Currently unavailable: for new students
Degree: Conservation Biology and Ecology (Masters) - Exeter University
Who am I?
Hi! My name is Megan, and I'm in my second year of an Integrated Masters in Conservation Biology and Ecology, studying at the University of Exeter's Cornwall Campus. I'm a tutor for A-level Biology and A-level Environmental Studies - my passion is biology and I have been tutoring it in one form or another since secondary school.
My aim is that our tutorial sessions are student-led. You know best what you need to cover or revise, so I will endeavour to tailor our sessions to your individual needs. Obviously ensuring a comprehensive understanding of the fundamentals of the topics is the most important and although I love to talk, I'll also use diagrams and written works to explain concepts to you.
I love biology and I want you to enjoy the sessions too, so that you look forward to your biology lessons and can feel confident about your exams.
If you’re interested then book a ‘Meet the Tutor Session’ through this website. Have some questions ready for me, and let me know what exam board you’re studying for and what I can help you with.
I look forward to meeting you!
|Biology||A Level||£20 /hr|
|Environmental Studies||A Level||£20 /hr|
Vanessa (Parent) December 22 2016
Vanessa (Parent) November 29 2016
Mrs E (Parent) February 17 2016
Mrs E (Parent) February 15 2016
The nerve impulse arrives at the pre-synaptic knob. Gated voltage-sensitive calcium ion channels open and calcium ions rapidly diffuse into the pre-synaptic knob. The influx of calcium ions stimulates synaptic vesicles full of the neurotransmitter acetylcholine to fuse with the pre-synaptic membrane. Acetylcholine is released into the synaptic cleft by exocytosis. Acetylcholine diffuses across the synaptic cleft. It bonds with receptor sites associated sodium ion channels, causing them to open. Sodium ions rapidly diffuse in and depolarise the post-synaptic membrane. If there is adequate depolarisation then an action impulse will be initiated in the post-synaptic neurone. Acetylcholine remaining in the synaptic cleft with be rapidly broken down by the enzyme acetylcholinesterase to prevent repeated stimulation of the post-synaptic neurone. The products (choline and ethanoic acid) diffuse back across the synaptic cleft into the pre-synaptic knob. ATP is then required to reform acetylcholine and ‘package’ it in the synaptic vesicles ready for the arrival of the next nerve impulse.see more
Logging and subsequently harvesting trees removes nutrients, like phosphates, from the system. The removal of the vegetation that would also normally act as a protective cover and windbreak increases the raindrop impact and wind velocity, whilst simultaneously decreasing the humus content. This accelerates soil erosion from wind and rain splash. Reduced humus content means there is less infiltration and the soil is looser, and so is more easily eroded and removed from the area in runoff. Removal of root systems reduces the root binding effect that gives the soil structure and holds it together. A further impact of deforestation is the reduced evapotranspiration rate, leading to decreased humidity and therefore reduced regional rainfall – contributing to accelerated desertification. These cumulative effects result in a reduction in the nutrient content of the soil and also in the depth of the layer of fertile topsoil.see more
Linkage occurs when the genes for two different characteristics are found on the same chromosome. This means that they do not independently assort during metaphase one of meiosis and so pass into gametes together; at fertilisation they then pass into the offspring and are inherited together. This reduces the possible allele combinations and so reduces genetic variation in the population. The majority of F2 organisms inherit the same combinations of characteristics as the F1 generations, as the only potential variation comes about as a result of crossing over events (which are comparatively rare). This should not be confused with Sex Linkage.see more