in neuromuscular junctions what is the T system? in the heinemann book it says " depolarisation waves travel down tubules (T system)"
the T junction is the transverse (system) tubules. It runs down the sarcolemma to the sarcomeres. What happens is that when the sarcolemma (the membrane) depolarises, the depolarization (thus Na+ wave) travels to the T-tubules, which depolarise downwards, causing the sacroplasmic reticulum to release Ca2+ ions (and then contraction stuff).
Do you see what i mean? Its best to see a diagram of it to understand. The link below is a pic i found on google which i think is the simplies way of seeing it. Look at the pic and read the paragraph above i just wrote and see if you can relate the two and understand it. http://3dotstudio.com/prenhall/nmjcoupling.jpg
lol the genomes and gene therapy stuff is quite intetesting hehe
can someone help me with this: -biological species concept & phylogenetic species concept (are we just meant to know about the difference?)
-genetic drift!
that is alll i promise!
Biological Species concept : group of similar organisms which can interbreed to form fertile offspings. They have similar morphological, physiological and biochemical features.
Phylogentic species concept: group of organisms similar in anatomy, biochemistry, behaviour, morphological etc, so the classification basics.
Genetic Drift: change in the frequency of an allele by chance. This is mainly in small populations where they have been separated from the main population.
btw please keep asking questions its a good way for everyone to revise... if we can explain it for you and us to understand then we understand it better ourselves! so keep asking! your doing everyone a big favour!!!
Difference between the two, PSC looks are the evolutionary relationship whereas BSC looks at biochemistry more (thus offspings fertility).
Module 3.. Primary Productivity and Gross Primary Productivity
Productivity is the rate at which energy is made at each trophic level. When looking at Primary Productivity your looking at the plants and the energy they make. The Gross PP is the rate at which the chemical energy is made. The due to respiration etc that energy is lost... so the Net PP is the remaining energy.
If you look in the OCR book you will find a page all about sex linked genes, recessive and dominant alleles and how they interact and codominance and also about linked genes which Science Rules has kindly summarised below:
Linkage is when two or more genes are located on the same chromosome. thsi is usually because they don't segregate independently during anaphase I of meiosis. It reduces the number of phenotypes resulting from the cross. I just carry out a normal cross but take all the information they give you into consideration- seems to work on
PP is the productivity of plants. GPP is the is the rate at which plants convert light energy to chemical energy. NPP is GPP-R. (R= respiratory heat loss)
Relax, it's fine - it just happens on the system i think lol
btw, i was meaning to ask - what's your signature about?
I hope so, thanks.
The signature is about the Libyan revolution - shows the old Kingdom flag with Sheikh Omar al Mokhtar (a fantastic military leader who fought the nazi fascists, with all their tanks and artillery, in Libya using only rifle -armed horseback riders and lightly armed men from the villages) who is known as being the 'Lion of the Desert' hence the Lion
There's also a film called Lion of the Desert about the great Mujahid.