Cell Membrane moleculesPhospholipids are spread out like chessmen on a board. Thus, the active groups of the four common phospholipid molecules are ChESS: choline, ethanolanine, serine, sphyngomyelin.
CentriolesCentrioles are useful organelles which play a key role in cell division, namely pulling the chromosomes apart. Centrioles are ropes made of 9 groups of 3 fibers, a 9+3 arrangement. How to remember this? Count the number of letters in "centriole", then count the syllables. You should get 9 and 3.
On the HourCell division is about the same as clock division: 1 hour.
Into INsulinINsulin gets sugar INto cells. Without insulin, a person can have lots of sugar in his blood and still die from a lack of sugar. Excess sugar is removed via urine. Romans noticed bees attracted to the urine of diabetics and coined the term diabetes to describe the overflow of sugar.
Tubules & Filaments.Eukaryotic cells are held together by microtubules, micro filaments, and intermediate filaments. I find it easy to remember what each does by matching key letters in each term with their respective duties. For example, MicroFilAments are made of Actin, move Food into MICROvilli, are responsible for Amoebal Movement, Cytoplasmic Streaming, and Muscular Contraction, and they Move Fast.
Microtubules on the other hand, are made of TUBulin, Move Slowly, and make the Chromosome fibers.
La Jeune Fils and Cell JunctionsA Frenchman gawking at a young lady dressed in form-fitting jeans might say "Des Tight Gaps" and REALLY be thinking about the three types of cell junctions: Desmosome, Tight, and Gap. Desmosome junctions, like good blue jeans, will stretch and are found in the lungs, amongst other sites. Tight junctions are useful for containing liquids and make up much of the GI tract. Gap junctions allow cytoplasm exchange between cells and help smooth muscle fibers contract in sequence.
Meiosis Explained.Meiosis comes from the Greek to reduce. Meiosis is the process of reducing the number of chromosomes by half. Without this crucial step in the formation of gametes, our cells would burst with DNA.
The goal of meiosis is to make egg and sperm cells with half the number of chromosomes (23 instead of 46) so the egg and sperm can together make a zygote having 46 chromosomes instead of 92. Meiosis appears to be mitosis happening twice without the G1, S1, G2 phases, thereby splitting the chromosomes in half before they replicate. The reduced number of chromosomes is called the haploid state.
In human sperm and egg production, meiosis occurs much as mitosis, but instead of entering interphase after the cell splits, it swings back into prophase and runs through the process again and ends with two daughter cells, each holding 23 chromosomes (the haploid state). Ovum production is slightly different, producing only one ovum, whereas spermatogenesis makes four sperm cells. The difference occurs in telophase I, where the ovum shoves 23 chromosomes into a bud and gets rid of it (women, they hate competition!).
Mitosis & MeiosisEasy way to tell the difference between the two types of reproduction at the cell level: mITosis makes Identical Twins ... mEioSis uses Egg & Sperm.
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