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5.5 gather and process information from secondary sources to outline and compare some of the structures used by animals to produce sound

gather and process information from secondary sources to outline the range of isotopes that have been useful in studying photosynthesis and explain how radioactive tracers can be incorporated into plants to follow a biochemical pathway, such as photosynthesis

Background

By “feeding” cells a substance “labeled” with a particular element, that substance can be tracked or traced through the processes in the cell. The chemical behaviour of the radioactive isotope in the labeled substance is the same as in a non-radioactive or “unlabeled” substance. The biochemical or metabolic fate of the radioactively labeled substance can be traced by determining the presence and position of the radioactive atoms. Almost all common small molecules are available in radioactive form.

The range of isotopes useful in studying photosynthesis are:

Isotope Radiation type Half – life Used for the movement of
Hydrogen as 3H
β
12.1 years

H+ across the thylakoid membrane

Carbon as 14C

β
5700 years

C from CO2(g)to glucose

Phosphorous as 32P

β
14.3 days

Pi and ADP to form ATP

Oxygen as 18O

None – measured by a mass spectrophotometer

O from H2O compared to CO2