Wilburworld of Science

Unit 6:  Cell Cycle, Mitosis, Replication, 
Protein Synthesis & Mutation
Objective:  Describe the cell cycle and the process of mitosis.  Explain the role of mitosis in the formation of new cells, and its importance in maintaining chromosome number during asexual reproduction.    Std. 2.6
Objective:  Describe the basic process of DNA replication and how it relates to the transmission and conservation of the genetic code.  Explain the basic process of transcription and translation, and how they result in the expression of genes.  Distinguish among the end products of replication, transcription and translation.    Std. 3.2
Objective:  Explain how mutations in the DNA sequence of a gene may or may not result in phenotypic change in an organisms.  Explain how mutations in gametes may result in phenotypic changes in offspring.    Std. 3.3
Objective:  Describe the basic structure (double helix, sugar/phosphate backbone, linked by complementary base nucleotide pairs) of DNA, and describe its function in genetic inheritance.    Std. 3.1
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All living things, both prokaryotes and eukaryotes, contain DNA. Loose DNA is called chromatin. Long strands of DNA can be wound up like a spool of thread. This compacted form is called a chromosome. A karyotype is a picture of all of the chromosomes in a nucleus.  
  When a prokaryote replicates, it is creating a new organism. All prokaryotes carry most of their genetic information in one small circular strand of DNA. These cells replicate through a simple process called binary fission.  
  The replication of eukaryotic cells (usually part of multicellular organisms) is much more complicated. Most of our cells only live for a short time and must constantly be replaced with new cells. Old cells must constantly make new structures, organelles and DNA for new cells by replicating their own and then splitting into two cells. This is called the cell cycle. Randomly dividing cell organelles into two new cells is a relatively simple process.
Replicating DNA, long molecules that store massive amounts of genetic information, and evenly sorting them into two cells is the more comlicated part of the cell cycle. There are two types of nuclear division in eukaryotes. Mitosis occurs in all of our body cells and results in cells identical to the pre-existing cells, having 46 chromosomes. Only sex cells (eggs/sperms) go through meiosis. This process results in gametes containing half the original number of chromosomes.
Every cell in your body contains DNA made up of billions of nucleotides. For every new cell your body makes, you must make an exact copy of your DNA. This is called replication.  
  All of the information that makes you-you is coded in your DNA. DNA can code for a trait (like your hair color) or a protein. You are made up of many different kinds of proteins. All reactions that occur in your body are accomplished by enzymes, which are also proteins. The formation of these proteins is called porteins synthesis. It has two major steps: transcription & translation.  

DNA Structure & Replication
Protein Synthesis