Cell Membrane Transport

Questions and Answers

What is the smallest unit of life in the human body?

Cell (correct)

Cell membrane

Organ

Tissue

Why do cells need to transport nutrients and waste products across their membrane?

To maintain a constant internal environment

To generate energy for the cell

To respond to external stimuli

To survive and function properly (correct)

What is the general rule of thumb for transporting molecules across the cell membrane?

The more complex the molecule, the smaller the transport mechanism

The larger the molecule, the larger the transport mechanism (correct)

The smaller the molecule, the larger the transport mechanism

The simpler the molecule, the larger the transport mechanism

Why is the potassium leak channel called a 'leak' channel?

Because potassium has a high concentration inside the cell Signup and view all the answers

What is the relative concentration of potassium ions inside and outside the cell?

Higher inside the cell, lower outside Signup and view all the answers

What is the opposite of the concentration gradient of potassium ions for sodium ions?

Lower inside the cell, higher outside Signup and view all the answers

What is the main difference between the transport of small solutes and large molecules across the cell membrane?

The transport mechanism used for small solutes is different from that used for large molecules Signup and view all the answers

What is the purpose of discussing transport mechanisms in the context of cell biology?

To understand how cells transport nutrients and waste products Signup and view all the answers

What is the direction of potassium flow in a cell with an open potassium channel?

Out of the cell Signup and view all the answers

What type of transport mechanism is involved when potassium ions flow out of a cell through an open channel?

Passive transport Signup and view all the answers

What is the name of the process that moves sodium out of a cell and potassium into a cell against their concentration gradients?

Sodium potassium pump Signup and view all the answers

What is the energy source used by the sodium potassium pump?

ATP Signup and view all the answers

What type of active transport is the sodium potassium pump an example of?

Primary active transport Signup and view all the answers

What is the name of the protein that helps sodium enter enterocytes in the gut?

Sodium channel Signup and view all the answers

What type of transport is involved in the movement of glucose into enterocytes in the gut?

Facilitated diffusion Signup and view all the answers

What is the purpose of the sodium potassium pump in a cell?

To maintain the ion gradient across the cell membrane Signup and view all the answers

What is the difference between passive transport and active transport?

Active transport uses energy, while passive transport does not Signup and view all the answers

What is the name of the process that involves the movement of solutes in space?

Diffusion Signup and view all the answers

What type of transport is used when sodium and glucose move in the same direction?

Secondary active transport Signup and view all the answers

What is the direction of sodium movement in antiport?

Into the cell Signup and view all the answers

What is the purpose of the vesicle in endocytosis?

To surround and transport a protein into the cell Signup and view all the answers

What is the term for the process of moving molecules into the cell using vesicles?

Endocytosis Signup and view all the answers

What is the role of the Golgi apparatus in protein transport?

To modify and package proteins into vesicles Signup and view all the answers

What is the energy requirement for secondary active transport?

Uses energy indirectly Signup and view all the answers

What is the difference between symport and antiport?

Symport moves molecules in the same direction, antiport moves them in opposite directions Signup and view all the answers

What is the term for the process of moving molecules out of the cell using vesicles?

Exocytosis Signup and view all the answers

What is the purpose of the sodium gradient in secondary active transport?

To provide energy for glucose transport Signup and view all the answers

What is the term for the movement of molecules down their concentration gradient?

Passive transport Signup and view all the answers

What is the process called when a vesicle fuses with the cell membrane and releases its contents outside the cell?

Exocytosis Signup and view all the answers

Why is exocytosis considered the opposite of endocytosis?

Because it involves the release of molecules outside the cell Signup and view all the answers

What is the result of a vesicle fusing with the cell membrane during exocytosis?

The release of acetylcholine outside the cell Signup and view all the answers

Why is it important to understand the mechanisms of moving molecules across the cell membrane?

To understand how cells fight infectious diseases Signup and view all the answers

What is the energy requirement for exocytosis?

It requires a lot of energy Signup and view all the answers

What is the site where the vesicle is initially formed in the process of exocytosis?

Golgi apparatus Signup and view all the answers

Study Notes

Cell Transport Mechanisms

The cell, the smallest unit of life, needs nutrients and must eliminate waste products, requiring the ability to transport substances across the cell membrane.
The size of the passenger or waste product determines the type of transport mechanism used.

Passive Transport

Passive transport occurs without the use of energy.
Types of passive transport include:
- Diffusion: movement of solutes in space
- Osmosis: movement of water
- Filtration: movement of substances in the kidney
- Facilitated diffusion: uses a protein channel to facilitate transport

Potassium Leak Channel

A potassium leak channel is a type of facilitated diffusion.
Potassium has a high concentration inside the cell and a low concentration outside.
When the channel is open, potassium flows down its concentration gradient from inside to outside the cell.

Active Transport

Active transport uses energy to transport substances against their concentration gradient.
Types of active transport include:
- Primary active transport: directly uses ATP energy
- Secondary active transport: uses a gradient set up by primary active transport

Sodium-Potassium Pump

A sodium-potassium pump is an example of primary active transport.
It uses ATP energy to transport sodium out of the cell and potassium into the cell against their concentration gradients.

Secondary Active Transport

In the gut, sodium enters the cell through a protein channel, and glucose enters with it, using the sodium gradient (symport).
Glucose is then transported out of the cell into the bloodstream, using a different protein channel and sodium flowing in the opposite direction (antiport).

Vesicular Transport

Vesicles are small pockets of cell membrane that surround cargo, such as proteins.
Endocytosis: vesicles fuse with the cell membrane, allowing cargo to enter the cell.
Exocytosis: vesicles fuse with the cell membrane, allowing cargo to exit the cell.
Both endocytosis and exocytosis use a lot of energy.

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Description

Learn about the importance of transporting nutrients and waste products across the cell membrane for a cell's survival. This quiz covers the basics of cell membrane transport and its functions.