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Hi There! As a college graduate in biology from Cal Poly, San Luis Obispo and a UCSC Masters in Education student, I'm ecstatic about science and teaching. If you're a high school student within Santa Cruz County that needs help with understanding biology I'd love to help out. Contact me so we can begin earning the grade you deserve! You can also check out my tutor website at http://santacruzca.universitytutor.com/tutors/60083 to see my reviews and times available.

10/23/10

What's the Scoop With RNA?

How does RNA differ from DNA?
A few ways actually..remember that the monomers (ribonucleotides and deoxyribonucleotides) which make up RNA and DNA are made up of 3 main groups 1) a sugar (ribose) 2) a nitrogenous base (Adenosine, Thymine, Uracil, Guanine, or Cytosine) 3) and a phosphate group. In RNA, the ribose contains a hydroxyl (-OH) group bonded to its 2nd carbon. DNA does not contain this -OH group on the 2nd ribose carbon, instead it has just a hydrogen, hence its name DEOXYribonucelic acid. Another difference between RNA and DNA, is that RNA contains the base uracil, rather than the nitrogenous base thymine like in DNA, that makes hydrogen bonds with adenosine. Lastly, RNA is most often found single stranded instead of being double stranded and bonded to an antiparallel strand as in DNA.

To sum up the differences, RNA differs from DNA by:
1) Containing a hydroxyl (-OH) group on the 2nd carbon of its ribose*
2) Having uracil as a nitrogenous base instead of thymine
3) Being single stranded 
*RNA is less stable than DNA due to this -OH group as it is more likely to interact with other chemical compounds!

Lastly, there are 3 major types of RNA you've probably heard about...rRNA, mRNA, and tRNA

rRNA refers to ribosomal RNA and makes up the 2 subunits ribosomes are made out of
mRNA refers to messenger RNA which is made during transcription then translated into proteins
tRNA refers to transfer RNA which is responsible for associating specific amino acids to a specific codon found within an mRNA sequence 

Is this a DEOXYRIBONUCLEOTIDE or a RIBONUCLEOTIDE?

 

10/22/10

Mitosis vs Meiosis

Do you know the difference between meiosis and mitosis? Mitosis results in the production of cells that are identicle to the parent cell where as meiosis produces cells that contain half the amount of the genetic material that the parent cell contains. Mitosis produces all kinds of cells that make up your body, for instance your skin cells. Meiosis on the other hand produces cells that become gametes (eggs and sperm).

Key differences between the process of meiosis and mitosis:
Meiosis is made up of 2 stages, meiosis I and meiosis II. Mitosis, however, is made up of only 1. The 1st stage of meiosis separates the homologous pairs of chromosomes inherited from your mom and dad. The 2nd stage of meiosis separates the sister chromatids that make up a replicated chromosome. The 2nd stage of meiosis is therefore identical to the process of mitosis! Other unique events that occur only during meiosis include crossing over - or the exchange of genetic material between homologous pairs of chromosomes. Also in meiosis, homologous pairs of chromosomes align forming a structure called a tetrad. 

Can you remember the different stages of Mitosis/Meiosis? An easy way to remember is to remember the word:

IPMAT - INTERPHASE, PROPHASE, METAPHASE, ANAPHASE, TELOPHASE

What happens at each stage?

10/18/10

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