
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Interneurons working to integrate signals received from the peripheral nervous system (sense organs)
Faces the lumen
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine

19. What are phagosomes
Membrane - bound - endocytosed bodies
Vitamin K - b12 - thiamin - riboflavin
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
An endogenous morphine

20. How does birth control work?
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges

21. Local vs long - distance mediators
***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
Paracrine (local) - endocrine (longer distance)
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc

22. micelles also pick up
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
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
Glycosaminoglycans - prots - AAs - lipids
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane

23. Luteal surge
RBCs - large proteins; What does enter is called the filtrate
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
All carbs absorbed at enterocytes are carried to liver by portal vein
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection

24. Some PNS nerves are found in brain - spinal cord
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
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
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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

25. FLAT PG: TSH aka thyrotropin
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
Interstitial fluid (eg prostaglandins - cytokines)
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

26. examples of different cavities... (compartments for viscera)
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Alpha 1-4 and 1-6 (branching) glycosidic linkages
It targets liver conc of prothrombin - fibrinogen etc
Increases surface area of food ball (bolus)

27. Polypeptides are formed with what kind of reaction?
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
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)
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

28. is intracellular AA conc hi or low?
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
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
Low because AAs are immediately used in translation

29. What does lipase attack exactly
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Two perpendicular semicircular canals involved in balance - equilibrium
Result: stress reaction; increase glycogenolysis - gluconeogenesis; fat/prot breakdown; increase blood glucose
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

30. 80-90% fat absorbed this way
Vitamin K - b12 - thiamin - riboflavin
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
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

31. What do the glomerulus and Bowman's capsule add up to...
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
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)
Processes: axons - dendrites
The renal corpuscle

32. glucagon secreted by
Regulated by gastrointestinal horms
Smooth ER
ER
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger

33. Failure of apoptosis can result in
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
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

34. During ejaculation - sperm...

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35. Glucose is a .... sugar; fructose is a .... sugar
Ammonia; must be converted to urea by liver and excreted in urine by kidney
Glucose
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... ...
Glucose = aldose fructose = ketose

36. What is the adventitia?
Lower blood pH
Testosterone and estradiol
Outermost layer of blood vessel
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

37. What hormones affect the stomach?
Hormones --->stimulate exocrine glands - acetylcholine (increases all secretion of gastric pits) - gastrin (from G cells) - histamine (increases HCl secretion of parietals) ...Ach increases all secretions; gastrin increases gastric acid (parietal cel
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

38. Difference between euk and prok flagella
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
It targets liver conc of prothrombin - fibrinogen etc
All carbs absorbed at enterocytes are carried to liver by portal vein

39. Aldosterone (sodium uptake - potassium secretion)
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 water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity

40. pancreatic amylase is much stronger than
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.
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
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

41. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Testosterone and estradiol
Zygotes are diploid
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
An endogenous morphine

42. What force is acting upon chyme to move it forward down sm intestine
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Increases solute conc and osmotic pressure of the ***medulla
Peristalsis (esophagus) and segmentation (bi - directional=mixing)

43. portal vein physiology...

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44. What determines number of chromosomes?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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

45. what happens to bile secretions
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
Mostly reabsorbed to liver
Testosterone and estradiol
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right

46. In effect LH - FSH stimulate
Prod of steroid hormones in testes - ovaries
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Albumin increases osmolarity of blood; increases osmotic pressure
Gonadotropin releasing hormone - GnRH

47. Embryology
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
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
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide

48. alpha - amylase in the mouth digests what kind of bond
Faces the lumen
Meiosis creates germ cells
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach

49. 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)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
'Microvilli function as the **primary surface of nutrient absorption in the gastrointestinal tract**. Because of this vital function - the microvillar membrane is packed with enzymes that aid in the breakdown of complex nutrients into simpler compoun
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

50. Where do absorbed fats go in the enterocyte
Only musc and esp ** liver can store large amounts
Ammonia; must be converted to urea by liver and excreted in urine by kidney
To the organelle w/ lumen: smooth ER; they are resynthesized into TAGs
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes