M1-2 Midterm Review

The midterm will be cover these three topics.

Food Waste

Many people throw away food because of the dates on the labels. They think the food is bad, but usually, it is safe to eat. In the United States, people waste a lot of food every year. The dates on food are often about how fresh the food tastes, not about safety. If you are not sure, you can use your eyes and your nose. If the food does not smell bad, you can probably eat it. We should try to keep food in the fridge and eat it before it goes bad. Be extra careful with unfrozen meat.

Cells and Viruses

When a sick person sneezes, a virus can spread through the air and be breathed into your lungs. It lands on one of your cells. Your cell has a cell membrane to protect it, but the tiny virus tricks the cell membrane into letting it inside. The cell must fight! The "boss" of the cell, the nucleus, has the instructions (DNA). The nucleus sends a message to make an antibody. An antibody is a special protein that fights the virus. To do all this work, the cell needs energy. The "powerhouse" of the cell is called the mitochondria. It makes energy for the cell to fight and stay healthy.

Photosynthesis: Solar Slugs

There is a special slug called Elysia chlorotica. It lives in the ocean. It looks like a bright green leaf. Most animals must eat food to live. But this slug is different. It eats algae (water plants) and keeps their green parts inside its body. Now, the slug can use sunlight to make energy, just like a plant! It is half animal and half plant. It can go for one year without eating food.