417 replies to this topic

[Mahuta ♥]

Since no one seemed to be offering help in biology, I am.
If anyone needs help with any topic in Biology, that is Higher and Standard Level. Including the following options:

• Cells and Energy (for SL, which is aHL topic)
  
• Microbes and Biotechnology
  
• Further Human Physiology

I'm here to help. I enjoy Biology *bio-freak yes*

This doesnt take much of my time and I'm doing it willingly.

---

Before you ask a question about a certain topic, make sure it's not listed below.


*TOPIC 2 (2.1.9-10)---*Stem cells and therapeutic use* (Second part of the post-scroll down)

*TOPIC 2 (2.4.8) -- *Endocytosis and Exocytosis*

*TOPIC 2 (2.5) -- *Cell Division (Interphase and Mitosis)*

*TOPIC 2 (2.5.5)--*how mitosis produces two genetically identical nuclei*


*TOPIC 4 (4.2)---*Meiosis*

*TOPIC 4 (4.4.8)---*Genetic engineering (reverse transcriptase)*

*TOPIC 4 (4.4)-- *Genetic engineering and biotechnology*


*TOPIC 5 (5.5.3)---*Plant Phyla and their external distinguishable features*


*TOPIC 6 (6.5)---*Nerves and Impulses*

*TOPIC 6 (6.1.3)---*Digestive Enzymes*

*TOPIC 6 (6.6.2/.3) --*Menstrual Cycle and Hormones*.


*TOPIC 7 -- *DNA replication, transcription and mRNA translation*

*TOPIC 7 (7.5)-- *Protein Structures*

*TOPIC 7 (7.6)---*Enzymes and enzyme inhibition*


*TOPIC 8 (8.1.4/8.2.5)---*Kreb's Cycle and Calvin's cycle.*

*TOPIC 8 (8.2.3)---*Light dependent reaction*

*TOPIC 8 (8.2.5)---*Light Independent reaction/ Calvin's cycle*

*TOPIC 8 (8.2.4)---*Photophosphorylation in terms of chemiosmosis*


*Topic 9 (9.3.6)-- *Plant science-Control of flowering in short/long day plants*


*TOPIC 11 (11.1.4) -Production of antibodies*

*TOPIC 11 (11.4.4) - *Oocytes and Follicles*


*OPTION C.1-- *Proteins*

• (C.1.1)--*Protein Structures*
  
• (C.1.2)--*Fibrous and Globular*
  
• (C.1.3)--*Polar and Non-polar Amino acids*
  
• (C.1.4)--*Functions of Proteins*

*OPTION C.2-- *Enzymes*

• (C.2.4)--Competitive and Non-competitive Inhibition*
  
• (C.2.5)--*End product inhibition*

*OPTION C.3-- *Cell Respiration*

• (C.3.2) -- *Glycolysis*
  
• (C.3.4)-Link Reaction, Kreb's Cycle and Transport Chain*
  
• (C.3.5)--Oxidative phosphorylation*
  
• (C.3.6)-Structure and Function of Mitochondria*

*OPTION F (F.1.7)--- *GRAM +VE and GRAM -VE eubacterial cell wall*

*OPTION F (F.2.8)---*METHANE GENERATION*

*OPTION F (F.4.1)---*Use of SACCHAROMYCES in BEER and WINE production*


*OPTION H(H.2.7)----*DIGESTION----ENTEROKINASE or ENTEROPEPTIDASE?*

*OPTION H- H.6, *GAS EXCHANGE*

Edited by Mahuta ♥, Mar 31, 2012 - 10:22.

[eblake]

I missed this topic

I'm doing a lab comparing rates of change in skin surface temperatures i.e. the rate at which skin exposed to cold recovers to normal temperatures.


I'm wondering if the time these trials are done would affect the rates of change? (becaues of different metabolic rates throughout the day). If so, would different muscle to fat ratio also affect these rates? (again because of metabolism).


Any help would be appreciated! I'm horrible with biology.

[Mahuta ♥]

Basically you're dealing with homeostasis here.
1) Time of the day obviosuly makes a difference as you'll have more sunlight (hotter) on the skin, which speeds up metabolism which means the skin recovers faster.

2)Whether the skin has hair on it or no, also makes a difference as hair stand upwards due to muscles under the skin contracting.

3) Muscle to Fat ratio also makes a different. The more muscles you have, the better your skeletal muscles will contract generating heat.

Bear in mind that the skin recovers back to normal temperature mostly due to heat generations by muscle contraction, which basically does that by aerobic respiration to generate it.


Good luck!

[eblake]

you're kind of really amazing   thanks.


Questions

1) Regarding methodology: I'm calculating the average rate of skin temperature recovery for 5 people who are classified as 'underweight', then another 5 for 'normal'. Then I'm taking the average of each group to come up with 2 means. How/with what kind of statistical tests should I compare these 2 means? Someone recommended using an F-test then the independent groups t-test or a wilcoxon test, but I haven't learnt any of them yet! Would simply comparing the 2 numerically i.e. saying one is higher than the other be too simple?

2) Regarding time of the day: It's indoors so I don't think sunlight is totally applicable here. I meant more as in varying metabolic rates throughout the day - should I be concerned about its effects on homeostasis?

3) thanks for the note on muscle contraction! I didn't know that.

[Mahuta ♥]

1) If I was you I would leave it simple. Doing something you know and keeping it simple is better than trying to make it look fancy by something you dont really know.
2) Obviously! Thats the most important thing in your research. Homeostasis is what cooling body nd skin down is about.
3) Noooo problem,lol.

Oh, and im sorry for the delay..because Im not home. I can still help though .

[avrila]

*Techniques of learning Bio*

Hi Mahuta... I also need help in BIology..
You know what, I never got a 6 yet so far... and in recent exam, only one person in my class manage to get 7. Our biology scores has really drop down. I wonder how you learn Bio easily.. Is it by just reading is enough. I only remember about biology when it is near to exam. Then, I will easily forget if I do not read it frequently. But I don't have time to read Bio all the time.

I really have problem to recall what I've learnt in Bio. And now I am doing Option H on Further Human Physiology. And we have to do notes on our own and present it in the class. I always have problem with this...

May be you can help by telling me how you learn Bio effectively... and any help with the Further Human Physiology will do.. Thanks..

Edited by Mahuta, Apr 13, 2009 - 21:06.
Added a title, so people know what each post is about.

[Mahuta ♥]

Alright coolness..no problem.

First of all, I learn it this way because I love it so much. Personallym i think bio is more of understanding than memorizing, especially Option H and the topics about human physiology.

By seeing that you took HL, Im assuming you like biology.

As for the notes, i think you should think about it as notes about your own body rather than simply IB biology notes.

Option H is my favorite one, so any help you need in that, dont hesitate.

Oh, and theres nothing magical, i just love it.

Where in the syllabus are you now? almost done?



And eblake, is everything good with your lab?

Edited by mahuta, Jan 27, 2009 - 22:36.

[avrila]

I am currently doing option H. Still in H.3.
and still have one more option to go; option E
Everyone in my school have to do Bio HL actually.
I do love Bio.. but I think I am lack of reading...
I cant write much now.. I'll get back to you if I come across any question that I do not understand...
Thanks ya...

Currently need to fix my EE... still got problems...
ok.. gtg...

[revvinevan]

Hi, for data processing in the IA, should we show how we got the answers to things such as the mean or standard deviation? Im not sure if this make any sense but i already have the raw data charts and I graphed the mean but do i need to show the data with the mean next to it in a table?
Also do we need to cite computer programs that we use? I mean, Im using excel to find the SD and the mean so if i dont show the work written out will they assume i used a program and then mark me down for not showing any kind of work besides just the answer? thank you

[heartworthy]

revvinevan, on Jan 29 2009, 05:14 PM, said:

Hi, for data processing in the IA, should we show how we got the answers to things such as the mean or standard deviation? Im not sure if this make any sense but i already have the raw data charts and I graphed the mean but do i need to show the data with the mean next to it in a table?
Also do we need to cite computer programs that we use? I mean, Im using excel to find the SD and the mean so if i dont show the work written out will they assume i used a program and then mark me down for not showing any kind of work besides just the answer? thank you

My teacher told us that we should give the formula and then show the first one or two calculations, and that was all IB needed to see. What do you think mahuta?

[IBdoc]

revvinevan, on Jan 30 2009, 12:14 AM, said:

Hi, for data processing in the IA, should we show how we got the answers to things such as the mean or standard deviation? Im not sure if this make any sense but i already have the raw data charts and I graphed the mean but do i need to show the data with the mean next to it in a table?
Also do we need to cite computer programs that we use? I mean, Im using excel to find the SD and the mean so if i dont show the work written out will they assume i used a program and then mark me down for not showing any kind of work besides just the answer? thank you

Yes, our teacher said we should. Just give the formula of the mean or the standard deviation and then replace with numbers, it's fairly easy. You always have to show how your got your answers or data.

[Mahuta ♥]

*Practical Advice*

Yes, the head of biology departement stated that you shouldnt  leave any chance for the examiner to deduct marks. As IBdoc said, its fairly easy and it garuntees marks. However, make sure you dont fill the document with mathematical things.

There's a book and a CD deals with all the IA stuff. They gave examples of a good one and a not so good one. The examiners commented that the not so good  one didnt look like a biological experiment report. This book is only available for children, as far as I know.
You should concentrate on the conclusion and evaluation more than the rest.

Good luck

[avrila]

Hi Mahuta...
I need help with Human Physiology. In H.6: Gas Exchange.
I'm confused with the term used and how it relates to each other.
I read over and over but still not very clear.

How to understand the term "partial pressure" easily and how does it relates with saturation of the  Hb with O2 and high/low affinity...

and also about Bohr shift and chloride shift.

Others can also drops your thoughts on this.. Thanks...

[Mushka]

hey, since you're offering help I was wondering if you could explain the different protien structures

The primary, Secondary, Tertiary and Quaternary please!
and like, possibly what each level does? liek the significance of each level of protein.

Thanks =)

[Mahuta ♥]

*OPTION H- H.6, GAS EXCHANGE*

Alright sorry for the late reply.. here it is

Partial Pressure:

All you have to know about partial pressure of oxygen is that it gives you the amount of oxygen in air, you dont really have to know anymore about it. Only that it is measure by kPa .

Saturation of Hb with O₂ and high/low affinity:

When Hb has high affinity for oxygen, it means that its holding on to oxygen more strongly. Having high oxygen affinity means that the Hb doesnt release oxygen readily.


The Bohr Shift:

I cant really draw the graph here, so it would help if you have it with you right now.

The graph shows to curves, one with 3pKa CO₂ and the other with 6 pKa, this shows the partial pressure of CO₂ in the tissues.

If you take a certain partial pressure of oxygen, say 10 (x-axis), and draw a line going upwards, until the it touched the curve, you see that

the % saturation og Hb with O2 at 6pKa of CO₂ is about 75%, where as with 3pKa its almost 97%.

Now, you need to realize that the body wants Hb to be less saturated. Because if its highly saturated, this means that its holding O₂,

whereas we want it to be released to the body

So basically, when you have 75% saturation of Hb, its better than having 97%.

All you need to know about the Bohr shift is what I just said, infact, you only need to know that:

At higher CO₂ levels, affinity of Hb for O₂ decreases, so it dissociates more readily at the same pKa of oxygen ( p(O₂))

This is the Bohr shift.

Note that if you're asked about the Bohr shift in the exam, you are allowed to draw the graph and annotate it, and you can get full marks on that, which is normally 6 marks.


Chloride shift:

When the cell respires, it releases CO₂.

The CO₂ diffuses into the RBC and reacts with water forming H₂CO₃^-

the H₂CO₃- dissociates to form H+ and HCO₃-

This causes a decrease in the amount of the negative ions, which will change the pH, meaning that the shape of Hb will change, which is not something we want to happen.
You have Cl₂ in your body. So to overcome this drop in cations, Cl^- ions move into the cell to balance the charge.
This is the chloride shift.

If I missed anything, please tell me.

Edited by Mahuta, Apr 13, 2009 - 21:09.

[dexter]

Hey Mahuta i was wondering if you can tell me the info required for 1) Stem cells and 2) Reverse Transcription? thank you alott oh and 3) levels of proeteins?

[avrila]

Thanks Mahuta. It sounds simpler now. I included it in my notes.

[Mahuta ♥]

*TOPIC 7 (7.5)- OPTION C (C1)-- PROTEIN STRUCTURES*

Levels/Structures of Proteins and significance:
This is basically the different structures protein can be found in.

Primary
This is the simplest structure and it shows the number of amino acids in their sequence. In another words, if you have a protein in the primary structure, you are most likely to see a sequence of amino acids. Primary structure proteins are found in every other structure. Therefore the significance of this structure is that it determines other ones. If you have a short primary structured protein, you can really have a large secondary structured.
Strcictly speaking, this structure is the structure of a single polypeptide

Secondary
The secondary structure is just as simply as the primary one. Only that the secondary structure includes a group of polypeptides,  that are held together by Hydrogen Bonds(very strong intermolecular bond).
This group of polypeptides could either be beta-pleated sheet or Alpha helices.
Beta Pleated sheet is the structure where H-bond forms between the N-H and C=O in polypeptides.
Alpha Helices is when the polypeptide forms a helix and H-bonds form between the sides, keeping the helix stable

You dont really need to know much about alpha and beta.

This type of strucutre is found alot in fibrous proteins.

Tertiary
This is a very common structure and it is the 3D protein structure. Unlike the secondary structure, the tertiary structure is when polypeptides fold up in a globular shape. This shape is help by 3 different intermolecular forces:
   1)Ionic Bond between atoms of R-group
   2)Disulfide Bridges/covalent bonds between the sulphurs
   3)Hydrogen Bonds between two R-groups
This structure determine all globular proteins such as Haemoglobin and insulin.

An easier way to think about this is if you have a primary structured protein that goes like A-B-D-C-A-D-B-C-A-B-D
If you imagine this sequence folded up so that the first A and the last D held together by one of the bonds, you get a 3D shape. Thats exactly what the tertairy structure is about.


Queternary
This is the most advanced structure. It invloves the linkage of 2 or more poly peptides. Take the example I just gave above.  think of 4 of those 3D structures held together into a one protein, thats the queternary structure.
One main feature of this structure is that it allows the binding of prosthetic group. It is a non-polypeptide substance, forming a conjugated protein.
A very good example is Haemoglobin. It consists of 4 polypeptides and the haem(iron) as the prosthetic group.

*TOPIC 2 (2.1.9-10)---Stem cells and therapeutic use*

Stem Cells:
Two main things:

1) That stem cells are cells that have the capacity to renew themselves. They do this by dividing into different types of cells. This is called differentiation.
All cells have all the genetic information that allows them to be any type of cell. Its only that they use a certain number of genes that determines what cell they're going to differentiate into.

2)You need to know one therapeutic use of stem cells. Here's an example:
   http://click4biology...2.1.htm#Therapy

*TOPIC 4 (4.4.8)---Genetic engineering (reverse transcriptase)*

Reverse Transcription:

This comes under the use genetic engineering. An example of this is the production of human insulin by bacteria.
I cant really explain reverse transcription well if its not included in this process. So here's the process:

1)mRNA is taken from pancreatic cells.
2) It is turned into single stranded DNA by reverse transcriptase enzyme.
3) DNA Polymerase turns the single stranded DNA into double stranded one. This wuold include the insulin gene excluding introns.
4) A plasmid is extracted from bacterial cell by ristricting enzyme and is joined with the DNA.
5) DNA Ligase joins plasmid(recombinant) into bacteria.

So there's the only thing you need reverse transcription for, as far as I remember.

[avrila]

Mahuta, I am just wondering which one is correct.

What is the enzyme used to activate trypsinogen to become trypsin. In Course Companion and CJ Clegg, they mention enteropeptidase while in study guide, it said enterokinase. Are they the same? Which term should be used actually?

[Mahuta ♥]

*OPTION H(H.2.7)----DIGESTION----ENTEROKINASE or ENTEROPEPTIDASE?*

It is normally called enteropeptidase but is also called enterokinase.
It's better if you call it enteropeptidase as it probably makes more sense the fact that it has "pepti" in it (breaking down proteins)

Im sorry I replied late, I had my mocks today.