3.1 Questions

How is the cell membrane arranged?

• One phospholipid layer

• Two phospholipid bilayers

• A protein sheet

• Randomly scattered molecules

A phospholipid has:

• Hydrophobic head, hydrophilic tail

• Hydrophilic head, hydrophobic tail

• Two hydrophilic tails

• Only proteins

Which of the following is NOT a component of the cell membrane?

• Proteins

• Cholesterol

• Carbohydrates

• DNA

What is the function of cholesterol in the cell membrane?

• Makes ATP

• Stabilizes and maintains fluidity

• Breaks down waste

• Helps DNA replication

What does selective permeability mean?

• All molecules can enter

• No molecules can enter

• Only some substances can pass through

• Molecules stop moving

What do channel proteins do?

• Break down lipids

• Help move ions and small polar molecules across the membrane

• Store carbohydrates

• Produce cholesterol

What type of molecules do channel proteins transport?

• Large proteins

• DNA

• Ions and small polar molecules

• Lipids

A recognition protein receptor helps the cell:

• Communicate and identify other cells

• Produce ATP

• Make phospholipids

• Break down food

Where are peripheral proteins located?

• Inside the nucleus

• On the surface of the lipid bilayer

• Inside mitochondria

• In the cytosol only

What is passive transport?

• Movement high → low without ATP

• Movement low → high with ATP

• Movement only of water

• Requires vesicles every time