Unit C

Unit C Introduction

 

From one generation to the next, from single cell bacteria to people, all are part of a competition to create more individuals of our own species. How do we ensure our best is passed on to the next generation? Now that science has discovered most of the mechanics of the process of inheritance, a new question is arising: should we now manipulate inheritance to suit our whims? Should we have the power to decide exactly what the next generation will look like?

 

This unit is all about the cycle of life. From the secrets of cellular reproduction, to the story of why you may have your grandmother’s nose, this unit will explore how your biology is caught in an increasingly complex drive to survive on a changing planet.

 

In Unit A you examined how the human body uses the nervous and endocrine systems to maintain homeostasis. In Unit B you examined closely how the human reproductive system ensures the continuation of the species. In Unit C you will examine the mechanisms of reproduction at the cellular level, the principles deterring the inheritance of characteristics, and the mechanism of transmitting the genetic code from one generation to the next.

 

There are three modules in Unit C:

 

Module 5—Cell Division—the Processes of Mitosis and Meiosis

Module 6—Mendelian Genetics—the Transmission of Traits to the Next Generation

Module 7—Molecular Genetics—DNA, RNA, and Protein Synthesis

 

In Module 5 you will examine reproduction at the cellular level. Individual cells, like humans and all other multi-cellular organisms, need to ensure the next generation has all that it needs to survive and excel. In human reproduction, you saw how this creates a cycle as one is born, grows, mates, and gives birth to the next generation. In a similar way, cells follow a life cycle of growth, preparation, and division. In this module you will learn how the cell life cycle naturally progresses. You will examine how cells copy their instructions for the next generation. You will also discover how cells divide to form new, complete cells or divide to form incomplete cells that must find another cell with which it will join in order to become a new, whole organism. You will compare these methods of reproduction, examining their advantages and limitations. As you work through this module, you will begin to realize just how important the regulation of the cell cycle is as you consider cancerous or “wild” cell growth.

 

In Module 6 you will come to understand that the instructions copied by cells during the cell cycle code for traits observed in organisms. You will look more closely at how an organism passes on his or her traits to the next generation. As you consider these patterns of inheritance, you will learn about the works of Gregor Mendel and Thomas Morgan, and how they contributed to our understanding of genetics today. You will practise using predictive tools that will allow you to understand and explain the movement of hereditary traits, including disease and conditions, through a family pedigree.

 

In Module 7 you will examine the molecular basis for these traits in the cell, and you will gain an understanding of how cells express these traits through protein synthesis. As you examine the molecules present in our cells, you will reflect on how mutation can change the intended expression of our genetically inherited traits. Genetic change can result in disease. It can also result in enhanced abilities, and can be the basis of evolution as explored in Unit D.

 

Following are the major concepts you will explore and the skills you will develop in this unit:

• Explain the rules and steps involved in mitosis and meiosis that regulate the transmission of genetic information from one generation to the next.
  
  
• Describe the similarities and differences that exist in mitosis and meiosis that allow for growth, healing, and reproduction of organisms.
  
  
• Hypothesize how the understanding of the molecular nature of genes and DNA can help explain the transmission of traits, and how mutation at the molecular level results in changed proteins.
  
  
• Analyze how the knowledge of the molecular nature of genes and DNA has led to new biotechnologies and treatment of genetic disorders.

Think about the following questions as you complete this unit:

• What are the cellular processes that an organism uses for growth, healing, and reproduction to ensure the survival of his or her species?
  
  
• What regulates the transmission of genetic information from one generation to the next?
  
  
• How is DNA responsible for the production of proteins?
  
  
• How has the molecular knowledge of genes and DNA led to new biotechnologies and the treatment of genetic disorders?

As you work through this unit, you may go to the McGraw-Hill Ryerson online learning centre at www.albertabiology.ca. You can also jump directly to the student aids on Genetics.

 

As you work through the three modules of this unit, there will be self-checks, labs, lesson assignments, module assessments, and a unit assessment. Pieces for assessment will be clearly identified for submission to your teacher. All course work should be stored in your course folder.

 

Unit C is 40% of the Biology 30 course and should take approximately 50 hours to complete.

 

Before you begin the unit assessment, you may wish to do the review questions on pages 668–671 in your textbook, or you may consult with your teacher as to which of these questions it would be appropriate for you to answer. Or, if you have contact with your peers in this class, create a study group of two to four people. Within your group, complete the questions in the text or those suggested by your teacher. Each member in the group should save a copy of your completed answers to your course folder.

 

Submit a copy of your work to your teacher. If you are working independently, review your responses with your teacher. If you have formed a study group, once every group has submitted its response, your teacher will post an answer key to the discussion area or class website. Compare your group’s answers to those in the answer key. If you are unsure about a particular question, please contact your teacher.

 

When you have completed this unit, complete the following Unit Assessment and submit your work to your teacher.

 

Unit Assessment

 

Common across all modules in this unit is the idea of natural or desired life patterns and exceptions to these patterns that result in disruption or disease. For the module assessment, you will look in detail at breast cancer. You will need to consider how tumour cells have deviated from the natural cell cycle, how the inheritance of certain genes can increase the likelihood of developing this cancer, and how specific mutations in other regions of DNA ultimately lead to the initiation of cancerous growth. When you are ready to begin the unit assessment, go to the Unit Assessment section for instructions and a rubric indicating how the written response will be marked.

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