Macromolecule activity - Macromolecules Worksheet Part A. Classify ... - Free Printable

The image you've uploaded is a Macromolecules Worksheet that has already been completed with answers in red. Below, I’ll go through each part of the worksheet and explain the solutions to help you understand why each answer is correct.

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✔ Part A: Classify each as a carbohydrate, protein, or lipid

We classify biological macromolecules based on their structure and function.

| # | Molecule | Classification | Explanation |
|---|-----------------------|--------------------|-----------|
| 1 | Starch | Carbohydrate | A polysaccharide (many glucose units), used for energy storage in plants. |
| 2 | Cholesterol | Lipid | A steroid; a type of lipid involved in cell membranes and hormone synthesis. |
| 3 | Steroid | Lipid | Steroids are derived from cholesterol and are hydrophobic lipids. |
| 4 | Glycogen | Carbohydrate | Animal storage polysaccharide made of glucose. |
| 5 | Enzyme | Protein | Enzymes are proteins that catalyze biochemical reactions. |
| 6 | Saturated fat | Lipid | Fats with no double bonds between carbons; solid at room temp. |
| 7 | Polypeptide chain | Protein | A chain of amino acids; the backbone of proteins. |
| 8 | Glucose | Carbohydrate | A monosaccharide (simple sugar); primary energy source. |
| 9 | Polysaccharide | Carbohydrate | Long chains of monosaccharides (e.g., starch, glycogen). |
|10 | Phospholipid | Lipid | Major component of cell membranes; has a phosphate head and fatty acid tails. |
|11 | Glycerol | Lipid | The backbone of triglycerides (fats); 3-carbon alcohol. |
|12 | Monosaccharide | Carbohydrate | Simple sugars like glucose, fructose. |
|13 | Cellulose | Carbohydrate | Structural polysaccharide in plant cell walls; made of glucose. |
|14 | Amino acid | Protein | Building blocks of proteins. |
|15 | Unsaturated fatty acid| Lipid | Fatty acids with one or more double bonds; liquid at room temp. |

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✔ Part B: Identify the specific molecule from each description

These questions test your knowledge of macromolecule functions and structures.

| # | Description | Answer | Explanation |
|---|-----------|--------|-----------|
|16| Provides long-term energy storage for animals | Lipids | Triglycerides (fats) store energy efficiently in adipose tissue. |
|17| Provides immediate energy | Carbohydrates | Glucose is rapidly metabolized for quick energy. |
|18| Sex hormones | Lipids | Hormones like testosterone and estrogen are steroids (lipids). |
|19| Provides short-term energy storage for plants | Carbohydrates | Plants store energy as starch (a carbohydrate). |
|20| Animal and plant structures | Protein | Proteins form structural components (e.g., collagen, keratin). |
|21| Forms the cell membrane of all cells | Lipids | Phospholipids form the bilayer of cell membranes. |
|22| Speeds up chemical reactions by lowering activation energy | Protein | Enzymes (proteins) act as catalysts. |
|23| One sugar | Carbohydrate | Monosaccharide = single sugar unit (e.g., glucose). |
|24| Monomer of proteins | Protein | Amino acids are the monomers; they build polypeptide chains. |
|25| Provides long-term energy storage for plants | Carbohydrate | Starch is stored in plant roots, tubers, etc. |
|26| Steroid that makes up part of the cell membranes | Lipids | Cholesterol is a steroid that stabilizes membranes. |
|27| 3-carbon “backbone” of a fat | Glycerol | Glycerol + 3 fatty acids → triglyceride. |
|28| Provides short-term energy storage for animals | Carbohydrate | Glycogen is stored in liver and muscles. |
|29| Many sugars | Carbohydrate | Polysaccharides (e.g., starch, cellulose) are many sugars linked together. |
|30| Forms the cell wall of plant cells | Carbohydrate | Cellulose (a polysaccharide) gives rigidity to plant cell walls. |

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✔ Part C: Which specific molecule is each food mostly made of?

This tests real-world knowledge of food composition.

| # | Food | Answer | Explanation |
|---|--------------|--------------|-----------|
|31| Almond | Starch | Almonds contain fats and proteins, but *starch* is not dominant. Wait — this might be incorrect. Let's reconsider: almonds are high in fat, especially unsaturated fat. But the answer says "starch" — likely a mistake. However, the provided answer is starch, so we'll note it as possibly erroneous. Actually, almonds are rich in unsaturated fat and protein, not starch. So perhaps the intended answer was unsaturated fat. But since the sheet says starch, let’s assume a typo or mislabeling. |
|32| Spinach | Cellulose| Leafy greens like spinach have high cellulose (fiber) in cell walls. |
|33| Beef jerky | Protein | Meat products like beef jerky are dried and rich in protein. |
|39| Celery | Cellulose| Celery is fibrous due to cellulose in plant cell walls. |
|40| Soy beans | Starch | Soybeans contain significant amounts of carbohydrates (including starch), but also protein. However, they are known for high protein content. This may be misleading. Still, soybeans do contain starch as a major component. |
|41| Cranberries | Glucose | Fruits like cranberries are rich in simple sugars like glucose and fructose. |

> ⚠️ Note on Part C: Some answers appear questionable:
> - Almond → Should be unsaturated fat or protein, not starch.
> - Soy beans → Often listed as high in protein, though they do have starch.
>
> But since the worksheet shows these answers, it's possible the intent was:
> - Almond → unsaturated fat (but labeled as starch – likely error)
> - Soy beans → starch (reasonable if considering carbohydrate content)
> - Cranberries → glucose (correct)

But based on common nutritional knowledge:

- Almond: Mostly unsaturated fat
- Spinach: Mostly cellulose (fiber)
- Beef jerky: Mostly protein
- Celery: Mostly cellulose
- Soy beans: High in protein, but also starch
- Cranberries: Rich in glucose and other sugars

So while the answers given are mostly correct, #31 (almond) and #40 (soy beans) could be debated.

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✔ Summary of Key Concepts

| Macromolecule | Function | Examples |
|---------------|---------|----------|
| Carbohydrates | Energy storage, structure | Glucose, starch, glycogen, cellulose |
| Lipids | Energy storage, membranes, hormones | Fats, phospholipids, cholesterol, steroids |
| Proteins | Structure, enzymes, transport | Enzymes, antibodies, collagen, hemoglobin |

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🟩 Final Notes

✔ The worksheet is mostly correct, with only minor potential errors in Part C:

- #31 (Almond): Likely should be unsaturated fat, not starch.
- #40 (Soy beans): Could be protein, though starch is present.

Otherwise, the classification and explanations are accurate and reflect standard biology knowledge.

Let me know if you'd like a corrected version of the worksheet!