kim woods: BIO assignment 4
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bio_130_overview_4.rtfBIO: Overview 4
Molecular Biology, Cell Division, and Genetics
Now that you have an understanding of the structure and chemical properties of proteins and nucleic acids, you can apply that knowledge to studying Deoxyribonucleic Acid (DNA). This module will begin with an overview of molecular biology and will examine the structure, organization, and function of DNA and RNA and describe the processes of replication and transcription, i.e., how information is copied and passed along to new cells.
Once the DNA replication process is complete, the replicated DNA is distributed to new cells through mitosis (for most cells) and through the specialized process of meiosis (for sex cells). This module will discuss the specific mechanisms through which mitosis and meiosis occur, and will explain the sources of abnormal cell division and of variations in the combination of haploid cells.
The study of genetics is possibly the most important subfield of biology. It provides us with a unique view of human biology, from the molecular level to the whole organism. Potentially, it has the ability to shed light on the relationships between all organisms and to enable us to develop sustainable means of coexisting with other forms of life. In addition, this module will examine the principles associated with the transmission of characteristics from one generation to another. Gregor Mendel established these principles through his experimentation with plants.
Learning Objectives
Upon completion of this module, you should be able to:
5A
State the nucleotides commonly found in DNA and RNA.
5B
Describe DNA replication using base-pairing rules and DNA polymerase.
5C
Use the codon table to predict the amino acid sequence of a protein.
5D
Explain the use of mRNA and tRNA in the process of translation.
5E
Define gene, transcription, and translation.
5F
Specify examples of insertions, deletions, and frame shift mutations.
5G
Describe how the processes of transcription and translation relate.
5H
State why single cellular and multicellular organisms control gene expression.
5I
Identify the types of cellular activities that occur during S phase.
6A
Describe the events that uniquely define each stage of cell division.
6B
Explain the difference between a differentiated cell and a stem cell.
6C
Describe how cancer is caused by a failure to control cell division.
6D
List three important purposes of cell division.
6E
Differentiate between asexual and sexual reproduction.
6F
Describe how sexual reproduction increases genetic diversity through crossing over.
6G
Explain how nondisjunction can result in loss of genetic material or the gain of genetic material.
6H
Identify if the cell is diploid or haploid for each stage.
6I
List three important purposes of cell division.
7A
Define the concepts of dominant and recessive alleles.
7B
Determine the chances that children will carry two particular genes.
7C
Explain how people inherit varying degrees of traits, such as skin color.
7D
Determine how a person’s sex can influence the expression of his or her genes.
7E
Indicate how both external and internal environmental factors can influence the expression of genes.
7F
Explain how a person can have the allele for a particular gene, but not show it.
Module 4 Reading Assignment
Enger, E. D., Ross, F. C., & Bailey, D. B. (2012). Concepts in biology (14th ed.). New York: McGraw-Hill. Chapters 8, 9, and 10.
Optional Reading Assignment:
Chapter 11, Applications of Biotechnology.
Molecular Biology, Cell Division, and Genetics
In this module, you will learn about the cells of life known as our DNA. Deoxyribonucleic Acid (DNA) has two types of nitrogenous bases, which are known as pyrimidine and purine. Even though you might be thinking that DNA looks very complicated, it is actually made up of only four different nucleotides, which are the following:
- A is for Adenine
G is for Guanine
C is for Cytosine
T is for Thymine
The process of twisting together two strands of DNA is called the double helix. The double helix was discovered by Watson and Crick. In order for the double helix to form, it takes both a covalent and hydrogen bond to form so that DNA Replication can take place. DNA replication is a difficult concept to grasp, but basically, the two DNA base pairs become unzipped and then become a template for the new strands of DNA. The duplication of more than one DNA strand is called DNA replication. DNA replication copies a double-strand of the DNA molecule. Each of the strands of DNA become templates for the opposite strands of reproduction. The following chemicals are what make up the DNA strands:
- Adenine with Thymine
Cytosine with Guanine
Please watch the DNA Replication - Genes - the Units of Inheritance video.
There are many differences between RNA and DNA. DNA contains deoxyribose, and RNA contains ribose. DNA is a double-strand, whereas RNA is single-stranded and shorter than DNA. The DNA base pairs are also slightly different; for example, adenine is not paired with thymine as in DNA, but rather, adenine connects to uracil as in RNA. The following are the nucleotides in RNA: Adenine (A), Cytosine (C), Guanine (G), and Uracil (U). The following are the pairings of RNA:
- Adenine and Guanine are purines
Cystosine and Uracil are pyrimidines
RNA has an important job, which is to keep DNA from damaging itself during the replication process. The other major job of RNA is to transfer its genetic code into a protein, which then goes from the nucleus to the ribosome. This step helps stop the DNA from leaving the nucleus, which also helps protect it. RNA is created from DNA by the process of transcription. Messenger RNA (mRNA) is just like a text message from your phone being forwarded to someone else. The same genetic information is passed from the new polypeptide chain or protein strand to be copied into an mRNA. Then, the mRNA will move to the cytoplasm, and it will attach itself to the ribosome. mRNA moves to the ribosome by tRNA known as transfer RNA. tRNA is the vehicle that is used to transfer the mRNA to the ribosomal RNA (rRNA), which then synthesizes protein. At this point, the genetic information copied by the mRNA will be translated and new strains of DNA will be developed.
Cell division is important for DNA to replicate. There are two main cell divisions, which are known as meiosis and mitosis. Both cell divisions occur when the nucleus splits and DNA is replicated. Meiosis is associated with sexual reproduction, but mitosis is associated with growth and cell replacement/repair. Understanding cell division and the comparison between the two can become confusing, so here is a quick breakdown of the differences:
Genetics can be very interesting, but at the same time, it is also a very complex subject to understand. In the mid-19th–century, Gregor Mendel discovered the inheritance process, which allowed science to be able to discover inherited disease. In a normal situation, two copies of genes from each parent would copy and be normal. If a disorder was carried by either a recessive (g) or dominant (G), the person would have at least one or two copies of the genetic disorder. A person with the GG combination or Gg combination will also be affected by the disorder. If a person had the gg combination, he or she would not have the disorder. If there are two copies of a dominant gene present, a person has a higher chance of producing the disorder.
Required Presentations:
Click on the links below to view the Module 4 presentations.
Optional presentation: Chapter 11
