Atoms, Molecules, and Chemical Bonds
From Atoms to Molecules
Atoms and Elements
Everything in biology is made from atoms. Atoms are the smallest units of matter that still keep the properties of an element. Common biological elements include carbon, hydrogen, oxygen, nitrogen, phosphorus, and sulfur.
Chemical Bonds
Atoms connect through chemical bonds. Covalent bonds share electrons, ionic bonds involve attraction between charged particles, and hydrogen bonds are weak attractions that are very important in biology.
Important Elements
Types of Bonds
Covalent bonds
- Share electrons
- Usually strong and stable
Hydrogen bonds
- Weaker interactions
- Very important for DNA structure and protein shape
Which element is a major backbone of biological molecules?
Carbon can form four bonds, making it ideal for building complex biological structures.
Correct answer: Carbon
What is one difference between covalent bonds and hydrogen bonds?
This difference helps explain why some structures are stable and others are flexible.
Correct answer: Covalent bonds share electrons and are generally stronger, while hydrogen bonds are weaker attractions between molecules or parts of molecules.
Which bond type is especially important for holding together the two strands of DNA?
Hydrogen bonds connect complementary bases in DNA.
Correct answer: Hydrogen bonds