ESSAY ANALYSIS[First Year]

Give an account of the mode of action of enzymes and of the ways in which enzyme

activity can be regulated.Synopsis:Types of enzymes

Details about enzymes

What reactions they help with

Some theories

This is NOT asked for!!

Details about what?

Which?

This does not make sense!

1

Synopsis:What are enzymes?How do they work? (lock and key; induced fit)What factors affect enzyme activity?

(temp; pH; conc. of enzyme + substrate; cofactors; inhibitors)

Why are enzymes important?

NEVER USE QUESTIONS!!

2

Synopsis:Introduction: What are enzymes?

What is the activation energy?

First subtitle: Mechanism of enzyme based catalysis- Induced fit- DiagramSecond subtitle: Ways in which enzyme activity can be regulated

- The affect of temperature- The affect of pH- The affect of cofactors- The affect of enzyme concentration- The affect of substrate concentration- Inhibition that includes reversible and irreversible inhibition- Allosteric site- Negative feedback- Graphs

Conclusion: - Enzymes are highly specific- Enzymes are globular proteins (not all)- Enzymes are coded for by DNA

Too long.3

Synopsis:Introduction: What are enzymes?

What is the activation energy?

First subtitle: Mechanism of enzyme based catalysis- Induced fit- DiagramSecond subtitle: Ways in which enzyme activity can be regulated

- The affect of temperature- The affect of pH- The affect of cofactors- The affect of enzyme concentration- The affect of substrate concentration- Inhibition that includes reversible and irreversible inhibition- Allosteric site- Negative feedback- Graphs

Conclusion: - Enzymes are highly specific- Enzymes are globular proteins (not all)- Enzymes are coded for by DNA

No questions.

NO NEW INFORMATION IN conclusion

LEARN to write!!

What is missing in this synopsis?SynopsisIntroduction – definition of enzymesMain body: - Highly specific catalysis of enzymes- Factors affecting the rate of enzyme catalysed

reactions- Allosteric enzymes and negative feedbackConclusion – importance of enzymes

4

No mention of LOCK & KEY; INDUCED FIT mechanisms

No list of the factors

Give an account of the mode of action of enzymes and of the ways in which enzyme activity can be regulated.

1. To make a good synopsis look at title and identify KEY words.

2. Start building a LOGICAL sequence to answer title – copying out my notes is NOT what is needed.

3. Keep figures at a MINUMUM – title says ‘account’ so write a description.

Enzymes: occur in all cells; catalyse reactions [Introduction must be in general without details].

Mode of actionLock & key + Induced fitEnzyme structure determines its mode of action: globular proteins with specific active sitesAllosteric enzymes + negative feedback control

Regulation of enzyme activityFactors affecting rate of a reaction: temp, pH, cofactors, substrate + enzyme concentration, inhibitors

A large variety of enzymes in organisms but all work on the same principle i.e. substrate fitting in active site and making it more possible for reaction to occur.

Analyses of Introductions

Give an account of the mode of action of enzymes and of the ways in which enzyme activity can be regulated.

Metabolism and the role of enzymes:Metabolism is defined as the total sum of chemical reactions occurring in an organism. These reactions can be exergonic reactions, which means that they release energy, or endergonic, which means that they require energy. All chemical reactions require an initial input of energy, called activation energy (Ea) to get started. Enzymes ,which are catalysts, are molecules that speed up the rate of a reaction, without themselves being used up or permanently altered, by reducing.

Give an account of the mode of action of enzymes and of the ways in which enzyme activity can be regulated.

NO TITLE for introduction.1

Metabolism and the role of enzymes:Metabolism is defined as the total sum of chemical reactions occurring in an organism. These reactions can be exergonic reactions, which means that they release energy, or endergonic, which means that they require energy. All chemical reactions require an initial input of energy, called activation energy (Ea) to get started. Enzymes ,which are catalysts, are molecules that speed up the rate of a reaction, without themselves being used up or permanently altered, by reducing the activation energy.

Essay is ‘Give an account’ and not DEFINE.

No mention of ENZYMES in first 3 sentences.

Metabolism and the role of enzymes:Metabolism is defined as the total sum of chemical reactions occurring in an organism. These reactions can be exergonic reactions, which means that they release energy, or endergonic, which means that they require energy. All chemical reactions require an initial input of energy, called activation energy (Ea) to get started. Enzymes ,which are catalysts, are molecules that speed up the rate of a reaction, without themselves being used up or permanently altered, by reducing the activation energy. What type of molecules?

Too much information.

Metabolism and the role of enzymes:Metabolism is defined as the total sum of chemical reactions occurring in an organism. These reactions can be exergonic reactions, which means that they release energy, or endergonic, which means that they require energy. All chemical reactions require an initial input of energy, called activation energy (Ea) to get started. Enzymes ,which are catalysts, are molecules that speed up the rate of a reaction, without themselves being used up or permanently altered, by reducing the activation energy.Must use Ea

This shows that student is COPYING from some text and has no idea of how to

use abbreviations. Anyway, mentioning Ea is OUT OF CONTEXT.

Enzymes are the tools of nature. They are responsible for speeding up chemical reactions occurring within an organism. Enzyme reactions can either be Anabolic or Catabolic. Anabolic reactions are involved in synthesis within the body. These reactions are also known as condensation reactions. Catabolic reactions are involved in breaking down of substances. These reactions are also known as hydrolysis reactions.

2 Not biological!!

Enzymes are the tools of nature. They are responsible for speeding up chemical reactions occurring within an organism. Enzyme reactions can either be Anabolic or Catabolic. Anabolic reactions are involved in synthesis within the body. These reactions are also known as condensation reactions. Catabolic reactions are involved in breaking down of substances. These reactions are also known as hydrolysis reactions.

2 Not biological!!NOT CAPITALS!!

These are simply definitions!!

Enzymes are proteins that catalyse biochemical reactions; without enzymes these reactions would be far too slow to support life. This is why enzymes are found in every living cell, eukaryotic and prokaryotic. All enzymes, regardless in which organism they are found, do their job by lowering the activation energy necessary to start the reaction.

3

Length = 3 sentences = as expected.‘Enzymes’ mentioned right away = as expected.Student did well to include ALL cell types.

The best.

General mistakes

1. Draw as soon as you mention the figure.There are two types of chemical reactions. An exergonic reaction releases energy whilst an endergonic reaction requires energy. All chemical reactions require an initial energy to start the reaction called activation energy. Enzymes lower the activation energy as shown in Figure 1. This is because the greater the activation energy required, the slower the rate at a given temperature. Catalysts are molecules that speed up the rate of a reaction without themselves being used up or permanently used. They speed up reactions by reducing the activation energy (also shown in Figure 1). Without enzymes, reactions would be too slow to sustain life.

FIGURE DRAWN

2. One point must be discussed in one paragraph.

At low temperatures the rate of a reaction increases but at high temperatures [must say ‘above optimum’], molecules vibrate and twist so rapidly that some of their hydrogen bonds and hydrophobic interactions break thus enzymes become denatured. The rate of an enzyme-controlled reaction is doubled for every rise of 10C. Changes in pH alter the ionic charge of the acidic and basic groups and so disrupt the ionic bondings [must say bonds] that help to maintain the specific shape of the enzymes. Enzyme inhibitors are small molecules……

3. EVERY figure must have:

Fig. 1 The lock and key mechanism of enzyme action.

1. NUMBER e.g. Fig.1 and NOT Fig. 1.12. TITLE.3. LABELS.4. REFERENCE in text.

Analyses of Conclusions

Give an account of the mode of action of enzymes and of the ways in which enzyme activity can be regulated.

Enzymes are the ‘sparks’ that start and quicken the essential chemical reactions our bodies need to live. They are necessary for digesting food, for stimulating the brain, for providing cellular energy, and for repairing all tissues, organs and cells. These reactions would be too slow without enzymes meaning that if enzymes were not present, no life would be possible. This shows the ezymes great importance and vital function in organisms’ bodies.

1

Give an account of the mode of action of enzymes and of the ways in which enzyme activity can be regulated.

Enzymes are the ‘sparks’ that start and quicken the essential chemical reactions our bodies need to live. They are necessary for digesting food, for stimulating the brain, for providing cellular energy, and for repairing all tissues, organs and cells. These reactions would be too slow without enzymes meaning that if enzymes were not present, no life would be possible. This shows the enzymes great importance and vital function in organisms’ bodies.

1Colloquial English!! Use PASSIVE VOICE!!

TOO LONG!!

Student does not realise that essay was NOT about humans!!

Useless sentence!!

Having said that, enzymes are not simple, cause they carry a lot of functions, and they work dependently on six different factors. Without these enzymes, which work for the metabolism, the organism wouldn’t be able to live.

2

Not related!!

Wrong expression!!Cannot write!!

It can be concluded that the mode of action of enzymes is very specific and efficient, however enzyme activity has to be regulated so that nothing is wasted by accumulating products that the organism does not need.

3

Give an account of the mode of action of enzymes and of the ways in which enzyme activity can be regulated.

Compare this with the next.

Enzymes are important to help speed up and help chemical reactions take place as they should and without them the body a life processes would not function properly as they should.

4

No. 3 =VERY GOOD!!No. 4 = not biological at all – a literal translation!

BETTER LUCK NEXT TIME!!