Tuesday, December 11, 2007

Today ... we learned alot....

Posted by SeungS at the real slide is actually down there..

Metabolism and Enzymes... whoop dee doo...

Basically everyone says we need to eat to live and now you know why thanks to Ms Foglia hoorah for the teacher
anways the reason we need to eat is because we need energy and without it we would.... die.
ok so energy originates from the sun yay sun good for you then if the Earth is lucky being far and all gets some solar energy plants absorb it using there chloroplast from solar to chemical energy
This is where we need to eat to live comes in.
The food pyramid is actually a energy pyramid where the producers which are the green stuff (plants) get eaten by the... moving stuff (animals) called the primary consumers! then the secondary then the tertiary and so forth... not important moving on...
We basically need the energy for the basic 4 things proteins, carbohydates, those shapeshifters.. lipids, and personally my favorite sugar..
Now we don't have chloroplast I mean itd be awesome if we did but we dont.. so get over it...
Instead we have the ability to be the dominant life on earth by stealing from the producers by.. killing them! then using our mitochondria to spread the love(energy) IMPORTANT EVER LIVING ORGANISM HAS A MITOCHONDRIA so dont be a du*ba** and think only animals have them
now going back to the topic! all living organisms store energy and plants especially store energy to get eaten not suppose to be there goal but this is how GOD intended it to be and by that I mean being eaten by the primary consumers
All those "complications" of taste and looks of food are nothing all that matters about food is the raw materials and energy we get from them!
okay just for the people who are like "hmmm why are we storing this garbage?!"
well we store it because its not garbage but because ATP is unstable and we need it for future references.. DUH! also ATP is Adensine Tri Phosphate or simply put energy yeah!
So recap energy comes from the sun-solar energy which has ATP and organic molecules then to the plants then animals then other animals then we eat all of them! yummy..
Metabolism is how we get and use energy
We as living breathing aroused organims break and form bonds between molecules which is broken down to anabolic and catoblic.
anabolic is the building like BOB the guy who builds stuff
and catabolic is like Geroge W. bush who constantly breaks stuff especially Iraq and ocassionally the English language.
Anabolic is characterized by dehydration synthesis and synthesis which are difficult words meaning build see people have to make life difficult by making many different words for 1 freakin' meaning!
Catabolic has hydrolysis and digestion also kind of annoys me..
these also cannot be done without a little help from the AMAZING!!

The enzyme is needed to disturb and destabilize bonds between molecules to bond them together and take them apart. basically I would call the enzyme as
To digest molecules we need less organization because there is a lower energy state and this is done by another word that makes life difficult... exergonic which means gives off energy this can only be done through catabolism haha cannabalism.. gross
to build molecules we need more organization which is a higher energy state and you guessed it anabolism.. if you dont get it I really don't know how to spell it out for you anymore... (very slowly) we. need. more. energy. to builllldddd.
we need to build and break down at the same time as well because we need to break down materials for the energy to build more molecules using the energy just made..
come to think of it why don't we just not break things down huh?! JUST KEEP THE MOLECULE WITH ENERGY AND SLAP IT ON TO A THIGH!!!!
haha its basically the same thing as storing energy onto a thigh and later we can break it down yay procrastinators.. for those of you who don't know what procrastinators are first of all get a dictionary and look it up second of all learn some more english words and third it means people who always put stuff off until later..
hey heres something intresting.. paper is made from sugars but it tastes like c -r- AP and we all know AP stands for Autopilot so I said nothing wrong if you happen to get the joke it was unintentional and not my fault!
anyways paper is made from cellulose which is made from sugars but only some animals can digest cellulose so we have something else.( also those dumb animals think there better than us but we have the opposable thumb so HA! take that animals )
okay comubstion breaks down sugar which is a rapid break down but we cant do that because this combustion is at 451 degrees f and I don't know about any of you but personally I don't feel like being set on fire or boiling from the inside out...
instead we as humans break down the sugar slowly and little by little with thing called the .. THE ENZYME DUN DUH DUN DUH!!!
the reason behind the need of such an awesome thing as combustion to break down sugars is because unlike our hydrogen bonds these bonds are mucho stabile and mucho covalent so its hard as h-e double hockey sticks! Combustion basically is only required for high activation energy like sugar
The amazing enzyme is what we genius with alot of vocaulary call a catalyst
which reduces activation energy to like nothing yesss!! its like buying Gucci for the price of KFC
anyways we will all die... if the activation energy were still really high without the help of the catalyst enzyme
Now people have thought enzymes were only proteins...
but they were wrong... dead wrong...
actually recently it has been discovered that there is a rebel called the RNA which "is an enzyme but not yet a protein"... sounds like a Britney Spears song which one?
who cares?!
now fortunately for me this is all we learned today so HA! na na na na

also the next sherpa to take time out of there life to do this is....
Krystyn!!! jk its Marc :P

oh and teacher lady the time is wrong i published this at 4:12 P.M and one last thing theres no pictures but im pretty sure its a d*m good read
ooo last thing I promise. is it sherpa or shurpa?

Sunday, December 9, 2007

nervous systems- Brain development

Thrusday in AP Biology we discussed the brain which plays a major part in our nervous systems.

Our nervous system is in two parts the Central Nervous System and the Peripheral Nervous System.The CNS ( central nervous system) is made of the brain and spinal cord containing mostly interneurons, also known as associative nuerons and commonly called brain nerves. They recieve signals from the sensory nueron and send the signal to the muscles which are moved by the motor neurons. The PNS ( peripheral nervous system) is made of the sensory pathway which recieves information comming in from the senses and Motor pathways which send information to muscles. The motor pathways is divided into two group Somatic(voluntary) and Autonomic(involuntary). The somatic controlls things liek muscle movements we can control and the Autonomic controls things like our heart rate and digestive system. The autonomic nervous system can then be divided into the sypathetic and parasympathetic divisons. sympathetic controls our arousal and energey used in a "fight or fight" response which the parasympathetic calms and brings us to an easy resting and digesting state.

Cephalization is the clustering of nuerons in the brain at the front end of a bilaterally symetrical animal. The brain is at this location becuase it is where the majority of our senses are located. Organisms with radially or no symetry contain nerve nets such as the cnidarian which has no complex actions becuase it ahs not complex nervous system. orgnaisms wiht radilaly like echinoderms contain more organization but their base on nerve nets still limits complex movements. Organisms containing a brain and CNS have more complex muscle control. once a Brain is developed peripheral nerves can begin as well as an increase in internuerons. most complex brains are found in predator mollusks.

The evolution of vertebrate brains shows and increase in size and complexity of the forebrain and it shows the dominacne of the cerebrum which controls higher order thinking, which explains why humans have a larger forebrain and cerebrum than for example sharks or frogs.

The human brain consists of the forebrain, the midbrain and, the hindbrain.The hind brain are the oldest structures the provide autonomic and body functions. this includes the pons, medulla oblongata and cerebellum. the structures help in the cordination of movement such as blance the maintence of homeostatis and impulses to higher brian orders as well as many involuntary actios like breathing and heart rate. The midbrain is involved in the intergration sensory information, including visual and auditory reflexes. reticular formation controls our sleep and awakefulness which can be seen through an EEG by showing electrical activity, the more activity means the more change in electrical charge. The forebrain contains the most highly evolved structures in the human brain, it hold the cerebrum which is divided into two hemipheres left and right which control the opposite side fo the body, these hemispheres are connected between the corpus callosum. The left hempisphere coontrosl many functions involving school and thinknig, like language math and logic while the right hemisphere controls the socialness, artistic ability and creativeness, ect. the cerebrum is divided into lobes with different function the frontal which controls reasoning, temporal controllingg auditory, occiptal controllingg eyesight and parietalcontrollnig senses. The limbic system controls basic emotions. we also all ahve reflexes which are autonomic responses for survival. They are reations without going to the brain.

That concludes the nervous system and basic brain development.

tomorows sherpa will be.. seung ??

Wednesday, December 5, 2007

The Nervous System (cont.)

Today in 8th and 9th period AP bio we discussed the Nervous System. I'm going to start off with reviewing some of yesterdays lesson because it will help lead into today's lesson.

Well, first you want to know how a nerve impulse travels. An impulse starts with a stimulus and then the nerve is stimulated. The cell is originally negative on the inside and positive on the outside. Once it reaches threshold potential it opens up the channels in the cell membrane. The example we used in class was Na+ and K+. Once the Na+ channels in the membrane open up, the cations diffuse into the membrane. This causes the cell to become depolarized. That point on the neuron then becomes positive inside the cell, and negative outside because the charge of the sodium is positive. This needs to continue down the cell so in order for this to happen the rest of the gates need to open. The change in charge opens up the next Na+ gates down the line. These are called voltage-gated channels. This wave that moves down the neuron, the nerve impulse, is called action potential. Once this occurs the cell has to be re-set to the negative charge inside and positive outside. This is changed by a 2nd wave. This time the K+ channels open and the potassium ions diffuse out of the cell. This makes the inside of the cell negative, again and the outside positive. The combined waves travel down the neuron and in one direction. The wave is an active potential/nerve impulse, that travels from our brain to fingertips in milliseconds. The voltage-gated channels open and close in response to changes in charge across the membrane. The sodium channels open much faster than the potassium channels. But they both close slowly.
After this a neuron needs to re-set it. This happens by the Na+ moves back out and then the K+ moves back in. They are both moving against concentration gradients. In order to do this they need a pump. The sodium-potassium pump requires ATP. This pump allows 3 Na+ ions to be pumped out and 2 K+ ions to be pumped in. Now the neuron is ready to fire again.

Heres a video on this process:

Here is another video:

At the end of the axon the signal needs to make it to the next nerve cell. In order for this to happen the impulse needs to jump the synapse. The synaptic terminal releases neurotransmitters and the diffusion of chemicals across the synapse conducts the signal across the synapse. At the synapse the action potential depolarizes the membrane, which then allows the entrance of Calcium, which allows neurotransmitter vesicles to move and fuse with the membrane and release it to the synaptic cleft. The neurotransmitter than binds with a protein receptor, the ion-gated channels open and the neurotransmitter is degraded or reabsorbed. In the next nerve cell the chemical signal opens the ion-gated channels and Na+ diffuses into the cell and K+ out of the cell.

Myelin Sheath
The axon of nerve cells is wrapped with a set of cells, Schwann cells. These cells insulate the axon and causes the signal, sent to the nerve, to hop from node to node. The hoping from node to node is called saltatory conduction. This increases the rate 30x.
There are some times when the myelin sheath is attacked by the immune system. This cause a loss in signal and is a disease called Multiple Sclerosis.

Anything that affects neurotransmitters or mimics then affects the functions of the nerves. Gases, mood altering drugs, hallucinogenic drus, Prozac and poisons all affect nerve function.

We also discussed the some of the different kinds of neurotransmitters. Acetylcoline-transmits signal to skeletal muscle
Epinephrine and norepinephrine- fight or flight response
Dopamine- affects sleep, mood, attention and learning. Lack of dopamine-associated with Parkinson's disease. Too much-schizophrenia
Serotonin- affects sleep, mood, attention and learning

One more note: Acetylcholinesterase is an enzyme which breaks down acetylcoline neurotransmitter.

That concludes my sherpa report.
Tomorrows sherpa will be.....Kelly Prince.

Tuesday, December 4, 2007

Kidney's yey!!

Well as it always seems i useally get the longest powerpoints to do but thats ok challenges are good.

Mammalian System
Its key functions are...
Filtration- Collects blood and filters out water and soluble material.
Reabsorption- reabsorbs needed substances (water NaCl) back into the blood
Secreation- pumps out unwanted substances to urine.
Excretion- removes excess fluids and harmful toxis from teh body

One of the main parts of the kedney is the Nehron. Each KIdney has 1 million, yes million (thats alot) nephrons. Its function is to filter out urea & other solutes (sugar salts). The process is the Nephron filters blood plasma (the liquid part of the blood) through it. Valuable solutes and water are reabsorbed.
Filtered out- Water (good) glucose (good) salts/ions (good) urea (bad very bad)
Not filtered out_ cells and proteins (toob ig to fit through the membrane).

THe kidneys are an interaction between the Circulatory sustem and exretory system.
The Circulatory cystem includes the glomerulus (a ball of capillaries).
The ecretory system includes- nephrons, the bowmans capsule, the loop of henle, and the collecting duct.

nephron re-absorption
Proximal tubule- the 1st series of loops in the nephron. Most of the "good stuff" is re abosrbed bak into the blood here.
NaCl- Na+ is re-absorbed by useing atp and Cl- follows by diffuseion. This process only takes half teh engery needed to absorb NaCl regullary.
ALso Absorbed- water glucose and HCO3.
Loop of henel
-Decending limb
high permiablility to water. This is becasue it contains many awuaporins in cell membranes. Low permiability to salt, this is because its missing salt channels.
-Ascending limb
Low permeablity to water, lack of aquaporens. It contains a CL- pump Na+ follows it by diffusion. Different membrane proteins. This means salts are reabsorbed.
Distal tubule Salts water and HCO3 are reabsorbed.
Collection Duct- Water is reabsorbed
. Urea is passed through the bladder and exreted.

TO do all this diffusion Osmotic Control is uised int he nephron. This reduces the cost of energy. This is because diffusion is used instead of active transport.

Regulating the Internal Environment

Today we learned a way cells maintain homeostasis. Negative feedback occurs, this is where different receptors and effectors bring about a reaction to maintain the favourable balance.

During class we went over a few specific examples. Ms. Foglia explained to us the regulation of body temperature. When the body's temperature increases the brain sends nerve signals through the body causing us to sweat and dilates the surface blood vessels. Also she explained the body's response to a decrease in body temperature. In this case the body sends nerve signals through the body causing us to shiver and constrict the surface blood vessels.

We also went over negative feedback in the endocrine system. We went over blood osmolarity, which is the measurement of the concentration of solutes dissolved in the water. Blood osmolarity affects blood pressure. When increased blood pressure increases. When blood pressure and blood osmolarity are increased the pituitary gland releases anti-diuretic hormones (decrease the need to urinate). This increases water reabsorption and increases thirst, bringing blood pressure back to its set point. When blood osmolarity and blood pressure are low JuxtaGlomerular Apparatus releases renin which activates angiotensinogen. Angiotensinogen is an inactive protein but in this process is activated, becoming angiotensin (zymogen). The angiotensin triggers the aldosterone which increases the absorption of salt and water in the kidneys.

This occurs not only in our bodies but in our everyday lives. We too use negative feedback, when criticized we change to make ourselves better.

Tomorrow's sherpa will be Mia =]

The Nervous System:

Hey period 8 and 9, this is what Tuesday's lecture was on:

Ok so The Nervous System! Err, Umm, What To Say.......Yea

So why do animals need a nervous system and what characterisitcs are needed in a nervous system. A Nervous system needs to be -Fast!, -Accurate! and needs to -Reset Quickly!.

Ok, so the nervous system has cells called neurons. They happen to be the most specialized cells in animals. They can be extremely large, for example like the Blue Whale and Giraffe (10-30 Meters and 5 Meters) or Small, for example like in humans (1-2 meters depending on the size of the person). Ok so in the Neuron, which is a nerve cell and it has many parts to it. There are Dendrites, which are branch like structures that receive signals. Then there is the cell body which leads to the axon. The axon furthers the signal to the synapse where it leaves the neuron and keeps traveling. Ok, so the neuron fits its function well, as their are many possible entries for the signal to travel to, so theres a possibility that more information can be gathered. But, theres only one path out out neuron.

So, a neuron has many protein channels. Once one opens, the rest open with succession, an "all or nothing response". So the cell is surrounded by a "sea" of charged ions. There are anions, which a concentrated on the inside of the cell and are negative, for example Chlorine and Amino Acids, and there are Cations, which are concentrated in the extracellular fluid and are positive, for example Potassium and Sodium. The potassium channel happens to leak some potassium, which is normal, but this is an extremely slow process. Cells actually have voltage and this could be measured. An unstimultated neuron at its resting potential has a voltage of -70mV or mini-volts. So their happen to be opposite charges on the opposite sides of the cell membrance which is polarized. The inside is negative while the outside is positive. This means there is a Charge Gradient! Energy

So how does a nerve impulse travel? Ok, first the nerve is stimulated. Once the threshold potential is rached, the Sodium channels in the membrane open up and the Sodium ions diffuse into the cell. At this point the charges on the neuron are reversed. It becomes positive on the inside and negative on the outside. This means the cell becomes Depolarized. So how does the signal keep traveling down? Well remember how I said if one Sodium channel opens up, the rest open up in succession, yea so that happens in a line. The Sodium ions continue to diffuse into the cell. Finally the wave that
mmoves down the neuron is called the action potential or basically a nerve impulse. (The rest of the Dominoes fall! Yay!)

Ok, hopefully you got that. Now how does that 2nd wave travel down the neuron. Well it has to re-set itself. So basically the Potassium channels open up, but much slower than the Sodium channels. Then the Potassium ions diffuse out of the cell. Therefore the charges reverse back to the original state, negative on the inside and positive on the outside. (Setting up the dominoes! Quickly!) So the signal moves down one and in one direction only. The flow of Potassium out of the cell stops the activation of Sodium channels in the wrong direction. (Ready Again!)

Ok so thats basically it! Allright thats it, Thanks guys, Umm the Sherpa for Wednesday is "I Dont Know" Ok then, Night


Sunday, December 2, 2007

Regulating the Internal Environment

Well guys and ms.Folglia i would first like to apoligize for writing this blog so late even though it was supposed to be up on friday. So SORRY :( .

ALRIGHTY THEN. Where do we start? OH yeah Regulating the internal environment.

Well first of all we have to know what HOMEOSTASIS means and basically all homeostasis is, is maintaina balance in the internal environment. It is keeping the internal environment ballanced and regulated. Some examples of