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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. Difference between euk and prok flagella
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
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
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)

2. On what surface of the retina is the eye most sensitive
Fovea (highest amount of cones)
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Processes: axons - dendrites

3. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
Digestion
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... ...
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Sensory neurons are affector; motor neurons are effector // dorsal afferent (dorsal - Back- side of spinal cord carries sensory signals to brain; ventral effector

4. During ejaculation - sperm...

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5. What force is acting upon chyme to move it forward down sm intestine
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Many modern drugs are ligands for GPCRs
Mouth - esophagus - stomach - duodenum - jejunum - ileum - ascending colon - transverse colon - descending colon - sigmoid colon - rectum - anus
90-140 mg/dl

6. main point of fat transport...
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
Outermost layer of blood vessel
cornea (1.4 refractory index; bends light) - pupil (size of pupil is determined by contraction state of the iris) - aqueous humor
Digestion

7. A group of cell bodies in CNS is nucleus - outside CNS is...
Smooth ER
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
Inner lining of blood vessels
Ganglion

8. only monosaccharides are absorbed
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity
Which is why lactase - maltase - dextrinase - sucrase are on brush border
Beta cells
In mouth - breakdown of starch into polysaccharides

9. Local vs long - distance mediators
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Paracrine (local) - endocrine (longer distance)
Zygotes are diploid

10. physiology of gall bladder - liver and pancreatic secretions
FAT=9 cal per gram Carbs=4.5 cal per gram - Prot=4 cal per gram - these seem to be for anhydrous forms
Note: enteric= small intestine - double layer of peritoneum that suspends jejunum/ileum from posterior abdominal wall = connective tissue
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
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

11. The bolus (chewing) is digested to what in the stomach
PNS- Somatic - afferent (dorsal root ganglion) + efferent (ventral horns) PNS- ANS- afferent (sensors on viscera) + SYMP - PARA pre - post - ganglionic neurons
Chyme (by combined activity of exocrine glands)
In mouth - breakdown of starch into polysaccharides
All carbs absorbed at enterocytes are carried to liver by portal vein

12. pancreatic amylase is much stronger than
Salivary amylase; both hydrolyze glycosidic linkages
Thru tight junctions by favorable osmotic gradient
Increases surface area of food ball (bolus)
Creates one ovum (23 N) and three polar bodies

13. small intestine=
Glucose = aldose fructose = ketose
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... ...
Most absorption occurs in sm intestine
Duodenum (wraps around pancreas; most digestion occurs here) - jejunum (pH 7-9; 2m) - ileum

14. FLAT PG: TSH aka thyrotropin
(diploid and haploid individuals = ALTERNATION of GENERATIONS) a fusion of gametic and zygotic life cycles
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
PH 6.0; this accomplished by pancreatic secretion of bicarbonate which ups pH
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine

15. What testosterone released by secondary follicle by LH stim is converted to...
Estradiol
Beta cells
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
Estradiol (estrogen - steroid horm); prepares uterine wall for pregnancy; just before ovulation - release of estradiol stims LH in pos feedback

16. What else do parietals do?
AAs can be burned for energy or converted to fat for storage
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
Secrete intrinsic factor; important for absorbing vitamin B12 in sm intest
Sorts - modifies - concentrates proteins from the ER

17. cholinergic receptors: NICTONIC and MUSCARINIC Nicotinic: neuromuscular effectors (ionotropic) Muscarinic: PARA effectors (GPCRs) Adrenergic: SYMP effectors (GPCRs)
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
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
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Estradiol

18. keep in mind that enterocyte is like a regular euk cell
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... ...
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
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)
Has memb - bound organelles - etc...

19. Chewing does what?
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
Increases surface area of food ball (bolus)
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

20. Mucus - digestive enzymes released thru
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
Primitive streak - which consists of cells of the MESODERM ****
Glands w/ducts: Exocrine glands
Within the paravertebral ganglion - running parallel to spinal cord

21. What hormones affect the stomach?
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
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
- 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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord

22. in the presence of ADH what happens to movement of water across nephron membr
Water flows from the tubule - concentrating the filtrate - raising BP
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
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
Somatic sensory = dorsal root ganglia (outside spinal cord); somatic effector = ventral horns of spinal cord

23. Interaction of corpus luteum/placenta
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5
Corpus luteum degrades into corpus albicans
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Photon (hv)- rhodopsin - conformation change - GPCR- Na less permeable - hyperpolarized rod cells - generates AP= photobleaching at visible light wavelengths (390-700nm)

24. What controls release of LH - FSH from anterior pituitary
Gonadotropin releasing hormone - GnRH
***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
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
'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

25. Sensory - motor neurons are part of which nervous system
Reconstituted into TAGs at smooth ER; first stop for most digested fat is liver
Digestion
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
Peripheral nervous sys

26. Posterior pituitary hormones (Small Peptides)
Tight regulation of parietal cells needed b/c gastric acid secretion is E- intensive; parietal cells are hi in mitochons
Oxytocin and ADH (aka vasopressin)
Food is digested from mouth to stomach (denaturation by gastric acid - digested by pepsin) to duodenum (more digestion); then absorption occurs in jejunum and ileum
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

27. Where is bile produced
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Posterior pituitary hormone; acts on uterus - mammary glands; causes uterine contractions - milk ejection
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**

28. large intestine E. coli aid absorption of...
Eukaryotes
Glucose
Vitamin K - b12 - thiamin - riboflavin
Interstitial fluid (eg prostaglandins - cytokines)

29. What (typically - ie not pre - ovulation) feeds back to decrease LH - FSH production?
Testosterone and estradiol
Outer ear= pinna (auricle)- external auditory canal - eardrum (tympanic membrane) inner ear= malleus - incus - stapes - ...oval window - cochlea - where sound is transduced into neural signal...enters cochlea at scala vestibuli - where pressure chang
Mostly reabsorbed to liver
Pancreas; active at sm intestinal pH; hydrolyzes peptide bonds of (pepsin - digested) peptides

30. Inside the kidney: ...JGA (w/granular cells sensitive to hydrostatic pressure able to secrete renin - activate aldosterone - increase BP) is adjacent to distal tubule - monitors filtrate pressure
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
SYMP: spinal cord --->paravetebral ganglion PARA: spinal cord - brain; cell processes --->ganglion near effector organ (preganglionic neurons) extend outside of spinal cord to synapse at ganglia - go on along postganglionic neurons
- 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
'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

31. How does the body mobilize fat stores
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
***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
Food is digested from mouth to stomach (denaturation by gastric acid - digested by pepsin) to duodenum (more digestion); then absorption occurs in jejunum and ileum
- 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

32. FLAT PG: prolactin
Processes: axons - dendrites
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
Peptide; prolactin promotes milk production; prolactin release is stimulated by act of suckling - which in turn inhibits menstrual cycle
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

33. Examples of GPCRs in sensory systems/signal transduction: What is the ligand or messenger in each case? ...SIGHT - SMELL - MOOD - FIGHT/FLIGHT etc
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases
Most absorption occurs in sm intestine
All carbs absorbed at enterocytes are carried to liver by portal vein
visual (rhodopsin is receptor - derived from Vit A; conformation change occurs with photon to hyperpolarize rod cells; cone cells use photopsin for receptor) - olfactory - mood (NTs targeted by antidepressants - antipsychotics - etc; GABA is inhibit

34. How is the follicle developed during oogenesis
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
After morula - with blastocyst (+8 cell count)--->totipotent to embryonic stem cell and so on
Inner lining of blood vessels
Arrested at primary oocyte; hypothalamus GnRH->FSH released at puberty stims granulosa cell development; granulosa secrete zona pellucida = primary follicle

35. lysosome main function and derivation
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Beta cells
Contains hydrolytic enzymes; thus - digests endocytosed substances; derived from golgi
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals

36. Cell bodies of SYMP postganglionic neurons lie far from effector...
Many modern drugs are ligands for GPCRs
Water flows from the tubule - concentrating the filtrate - raising BP
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)
Within the paravertebral ganglion - running parallel to spinal cord

37. Embryology
Zygote (fertilization in fallopian tubes); morula (up to 8 cells - undifferentiated ie totipotent); blastocyst (4+ days - implants into uterus; HCG secretion stims corpus luteum; gradually placenta replaces HCG as estrogen/progest source; cells not t
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
Sensory (afferent - dorsal) - motor (efferent - ventral)
Formed in kidney (nephron) - sent thru renal pelvis - down ureter to bladder - drained by urethra'

38. Human chorionic gonadotropin...
Secreted by implanted egg; HCG prevents degeneration of the corpus luteum; HCG in blood/urine is first sign of pregnancy
Prod of steroid hormones in testes - ovaries
It targets liver conc of prothrombin - fibrinogen etc
Sudiferous (sweat) - sebaceous - digestive (bile - pancreatic enzs) - mucosal

39. In effect LH - FSH stimulate
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
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Has memb - bound organelles - etc...
Prod of steroid hormones in testes - ovaries

40. After meiosis II - Female

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41. Glycogenolysis/gluconeogenesis
An ether phospholipid; hi conc in myelin; thus - hi conc in heart tiss - nervous tiss
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
Only musc and esp ** liver can store large amounts
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete

42. amylase acts where on carbs
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)
Has memb - bound organelles - etc...
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**
- 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

43. What is gastric acid?
vitreous humor - retina - fovea
HCl; secreted by parietal cells under stim by gastrin
Night vision
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

44. Anterior eye vs. posterior eye
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
The renal corpuscle
Determined by whether in front of or behind the lens
***nicotinic is ionotropic; muscarinic is GPCR

45. What happens when rod cell is depolarized
Sorts - modifies - concentrates proteins from the ER
= catecholamines; fight/flight; vasoconstrictors of internal organs - skin; vasodilators of skel musc; also considered stress hormones; epinephrine - norepinephrine
Night vision
Know that 90% digestion - absorption occurs in sm intestine --> fine breakdown of carbs - fat - prots

46. For focal point that is nearby - what will the lens look like
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Renal pyramids --->renal calyx-->renal pelvis -->ureter -->urethra
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
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

47. food in duod stims release of gastrointestinal hormones
Trypsinogen is activated by enterokinase in the brush border; in turn - it activates other enzymes
RBCs - large proteins; What does enter is called the filtrate
Facilitated diffusion: no symport w/ secondary transport
Gall bladder - pancreatic secretions increase - arrive via ampulla of vater (duct glands); insulin secretion increases (fed state; ductless glands)

48. examples of different cavities... (compartments for viscera)
Form barrier to extracellular fluid
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
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**
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid

49. What is a toxic byproduct of gluconeogenesis from proteins
Fat is insoluble in blood and requires a carrier like lipoproteins (vLDL...HDL) or albumins; ...vLDL has hi triglycerides - hi cholesterol
An endogenous morphine
Focuses light thru the vitreous humor onto retina; acts as a converging lens (image is real - inverted)
Ammonia; must be converted to urea by liver and excreted in urine by kidney

50. fat digestion is time - intensive
Needs time for bile - lipase - micelle migration - enterocyte uptake
- 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
Direction of differentiation
Peripheral nervous sys