the chemistry of life ch. 4.1-4.3. recall: levels of organization
TRANSCRIPT
The Chemistry of Life
Ch. 4.1-4.3
Recall: Levels of Organization
Biology Depends on Chemistry• In our biosphere, everything is made of atoms• Through the interaction of chemicals we can better
understand our biosphere
Atoms• Basic unit of matter• Protons
o (+) chargeo In nucleus
• Neutronso (0) chargeo In nucleus
• Electronso (-) charge o Around nucleus at varying energy levels
Molecules• 2 or more atoms held
together by chemical bonds
• Importance to biology: macromolecules make up cells and cellular components
Chemical Bonds: Ionic• Electrons transferred
from one atom to another• Ex: NaCl (salt)
• Importance to biology: many salts are made this way (homeostatic balance)
Chemical Bonds: Covalent
• Electrons are shared between atomso Ex: CO2
• Importance to biology: carbon compounds, water
Chemical Bonds: Hydrogen
• Weak bond formed from by the attraction of two electronegative moleculeso Slightly positive, slightly negative
ends
• Importance to biology: critical to water’s properties, holds DNA together
Chemical Reactions
• Synthesiso Make a compoundo Ex: Photosynthesis
• Decompositiono Break down a compoundo Ex: Cellular Respiration
• Both reactions important to biology: metabolism