Chapter 1 Biology and You

Biology is the study of life. All living organisms share certain general properties that separate them from nonliving things. Properties of Life  Cellular organization  Reproduction  Metabolism  Homeostasis  Heredity  Responsiveness  Growth and development

All living organisms share certain general properties that separate them from nonliving things. All Living Things:  Cellular organization - composed of one or more cells  Reproduction - able to reproduce  Metabolism - obtain and use energy to run life processes  Homeostasis - maintain a consistent internal environment  Heredity - pass traits to offspring  Responsiveness - respond and adjust to the environment  Growth and development - grow and develop

Unifying Themes of Biology As you study biology you will repeatedly encounter the following seven themes. 1.Cellular Structure and Function 2.Reproduction 3.Metabolism 4.Homeostasis 5.Heredity 6.Evolution 7.Interdependence The Seven Properties of Life

1. Cellular Structure and Function  Cells :  highly organized  tiny structures  thin coverings called membranes.  smallest unit capable of all life functions  In all living things 2. Reproduction  process by which organisms make more of their own kind 3. Metabolism  sum of all the chemical reactions carried out in an organism.  Almost all energy used by living organisms is originally captured from sunlight. 4. Homeostasis  maintenance of a stable internal conditions  in spite of changes in the external environment  organisms unable to balance internal conditions vs environmental conditions could become ill and die.

5. Heredity  passing of traits from parent to offspring.  basic unit of heredity is called a gene coded in a molecule called deoxyribonucleic acid (DNA).  Genes determine an organism’s traits.  change in the DNA of a gene is called a mutation.  Most mutations are harmful  some mutations can help an organism survive. 6. Evolution  change in the inherited characteristics of species over generations.  species : group of genetically similar organisms that can produce fertile offspring  Natural selection: process in which organisms with favorable traits are more likely to survive and reproduce. 7. Interdependence  organisms in a biological community live and interact with other organisms.  Ecology: interactions of organisms with one another and with the nonliving part of their environment.  Organisms are dependent on each other and on their environment.

Biologists are working to solve today’s problems, such as:  Preserving our environment  Improving the food supply  Understanding the human genome  Fighting disease

Preserving our environment  Conservation biologists are exploring ways to achieve a balance between people’s growing need for land and the need to preserve the environment. Improving the food supply  Genetic engineering of crop plants has made some plants resistant to herbicides, or poisonous to insect pests, or more nutritious. Understanding the human genome  A genome is the complete genetic material contained in an individual. Government- funded and private research teams from several countries completed sequencing of the human genome.

Climate and Environmental Change

Fighting Disease  AIDS  fatal disease caused by HIV (human immunodeficiency virus),  attacks and destroys the human immune system.  New vaccines are being tested that attack two or more parts of the HIV virus at the same time.  So that while one part may mutate, it us unlikely that both parts will mutate in the same virus particle.  There is finally hope of a successful vaccine to control the outbreak of AIDS.

 Cancer  growth defect in cells  breakdown of the mechanism that controls cell division.  Several forms of cancer result from having too many copies of a certain protein  Anticancer drugs that stick to these extra cell proteins appear to offer great promise.

Emerging diseases  Biologists are fighting new diseases not known in the past.  Some of these diseases include West Nile virus and mad cow disease.  Can you think of others?

 Gene Therapy : replacement of a defective gene with a normal one.  possible to use a virus to transfer a normal copy of a gene into a cell.  cystic fibrosis: hereditary disease in which a thick sticky mucus clogs the body’s breathing passages  Early attempts failed because the virus used caused health problems.  New attempts using a different virus are more promising.