Biology topics...

[Predentknight]

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Can someone simplify these topics.....

1. Ovulation, and the role each hormone plays as far as negative and positive feedback. - though i had this straight but apparently not...

2. Hardy Weinberg equilibrium..(simplified!)

3. The Nephron - the way I have it straight right now.. the glomerulus within the bowmans capsule filters due to the effect of bp, then passes through the distal convoluted tubule down the descending loop of henle where water passivley flows becomes less concentrated. The ascending loop of henle water passively flows out and cl- is actively transported in. Then passes through the proximal tubules where Vasopressin acts to reabsorb water??(anything else here) and on to the renal artery and into the collecting duct which connects to the bladder. This is off the top of my head if I am missing details can you fill me in.


any other topics that you may be unclear on feel free to post and I will do my best to starighten out any topic that I may be knowledgable on.

 

[theedaddy77]

2. . Hardy Weinberg equilibrium..(simplified!) = w/e u think about this one u dont want to change gene frequency. that is the guiding rule

3. "3. The Nephron - the way I have it straight right now.. the glomerulus within the bowmans capsule filters due to the effect of bp, then passes through the distal convoluted tubule "
u mean the proximal tuble where most reabosorbtion happens

"down the descending loop of henle where water passivley flows becomes less concentrated. "
yeah u prob mean where water passivly flows out increasing the concentration of the stuff in the loop

"The ascending loop of henle water passively flows out and cl- is actively transported in. "
No where water can't flow in or out and urea and other **** pumps out therefore in this part of the loop u are makeing it less concentrated

"Then passes through the proximal tubules where Vasopressin acts to reabsorb water??"
right but distal tuble

"and on to the renal artery and into the collecting duct which connects to the bladder."
collected duct where adh can act open it again and goes to the bladder. While in the collecting duct water goes out so makes it more concentrated

for 1 im hoping that osem person gives a lecture on that topic cause i have no idea....

 

[TexasDent]

You also probably want to know that the hormone ADH functions directly in increasing water reabsorption. I don't remember exactly how Vasopressin works but I think it indirectly increases water reabsorption by increasing the reabsorption of Na+ ions.

Someone correct me if that is not exactly how Vasopressin functions in water reaborption.

 

[TexasDent]

You also probably want to know that the hormone ADH functions directly in increasing water reabsorption. I don't remember exactly how Vasopressin works but I think it indirectly increases water reabsorption by increasing the reabsorption of Na+ ions.

Someone correct me if that is not exactly how Vasopressin functions in water reaborption.

Just kidding, I had vasopressin and aldosterone confused. Vasopressin is the same thing as ADH. It is Aldosterone that increases the passive reabsorption of water by increasing the active reabsorption of Na+ ions.

 

[vert]

3. The Nephron - the way I have it straight right now.. the glomerulus within the bowmans capsule filters due to the effect of bp, then passes through the distal convoluted tubule down the descending loop of henle where water passivley flows becomes less concentrated. The ascending loop of henle water passively flows out and cl- is actively transported in. Then passes through the proximal tubules where Vasopressin acts to reabsorb water??(anything else here) and on to the renal artery and into the collecting duct which connects to the bladder. This is off the top of my head if I am missing details can you fill me in.

make sure you don't confuse the bloodflow and the nephron.

Bloodflow: Renal artery --> Renal arteriole --> glomerular capillaries --> peritubular capillaries --> vasa recta --> inferior vena cava.

Nephron: bowman's capsule --> proximal convoluted tubule --> proximal straight tubule --> descending loop of Henle --> ascending loop of Henle --> macula densa --> distal convoluted tubule --> cortical collecting duct --> medullary collecting duct

 

[osimsDDS]

The Kidney(s):

Bowmans capsule and the glomurous is where the blood comes in and is filtered at first. Through pressure the blood enters the glomurous via bulk flow and ions, glucose, aa, and other small things in the blood pass while the cells of the blood like RBC get sifted by the glomurous. Now after it goes through to the proximal convoluted tubule where most reabsorption of all of those ions, glucose, and aa takes place. At the descending loop of henle is where reabsorbtion of water takes place into the interstitial tissues surrounding the nephron. Then at the ascending loop of henle it gets less concentrated and water flows back into the "tube." Then while it goes down the collecting duct water gets really absorbed because the medulla part of the nephron is very concentrated and water flows out of the collecting ducts right before the urine flows into the ureter...

hope thats right and also helps..

 

[wkawk2416]

i agree most of the parts that everyone explained

but i thought when the fluid goes through ascending loop of henle, water does not reabsored to the medulla of kidney.

the reason that the fluid gets less concentrated is salt (NaCl) is actively (outer medulla) and passively (inner medulla) reabsorbed to the medulla, but water does not, and the concentration of water does not change. Therefore, the fluid gets less concentrated.

Please correct me if i am wrong.

 

[Predentknight]

I am not sure if ^ is correct.


As I was reviewing my Kaplan midterm, Is this correct?

#4 Bio: endosymbiotic hypothesis, Kaplan says chloroplasts descended from prokaryotic autotrophs. I thought they descended from prokaryotic heterotrophs.??! is Kaplan wrong or am I wrong

 

[osimsDDS]

i agree most of the parts that everyone explained

but i thought when the fluid goes through ascending loop of henle, water does not reabsored to the medulla of kidney.

the reason that the fluid gets less concentrated is salt (NaCl) is actively (outer medulla) and passively (inner medulla) reabsorbed to the medulla, but water does not, and the concentration of water does not change. Therefore, the fluid gets less concentrated.

Please correct me if i am wrong.

you are correct, when I wrote it last night i took a second to think after and i thought i messed something up, my bad ppl sorry...you are correct, ions leave the ascending loop of henle and enter the interstitial cells therefore when it comes back aruond in the collecting duct the interstitial cells (medulla) is very hypertonic and water will diffuse out of the collecting ducts...

 

[wkawk2416]

I am not sure if ^ is correct.


As I was reviewing my Kaplan midterm, Is this correct?

#4 Bio: endosymbiotic hypothesis, Kaplan says chloroplasts descended from prokaryotic autotrophs. I thought they descended from prokaryotic heterotrophs.??! is Kaplan wrong or am I wrong

i think kaplan is right. chloroplast itself descends from prokaryotic autotrophs, and eukaryote that contains chloroplasts descended from prokaryotic heterotrophs. in other words, prokaryote heterotrophs which gains energy from other molecules engulfs autotroph prokaryots and that autotroph prokatyots eventually becomes chloroplast in the eukaryotes.

 

[osimsDDS]

it is also good to note in this that since the chloroplast and mitochondria both have double membranes, the ETC and also the light reaction occured on the cell membrane of those autrophic prokaryotes that were ingulfed by heterotrophic prokaryotes and then those membranes became what is now the inner mitochondrial membrane where ETC is and also thylakoid membrane where light reaction occur...thats basically how i memorize it...