Archive | December 2012


The activities of a cell can be divided into 3 major stages: interphase, mitosis, and cytokineses.  Even mitosis is divided into 4 stages: prophase, metaphase, anaphase, and telophase. In propahse, replication of DNA takes place. In metaphase, spindle fibers start to form and attaches to chromosomes.  Then in anaphase, chromatids pulls the chromosomes to the opposite of the cell. In telophase, cleavage between cells appear and nuclear membranes starts to form again. Then two new cells appear.Ta-da!


Factors that affect photosynthesis

There are factors that affect the process of photosynthesis: temperature, CO2 concentration, and light intensity.  When temperature is high, the rate of photosynthesis goes up. But then, if it passes some level, the rate will suddenly drop and it won`t work anymore. When light intensity goes up, the rate will also go up. But when it reaches certain level, the rate will be steady. Same thing happens to CO2 concentration. When CO2 concentration goes up and the rate reaches maximum, the rate will be just stable.


It only happens in plant. It transfers light energy into chemical energy.

Simple inorganic compound –light energy–> complex organic compound

Photosynthesis occurs in Chloroplast. In the Chloroplast, there is organelle called chlorophyll that makes photosynthesis to happen. Plants take Carbon Dioxide (CO2) in and water (H2O) and turns them into oxygen and protein. This is how they make food for themselves.


DNA Transcription and Translation

How does the genetic information in the DNA gets turned into fully functioned protein?

(transcription)                          (translation)

DNA ——————–> mRNA ———————-> Functional protein = enzymes, hormones

This is the process of  genetic information in the DNA gets turned into fully functioned protein.  Transcription is the first type of gene expression (Wikipedia). DNA is copied to RNA by an enzyme. First, Helicase comes in and unwinds and unzips the DNA. RNA polymerase attaches the free RNA Nucleotides to the mother strand of the DNA. Then the single stranded mRNA is formed and the next process happens which is translation.

Translation is the process is the process through which cellular ribosomes manufacture proteins, in which messenger RNA (mRNA) is sequentially decoded by transfer RNA (tRNA) (Wikipedia).


Enzymes are chemicals that boost the chemical process that is happening inside our body. It has specific shape and only works to specific types of chemical and to a particular reaction. They cannot be destroyed or used up in the reaction.

The job is of enzyme is to move forward and to move backward. Enzymes are sensitive to pH level and  temperature. One part of the enzymes is the active sites. Active sites is where the substrate bonds. Examples of enzymes are pepsin, amylase and peptidal transferase. Usually, enzymes` names end in -ase.


Enzymes are protein. They are biological catalyst that increases the rate of chemical reaction but remain unchanged by reaction. There are specific enzymes for specific substrates. For example, when starch meets amylase which is inside our mouth in our saliva, it is broken down to sugar as a product. Protein is also broken down to amino acids when dealt by pepsin.

There are also factors that affect enzyme activity. Like temperature, pH level, substrate concentration. When temperature is increased, the activity of enzymes increase. But then, when maximum temperature has reached, the enzymes die and no longer work.It is called enzyme denaturing. pH level works in a different way. Different enzymes have different optimum pH level. For instance, amylase works in saliva which is just about 6. So when amylase goes to stomach which has pH level of 3, then it won`t work as it did in the mouth. Also, in terms of substrate concentration, the more substrate there are, the more the activity of the enzymes. But when it has reached the optimum level of working, then it will just be the same speed all through out.

DNA part 2_ Replication

DNA replicates itself to make a copy of DNA. It occurs when the cell is about to die or when the cell is replicating. It occurs in the nucleus.   There are two enzymes that help DNA to replicate.  There are DNA Polymerase and Helicase. Helicase unwinds and unzips the DNA. then free DNA nucleotides come in and forms a new DNA and it is back with DNA polymerase. It is a very difficult process. And it is happening inside our body till this moment. Human body is amazing!