Chemical Composition of the Body and Cells

Question 1

Net positive charge

Answer 1

Cations

Question 2

Net negative charge

Answer 2

Anions

Question 3

Covalent bonds

Answer 3

• Forms when one or more electrons in the outer shell are shared between the 2 atoms
• Number is dependent on number of electrons in outer shell

Question 4

• Bonds between atoms with similar electronegativities
• Electrons equally shared
• Less soluble in water
• Found in lipid bilayers
• May associated with a polar molecule that serves as a carrier

Answer 4

Nonpolar covalent bonds

Question 5

• 2 atoms with electronegativities form a covalent bond, the shared electrons spend more time around atoms with higher electronegativity
• The more electronegative atoms acquires a slight negative charge
• Do not have a net electrical charge
• More soluble in water
• Readily dissolve in blood, interstitial fluid & intracellular fluid

Answer 5

Polar covalent bonds

Question 6

Hydrogen Bonds

Answer 6

• Electrical attraction between 2 polar molecules
• Very weak
• Important in molecular interactions and determining shape of large molecules

Question 7

• Molecules that have polar or ionised region and a nonpolar region
• Form clusters in water
• Important in cell membranes

Answer 7

Amphipathic Molecules

Question 8

Solubility in water

Answer 8

• Molecules with ionic or polar covalent bonds have an electrical attraction to water molecules
• Molecules with nonpolar covalent bonds are hydrophobic