How many among the given amino are essential and must be obtained from food?
Phenylalanine
Valine
Leucine
Glycine
Isoleucine
Threonine
Aspartic acid

Options

A. 4
B. 5
C. 6
D. 7

Answer

To determine how many of the given amino acids are essential and must be obtained from food, we can follow these steps:

### Step 1: Identify the amino acids listed in the question.
The amino acids provided are:
- Phenylalanine
- Valine
- Leucine
- Glycine
- Isoleucine
- Threonine
- Aspartic acid

### Step 2: Classify each amino acid as essential or non-essential.
1. **Phenylalanine** - Essential amino acid
2. **Valine** - Essential amino acid
3. **Leucine** - Essential amino acid
4. **Glycine** - Non-essential amino acid (can be synthesized by the body)
5. **Isoleucine** - Essential amino acid
6. **Threonine** - Essential amino acid
7. **Aspartic acid** - Non-essential amino acid (can be synthesized by the body)

### Step 3: Count the essential amino acids.
From the classification:
- Essential amino acids: Phenylalanine, Valine, Leucine, Isoleucine, Threonine
- Non-essential amino acids: Glycine, Aspartic acid

Counting the essential amino acids, we find:
- Phenylalanine: 1
- Valine: 2
- Leucine: 3
- Isoleucine: 4
- Threonine: 5

### Conclusion
There are **5 essential amino acids** among the given amino acids that must be obtained from food.

### Final Answer
The number of essential amino acids among the given options is **5**.

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