A level Biology: Post your doubts here!

[confused123]

that

Basically, you draw a diagram and below/ beside it, explain what is happening in your diagram. Suppose you draw the stages of mitosis - annotating would mean that for each stage, next to the diagram of the cell, write in brief what's happening (chromosomes shrinking, spindle fibres forming, nucleolus breaking down, etc.)

diagram needs to be enlarged or lower power high power plan diagram?

 

[lavanyamane]

that
diagram needs to be enlarged or lower power high power plan diagram?

Yes, in practicals, but it totally depends on the question. It'll always tell you if the diagram should be drawn as a plan diagram or what. I was just explaining what annotation means

 

[raamish]

http://www.xtremepapers.com/papers/...nd AS Level/Biology (9700)/9700_s11_ms_31.pdf

1b(iii) what is the relationship of absorbance of light here?

Also, in diagram of a vein tunica intima should be double layered like the epidermis in plants or should it be a single line?
will cell surface membrane be double layered also?

 

[confused123]

Yes, in practicals, but it totally depends on the question. It'll always tell you if the diagram should be drawn as a plan diagram or what. I was just explaining what annotation means

yeah thanks, i was also inquiring about annotation. does it involve enlarging along with labelling? how much detail does it require. tell me if the answer in the image attached is correct . what's missing? Thanks..

 

[lavanyamane]

yeah thanks, i was also inquiring about annotation. does it involve enlarging along with labelling? how much detail does it require. tell me if the answer in the image attached is correctView attachment 10322 . what's missing? Thanks..

You've drawn the diagram, but there's no annotation. You have to write about the appearance of two tissues, too. Now I don't know the slide, so I can't help you with WHAT the stuff you write should be.

 

[Henry930821]

Hey guys. For paper 3, usually the last question of the paper in which they ask u to give observable differences between the two specimens. Let's say the question did not state how many differences required but the marks allocated for that question is 4. If we gave 5 differences when the marks were supposedly credited for 3 differences, and the extra ones are incorrect. would the wrong answers cancel the correct answers? Is there such thing as wrong cancel right in paper 3? And how would the examiner mark it? Will he or she choose only the correct ones while ignoring the incorrect ones? Thx in advance

 

[confused123]

Hey guys. For paper 3, usually the last question of the paper in which they ask u to give observable differences between the two specimens. Let's say the question did not state how many differences required but the marks allocated for that question is 4. If we gave 5 differences when the marks were supposedly credited for 3 differences, and the extra ones are incorrect. would the wrong answers cancel the correct answers? Is there such thing as wrong cancel right in paper 3? And how would the examiner mark it? Will he or she choose only the correct ones while ignoring the incorrect ones? Thx in advance

4 marks means 4 differences. if u wrote the extra one and its wrong then u might get penalty for that. not sure

 

[narutogirl]

T___T
can someone please draw the alveoli..desperate T__T

 

[Jaf]

This part from the syllabus:

(p) state and explain the differences between blood, tissue fluid and lymph;

I can't think of too many differences. :S Does anyone have a list?

 

[Saad (سعد)]

This part from the syllabus:

I can't think of too many differences. :S Does anyone have a list?

Bismillah, Tawakkaltu 'alal-Allah.

Tissue fluid is blood without blood cells and large proteins. Lymph is identical to tissue fluid except that its found in the lymphatic system and not in tissues.

I think.

 

[raamish]

what does fluidity of the membrane mean?

 

[Saad (سعد)]

what does fluidity of the membrane mean?

The membrane is fluid; its not solid. The phospholipids and protein molecules float around (you can understand that by watching the video below).

Now that you mentioned cell membranes...

This is for all of us:

We will show them Our Signs in the universe, and in their ownselves, until it becomes manifest to them that this (the Quran) is the truth. Is it not sufficient in regard to your Lord that He is a Witness over all things? [Qur'an 41:53]

That thing in the video above, which is more complex than the largest cities on the planet, is one cell. There are a hundred trillion of those in your body, working full time, 24/7, 365 1/4 days a year, since the day you were born till the day you will die.

And there are 7 billion people on the planet, just like you, with those same cells, and that same complex mechanism, doing the same stuff.

Behold the marvels of Allah, believe, exalt Him with His praise, send blessings upon His Noble Messenger (Sall-Allahu 'Alayhi wa Sallam). And with the knowledge He has given us all from His Mercy, ace the exams we face with His Help, with the intention of gaining His Good Pleasure, and attain success in both worlds, with His Will, insha'Allah.

Subhan Allahi wa biHamdihi, Subhan Allahil-Azeem, Sall-Allahu 'alan-Nabiyyil-Ummiyil-Kareemi wa 'ala Aalihi wa As-haabihi wa Sallam, wal-Hamdulillahi Rabbil-'Alameen.

 

[confused123]

The membrane is fluid; its not solid. The phospholipids and protein molecules float around (you can understand that by watching the video below).

Now that you mentioned cell membranes...

This is for all of us:

We will show them Our Signs in the universe, and in their ownselves, until it becomes manifest to them that this (the Quran) is the truth. Is it not sufficient in regard to your Lord that He is a Witness over all things? [Qur'an 41:53]

That thing in the video above, which is more complex than the largest cities on the planet, is one cell. There are a hundred trillion of those in your body, working full time, 24/7, 365 1/4 days a year, since the day you were born till the day you will die.

And there are 7 billion people on the planet, just like you, with those same cells, and that same complex mechanism, doing the same stuff.

Behold the marvels of Allah, believe, exalt Him with His praise, send blessings upon His Noble Messenger (Sall-Allahu 'Alayhi wa Sallam). And with the knowledge He has given us all from His Mercy, ace the exams we face with His Help, with the intention of gaining His Good Pleasure, and attain success in both worlds, with His Will, insha'Allah.

Subhan Allahi wa biHamdihi, Subhan Allahil-Azeem, Sall-Allahu 'alan-Nabiyyil-Ummiyil-Kareemi wa 'ala Aalihi wa As-haabihi wa Sallam, wal-Hamdulillahi Rabbil-'Alameen.

excuse me, this thread is about biology question and queries. don't do such a thing to preach religion at wrong place. make a separate thread for ur cause. your cause might be noble for many but you should see the heading before posting stuff.

 

[Saad (سعد)]

excuse me, this thread is about biology question and queries. don't do such a thing to preach religion at wrong place. make a separate thread for ur cause. your cause might be noble for many but you should see the heading before posting stuff.

The video is about Cell Structure.

Raamish asked about the fluidity of the membrane; I remembered this video and that it portrays the plasma membrane and other cell structures really well. Then I couldn't help but to add what I felt was amazing about all this.

If you find it too different from the topic, you can ask a Mod or someone in authority and if they feel the same way, they can tell me and I'll leave the video here and move the rest to a more fitting place.

 

[pearl angel]

hey...could i get some really good notes on the chapters immunity and infectious diseases??

 

[xxfarhaxx]

hy cn i hav notes on AIDS?? if anyone knw any links or notes pls do upload!!​

 

[confused123]

you

hey...could i get some really good notes on the chapters immunity and infectious diseases??

you can ask question related to immunity in that way your chapter revision will be covered as well. still the Cambridge endorsed book is the best for study

 

[confused123]

hy cn i hav notes on AIDS?? if anyone knw any links or notes pls do upload!!​

you can ask question related to AIDS in that way your chapter revision will be covered as well. still the cambridge endorsed book is the best for study

 

[confused123]

What is the function of DNA polymerase?

The role of B and T lymphocytes?

Which bonds are involved in primary, secondary, tertiary and quarternary structures?

The effects of Tobacco and Nicotine on health?

What is the function of squamous epithelium?

Thanks.

 

[littlecloud11]

What is the function of DNA polymerase?

The role of B and T lymphocytes?

Which bonds are involved in primary, secondary, tertiary and quarternary structures?

The effects of Tobacco and Nicotine on health?

What is the function of squamous epithelium?

Thanks.

DNA polymerase : catalyses the polymerization of deoxyribonucleotides into a DNA strand. It adds free nucleotides to elongate the DNA strand being formed during replication. However, it cannot initiate the formation of the stand, you need a primer for that. The polymerase enzyme can only continue to add nucleotide by complimentary base pairing to the pre-existing 3'-OH group.

Bonds present. Primary: peptide bonds.
Secondary: Hydrogen bonds.
Tertiary: ionic bonds (between the acidic and basic groups), disulphide bonds (between cysteines), hydrophobic interactions (non-polar groups), hydrogen bonds (if side groups contains hydroxyl or amine groups)
Quaternary structure: Same as the bonds involved in the tertiary structure, depending on the side chains of the polypeptides involved.

Tobacco effects: heart attacks, strokes, chronic obstructive pulmonary diseases (COPD), hypertension, cancer.
Nicotine: High blood pressure, high heart rate, addiction, high breathing rate, hyperglycemia, weight loss, increased 'stickiness' of blood platelates.

Function of squamous epithelium: Aids passage of materials by diffusion by forming a smooth, moist interior (in the alveoli of lungs); protection of underlying tissues (in the skin, mouth, esophagus etc.)