Each multiple choice question is worth 3 points.
Mitochondria move around the cell along microtubules.
Mitochondria have a negative charge inside to help import positively charged proteins. Mitochondria have receptors on their outer membrane which bind newly synthesized proteins and help them move across the membrane into the matrix. Lipids block the diffusion of ions across the plasma membrane. G proteins are covalently attached to lipid molecules. Phospholipid head groups can be cleaved to form the second messenger IP 3 .