Meiosis is a process of cell division that takes place only in sex organs, in order to produce sperm or egg cells. Sperm or egg cells must have half the number of chromosomes of normal, somatic cells, so that when they fuse during fertilization, the result is a zygote with the complete number of chromosomes. [...]
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The difference between mitosis and meiosis
Mitosis is the process of cell division where one cell divides into two cells which are identical to the original cell. This takes place in all our somatic (“normal”) cells. Meiosis is a special form of cell division that only takes place in the sex organs (gonads) of organisms that undergo sexual reproduction, in order [...]
The difference between chromatin, chromatid and chromosome
It’s easy to confuse these 3 terms! Let’s try to clear things up here. DNA, the blueprint of life, is organized into structures called chromosomes. In prokaryotic cells, chromosomes are circular, whereas in eukaryotic cells, they are linear strands. Different organisms have different numbers of chromosomes: human cells usually have 46 chromosomes, dogs have 78 [...]
Photosynthesis Lab: What to Expect
As mentioned earlier, the rate of photosynthesis should increase when you give the plant more light, more carbon dioxide and the optimum temperature. However, at high light and high carbon dioxide, photosynthesis will reach its maximum rate and won’t go any higher. For more details, check this page on photosynthesis: http://click4biology.info/c4b/3/Chem3.8.htm (I will eventually get [...]
Photosynthesis Lab: What to Measure?
What to Measure? Now, how would you measure the rate of photosynthesis? Again, let’s look at the equation for photosynthesis: CO2 + H2O + light –> O2 + glucose There are 2 things we can quickly measure in this experiment (the dependent variables): amount of oxygen produced, or, amount of carbon dioxide used. If the [...]
Photosynthesis Lab: Set Up
A commonly-used plant for such experiments is the Elodea, an aquatic (underwater) plant also referred to as pondweed. You can buy this at aquarium stores. The set up depends on which question you would like to study. In general, the plant is placed in a test tube filled with diluted sodium bicarbonate solution (1%). Sodium [...]
Photosynthesis Lab
Here are some ideas for planning experiments for studying plant photosynthesis. Remember that the simple equation for photosynthesis is: CO2 + H2O + light –> O2 + glucose There are many questions you can ask about photosynthesis, such as: Does light intensity affect the rate of photosynthesis? Does temperature affect the rate? What about levels [...]
Cytokinesis
Cytokinesis is the final stage in the cell cycle. The cytoplasm of the dividing cell is separated in two. The way this happens is different for animal and plant cells. In animal cells, the cell forms a contractile ring in the middle of the dividing cell. As the ring contracts, it creates a cleavage furrow, [...]
Interphase
Dividing cells spend most of their time (around 90%) in interphase. However, they are not just resting, but preparing for the next division. The first part of interphase, the G1 phase (Gap 1), is the period during which cells are growing, synthesizing proteins and making more organelles. Cells need to double their organelles and size [...]