In this Grade 7 Life Science lesson from Chapter 21, students explore the causes of infectious disease, learning how microorganisms such as bacteria and viruses act as pathogens that spread illness. The lesson covers key developments like the germ theory and the discovery of antibiotics like penicillin, explaining how these scientific advances led to modern disease treatment. Students also examine how pathogens spread and what steps can be taken to prevent infection.
Section 1
Microorganisms Cause Infectious Diseases
Bacteria and viruses can cause sickness when they enter our bodies. Bacteria are single-celled organisms that live everywhere, while viruses must enter living cells to reproduce. Both are pathogens that spread diseases.
Section 2
Pathogens Travel Through Multiple Pathways
Infectious diseases spread through food, water, and air. They also transfer through person-to-person contact and animal bites. Knowing these pathways helps people prevent disease by washing hands and taking other precautions.
Section 3
Scientists Combat Disease With Medical Advances
Antibiotics discovered by Alexander Fleming kill bacteria but not viruses. Vaccines prevent many diseases, but pathogens can develop resistance when medications are overused. Scientists continually research treatments for new illnesses.
Section 4
Genetics Influences Non-Infectious Diseases
Some diseases present at birth come from inherited genes, like cystic fibrosis and sickle cell disease. Others develop later in life due to both genetic factors and lifestyle choices, including heart disease and certain cancers.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter
Expand to review the lesson summary and core properties.
Section 1
Microorganisms Cause Infectious Diseases
Bacteria and viruses can cause sickness when they enter our bodies. Bacteria are single-celled organisms that live everywhere, while viruses must enter living cells to reproduce. Both are pathogens that spread diseases.
Section 2
Pathogens Travel Through Multiple Pathways
Infectious diseases spread through food, water, and air. They also transfer through person-to-person contact and animal bites. Knowing these pathways helps people prevent disease by washing hands and taking other precautions.
Section 3
Scientists Combat Disease With Medical Advances
Antibiotics discovered by Alexander Fleming kill bacteria but not viruses. Vaccines prevent many diseases, but pathogens can develop resistance when medications are overused. Scientists continually research treatments for new illnesses.
Section 4
Genetics Influences Non-Infectious Diseases
Some diseases present at birth come from inherited genes, like cystic fibrosis and sickle cell disease. Others develop later in life due to both genetic factors and lifestyle choices, including heart disease and certain cancers.
Book overview
Jump across lessons in the current chapter without opening the full course modal.
Continue this chapter