bio (0216) - MaB: [p] conserving water

strange prac today using nail polish.

we took a few leaves, and applied nail polish onto small areas on both the upper and lower surfaces of the leaf, then waited for it to dry.

once the nail polish was dry, we removed it using tweasers and looked at it under a microscope.

what we found was the imprint of the leaf on both sides, revealling that the lower surface of the leaf hand much more stomates (hundreds) than the top surface (about ten within that small area)

stomates are found under the leaf because it allows gaseous transfer without excessive loss of water.

bio (0209) - MaB: [p] dissecting kidney

kidneys smell gross.

i thought i'd just put that out there LAWL

mr spies was talking about how cow kidneys are realy big, like basketball diameter, but meh, it was sheep kidneys today, since they're similar size to people kidneys.

ours was majorly squishy and hard to cut through.

in the end we got decent cut out of it, seeing the three things we needed to see.

- the pelvis where urine is collected
- the.. mutella? LAWL i forget.. i'll edit this blog.. but the point is.. look at your book fool!

bio (0208) - MaB: enantiostasis

like homeostasis ish.

homeostasis maintains inner conditions regardless of external conditions, eg with temperature.

see enantiostasis changes physiological functions to adjust to environments.

estuaries are examples of these, organisms that respond to change in salinity.

eg animals such as sharks can swim from ocean up rivers, coz they can adjust to change in salinity.

bio (0129) - MaB: kidneys

the kidneys have a number of jobs as we have discussed before.

they control water levels in the blood, and therefore the blood pressure within vessels. they control pH of blood and excrete waste, eg urea.

urea is a nitrogenous waste, and if split to ammonia, could be harmful to the body. it comes from deaminizing (breaking down of amino acids) and this is done in the liver.

some animals (that lay eggs) dont produce urea however, they produce uretal acid. this is because it isnt soluable. why is that important? coz the waste of the baby in the egg does not float around in the yolk. see in mammals.. waste just transfers to the mother and she excretes it.

so this includes birds, and as we later found out, reptiles. then i asked about monotremes.. and i couldnt get an answer.

bio (1210) - MaB: [p] analysing xylem

check prac report to double check, celery was left to absorn coloured water for af ew adys, and today was cut up, transverse and longitudal (thinly) and looked at under a microscope.

what was seen was drawn. observed uncoloured phloem adjacent xylem and lignin wrapped around xylem in the longitudal thingo

bio (1207) - MaB: xylem & phloem

late posts.

golly i'm behind. i really have to study for biology too. i am dead.

well.. no turning back.. must press on. notes time.

as we know, xylem and phloem are the transport systems in plants. today we got into detail.

XYLEM

they are single-cell thick tubes. how it starts is its a column of cells, and the tops and bottoms dissolve leaving a tube. xylem is made of dead cells.

PHLOEM

they're living cells. they're not exactly hollow tubes, instead of the tops and bottoms of the cells dissolving completley, they have holes and are hence known as sieve cells. since they're living, they need to function, but have no nucleus, so phloem cells have companion cells to do metabolizing for them.

xylem and phloem are always adjacent, so that water can diffuse from the xylem to the phloem as necessary to transport organic material. the process uses active transport, which means it spends energy to do this. it's all diffusion until the concentrated sugar (from the source, normally leaves) until gets to the sink (target, anywhere)

umm.. i think thats all to say, unless i remember later

bio (1124) - MaB: organ blood

first of all.. to catch up on what i missed the day before.. we talked about (without me) donated blood and artificial blood.

turns out not all of the blood that is donated is used, only parts of it. like anemic people need the red blood cells, people with severe bacterial infections need white, etc.

as for arteficial blood, it is a chemical that can actually last longer than normal blood. however, it only does the role of delivering oxygen and taking carbon dioxide, it does not fight any infections.

anyway.. onto today's topic. blood in organs, would be composed of different things. besides oxygen that comes out of blood, and carbon dioxide that goes in.. it depends where you are really.

eg. blood would be loaded with nutrients after leaving the intestines.

blood would have heaps of waste products on its way to the kidneys, and heaps of water. it'll dump all that off, and some water and nutrients could be returned.

blood from the lungs obviously would have heaps of oxygen in it.

blood from the liver would have glycogen in it, or it could carry toxins to the liver such as alcohol.

and of course, blood would carry carbon dioxide from any tissue that it passes through, after leaving some oxygen behind.

bio (1120) - MaB: blood vessels

we related the structure of blood vessels to the function today.

arteries are large, and have thick elastic walls. they can expand and contract, but are restricted by cologens, and they are thick so taht they can withstand the pressure of pulses. the pulses drive blood through the arteries. small arteries that branch off arteries are called arterioles.

veins are smaller, and have smaller holes than arteries, but bigger in proportion. there is no pump pushing the blood through veins, but they have valves which preevnt blood from going backwards (they close up if blood goes backwards) smaller veins are called venules.

capillaries are the tiny in between ones. they have walls, once cell thick, for easy diffusion, and dont fit much blood in. they are used to deliver blood to and from the cells.

lymph is a white substance found deep within tissue (whereas blood is not found deep in the tissue coz capillaries dont go there). lymph is a white liquid with dissolved substances from the body in it, and goes through lymph vessels to go back to the heart. lymph is also a rich source of white blood cells, so its a way white blood cells get around to fight off infection. lymph vessels meet around the shoulders in lymph nodes, and the tonsils are used to fight infections in the throat (coz white blood cells are abundant in lymph). people whos tonsils cannot fight infection anymore, have them removed.

bio (1119) - MaB: oximeters

the lesson was spent watching quite a few youtube videos, little theory behind it.

we were talking about the different ways of measuring gases in the blood. there are two major ways.

the first, uses those thingies that they clip onto your thumb in hospital, a pulse oximeter. it measures the pulse because there are large arteries near the edge of the skin there. the way it measures gas is like this:

light (infrared and ultraviolet) is sent through the finger, and detectors on the other side pick up the signal. if the haemoglobin has oxygen, the signal will be more distorted. this is used to measure the % of oxygen in blood.

this can fail if there is carbon monoxide in the area. carbon monoxide attaches to haemoglobin, and it actually has higher priority than oxygen, and it cannot be dumped off like oxygen can. that's why high amounts of carbon monoxide is dangerous.

the other method of measuring blood gases is by simply using a blood test. blood is drawn from the second major artery in the radius of the non-dominant hand. it is taken to a lab for testing after.

bio (1118) - Mab: [p] exhaled air pH cont.

the last bit of this prac done today, using data loggers, pH probes and pH amplifiers.. which looked like transformer cables for the probes.

using a straw i blew into a small beaker filled with 40mL of water for 2min (120sec) and the data logger recorded progress.

it started at around 7.62, and by the end.. right at the end, it hit 4.97.

so that was that

bio (1117) - Mab: [p] exhaled air pH

so.

one of the products of respiration is CO2, which we breathe out when we exhale. now they move around the body through the blood as well, and they are bumped around by hydrogen. so when we exhale, we're actually exhaling hydrogen too. therefore, our breath should be slightly acidic. we tested this today.

first of all, we got limewater, and blew into it using a straw. of course it turned milky, proving that we exhale CO2

the second part, the probe was being dodgy, so we skipped ahead to using universal indicator, which was also dodgy.

first it said our distilled water was acidic, so we had to change bottles.

so anyway.. it started off green (pH 7) and thompson blew into it for 2min. within the first 30 seconds though, it changed colour and came down to pinky-orange (pH 5) and that's where it stayed 'til the end pretty much

bio (1116) - MaB: haemoglobin

letsee.. a lot to talk about in today's post.

today's subject of discussion was haemoglobin, the substance within red blood cells that attracts oxygen and takes it to cells in the body.

haemoglobin is composed of haem (made of iron, thus is red) and globin, which is a helix of proteins that is folded around 5-7 times.

mr mahfouz explained that there is approx 2-3 million molecules of haemoglobin in a single RBC (red blood cell), and remember there are 4-7million RBCs in 1mL of blood, and on average 5L of blood in a person. so that's a crapload of haemoglobin, and considering they each fit 4 oxygen molecules, thats a lot of oxygen.

thing is the book said 200-300 million, i dunno where the error is there.. i have to clear that up tomorrow.

so. once again fouzeh described haemoglobin's oxygen capacity to be like car seats. 4 seats. and once one is fillled, all 4 must be filled immediately. so that haemoglobin carries either 4 or 0 oxygen molecules.

fouzeh used a brilliant analogy of the haemoglobin's ability to easily obtain oxygen from the alveoli as a "beautiful blonde girl". someone who can really easily attract/pick up a guy (oxygen) and a few minutes later.. just as easily dump him (somewhere in the cells hahaha)

fouzeh talked about something called partial pressure, which is basically air pressure. air pressure is measured in mmHg (mm of mercury) i dont know why.. i'll ask that tomorrow too. but it basically means, in 1cm^2 of land on the earth, all the way upwards 'til the end of the atmosphere, what is the concentration of air. it turns out to be 760mmHg. and approx 21% is oxygen, so we get something like 160.

we looked at a diagram to haev a look at the PO2 (P = partial pressure, O2 = oxygen) and PCO2. the oxygen moved around quite abit, i suppose tahts coz haemoglobin is made for carrying oxygen. the way it transports this is simple, it's all diffusion. oxygen moves from an area of high concentration (lungs) to areas of low concentration (blood vessels) to be carried around. when it eventually reaches capillaries (very narrow vessels, like 1 cell wide in diameter) oxygen is dumped in the cells and the liquid surrounding them.

around 98% of oxygen is carried around by blood cells, the other 2% is dissolved in the blood's plasma.

fouzeh used an example.

8 years ago when the socceroos were going to south america for the world cup, they were told that it wouldnt be good for them, coz they would be playing 1000m above sea level (where air pressure/concentration) is lower. so to fix that, they were sent there two weeks prior to the game, to adapt. so that their body could produce more blood cells, and wider vessels to fit them.

apparently mountain folk have wide vessels.

last thing, haemoglobin saturation. if there are 4 haemoglobin molecules, and 2 of them haev oxygen attached, it would be 50% saturation. etc

bio (1112) - MaB: [p] size of blood cells

i missed out on half the lesson coz of prefect meeting.. but i got the general geist.

it goes like this..

at 100x zoom (10 in the lens x 10 in the thingy) we measure (using a transparent ruler) the diameter of the field of view (circle that we see) getting around 1.8 - 2mm, which is converted to 180-200 micrometers

then we zoom into 400x zoom and count the amount of red blood cells seen in an imaginary diameter (around 50) and compare it to the length of the diameter to obtain the size of red blood cells.

white blood cells to measure size, are measured in porportion to the red, (about 1.5 times the red)

their nucleus appeared big and purple

bio (1106) - MaB: plant temp. regulation

its mostly written on the sheets anyway.. but plants regulate temp in a number of ways..

in extreme heat, plants adapt bbbbyyy:

- having leaves that droop down like eucalypts, they get less direct hits from the sun.
- leaves with zig-zaggy edges lose more heat, coz edges are where the most heat is lost. zigzaggy edges lose more heat coz of higher length to surface area ratio
- heat is lost naturally through radiation and transpiration
- there are heat-shock proteins in some plants that protect the enzymes
- some plants actually drop leaves during summer

in extreme cold, they adapt bbbbyyyy:

- some plants have anti-freeze systems, ie. the cells are highly concentrated and so difficult to freeze.
- some plants dont release seeds until the temperature is warm enough
- some plants just die completely, then regenerate when its time

bio (1105) - MaB: temperature adaptations

talked about adaptations for native animals today, in particular about temperature moderation.

bringing back our friend the kangaroo

structural adaptations for heatloss include long ears (like the bilby has as well)

and behavioural to lose heat include licking forelimbs (evaporation, and there are heaps of blood vesselsa round here, just like the bilby's ears) and they sit in the shade when its hot

physiological adaptations include the fact they have really concentrated urine, to reduce waterloss as much as possible.

reptiles come out in the sunlight when its cold, and burrow when its hot.

dark colours absorb light, but we all knew that, but it almost means they absorb more heat.

and talking about the difference between torpor and hibernation:

- hibernation lasts for months (usually whole winter)
- hibernation greatly drops metabolism, heart rate and breathing
- temperature drops a little, but stays constant

- torpor only lasts for a week or two
- is common in bats
- their temperature drops greatly

also note that smaller animals lose heat faster because they have a higher surface area to volume ratio

bio (1104) - MaB: temperature adaptations

today we talked about different animals living in different temperatures.

on earth, species can survive in temperatures as low as -50, all the way up to 250.

except, each individual species has a narrow bracket thing in which they can survive. eg, we humans can live in say 15 to around 30/40 without any major adaptations (eg clothes or aircon or whatnot)

we talked about endotherms like people, who produce their own heat, therefore must eat everyday. and ectotherms like crocs who acutally only eat like once a week O_O

so like.. its coz we regulate our temperature.

for animals that hibernate, what they do is in their sleep (which they only breathe like once per 5min, its really really hardcore sleep) what they do is they burn off their fat, and they have like a body clcok that wakes them up after winter.

adaptations for diff temps include ears, which are larger/longer in hot areas to lose more heat, like with kangaroos or dogs. likewise, arctic foxes have small ears.

marine mammals like whales can live in icy cold waters due to their layers of blubber keeping the heat that they produce from escaping. what happens with whales and dolphins in their blood, is they have countercurrents, which means their veins and arteries are like right next to each other, so the should-be cold used blood gets warmed up before it hits the heart again.

bio (1103) - MaB: feedback flowcharts

went over our unsure charts from yesterday.

the actual diagram had "change" in the middle, and going around in ilke a figure of 8, the top would be the opposite of the bottom.

eg. the top would go.. sense increase in heat -> sends message -> control centre at top -> thingy that does change -> change (negative feedback)

thats a crappy example coz i forget and i cbf getting my book behind me, but you get the point. the bottom would be for decrease in temp.

we compared an oven to a human. ovens have thermostats that detect overheat or underheat? haha and a switch that triggers it to warm up or stop.. this is like a human homeostasis system.

the thing is about these charts though.. is that they focus on only one change, and sensing ambient changes.. but not internal changes.

bio (1102) - MaB: [c] feedback mechanisms

today we sort of compared a simple feedback mechanism to other things.. like temperature regulation in computers and people.

two sites that i found most handy today though were:

http://www.bio.miami.edu/~cmallery/150/physiol/sf38x17.jpg

http://www.bio.miami.edu/~cmallery/150/physiol/c44x10thermo-reg.jpg

bio (1027) - MaB: [p] enzymes in different pH

today once again we played with milk and rennin.

we used 10mL of milk in 3 tubes, heated to approx 37* - 40*, and then in each, poured 2mL HCl, or 2mL distilled water, or 2mL NaOH

only the acidic one had a result.

milk was spilled on the hot plate today.. it smelt nice for some reason.

bio (1023) - MaB: [p] substrate concentration

in today's prac, we tested the effects of substrate concentration on enzyme reaction rates.

its too bad we didnt finish -.-

basically.. we added 3mL of rennin enzyme to 10mL of solution. the milk concentration varied though, and we added water so that the solution was always 10mL.

we tested 10mL, 7mL, 5mL and 3mL, and made sure that the solution was at 37*C before we started the reaction. we timed it, but did not finish.

damn.