Biology Revision for "O" level examinations

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-You should be able to define diffusion. "Diffusion is a form of passive transport (no energy required) in which substances flow from an area of high concentration to an area of low concentration:" OR Diffusion is the movement of a substance from a region of higher concentration to a region of lower concentration. Diffusion is the movement of gas or solute molecules from a region of higher concentration to a region of lower concentration until they are equal (from  BBC  ) -E.g. of diffusion in animal and plants  1. Oxygen and carbon dioxide gases are small enough to pass from the alveoli of the lungs to the single celled    capillaries that surrounds the alveoli.  2. Diffusion occurs when digested food in the blood stream (high in concentration) enter individual cells (low concentration of nutrients).  3.Pl ants transfer food particles  from phloem and water  particles from xylem through the process of  diffusion .  A simple example of diffusion taking place

Hello folks. The internet is not just used for facebook. It is a wonderful source of knowledge. As students you need to be very careful how you manage your time on the internet.     Below is an awesome website. Please make full use of it. It is quite interactive and concise. While it was created for use by GCSE students, it does have relevant contents for CSEC students to make use of. All the best in your studies. http://www.bbc.co.uk/schools/gcsebitesize/science/

Hello everyone. I would like to congratulate all those students who have excelled at this years CSEC examinations. Only through hard work and determination can success be achieved. For students preparing for exams next year, I do have that you have spent the long vacation preparing for one of the most important year of your high school life. My best advice is to begin studying for exams now, if you have not already done so. Make a study timetable (and include relaxation time). Then stick to your study timetable at least      90 % of the time. With this I can guarantee that you will be successful. All the best in your studies!!

Cells Hello everyone. One of the first things we lean in Biology is cells. All living organism consist of cell, and many structures (organelle) within the cell are common to most organisms, with a few exception. So what is a cell? " A cell is the smallest unit of an organism that is considered living". There is a debate whether virus is a living organism or not, and that would be looked at later. Cell theory 1. All organisms are composed of cells 2. Cells are alive 3. All cells come from other cells. You should know the function of the following organelles and be able to identify them on a diagram. 1. Cell wall :       protection                           Not found on animal cells (but on plant, fungus and bacterial cells) 2. Cell membrane/ Plasma membrane: regulate what enters and leaves the cell. 3. Nucleus:         Contains DNA and controls the cell 4. Mitochondria:  Site of cellular respiration. 5. Chloroplast   :  Site of photosynthesis, and only found in