Comprehensive biology worksheet detailing the composition of the cell membrane, including a coloring guide for phospholipids and a labeling diagram.

Problem Overview:

The task involves understanding the composition and functions of the cell membrane, as well as identifying its components in a diagram. The worksheet provides information about the structure of the cell membrane, including phospholipids, proteins, cholesterol, and other molecules. It also lists the functions of the cell membrane and asks for labeling of parts in a provided diagram.

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Solution:

#### 1. Key Concepts from the Text:
- Cell Membrane Composition:
- The cell membrane is a phospholipid bilayer.
- Phospholipids have hydrophilic heads (water-attracting) and hydrophobic tails (water-repelling).
- The heads consist of a phosphate group and glycerol, while the tails are fatty acid chains.
- Cholesterol is embedded in the membrane to increase fluidity.
- Proteins are embedded in the membrane and can be integral (spanning the bilayer) or peripheral (attached to one side).

- Functions of the Cell Membrane:
- Cell signaling: Communication between cells.
- Selective transport: Regulating what enters and exits the cell.
- Excretion of wastes: Removing waste products.
- Structural support: Providing shape and stability to the cell.

- Passive Transport:
- Water and non-polar molecules move through the membrane without energy input, following the concentration gradient.

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#### 2. Labeling the Diagram:
The diagram shows a cross-section of the cell membrane. Each part is labeled with a letter (A, B, C, D, E, F, G, H, I). We need to identify each component based on the given color-coded legend.

##### Legend:
- A: Phospholipid bilayer (no color)
- B: Integral protein (pink)
- C: Fatty acid tails (orange)
- D: Phosphate heads (yellow)
- E: Peripheral protein (red)
- F: Cholesterol (blue)
- G: Glycoprotein (green)
- H: Glycolipids (purple)

##### Step-by-Step Identification:
1. A (Phospholipid Bilayer):
- This is the main structure of the membrane, consisting of two layers of phospholipids.
- Located at the core of the diagram.

2. B (Integral Protein):
- These proteins span the entire phospholipid bilayer.
- Visible as pink structures crossing the membrane.

3. C (Fatty Acid Tails):
- The hydrophobic tails of phospholipids are located inside the bilayer.
- Shown as orange structures within the membrane.

4. D (Phosphate Heads):
- The hydrophilic heads of phospholipids face outward.
- Shown as yellow structures on the outer and inner surfaces of the membrane.

5. E (Peripheral Protein):
- These proteins are attached to the surface of the membrane but do not span it.
- Visible as red structures on the outer surface.

6. F (Cholesterol):
- Embedded within the phospholipid bilayer to maintain fluidity.
- Shown as blue structures interspersed within the membrane.

7. G (Glycoprotein):
- Proteins with carbohydrate attachments, involved in cell recognition.
- Shown as green structures on the outer surface.

8. H (Glycolipids):
- Lipids with carbohydrate attachments, also involved in cell recognition.
- Shown as purple structures on the outer surface.

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#### Final Labels:
Based on the above analysis, the labels for the diagram are:
- A: Phospholipid bilayer
- B: Integral protein
- C: Fatty acid tails
- D: Phosphate heads
- E: Peripheral protein
- F: Cholesterol
- G: Glycoprotein
- H: Glycolipids

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Final Answer:

\[
\boxed{
\begin{aligned}
&\text{A: Phospholipid bilayer} \\
&\text{B: Integral protein} \\
&\text{C: Fatty acid tails} \\
&\text{D: Phosphate heads} \\
&\text{E: Peripheral protein} \\
&\text{F: Cholesterol} \\
&\text{G: Glycoprotein} \\
&\text{H: Glycolipids}
\end{aligned}
}
\]