Unit 8: Structure and Function of Cells WHAT IS LIFE? Unit 8: Structure and Function of Cells

BART SIMPSON: LIVING or NON-LIVING?

CHARACTERISTICS OF LIVING THINGS All living things share 6 important characteristics with all other living things. All living things… Are made of cells Contain similar chemicals Use energy Grow and develop Respond to their surroundings Can reproduce

CELLULAR ORGANIZATION All organisms are made of cells, which carry on the function necessary to sustain life. Organisms may be made up of just one cell, such as in bacteria; or made up of about 50 trillion cells such as in Justin Bieber. Cells are the basic unit of structure and function in an organism. Structure is the way its made. Function is the job it does.

THE CHEMICALS OF LIFE All living things are composed of chemical compounds. The most abundant is water. Carbohydrates are a main energy source. Proteins and lipids are building materials. Nucleic acids are the genetic instructions that direct a cells activities. Written in 1954, some of the material and current facts in this book are dated. However, Asimov is such a good expository writer that in most cases it does not matter. He covers the basics of proteins, vitamins and enzymes in such a lucid style that it is still possible to learn a great deal of the basics from this book. Since it is designed to explain the fundamentals of the complex chemicals of life and most of the advances since the writing are in the working out of the details, there are very few places where his statements are incorrect. Asimov starts with the structure of proteins, how they are built, their complex structure and how they act as catalysts throughout the human body. This is followed by explanations of vitamins, how they work, their structure and what happens when the body experiences a shortage. The final sections deal with hormones, where they are produced and how they interact to control the metabolism of the body. Fifty years after it was written, I can still recommend this book as a primer on the fundamental chemistry of the mammalian body. While many things have changed since then, the quality of the writing trumps nearly all of the obsolescence The Will Smith movie I, Robot was based on an Asimov short story. The asteroid 5020 Asimov, a crater on the planet Mars,[10] a Brooklyn, New York elementary school, and one Isaac Asimov literary award are named in his honor.

ENERGY USE Cell of organisms use energy to do what living things must do, such as grow and repair injured parts.

GROWTH AND DEVELOPMENT Living things grow and develop. Growth is the process of becoming larger, while development is the process of change that occurs during an organism’s life to produce a more complex organism.

RESPONSE TO SURROUNDINGS Like a plant bending toward the light, all organisms react to changes in their environment. A change that causes an organism to react is called a stimulus.

REPRODUCTION Living organisms have the ability to reproduce, or produce offspring that are similar to the parents.