Mr Rayon

Introduction Any organism whose temperature alters very little, despite variations in the surrounding temperature, must have mechanisms that are regulating its body temperature. Under normal circumstances, humans maintain a body core temperature in the range of 36.1°C to 37.8°C. When the core temperature is in this range, it provides the optimum conditions for the body to functions. External factors, infection or exercise can cause the body to make changes to regulate its core temperature. And these responses may be physiological or behavioural. Purpose To investigate the responses of the human body to extremes of ambient temperature. Materials Each group will require: -oral thermometer -skin thermometer -alcohol swabs -buckets/tubs -hot and cold water -ice cubes -spray bottle -stopwatch -electric fan -heater -sleeping bag -bathing suit -hat, scarf and gloves Procedure -Read the procedure and formulate an hypothesis about the effect that extremes in ambient temperature (after 20-minute exposure) will have on core temperature (as measured by an oral thermometer) and skin temperature in humans. Complete this section of data sheet 1. -Identify the variable, control and the factors that will be kept constant. The experimental procedure whould take no longer than 30 minutes. -Work in groups of 3 or 4. Stop if the subject/s feel unwell at any time. Cold subjects: -Record skin and core temperatures of the subject before you begin (Table 4.1). -Make the subeject/s as cold as possible by: -wearing bathers -placing in a cold breezeway -placing feet in buckets of icy water -exposing the body to ice from a spray bottle containing icy water Hot subjects: -Record skin and core temperatures of the subject before you begin (Table 4.1). -Make the subject/s as hot as possible by: -wrapping in a sleeping bag -wearing a hat, scarf and gloves -sitting in front of a heater -For both cold and hot subjects, record the core and skin temperature every 2 minutes, as well as any other observations (Table 4.1) -Record the class results Results Data Sheet 1 2) Identify the: a) variable: I'm guessing this would be temperature.b) control (explain how it will be used): I'm not sure what the control is here. We had only two groups. Two people from each group were put into conditions of extreme cold or warm external environment. c) constants: __________________________________________________________________________________________________ Well, the above is what's written in the sheet of the practical part of a SAC that my school did for biology. I have used the red colour to indicate the parts that are not typed in my practical sheet, and are just my thoughts. Any way in the above what would be the control and constants? Can someone clarify if temperature would be the variable? I think we were suppose to go through this in class but my teacher forgot. What's typed here as well as the next page (not shown here) will be brought to school as reference material for my SAC on Monday. We are also allowed to bring one A4 sheet of notes as a cheat sheet. Any thoughts on the questions above will be appreciated!

Oh no it's postponed. It will be tomorrow or Monday I think. EDIT: So if you really want to help you still can!

Hi there! I have a SAC tomorrow on thermoregulation (the practical). Would anyone would be able to answer a few questions that I might think of in preparation for the written work that is to be done during class time (day after tomorrow)? For SACs we usually just get a series of questions instead of doing practical reports. Basically, the SAC will be on the effects of the human body to a range of different temperatures, with strong emphasis in the extremes. i.e. how the body responds to really cold and really hot environments. So far I've done a bit of researching and reading on the topic and found little things like: vasoconstriction or vasodilation of arterioles and capillaries. However, does anyone know if there is more that I can do? How can I prepare for this oncoming SAC? What sorts of questions should I expect in the SAC (question sheet)? We are usually allowed one sheet of A4 paper as a cheat sheet so it would not have questions as simple as, "...how does shivering generate heat? Explain". Anyway...feel free to ask me any questions on the topic as I need all the help I need!

I do have a SAC tomorrow, but it's on the nervous and hormonal system (thermoregulation). It will demonstrate how the human body responds to different temperatures. For example, the contraction of errector pili muscles (think I spelt that right) to pull hair up and trap heat, when external conditions are cold. I have gone through everything and memorised the common responses made by the body to extremely hot and cold external environments. But I am not sure what to do next. Any ideas on how I can prepare for this? Yes, that would be great! Well, that's what I heard. I asked a tutor at yourtutor.com.au also and essentially they said that it is sort of true. I think there is a period where they are both secreted, before the inhibition of one starts to effect the secretion of the other. Can anyone confirm? However, I'm not quite sure because I have a diagram of all this in my textbook and it does not mention this. It sort of contradicts my above theory. But it's definitely worth looking into. Well, I wouldn't know, every school does these things a little bit different. Have you been to this site: http://www.vcenotes.com ? There are lots of VCE students online that may be able to help you with that over there. BTW, what textbook/s do you use to study biology? Merged post follows: Consecutive posts merged When I said the above quote, I meant if there was a high blood glucose level, would only insulin be produced? i.e. the secretion of insulin would inhibit that of glucagon. Or is glucagon still produced but in lesser quantities along with more insulin? I know it's not something big to worry about, but I have to get the wording right. In an exam, it could be this knowledge that seperates me from a point or two.

I got it from here: http://www.biologymad.com/resources/A2%20Homeostasis.pdf Check out the last sentence of page 4. Merged post follows: Consecutive posts merged Okay, so let me just ask you this question. If blood glucose levels were to go above the normal range, would alpha cells in the pancreas produce less glucagon and beta cells in the pancreas produce more insulin? Well, that's what my textbook says. But apparently, there is more to it then that. I'm not sure which is right?

Is it true that insulin and glucagon can never both be produced at the same time? If so, why? I find this pretty interesting...

Hi everybody! I'm interested in hearing how the body responds when it is faced by conditions of freezing and hot climate. For example, vasodilation of arterioles and capillaries occur when the body is faced by extremes in heat. However it does the opposite when conditions are cold. Does anyone know where I can possibly get a list of all these different responses to different external temperatures faced by the body? Or if this is not possible, if anyone could tell me some interesting reponses made by the body to different temperatures. Anything relevant said of the above will be appreciated!

...

Oh yes, I guess so. When I go on here my mind always tell me to go the biology section instead. Woops...do I have the power to move a thread? I wonder...

The Gila monster is a venomous lizard, native to several south-western US states. This lizard eats only four times a year. It has the ability to activate its pancreas at these times, whereas at other times the pancreas is inactive. The saliva of this lizard has a hormone, exendine-4. This a 39-amino acid peptide that is secreted when the lizard eats. The effect of exenrine-4 is to stimulate insulin production, inhibit glucagon secretion and slow down the rate of the stomach emptying. a) Name the cells in the pancreas that produce insulin. b) Why is it necessary for the lizard to produce insulin at a meal? c) Explain the significance of the action of exendin-4 in inhibiting glucagon production. Synthetic exendin-4 is currently being trialled as a drug teatment for people with type 2 diabetes. Excess glucagon production is a major factor in their heperglycaemia. Synthetic exendin-4 has all the properties of the naturally occurring exendin-4, d) How does slowing down the emptying of the stomach help people suffering from type 2 diabetes? The drug, exendin-4, stimulates insulin secretion in the presence of elevated glucose concentrations, but not when blood glucose levels are low. e) Explain how this property of exendin-4 gives an advantage over insulin injections for diabetics. f) Exendin-4 has the disadvantage that it needs to be injected. Give one possible reason why it needs to be injected rather than taken orally. _______________________________________________________________________________________ Are these reponses right? Well, any help, clarification or/and confirmation on the above will be appreciated. 6a) Beta cells of the pancreas b) The insulin production would decrease the blood-glucose levels after the lizard has finish eating its meal. c) If glucagon production production were to take place (as is the case in the absence of exendin-4) the blood-glucose levels would skyrocket after the meal. This would lose the lizard lots of energy, and make it harder for it to survive if it only eats four times a year. d) Slowing down the emptying of the stomach helps people suffering from type 2 diabetes by making them feel fuller, longer. e) Not sure f) Not sure

As usual you haven't been a dissapointment. Your contributions to this forum continue to impress many.

What's the difference between a synapse and a synaptic cleft? I've looked at the definition that my textbook gives me but they seem sort of similar. So, are these synonyms or are they supposed to be different? If they are different when would it be appropriate to use one of them as opposed to the other? If anyone could show two different sentences where it would be most appropriate to use the two terms, it would be greatly appreciated!

Okay...this one seems interesting. Do you know where I can out more about this experiment (I assume it is well known)?

...specifically involving the pressure receptors under the skin.

After a heart attack, people often have small amounts of lactate in the blood, which comes from the injured heart muscle. Suggest an explanation for this observation. Well, I know that during anaerobic respiration lactic acid or lactate (for what I presume is the same thing) is produced as a by-product of respiration. However I fail to see the connection here? I don't really want to assume things which I am not sure of. Any help will be appreciated!

Enzymes are responsible for both sperm and male sex hormone production in the testicles of human males. Some of these enzymes have an optimal termperature of 33°C, which is about 4°C lower than body temperature. If this termperature is increased or lowered, sperm and testosterone production is adversely effected? b) What anatomical feature helps the testicles to maintain a lower temperature? I'm not sure on what this question means by anatomical feature... the testicles are located below the core of the body? Would that be a sufficient answer?

Wow...I didn't mention the role of the detergent at all in my SAC. You are very lucky to have so much time to figure it out. As for the above, I'm not quite sure on what happened in that experiment. My teacher has not explained what sort of deductions we should have formulated based on observation. If you'd looked at one of my previous posts you will see that I wasn't sure exactly what happened to great detail also(thus the need for clarification). Incidentally, I know our practical was the same but for your written SAC, will you be doing a practical report? Merged post follows: Consecutive posts merged Hmmm...well interestingly my friend told me that the detergent allowed to reaction to start. But I don't believe him as I poured the detergent after the reaction began. Your teacher eh? Well now I feel heaps better about asking help...lol

http://news.yahoo.com/s/ap/20090310/ap_on_go_pr_wh/obama_stem_cells_40 Discuss

Procedure Catalase is an enzyme that works very rapidly. It is found in several organs and tissues, including the liver, where its role is to speed up the decomposition of hydrogen peroxide into oxygen and water. Hydrogen peroxide is a by-product of meabolism and is toxic, so its rapid conversion to water is therefore important. 1) Collect nine small pieces of liver. 2) Place three in a beaker half filled with water and boil strongly for 5 minutes. 3) Place three in a mortar with a little sand and grind with the pestle. 4) Label the test tubes A,B and C and place 5 mL of hydrogen peroxide and 3 drops of detergent into each. 5) Place the fresh liver into tube A, the ground liver into tube B and the boiled liver into tube C. 6) Record the height of the bubbles produced in each test tube. 7) Record any further observations. This was what we had to do for an experiment a few days ago. I have recorded what was observed and made my own deductions as to why certain things happened at different rates. However, I would like to see what most people would have thought to check if what I think is consistent. Incidently, has anyone done a similar experiment to this? Feel free to ask more questions about the experiment if addtional information is required to form your own conclusions. Note: I also have a practical report to do on this. And there will be questions for me on the above experiment today...so if anybody wants to help...you have six hours from now!

Well, I'll just type up what's on my practical sheet. Procedure Part B Diastase, also called amylase, is an enzyme that breaks down starch molecules into separte glucose molecules. Iodine is a stain that turns blue-black in the presence of starch, but stays yellow-brown when starch is not present. Therefore, the colour of iodine is an indicator of how much starch is present. 1) Label five test tubes 1,2,3,4 and 5. Two groups should label another five test tubes C1, C2,C3,C4 and C5 to act as controls. 2) To tubes 1-5 add 5mL of diastase solution, and to tubes C1-C5 add 5mL of distilled water. 3) Place the tubes in five water baths with temperatures as shown in Table 3.2. Leave in the water bath for 10 minutes and then remove. 4) While waiting, test a drop of the diastase and starch solutions for starch with iodine. Use the colour of this starch test as the maximum colour for later tests in the tubes. 5) Allow the test tubes to sit at room temperature for 5 minutes, then add 5mL of starch solution to each tube and stir. Use a sperate glass rod for each solution. 6) Test each tube for starch by placing a drop of the solution (from glass rod) on to the white tile and adding a drop of iodine solution. Record the colour as blue-black, dark blue, light blue and so on. Sorry, took me a while to find it. Answers to your questions: The tile is a single piece it is not separated into two sheets like a capacitor. There are no wires on it.

Hi everybody! I will be doing a practical report tomorrow but I don't know what one of the equipments used in the experiment is called. I tried to research it but I couldn't find out more. It sort of looks like a comboplate...but I really don't know. Any ideas on how I can find out more quicker? Any reliable sources? It's sort of hard to describe how it looks like...basically it is like a white tile with circular indentations all the same length in diameter. In the experiment we poured a solution into the "circular indentations" and recorded our observations within a restricted period of time. Any help will be appreciated!

I will be doing an experiment on enzymes tomorrow. It will involve catalase and a liver which will be grind. Anyone ever done a similar experiment? Merged post follows: Consecutive posts mergedNevermind...I guess it depends on the organism. Merged post follows: Consecutive posts mergedActually...does anyone know what the optimum temperature of catalase in either cow, pig or sheep? If the liver were to be removed from the animal would the enzyme still work best at a certain and particular temperature, as though the animal were alive? If so, what are these? Does anyone know? And...yes I know it's getting a little technical.Well any ideas will be appreciated!

so...about 7? As...suspected!

Does anybody know at what PH it works best at?

I know that proteins are polymers but are peptides considered polymers?