A level Biology: Post your doubts here!

[Snowysangel]

How do membrane bound proteins play a role in transporting materials in and out of the cell??

 

[Jaspreet Dhaliwal]

http://olevel.sourceforge.net/papers/9700/9700_s13_qp_11.pdf Question 4 anyone??

 

[Jaspreet Dhaliwal]

Hey could someone please help out?
http://olevel.sourceforge.net/papers/9700/9700_s13_qp_11.pdf

QUESTIONS 1 , 4 , 14 , 15 , 19 , 20 , 21, 22, 23 , 24, 25 , 26 ,28
I KNOW ITS A LOT OF QUESTIONS BUT PLEASE SOMEONE!

 

[SilverCrest]

What organelle other than the nucleus has DNA?! Could someone please reply,!?

ribosomes and mitochrondrion have DNA.they have theri own DNA which means that it is different from nuclear DNA

 

[Jaspreet Dhaliwal]

ano

Hey could someone please help out?
http://olevel.sourceforge.net/papers/9700/9700_s13_qp_11.pdf

QUESTIONS 1 , 4 , 14 , 15 , 19 , 20 , 21, 22, 23 , 24, 25 , 26 ,28
I KNOW ITS A LOT OF QUESTIONS BUT PLEASE SOMEONE!

anyone?

 

[Jinosupreme]

ano anyone?

1) it's MICROSCOPE, only can reach till micro μm, hence is 3 and 4
4) use formula (pie)r^2. See properly, there is 100 small divisions along the circle. Since 0.1mm(1 division of bigger scale) covers 40 smaller divisions, use ration method to calculate. 100/40 = (diameter)/0.1mm. Then u get 0.25mm. Then u need radius hence 0.25/2 = 0.125mm. change it to m. Hence (pie)(0.125 X 10^-3)^2 = ur answer. Change unit

15) not A because partially denatured is wrong, should be denatured or not, don't have partial. Other is quite obvious

19) the key of is HAPLOID - Capable of reproduction. Hence since its haploid, should be ASEXUAL REPRODUCTION since it cannot go through reduction division

 

[Jinosupreme]

ano anyone?

20) DNA replication occurs at interphase
21) statement 1 and 2 are interphase, only 3 is metaphase
22) maximum hydrogen bonds between 2 bases are 3 hydrogen bonds, 700 * 3 = 2100
24) transcription product is mRNA. Must know.

 

[Peaceful]

Differences between a Eukaryotic cell and a Prokaryotic cell?

 

[bubbles1997]

https://www.xtremepapers.com/community/threads/general-paper-8004-post-your-doubts-here.29599/

 

[Jinosupreme]

http://olevel.sourceforge.net/papers/9700/9700_s13_qp_12.pdf

need HELP IN Q3,4, 16, 40
3C
4A
16D
40A

 

[ZulfahSA]

http://olevel.sourceforge.net/papers/9700/9700_s13_qp_12.pdf

need HELP IN Q3,4, 16, 40
3C
4A
16D
40A

http://olevel.sourceforge.net/papers/9700/9700_s13_qp_12.pdf

need HELP IN Q3,4, 16, 40
3C
4A
16D
40A

For Question 4A
Note that the question is asking for the features that enable you to IDENTIFY that it is a prokaryote.
It is true that prokaryotes have cell wall, nucleus, ribosomes and DNA. However, eukaryotes also have those features. The only difference that tells you that it is a eukaryote or prokaryote is the DNA. Prokaryotes have a circular DNA and eukaryotes have linear molecules (chromosomes).

# The question is just trying to confuse you

Question 16D
For factors that increses the fluidity of the membrane are:
1) Unsatured phospolipid tail - Fatty acid tails are bent
2) Increse in temperature
3) Cholestrol

For 1 single bonds between carbon atoms in fatty acid chains means that it is saturated. Thus it decreases the fluidity of the membrane
2 Longer chains of fatty acid does not affect any fluidity of the membrane

Question 3 and 40 somewhat still confuses me

Correct me when I'm wrong! Thank you very much!

 

[ZulfahSA]

Differences between a Eukaryotic cell and a Prokaryotic cell?

 

[Kinki Tiffany 12]

What's the role of ribosome? It's a 4 mark question. Anyone?

 

[Snowysangel]

What's the role of ribosome? It's a 4 mark question. Anyone?

They're used in protein synthesis. MRNA is made in the nucleus and this contains instructions for protein synthesis. It goes to the ribosomes where amino acids are rearranged to build the specific kind of protein

 

[Aparajita]

Hey,
I am appearing for Oct/Nov A level Biology examination,I am in serious need of help.Can anybody provide me with the notes of meiosis genetics and gene control ,biotechnology and crop plant notes. Plase.

 

[mimi1077]

hello everyone, i just wanted to know if there is practical in a-level biology because our school does not offer a-level biology so i am planning to do it outside the school and if i did the as level how many papers are left to complete the full a-level?
thxxxxx for your time

 

[queen of the legend]

hello everyone, i just wanted to know if there is practical in a-level biology because our school does not offer a-level biology so i am planning to do it outside the school and if i did the as level how many papers are left to complete the full a-level?
thxxxxx for your time

yes ofcourse there is practical that is paper 3 in AS level
its very important for you to do your as from a good school provided they have good lab, experienced teachers. A2 anyhow you can work on with good tuition only
if you get to have a good base initially ull do well ..

 

[Busy Buddy]

question_3a) explain briefly how the stimulus at the finger produces an impulse in the sensory neuron? May/June 2005_paper 4

This is what the mark scheme says & I don't get it :

idea of energy conversion ( linked to receptor) ;
Na+ in / AW ;
depolarization ;
receptor / generator potential ;
ref. to threshold ;
(therefore) action potential / wave of depolarisation ;

How do you even write this in sentences?

 

[Atiqa asl]

hello everyone, i just wanted to know if there is practical in a-level biology because our school does not offer a-level biology so i am planning to do it outside the school and if i did the as level how many papers are left to complete the full a-level?
thxxxxx for your time

in as 3 paper are there which r ppr 1 2 3 and in a2 u have 2 paper 4 5 among them u have more weight age for paper 2 and 4
r u planning to give bio privately

 

[Atiqa asl]

What organelle other than the nucleus has DNA?! Could someone please reply,!?

Nucleus, Mitochondria, and Chloroplasts.