Bio Chapter 2

Organisms

________ & the environment is subject to the laws of physics and chemistry.

Electrons

________ form negatively charged "cloud "around nucleus.

Tracers

________ used to track atoms through the bodys metabolism.

organic molecules

They make up 96 % of living matter (carbon + hydrogen= ________)

Radioactive isotopes

________ decay spontaneously, giving off particles and energy.

Chemical compounds

________ can be broken down by chemical reactions & are arranged in a fixed ratio.

Isotopes

________: 2 atoms of the same element with different number of neutrons.

Organisms

________ are made up of matter.

==Chemical connection to biology

==

==Elements of Life

==

20-25% of 92 elements are required for life (oxygen, nitrogen

ammonia, carbon, hydrogen)

TRACE ELEMENTS

Elements required in very little amounts/minute quantities (ex

Neutron mass =

proton mass

Isotopes

2 atoms of the same element with different number of neutrons