Cell Membrane Proteins

Questions and Answers

What is the main function of glycoproteins?

To facilitate the movement of molecules across the cell membrane

To recognize and interact with other cells (correct)

To synthesize proteins

To provide energy for cellular processes

What is the main characteristic of peripheral proteins?

They are permanently attached to the cell membrane

They are involved in cell signaling

They are easily removable from the cell membrane (correct)

They require ATP to function

What type of proteins allow molecules to move through the cell membrane without using energy?

Channel proteins (correct)

Lipid-bound proteins

Integral proteins

Carrier proteins

What is the primary function of carrier proteins?

To facilitate the movement of molecules across the cell membrane Signup and view all the answers

What type of protein is stuck inside the cell and is really tough to remove?

Integral protein Signup and view all the answers

What is the composition of glycoproteins?

Protein plus sugar Signup and view all the answers

What is the approximate percentage of protein in most cell membranes?

50% or less Signup and view all the answers

What is the main component of a cell membrane?

Phospholipids Signup and view all the answers

What is the term for proteins that are embedded throughout the cell membrane?

Integral proteins Signup and view all the answers

Where are peripheral proteins typically located?

On the outside of the cell membrane Signup and view all the answers

Why are integral proteins difficult to remove from the cell membrane?

They are stuck inside the membrane Signup and view all the answers

What is the name of the structure formed by phospholipids in the cell membrane?

Lipid bilayer Signup and view all the answers

What is the function of proteins in the cell membrane?

To perform various cell membrane processes Signup and view all the answers

What is unique about the location of integral proteins compared to peripheral proteins?

Integral proteins are stuck inside the membrane Signup and view all the answers

What is the main function of a channel protein?

To allow substances to pass through the cell membrane Signup and view all the answers

Why are lipid-bound proteins rare?

Because they are stuck on the interior of the cell membrane Signup and view all the answers

What is unique about carrier proteins compared to channel proteins?

Carrier proteins can go against the concentration gradient Signup and view all the answers

What is the purpose of peripheral proteins?

To attach to the cell and trigger a response Signup and view all the answers

What is the role of glycoproteins?

To attach a chain of sugars to a protein Signup and view all the answers

Why do channel proteins not require energy to function?

Because they work with the concentration gradient Signup and view all the answers

What is the term for the movement of substances from an area of high concentration to an area of low concentration?

Down the concentration gradient Signup and view all the answers

What is the function of a lipid-bound protein?

To interact with the inside or outside of the cell Signup and view all the answers

What is the prefix 'glyco' derived from?

The Greek word for sugar Signup and view all the answers

What is the main difference between channel proteins and carrier proteins?

Channel proteins work with the concentration gradient, while carrier proteins work against it Signup and view all the answers

Study Notes

Cell Membrane Composition

The cell membrane can be composed of up to 75% protein, with most cell membranes having around 50% or less protein.

Phospholipids and Lipid Bilayer

Phospholipids are the building blocks of the cell membrane.
These phospholipids come together to form a lipid bilayer, which makes up the cell membrane.
The lipid bilayer is composed of two layers of phospholipids.

Types of Proteins in the Cell Membrane

There are two major types of proteins in the cell membrane: integral proteins and peripheral proteins.

Integral Proteins

Integral proteins are embedded throughout the entire cell membrane.
They are difficult to remove from the cell membrane.
Examples of integral proteins include channel proteins and carrier proteins.

Peripheral Proteins

Peripheral proteins are located on the outside of the cell membrane.
They can attach and remove themselves from the cell membrane or other proteins.
Peripheral proteins are involved in different cell processes.

Lipid-Bound Proteins

Lipid-bound proteins are rare and located inside the cell membrane.
They are stuck on the interior of the cell membrane and can interact with the inside of the cell.

Channel Proteins

Channel proteins are a type of integral protein.
They have a hole or channel through them that allows substances to pass through the cell membrane.
They do not require energy (ATP) to function.
Channel proteins work with the concentration gradient, allowing substances to move from high to low concentration areas.

Carrier Proteins

Carrier proteins are also a type of integral protein.
They carry substances into the cell, protecting them as they enter.
They can also work in reverse, carrying substances out of the cell.
Carrier proteins can work against the concentration gradient, requiring energy (ATP) to function.

Glycoproteins

Glycoproteins are proteins with a chain of sugars attached.
They can be found on integral proteins, peripheral proteins, or channel proteins.
Glycoproteins are involved in signaling, allowing cells to recognize each other.

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Description

Learn about the importance of membrane proteins in cell membranes, making up to 75% of the cell membrane composition. Understand their role in various cell processes.