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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. Where does blood to be filtered by kidney enter the nephron?

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2. How do parietal cells work ** (involves CO2)
90-140 mg/dl
Primitive streak - which consists of cells of the MESODERM ****
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)

3. what cannot cross the fenestrations of the renal corpuscle
Nitrogen
Polysaccharides w/proteoglycans attached = glycosaminoglycans; often give pliability
Paracrine (local) - endocrine (longer distance)
RBCs - large proteins; What does enter is called the filtrate

4. Tight junctions
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
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
Mostly reabsorbed to liver
Form barrier to extracellular fluid

5. chylomicron concentration in blood after meal
Peak at 1-2hr after meal; chylomicrons themselves have half - life of about 1hr after formation in enterocytes
Fat synthesis; carbs stored as free fatty acids - esterified to TAGs (requires small amount of E)
Moves down thru esophageal sphincter
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

6. at lo blood sugar...
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
The wall of the body or of a body cavity or hollow structure
Ventrally (picture skeletal vertebrae)
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)

7. Interaction of corpus luteum/placenta
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Follicular (proliferative)= 8d - Luteal (post - ovulation; corpus luteum secretions)= 13d - Menstruation (shed uterine lining if no implantation)= 5

8. How does reabsorption force nutrients across apical membrane of proximal tubule
Ventrally (picture skeletal vertebrae)
Via secondary active transport proteins (COSTS E TO FILTER BLOOD - ESTABLISH FLUID/ION BALANCE)
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant

9. Liver Functions
The crypts of Lieberkuhn: sm intestine pH is not right; brush border enzs won't work right
Paracrine (local) - endocrine (longer distance)
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
TAGS--->FFAs; remember that FFAs are broken down for energy in mito matrix by beta - oxidation

10. testosterone can be aromatized to...
On the chyme exiting the stomach and entering duodenum thru the pyloric sphincter
Increases blood Calcium
Estradiol
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

11. euk cell has two principal sides
Liver breaks down glycogen (glycogenolysis); at hi blood sugar it builds up glycogen (glycogenesis)
sucrose (gluc+fruc) - lactose (gluc+galactose) - starch (gluc+gluc)
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
Lumen (ie continuous w/body cavity) and cytosol

12. What are the memb - bound enzymes of the brush border?
Glucose and ketone bodies (not from glycogen stores)
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)
Creates one ovum (23 N) and three polar bodies
CARB- Digesting: dextrinase (polysachs produced by hydrolysis of starch) - maltase (glucose - glucose) - sucrase (glucose - fructose) - lactase (galactose - glucose) - Protein- Digesting: peptidases - NUCLEOTIDE- Digesting: nucleosidases

13. Neuronal cell bodies have extensions ie
Dehydration reaction; broken apart with enzyme - catalyzed hydrolysis
Processes: axons - dendrites
Inner lining of circulatory system
Zygote - morula (first four days) - blastocyst (4 day+; implants in uterine lining) - gastrula (2 week) - neurula (3 week)...

14. components of interstitial fluid
Glycosaminoglycans - prots - AAs - lipids
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Small amounts of hydrolyzed phospholipids and cholesterol: like other fat mols these can diffuse thru enterocyte membrane
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.

15. Ovum development is halted At what stage until fertilization...
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
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Bacterial flagellin: hollow filament (not microtub); euk: 9+2 microtubule w/dynein bridges
Ketone bodies; thus excessive reliance on fat for energy (eg low carb diets) results in ketosis; blood acidity increases

16. amylase acts where on carbs
Form barrier to extracellular fluid
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
ER
Salivary amylase (weak); sm intest amylase (breaks down large polysaccharides)

17. Different tissues working together
'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
Drugs - toxins - bile pigments (color the urine) - uric acid - antibiotics
Organs
Zygotes are diploid

18. Posterior pituitary hormones (Small Peptides)
Oxytocin and ADH (aka vasopressin)
Albumin increases osmolarity of blood; increases osmotic pressure
Somatic nervous sys - autonomic nervous sys
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)

19. For focal point that is nearby - what will the lens look like
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
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
In mouth - breakdown of starch into polysaccharides
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle

20. What determines number of chromosomes?
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Many modern drugs are ligands for GPCRs
Spike in estrogen - LH levels; secondary follicle bursts - releases into body cavity - swept along by fimbriae
Interstitial fluid (eg prostaglandins - cytokines)

21. bile + fat forms
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
After 4 day+ - morula cells have formed fluid - filled ball (blastocyst); this implants in uterus at day 5-7; blastocyst is made up of EMBRYONIC STEM Cells; once implanted w/blastocyst - female is pregnant
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
Micelles; micelles transport lipase products to enterocytes for absorption at brush border

22. signal transduction occurs by 2 paths
Calcitonin (peptide; lowers blood Ca); T3/T4 (tyrosine - derived; increase basal metabolic rate); T4= thyroxine
1) by integral ion channels 2) transmitted by second messenger system
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

23. Glycogenolysis/gluconeogenesis
At metaphase II of meiosis II (halted during reductional division); if fertilized - process continues toward haploid gamete
Moves down thru esophageal sphincter
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions
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

24. these transport proteins - when concs are high enough...
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Can be saturated; conc of a solute is called the transport maximum --->excess goes into urine
Albumin increases osmolarity of blood; increases osmotic pressure
Digestion

25. ligands are the messenger compounds that target secondary messenger systems on effectors
Many modern drugs are ligands for GPCRs
Synthesizes lipids (including steroids); detoxifies drugs; is continuous with lumen
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
HCl; secreted by parietal cells under stim by gastrin

26. lysosome pH
Protein digestion begins in stomach; low pH denatures proteins - kills bacteria; mixes - stores food and destroys it to chyme (BOLUS-->CHYME)
5
Spinal cord ventral horns; somatic motor neurons use acetylcholine for NTs (voluntary)
Glands w/ducts: Exocrine glands

27. from thoracic duct - chylomicrons stick to capillary walls...
**only para effectors have muscarinic receptors; symp effectors are adrenergic (epi - norepi); **neuromuscular junction uses nicotinic receptors
Number of centromeres - Not number of chromatids eg - two sister chromatids connected by one centromere = one chromosome
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity
Where lipoprotein lipase hydrolyzes TAGs; products diffuse into target tiss (mostly liver - adipose tissue)

28. Mucus - digestive enzymes released thru
(diploid organism) humans are part of gametic life cycle ie produce gametes; diploid germ - line stem cells undergo meiosis to form haploid gametes
Lysosome
Glands w/ducts: Exocrine glands
RBCs - large proteins; What does enter is called the filtrate

29. Between meals most fats appear in blood as
Eg spinal nerve - cranial nerve; Not All Nervous Tissue In Brain - SC Is CNS Tissue
Adrenocorticotropin; stims adrenal cortex release of glucocorticoids (eg cortisol - a steroid) stress hormones via second messenger system using cAMP
Lipoproteins; albumin carries free fatty acids when fat is mobilized from adipose tissue - etc
Parathyroid hormone (peptide; increases blood Ca); thus - might increase osteoclast/decrease osteoblast activity

30. Meiosis I: REDUCTIONAL DIVISION Interphase: G1 (growth; enzymes - structural proteins needed for gametic production are synthesized); S (DNA of homologous chromosomes is duplicated; mother cell goes from 46 2N to 46 2N with sister chromosomes connect
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
Glucose

31. Path of urine

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32. What is gastric acid?
Has memb - bound organelles - etc...
Gastrulation occurs: formation of three primary germ layers = differentiation
Prophase I: crossing over occurs; nuclear envelope is absorbed into ER; chromosomes condense)
HCl; secreted by parietal cells under stim by gastrin

33. gradual increase in FSH typical of primary follicle development;
Secondary follicle: Theca cells differentiate from interstitial tissue - surround follicle - secrete testosterone when stimd by LH (compare to Leydig cells)
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
Nourishes follicle growth; stimulates granulosa cell growth around primary oocyte at puberty = primary follicle; also - stimulates Sertoli cells in males
Changes: volume of filtrate does not change: osmolarity of filtrate --->reabsorbed ions like sodium carry water across membrane

34. Morula (...totipotent)
Zygote (morula) composed of eight or more cells; All cells at this stage are TOTipOTENT STEM Cells: do not grow - form by cleavage
On to the distal tubule where sodium - calcium are reabsorbed - protons - bicarbonate - potassium are secreted via membrane transport proteins
Peristalsis (esophagus) and segmentation (bi - directional=mixing)
Below hypothalamus

35. 80-90% fat absorbed this way
Moves thru lymph sys; emptied into large veins (thus into bloodstream) of the neck at Thoracic duct
Diarrhea: excess water loss in feces; poor absorption of vitamins - minerals
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Nitrogen

36. What are phagosomes
Membrane - bound - endocytosed bodies
Break down TAGs to monoglycerides and free fatty acids
Lower blood pH
Liver is the control center for blood glucose; is fed by portal vein from sm intest

37. interneurons
Smaller - more water soluble short - chain FAs go directly to bloodstream at villi capillaries
Fallopian tubes
Glucocorticoid (cortisol); mineralocorticoid (aldosterone)
Transfer signals from neuron - neuron; 90% of neurons are interneurons

38. Failure of apoptosis can result in
pericardial cavity - pleural cavity (contains lungs) - peritoneal cavity (abdominal)
Faces the lumen
Cancer; apop can be programmed cell death; mitochon can play important role in apop
Mostly reabsorbed to liver

39. What is somatostatin
Only musc and esp ** liver can store large amounts
Secreted by delta cells of Islets of langerhans; inhibits insulin and glucagon; slows digestion
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
Meiosis creates germ cells

40. Thus inhibiting parietal cells could do What to blood pH
**NO*** lipase digests fat; no bonds broken by bile; only opens up more SA for lipase
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
Maintains hi estrogen levels; body does not recognize luteal surge - ovulation does not occur; hi progesterone can lessen shedding by thickening the uterine lining
Lower blood pH

41. Some epithelial cells are... others...
- enterocytes w/ *microvilli brush border*: membrane - bound digestive enzymes for carbs - fats - nucleic acids - goblet cells: secrete mucous - Deep between villi are the intestinal exocrine glands - the crypts of Lieberkuhn - which secrete pH 7.6 i
Organs
Within the paravertebral ganglion - running parallel to spinal cord
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)

42. Where does the juxtaglomerular apparatus come into play...renin --->inc angiotensins -->inc aldosterone - ups BP
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... ...
Lens will be rounded; contraction of the lens (ie focusing) is done by ciliary muscle
Serous membrane (slick - reducing friction) that forms lining of the coelom --> secretes lubricating fluid
Development of placenta begins with implantation; eventually - by end of first trimester - placenta will replace corpus luteum and its estrogen/progest secretions

43. 3 phases of menstrual cycle
Inactive: rhodopsin is activated by photons; activated rhodopsin hyperpolarizes rod cells - causes photobleaching
Fructose is a structural isomer of glucose
Buildup of macromolecules in lysosome due to deficient lysosome enzymes
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)

44. medium for paracrine hormones
Interstitial fluid (eg prostaglandins - cytokines)
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**
Determination is a pre - programmed fate - differentiation is the actual materialization of that fate
An endogenous morphine

45. What is the function of the loop of Henle
Paracrine (local) - endocrine (longer distance)
Increases solute conc and osmotic pressure of the ***medulla
Corpus luteum degrades into corpus albicans
vitreous humor - retina - fovea

46. What is the net effect of the distal tubule
Smooth ER
Night vision
Result is proton secreted into lumen - bicarbonate into interstitial fluid (diffuses into blood); result is also increased blood pH and decreased pH stomach
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

47. How does glycogen compare to starch
Has memb - bound organelles - etc...
Increases blood Calcium
Conjunction of cell body w/axon
It is the animal counterpart of starch; it is more highly- branched - thus releases more glucose monomers upon repeated hydrolysis than starch

48. What does peroxisome do
ER
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
Oxidizes macromolecules; breaks down very long - chain FAs by beta - oxidation; products (acetyl - CoA) are shuttled to mitochondrion for citric acid cycle

49. FSH - LH - HCG - inhibin are...
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
Notochord (mesoderm) induces ectoderm to thicken into neural plate --->neural tube --->spinal cord
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
Peptides

50. The esophageal sphincter is...
Conjunction of cell body w/axon
90-140 mg/dl
Normally contracted
Visceral layer= parietal layer; serous membrane is the container of the coelom/peritoneal cavity