Table of Contents
- 1 Which type of transport requires energy to move sodium ions from a low concentration across apex?
- 2 What type of transport mechanism is required to move sodium ions against their concentration?
- 3 What are the similarities and differences between facilitated diffusion and active transport by a protein pump?
- 4 Does water move freely across cell membranes?
Which type of transport requires energy to move sodium ions from a low concentration across apex?
During active transport, substances move against the concentration gradient, from an area of low concentration to an area of high concentration. This process is “active” because it requires the use of energy (usually in the form of ATP). It is the opposite of passive transport.
What type of transport mechanism is required to move sodium ions against their concentration?
The electrical and concentration gradients of a membrane tend to drive sodium into and potassium out of the cell, and active transport works against these gradients. To move substances against a concentration or electrochemical gradient, the cell must utilize energy in the form of ATP during active transport.
How does sodium move across the cell membrane?
Sodium ions pass through specific channels in the hydrophobic barrier formed by membrane proteins. This means of crossing the membrane is called facilitated diffusion, because the diffusion across the membrane is facilitated by the channel. In this case, sodium must move, or be pumped, against a concentration gradient.
What is the transport of ions from high concentrations to low concentrations?
Diffusion
Diffusion is a process of passive transport in which molecules move from an area of higher concentration to one of lower concentration.
What are the similarities and differences between facilitated diffusion and active transport by a protein pump?
Differentiate between facilitated diffusion and active transport.
| Facilitated Diffusion | Active Transport |
|---|---|
| In transportation, facilitated diffusion uses both gated channel proteins and carrier proteins. | Active transport uses proteins from the carrier. In order to adjust the shape of the carrier protein, energy is used. |
Does water move freely across cell membranes?
Similarly, water moves across cell membranes by diffusion in a process called osmosis, but not everything can freely pass through cell membranes, which is why they are referred to as semi-permeable.
Can electrolytes move across cell membranes?
Electrolyte ions may not be able to passively diffuse across a membrane, but may instead require special mechanisms to cross the semi-permeable membrane. The mechanisms that transport ions across membranes are facilitated diffusion and active transport.
What is needed for active absorption?
The plants prefer the type of absorption based on their needs for water and nutrients. Active absorption involves the absorption of water by roots. In this process, it is absorbed with the help of ATP, while in passive absorption, ATP molecules are not involved. The force for absorption is created in mesophyll cells.