Sexual Reproduction

Individual organisms come and go, but, to a certain extent, organisms transcend time by producing offspring. Through the fusion of male and female sex cells, two individuals produce offspring that have genetic characteristics of both parents.

Sexual Reproduction

• Fertilization
• Chromosomes and Sex
• Sex Chromosome Abnormalities

Biology Spotlight10

How Plant Viruses Cause Disease

Saturday August 13, 2011

Tobacco plants affected by the cucumber mosaic virus (left) and resistant to it (right). Credit: Carl Davies CSIRO

Health Benefits of Spicy Foods

Friday August 12, 2011

Image Credit: akeeris/ FreeDigitalPhotos.net

Did you know that adding certain spices to your food could have positive metabolic benefits? Spices such as rosemary, oregano, cinnamon, turmeric, black pepper, cloves, garlic powder, and paprika increase antioxidant activity in the blood and decrease insulin response. In addition, Penn State researchers found that adding these types of spices to meals high in fat decreases triglyceride response by about 30 percent. High triglyceride levels are associated with heart disease.
In the study, the researchers compared the effects of eating high-fat foods with spices added to that of high-fat foods without spices. The group that consumed the spicy food had lower insulin and triglyceride responses to their meal. Along with the positive health benefits of consuming the meals with spices, the participants reported no negative gastrointestinal problems. The researchers contend that antioxidant spices like the ones in the study could be used to reduce oxidative stress. Oxidative stress has been linked to the development of chronic disease such as arthritis, heart disease, and diabetes.
The researchers point out that in order to cause disease, the satellite's genes must match the host's genes. This is why plant viruses only affect a limited number of hosts. The matching viral genes attach to the plant genes and splice or cut the genes leading to the production of different proteins. In this case, the genes that produce green chlorophyll pigment are altered, preventing chlorophyll production. The researchers were also successful in blocking the CMV disease by genetically modifying the chlorophyll-producing gene in plants so that it no longer matched the viral gene.