What is the primary characteristic of cell membranes that allows them to control what enters and exits the cell?

• Endocytosis

• Active transport

• Osmosis

• Selective permeability

How do nerve cells transmit messages from one part of the body to another?

• Through electrical impulses

• By releasing hormones

• Via a wave of ions along the membrane

• By direct cell-to-cell contact

What is the key structural molecule in the membranes of eukaryotes and bacteria?

• Phospholipid

• Carbohydrate

• Cholesterol

• Protein

What term describes a molecule that has both hydrophilic and hydrophobic parts?

• Polar

• Hydrophobic

• Amphipathic

• Hydrophilic

What structure forms when phospholipids are mixed with water and their tails cluster together?

• Vesicle

• Liposome

• Bilayer

• Micelle

What model describes the structure of cell membranes as a mosaic of various components?

• Double helix model

• Fluid mosaic model

• Induced fit model

• Lock and key model

What type of protein spans the entire width of the cell membrane?

• Glycoprotein

• Transmembrane protein

• Integral protein

• Peripheral protein

What role does cholesterol play in the cell membrane?

• Transports molecules across the membrane

• Regulates membrane fluidity

• Acts as a signal receptor

• Forms the bilayer structure

What are glycoproteins and glycolipids primarily involved in?

• Energy production

• Transporting molecules

• Cell signaling

• Marking individual tissues

Why is the cell membrane described as a 'fluid' mosaic?

• Because it is made of liquid

• Because it is flexible

• Because it can change shape

• Because its components are constantly moving