[Free Registration/Login may be required to access all resource tools.] The cell membrane is semi-permeable. Sometimes molecules need the help of special transport proteins or an input of energy to help them move across it. When an input...

Learn about the process of cellular respiration in the human body.

Discover the five characteristics that all living things have in common.

[Free Registration/Login may be required to access all resource tools.] Energy is the ability to do work. In organisms, this can be physical work, like walking or jumping, or it can be the work used to carry out the chemical processes in...

Through interactive learning exercises, students examine the different definitions of energy and how enzymes regulate how the energy is stored and used during cellular respiration. They also take a close look at photosynthesis to learn...

For this life science classroom activity, students will use cooperative learning and whole class discussions to be introduced to the concept of energy flow through organisms, and understand the basic processes of photosynthesis and...

[Free Registration/Login may be required to access all resource tools.] How does the food you eat provide energy? Through the process of cellular respiration, the energy in food is changed into energy that can be used by the body's...

[Free Registration/Login may be required to access all resource tools.] Sometimes cells need to obtain energy from sugar, but there is no oxygen present to complete cellular respiration. In this situation, cellular respiration can be...

[Free Registration/Login may be required to access all resource tools.] Why do you need air to live? Of course if you didn't breathe, you couldn't survive. You need the gas oxygen to perform cellular respiration to get energy from your...

[Free Registration/Login may be required to access all resource tools.] The cells of protists need to perform all of the functions that other cells do, such as grow and reproduce, maintain homeostasis, and obtain energy. They also need...

Read about Hans Krebs' childhood and how it influenced his interest in science. Read about the importance of mentors in his life as he did research in chemistry.

The aim of this article is to relate the history of oxygen in the atmosphere to the evolution of photosynthesis, aerobic respiration, mitochondria, and life on earth.

Welcome to Planet Ark's daily Reuters World Environment News - the most comprehensive source of environmental news on the Net. To read previous news stories, please use the search engine below to find stories relating to any...