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MCAT Prep - 2

Subjects : mcat, science

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. Posterior pituitary hormones (Small Peptides)
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes
Oxytocin and ADH (aka vasopressin)

2. Gastrin from G cells stims parietal cells...
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Nitrogen
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
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

3. What is the net effect of the distal tubule
Lowers osmolarity of the filtrate (IONS - Water Are Taken Back Up By The Kidney)--->at the end of the distal tubule (the collecting tubule) is where aldosterone acts - along with the JGA
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability

4. physiology of gall bladder - liver and pancreatic secretions
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
In mouth - breakdown of starch into polysaccharides
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
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase

5. Path of food entering body...
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
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Many modern drugs are ligands for GPCRs
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

6. What is the adventitia?
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
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
Lots of water - minerals (electrolyte balance) - vitamins (aided by gut bacteria)
Outermost layer of blood vessel

7. Stomach has no lacteals
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
Most absorption occurs in sm intestine
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

8. almost all exocytosed proteins pass through this
Smooth ER
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
Digestion
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis

9. FLAT PG: prolactin
Direction of differentiation
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

10. What does lipase attack exactly
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.
'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
Inner lining of circulatory system
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

11. What is the function of the loop of Henle
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Increases solute conc and osmotic pressure of the ***medulla
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase

12. What does peptic refer to in general
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Regulated by gastrointestinal horms
Digestion

13. overall - fatty - prot - rich food in duod causes
Creates one ovum (23 N) and three polar bodies
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Sympathetic: dilates pupil (for night hunting)

14. Exocrine GlandS: stomach
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
At the first capillary bed of the nephron called the glomerulus which is encased by ***Bowman's capsule
- 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

15. week three: neurulation; mesoderm induces ectoderm; thus - NEURULATION INVOLVES SC Development - at week three
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
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
All carbs absorbed at enterocytes are carried to liver by portal vein
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

16. What is gastric acid?
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
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Abdominal cavity - which is coated in serous fluid
HCl; secreted by parietal cells under stim by gastrin

17. What do lipases do
Break down TAGs to monoglycerides and free fatty acids
Abdominal cavity - which is coated in serous fluid
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)
Carry signals to musc OR Gland

18. testosterone can be aromatized to...
Estradiol
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Direction of differentiation

19. FSH - LH - HCG - inhibin are...
Peptides
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Glands w/ducts: Exocrine glands
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)

20. Four tissues
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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
Nervous - muscle - epithelial (defines inner/outer) - connective (extensive matrices)
Peripheral nervous sys

21. duodenum must have receptors for fat content - protein because
Glucose and ketone bodies (not from glycogen stores)
Lysosome
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
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy

22. only monosaccharides are absorbed
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
Which is why lactase - maltase - dextrinase - sucrase are on brush border
The wall of the body or of a body cavity or hollow structure
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)

23. What is a normal blood glucose range
Trypsin(- ogen; activates other panc enzymes after it is activated by enterokinase of sm intest); chymotrypsin - amylase - lipase
90-140 mg/dl
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
'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

24. going down the loop of Henle - water - permeable - filtrate osmolarity goes up as water leaves...
Going up - water - impermeable: salt is actively pumped out - filtrate osmolarity goes down as salt leaves
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics

25. micelles vs liposomes
Liposome has phospholipid bilayer
Nitrogen
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
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

26. After meiosis II - Male

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27. On what surface of the retina is the eye most sensitive
Conjunction of cell body w/axon
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Fovea (highest amount of cones)
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

28. Important aspect of crypt of Lieberkuhn - secreted intestinal juice
Lumen (ie continuous w/body cavity) and cytosol
Contains lysozyme - which regulates bacteria within intestine; breaks down peptidoglycans (**bact wall); innate immunity
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
Smooth ER

29. when thinking of proteins - think
About 7.2
Lower blood pH
Nitrogen
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

30. Local vs long - distance mediators
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
Paracrine (local) - endocrine (longer distance)
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

31. Think of spinal cord injury
Injury that does not sever SC (causes deep lesion from back - front) might cause loss of feeling without full loss of motion
'tones the bone'; decreases free Calcium conc; acts opposite to parathyroid hormone; thyroid polypeptide
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion

32. After meiosis II...
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Glucose = aldose fructose = ketose
Four 23 N daughter cells are formed from one 46 2N mother (germ - line) cell; four haploid gametes

33. euk cell has two principal sides
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
Lumen (ie continuous w/body cavity) and cytosol
(haploid organism) many fungi and protozoa; individuals are typically haploid; fertilization may occur with immediate meiosis back to haploid state

34. almost all cells can store Some glycogen - but...
Only musc and esp ** liver can store large amounts
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback
Micelles; micelles (made of bile) go back and forth between brush border and chyme
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins

35. is intracellular AA conc hi or low?
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Low because AAs are immediately used in translation
Increases blood Calcium

36. portal vein physiology...

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37. When 'coumadin targets liver enzymes to act as anticoagulant'...
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Cancer; apop can be programmed cell death; mitochon can play important role in apop
It targets liver conc of prothrombin - fibrinogen etc
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae

38. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Fallopian tubes
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

39. How does blood sugar move into tissues?
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
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
Facilitated diffusion from hi to lo conc
HCl; secreted by parietal cells under stim by gastrin

40. Bile salts and lipase
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
Lysosome
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
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching

41. Meiosis I Anaphase I
Cancer; apop can be programmed cell death; mitochon can play important role in apop
ER
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Homologous chromosomes separate - migrate towards opposite poles/centrioles

42. Where else does ADH act
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
'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
At the collecting duct: becomes more permeable to water which passively diffuses *into the medulla* concentrating the urine
It targets liver conc of prothrombin - fibrinogen etc

43. What else do parietals do?
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
An endogenous morphine

44. What are the memb - bound enzymes of the brush border?
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
Oxytocin and ADH (aka vasopressin)
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes

45. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Neurons may perform one of three functions....
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
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... ...
Facilitated diffusion from hi to lo conc

46. Where are these exocrine glands located
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
In gastric pits; secretions combine into gastric juice
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.
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded

47. STOMACH: no absorption
Chylomicrons are much bigger
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
Homologous chromosomes separate - migrate towards opposite poles/centrioles

48. In effect LH - FSH stimulate
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Prod of steroid hormones in testes - ovaries
Conjunction of cell body w/axon

49. signal transduction occurs only in
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
Eukaryotes
1) by integral ion channels 2) transmitted by second messenger system
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH

50. From that point...
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.
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Determined by whether in front of or behind the lens
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss