Digestive Enzymes WS 3 copy ... - Free Printable

The worksheet you've uploaded is about enzymes, and it appears to be a biology assignment focused on understanding the structure, function, and specificity of enzymes. Let's go through each part of the worksheet and solve the problems, providing explanations for each answer.

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✔ Section 1: Reading Comprehension & Definitions

#### What are enzymes?
> Enzymes are biological catalysts – they speed up the chemical reactions that take place inside all cells, but without being used up in the process.
> Cells create enzymes based on instructions carried in the cell’s genes (DNA).

Explanation:
Enzymes are proteins that act as biological catalysts, meaning they increase the rate of chemical reactions in living organisms. They are not consumed during the reaction, so they can be reused. Their production is genetically controlled — DNA provides the code for making specific enzymes.

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#### What are enzymes made of?
> Enzymes are protein molecules, and so are made up of amino acids. Most enzymes contain between 100 and 1,000 amino acids. These amino acids are joined together in a long chain, which is folded to produce a unique 3D structure. Different types of enzymes have different shapes and functions because the sequence and type of amino acids in their structure is different.

Explanation:
Proteins are polymers made from amino acids linked by peptide bonds. The sequence of these amino acids determines how the protein folds into its final 3D shape. This shape is crucial for enzyme function, especially at the active site.

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#### Why are enzymes so specific?
> Enzymes are very specific about which reactions they catalyze. Only molecules with exactly the right shape will bind to the enzyme and react. These are the reactant, or substrate, molecules. The part of the enzyme to which the reactant binds (attaches) is called the active site. This is a very specific shape and the most important part of the enzyme.

Explanation:
This is known as the lock-and-key model of enzyme action. The active site has a unique shape that only fits a specific substrate (reactant). Because of this precise fit, enzymes are highly specific — one enzyme typically catalyzes only one type of reaction.

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✔ Question 1: Fill in the gaps

#### a) Fill in the gaps using the words from the box:
Words: *different, catalysts, function, the same, amino acids, catalysts*

##### i) Enzymes are biological catalysts that speed up chemical reactions in living organisms.
✔ Already correct — no gap to fill.

##### ii) Enzymes are protein molecules, which are made up of long chains of amino acids.
✔️ Correctly filled.

##### iii) The sequence and type of amino acids are different in each protein, so they produce enzymes with many different shapes and functions.
✔️ Correct — because each enzyme has a unique amino acid sequence, leading to different structures and functions.

##### iv) The shape of an enzyme is very important to its function.
✔️ Correct — the shape determines how the enzyme interacts with substrates.

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#### b) Name one of the processes in the human body where enzymes are involved.
👉 Answer: Digestion (as written)

Explanation:
Enzymes like amylase (in saliva), pepsin (in stomach), and lipase (in pancreas) break down food molecules during digestion. Other valid answers could include respiration, DNA replication, or protein synthesis.

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#### c) Label the image with: active site, reactant, enzyme

From your handwritten labels:

- Green "E" shape → enzyme ✔
- Arrow pointing to the indented part of the green shape → active site ✔
- Yellow puzzle piece → reactant (also called substrate) ✔

Explanation:
- The enzyme is the large molecule (green).
- The active site is the region where the substrate binds.
- The reactant (or substrate) is the smaller molecule (yellow) that fits into the active site like a key into a lock.

This illustrates the lock-and-key model of enzyme action.

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✔ Final Answers Summary:

| Question | Answer |
|--------|--------|
| 1a ii) | amino acids |
| 1a iii) | different |
| 1a iv) | function |
| 1b | Digestion (or any other valid process like respiration, photosynthesis, etc.) |
| 1c | Labels correctly placed: enzyme (green), active site (indented area), reactant (yellow) |

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🔍 Key Concepts Recap:

1. Enzymes are proteins made of amino acids.
2. They act as biological catalysts — speed up reactions without being used up.
3. Each enzyme has a specific 3D shape due to its amino acid sequence.
4. The active site binds only to specific substrates → explains specificity.
5. Enzyme activity depends on shape → temperature and pH can affect it by changing shape.

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✔ You’ve done a great job completing this worksheet! All your answers are correct and well-labeled. Keep up the good work!