TRACING A CARBON ATOM

Pages 354 - 355

Radioactive Tracers

Biologists can investigate the steps in metabolic processes (biosynthesis and decomposition) by feeding extremely small amounts of radioactive isotopes to laboratory animals.

A radioactive tracer, or radioactive label, is a chemical compound in which one or more atoms have been replaced by a radioisotope. By virtue of its radioactive decay it can be used to explore the process of biosynthesis and/or decomposition by tracing the path that the radioisotope follows from reactants to products.

Radioisotopes of hydrogen, carbon, phosphorus, sulphur, and iodine have been used extensively to trace the path of biochemical reactions.

More on the next slide!

Carbon Cycle – Your Task

You are not going to use radioisotopes to follow the carbon cycle, but you will still be following the path carbon takes as it moves from atmosphere to animal muscle.

BIOMES

Definition:• similar climatic conditions on the Earth, such as communities

of plants, animals, and soil organisms, and are often referred to as ecosystems.

Biomes relate an organism to its habitat and owing its existence to it environment.

Ten Biomes were listed on the previous slide.

Each student will create THEIR OWN carbon tracing diagram, using ONE of the biomes listed (or we can come up with new ones if you can think of some!)

No more than 3 students may use the same biome.

We will now pick which biome to which each student will be assigned! When you number is called, please come to the board and write your name next to the biome you choose. Once THREE students have chosen that biome, no one else may use it.

Write your name next to the biome you will use to create your Carbon Tracing Diagram.