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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. Energy from fat - prot - gluc
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
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
Abdominal cavity - which is coated in serous fluid

2. Induction affects...
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
Direction of differentiation
Peptide; responsible for luteal surge (driven in part by LH-->testosterone -->estradiol -->LH positive feedback); results in ovulation (follicle bursting) - releasing egg into fallopian tube/oviduct
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

3. Meiosis I Metaphase I
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle

4. Where does the bolus go after mouth chews food
Fructose is a structural isomer of glucose
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Moves down thru esophageal sphincter
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

5. duodenum must have receptors for fat content - protein because
Systems (eg digestive system consists of many organs)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'
Digestion
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

6. How does water cross the apical membrane
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
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Thru tight junctions by favorable osmotic gradient
Water flows from the tubule - concentrating the filtrate - raising BP

7. large intestine E. coli aid absorption of...
Low because AAs are immediately used in translation
Below hypothalamus
Vitamin K - b12 - thiamin - riboflavin
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus

8. physiology of gall bladder - liver and pancreatic secretions
The renal corpuscle
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
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

9. 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)
Micelles; micelles transport lipase products to enterocytes for absorption at brush border
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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
Testosterone and estradiol

10. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Micelles; micelles (made of bile) go back and forth between brush border and chyme
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors

11. calcitonin

12. Creating gradients requires what?
Glucose = aldose fructose = ketose
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
Liver is the control center for blood glucose; is fed by portal vein from sm intest
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra

13. What is the net effect of the loop of Henle
Hypothalamus --->AP--->target tissues eg TSH - thyroid - T3/T4 release - increase basal metabolic rate
***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
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)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons

14. thyroid hormones: Not All One Kind of HORM
Glucose and ketone bodies (not from glycogen stores)
Ganglion
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
'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

15. Meiosis I Anaphase I
In mouth - breakdown of starch into polysaccharides
Homologous chromosomes separate - migrate towards opposite poles/centrioles
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
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

16. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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)
vitreous humor - retina - fovea
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

17. 80-90% fat absorbed this way
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
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Membrane - bound - endocytosed bodies
Fallopian tubes

18. A contracted iris occurs with what kind of stimulation
Sympathetic: dilates pupil (for night hunting)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Gastric inhibitory pep; increase of pancreatic - enz activating enzymes (which cleaves zymogens like trypsinogen); increased gall bladder contraction; decreases stomach mobility
Faces the lumen

19. Bile salts and lipase
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
Sympathetic: dilates pupil (for night hunting)
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
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

20. What else do parietals do?
'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.'
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest

21. Mucus - digestive enzymes released thru
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Glands w/ducts: Exocrine glands
Beta cells
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

22. protein absorption at enterocyte
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
Transfer signals from neuron - neuron; 90% of neurons are interneurons
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
Increases surface area of food ball (bolus)

23. Neuronal cell bodies have extensions ie
Night vision
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
Processes: axons - dendrites
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

24. 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
Receive signals from receptor cell w/ ability to interact with its environment; 99% sensory input is discarded
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Chylomicrons are much bigger

25. Spinal cord horns (thick knobs) point
Hydrostatic pressure forces some plasma thru *fenestrations of the glomerular endothelium* and into Bowman's capsule; B.C. is continuous with lumen of nephron
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
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... ...
Ventrally (picture skeletal vertebrae)

26. Failure of apoptosis can result in
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Has memb - bound organelles - etc...
Cancer; apop can be programmed cell death; mitochon can play important role in apop

27. Fructose relates how structurally to glucose
Nitrogen
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle
Fructose is a structural isomer of glucose
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

28. Think of spinal cord injury
Ectoderm: outer coverings - nervous system Mesoderm: between covering ie musc - bone - etc - endoderm: digestive tract - viscera
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
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....

29. is intracellular AA conc hi or low?
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)
Low because AAs are immediately used in translation
ER
Thru tight junctions by favorable osmotic gradient

30. lysosome main function and derivation
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
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
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
Night vision

31. motor (efferent) neurons --> VENTRAL
- 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
RBCs - large proteins; What does enter is called the filtrate
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
Carry signals to musc OR Gland

32. micelles vs liposomes
Liposome has phospholipid bilayer
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
Increases solute conc and osmotic pressure of the ***medulla
Salivary amylase; both hydrolyze glycosidic linkages

33. amylase acts where on carbs
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Form barrier to extracellular fluid
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

34. overview of prot digestion
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
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
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

35. inhibin secreted by
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Testes>Semeniferous tubules>Sertoli cells; feedback on AP FSH production
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

36. review: parietals secrete intrinsic factor...
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Lysosome

37. Epithelium of the sm intestine: enterocytes lined w/brush border (digestion/absorption); goblet cells (mucous); crypts of Lieberkuhn exocrine glands (lysozyme)
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots
Salivary amylase; both hydrolyze glycosidic linkages
Liposome has phospholipid bilayer
Glucose

38. in the dark is rhodopsin active or inactive?
RBCs - large proteins; What does enter is called the filtrate
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Sorts - modifies - concentrates proteins from the ER

39. How long are peptides when absorbed at brush border
Water flows from the tubule - concentrating the filtrate - raising BP
Regulated by gastrointestinal horms
Di - tri - peptides; inside enterocytes are hydrolyzed to amino acids
- 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

40. when thinking of proteins - think
The wall of the body or of a body cavity or hollow structure
Contain capillary network - lymph vessels (lacteals)
Epithelial tissue near semniferous tubules
Nitrogen

41. Sensory neuron cell bodies vs. somatic motor cell bodies
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
5
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

42. How does duod deal with hi HCl from stom
Determined by whether in front of or behind the lens
Ups bicarbonate secretion by pancreas; raises pH to 6.0
'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
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

43. On what surface of the retina is the eye most sensitive
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
Fovea (highest amount of cones)
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Lower blood pH

44. energy source of neurons
'visceral organs develop adjacent to a cavity and invaginate into the bag - like coelom'
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Glucose and ketone bodies (not from glycogen stores)
Form barrier to extracellular fluid

45. What is main difference is signal transmission in nicotinic vs muscarinic?
Smooth ER
Corpus luteum; secretes estradiol - progesterone throughout pregnancy OR if no pregnancy - for about 2 weeks (till menstruation = shedding of uterine lining)
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
***nicotinic is ionotropic; muscarinic is GPCR

46. 3 phases of menstrual cycle
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
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

47. glucagon secreted by
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
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
Alpha cells; stims gluconeogenesis in liver; acts via cAMP second messenger
***nicotinic is ionotropic; muscarinic is GPCR

48. from the loop of henle...
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
***nicotinic is ionotropic; muscarinic is GPCR
Two perpendicular semicircular canals involved in balance - equilibrium
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

49. After meiosis I - daughter cells are...

50. in fat and liver cells monoglycerides and ffas are once again
Alpha 1-4 and 1-6 (branching) glycosidic linkages
Sorts - modifies - concentrates proteins from the ER
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
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver