Introduction to Cells

10 Questions

What is the main function of the cell membrane in relation to the cell's environment?

To separate the interior of the cell from the outside environment

What is the term for the study of cells?

All of the above

What is the function of integral proteins in the plasma membrane?

To perform various functions

What is the characteristic of the head section of phospholipid molecules?

It is hydrophilic

What is the term for the smallest unit of life?

Cell

Which type of protein is characterized by being able to perform functions both inside and outside of the cell?

Transmembrane proteins

What is the primary function of the plasma membrane in terms of regulating the cell's internal environment?

To monitor and maintain the cell's chemical climate

What is the main characteristic of the lipid bilayer that allows it to regulate the movement of molecules across the cell membrane?

Its semi-permeable nature

Which type of protein is attached to the exterior of the lipid bilayer and can be easily removed without harming the bilayer?

Peripheral proteins

What is the primary function of proteins in the plasma membrane?

To monitor and maintain the cell's chemical climate

Study Notes

Cell Biology

The cell is the basic structural, functional, and biological unit of all known organisms.
Cells are often called the "building blocks of life."
The study of cells is called cell biology, cellular biology, or cytology.

Cell Structure

Cells have many parts, each with a different function.
The cell membrane (also known as the plasma membrane or cytoplasmic membrane) separates the interior of the cell from the outside environment.
The cell membrane is a biological membrane that encloses the protoplasm (the nucleus and the cytoplasm with its organelles and inclusions) and separates one cell from other cells and from the external environment.

Cell Membrane Composition

The cell membrane is made of millions of smaller molecules that create a flexible and porous container.
The main components of the cell membrane are proteins and phospholipids.
Phospholipid molecules are shaped with a head and a tail region, where the head is hydrophilic (likes water) and the tail is hydrophobic (does not like water).
The lipid bilayer is formed by the arrangement of phospholipid molecules, with the hydrophobic tails facing inward and the hydrophilic heads facing outward.

Proteins in Plasma Membrane

There are three types of proteins in the plasma membrane:
- Integral proteins: embedded within the lipid bilayer, extending through the lipid bilayer to contact the interior and exterior of the cell.
- Peripheral proteins: attached to the exterior of the lipid bilayer, easily separable from the lipid bilayer.
- Lipid-bound proteins: located entirely within the boundaries of the lipid bilayer.
- Transport proteins (proteins channel): facilitate the transport of molecules across the membrane.

Function of Plasma Membrane

The plasma membrane separates the contents of the cell from its outside environment and regulates what enters and exits the cell.
It protects the integrity of the interior of the cell by allowing only selected substances into the cell and keeping other substances out.
It serves as a base of attachment for the cytoskeleton in some organisms and the cell wall in others.
The cell membrane supports the cell and helps in maintaining the shape of the cell.