SAT Subject Test in Biology › Other Cell Functions
Which of the following types of transport require ATP?
The Na+/K+ pump releasing 3 sodium ions outside of the cell and 2 potassium ions into the cell
Glucose moving into the cell, down its concentration gradient, through a channel
Water moving from an area of low solute concentration to an area of high solute concentration
Water moving down its concentration gradient through an aquaporin
Sodium ions moving from an area of high concentration to an area of low concentration through a voltage-gated sodium channel
The Na+/K+ pump is active transport and therefore requires ATP. Since the pump is moving ions against its concentration gradient, it requires ATP to change the conformation of the pump to release the ions. All of the other forms of transport are either diffusion (moving down its concentration gradient) or facilitated diffusion (moving down its concentration gradient with the help of a channel or carrier).
Good tip: Pumps are used for active transport while carrier proteins or channels are used for facilitated diffusion which is a type of passive transport.
All of the following are a part of the Cell Theory EXCEPT __________.
cells arise from nonliving substances
all living things are made up of cells
the cell is the basic building block of life
cells carry genetic information
the chemical reactions necessary for life take place in the cell
Cells do not arise from nonliving substances, though scientists used to believe they did. Through several experiments by many different scientists, it became clear that indeed all cells arise from preexisting cells.