Keystone Biology Review Cells

Carbon dioxide and oxygen are molecules that can move freely across a plasma membrane.  What determines the direction that carbon dioxide and oxygen molecules move?

• orientation of cholesterol in the plasma membrane
• concentration gradient across the plasma membrane
• configuration of phospholipids in the plasma membrane
• location of receptors on the surface of the plasma membrane

A sodium-potassium pump within a cell membrane requires energy to move sodium and potassium ions into or out of a cell.  The movement of glucose into or out of a cell does not require energy.  Which statement best describes the movement of these materials across of cell membrane?

• Sodium and potassium ions move by active transport, and glucose moves by osmosis
• sodium and potassium ions move by active transport, and glucose moves by facilitated diffusion
• sodium and potassium ions move by facilitated diffusion, and glucose moves by osmosis
• sodium and potassium ions move by facilitated diffusion and glucose moves by active transport

The cell membrane serves many functions.  One of the cell membrane's functions is to help the cell maintain homeostasis.  Which of the following statement best supports this claim?

• the cell membrane contains a polar region and a nonpolar region
• the cell membrane contains proteins
• the cell membrane contains phospholipids
• the cell membrane regulates what goes in and out of the cell

Since sodium-potassium pumps require an input of energy to operate, they are an example of...

• passive transport
• facilitated diffusion
• filtration
• active transport

The movement of oxygen molecules from an area of higher concentration to an area of lower concentration is known as __________.

• diffusion
• osmosis
• respiration
• photosynthesis

Homeostasis

• allows for a wildly fluctuating internal environment
• is impossible in vertebrates
• is the maintenance of a relatively stable internal environment and often incorporates a form of feedback regulation
• is the maintenance of a relatively stable external environment and often incorporates a form of feedback regulation

Tags

NGSS.HS-LS1-3

Homeostasis in the human body is often maintained by a: 

• neutral feedback loop 
• solar feedback loop
• positive feedback loop
• negative feedback loop

Tags

NGSS.HS-LS1-3

Molecules moving from high concentration to low concentration through the phospholipid membrane is called...

• Facilitated Diffusion
• Simple Diffusion
• Active Transport
• Endocytosis 

Molecules moving against the concentration gradient (from low to high) is...

• Facilitated Diffusion
• Simple Diffusion
• Active Transport
• Osmosis

Molecules diffusing with the concentration gradient through a protein channel is...

• Facilitated Diffusion
• Simple Diffusion
• Active Transport
• Osmosis