Unit 4: What chemical processes support life?

Metabolism

Metabolism is the sum of all chemical reactions that occur in an organism.

Metabolic rate (MR)

The MR is the total amount of energy that is metabolized per unit time and is the speed at which chemical reactions take place in the body.

Basal metabolic rate

This is the minimum amount of energy your body needs at rest to maintain vital functions. BMR is measured in a fasted state and under specific environmental conditions.

Anabolism + Anabolic reactions

Anabolic reactions refers to how smaller molecules react with one another and build up to form larger molecules.

❏ An example of this type of reaction is the way in which proteins are formed from amino acids joining together.

Catabolism + Catabolic reactions

Catabolic reactions refer to how larger molecules are broken down into smaller molecules, ultimately releasing energy.

❏ An example of this reaction is respiration.

Factors that affect the metabolic rate

1. Age

2. Gender

3. Inherited factors

4. Exercise levels (activity levels)

5. Proportion of muscle to fat

6. Reproduction status (pregnancy)

How does temperature affect the metabolic rate

1. If the temperature increases, then the molecules will possess more energy through which there will be an increase in collisions amongst them, meaning that more reactions will take place.

   Temperature and Metabolic rate are directly proportional to one another.

How do catalysts affect the metabolic rate

Catalysts will speed up the rate of the reaction without being used up as they reduce the activation energy.

• Enzymes are biological Catalysts.

• The presence of a catalyst and the metabolic rate are directly proportional.

Anabolism + examples

This is the constructive phase where smaller molecules are used to build larger, more complex molecules like proteins, fats, and carbohydrates. This process requires energy.

When you lift weights and damage muscle fibers, your body goes into repair mode, using amino acids (protein building blocks) to rebuild and strengthen the muscle tissue.

Catabolism + examples

This is the breakdown phase where larger molecules are broken down into smaller ones to release energy for the body's various functions. During digestion, carbohydrates are broken down into glucose, a simple sugar, which the body can readily use for energy.

Increased vs. Decreased catabolism

• Increased catabolism: This can lead to weight loss, muscle breakdown, and fatigue if not balanced with sufficient calorie intake.

• Decreased catabolism: This can result in weight gain and potential health problems like obesity if not accompanied by adequate physical activity.

Increased vs decreased anabolism

• Increased anabolism: This can promote muscle growth and tissue repair, but if calorie intake is excessive, it can also lead to weight gain.

• Decreased anabolism: This can hinder growth, wound healing, and overall body repair.

Define respiration

Respiration is the process of breaking down glucose to release energy.

Aerobic respiration

Aerobic respiration is a biochemical process that releases energy (ATP) from sugar in the presence of oxygen. This type of respiration occurs in the mitochondria and uses enzymes to be carried out.

Anaerobic respiration 

Anaerobic respiration is the process of breaking down glucose in the absence of oxygen. Anaerobic respiration produces lactic acid in humans and ethanol in plants and yeast.

Aerobic respiration word and chemical equation

Glucose + Oxygen →Carbon Dioxide + Water + ATP

C6H6O6 + O2 →6CO2 + 6H20 + ATP

Anaerobic respiration chemical and word equation

Glucose →Ethanol or Lactic acid + Carbon Dioxide + ATP

C6H1206 →2C2H50H + 2 ATP

Stages of aerobic respiration (REFER TO NOTION HERE!)

Stage one: Glycolysis

Stage one takes place in the cytosol (in the cytoplasm) where the enzymes are located. This process does not require oxygen.

In this process:

The glucose molecules are split into two 3-carbon molecules

• (pyruvic acid) which release small amounts of ATP.

Stage two: The Krebs Cycle

Stage two requires oxygen and takes place in the mitochondria of the cell.The pyruvic acid is converted to acetyl coenzyme A which breaks down to form carbon dioxide and water. ATP is released.

Suggest uses of anaerobic respiration in industry

Alcohol fermentation.

Alcohol fermentation occurs in some bacteria, yeasts, and in plants that are deprived of oxygen.

The pyruvic acid that has been formed is changed into ethanol and carbon dioxide.

Pyruvic acid     > Ethanol + Carbon Dioxide + ATP

Uses of alcohol fermentation:

1. Baking.

   1. The Carbon Dioxide causes the dough to rise.

2. Beer and wine production.

Compare aerobic and anaerobic respiration

Function of the matrix - mitochondria

The matrix contains enzymes that are critical for the completion of the citric acid cycle and plays an important role in the synthesis of ATP molecules. The mitochondrial DNA is found in the matrix.

Cristae - mitochondria

The cristae creates are the folds of the inner membrane to give it a larger surface area to provide it with a greater space for processes that take place across the membrane.

Outer membrane

‘The gateway of the mitochondrion’. The outer membrane has pores that allow smaller proteins in, and it has protein complexes to allow larger proteins in.

Granules

The granules act as a ‘contact site’ between the inner and outer membranes so that the enzymes can function more efficiently.

Function of the mitochondria

The main function of the mitochondria is to produce energy in the form of adenosine triphosphate (ATP) through the process of cellular respiration.

Chemical reactions of aerobic cell respiration

Glycolysis: Glucose is broken down into pyruvate, producing a small amount of ATP and NADH.

Pyruvate decarboxylation: Pyruvate is converted into acetyl-CoA, releasing carbon dioxide and producing NADH.

Krebs cycle (Citric acid cycle): Acetyl-CoA enters the cycle, leading to the production of ATP, NADH, and FADH2, as well as releasing carbon dioxide.

Electron transport chain: NADH and FADH2 donate electrons, leading to the production of a large amount of ATP through oxidative phosphorylation.

Photosynthesis definition

The process that plants use in the presence of sunlight to convert carbon dioxide taken in by their leaves and water taken in through the roots to produce oxygen and sugar (glucose) and energy-rich organic compounds. This process takes place in the chloroplast of the plant cell with the presence of the green pigment of chlorophyll.

Word and chemical equation for photosynthesis

Carbon Dioxide + Water → (in the presence of light energy and chlorophyll) Glucose + Oxygen

Explain why photosynthesis is necessary for organisms on earth to survive (food production)

Food Production: Plants, algae, and some bacteria use photosynthesis to manufacture their own food (glucose) from carbon dioxide and water. These organisms, called producers, form the base of the food chain, providing sustenance for herbivores, who in turn are eaten by carnivores. Without photosynthesis, there would be no food source for most life forms.

Explain why photosynthesis is necessary for organisms on earth to survive (oxygen release)

Oxygen Release: A critical byproduct of photosynthesis is oxygen gas (O2). This oxygen is released into the atmosphere and is essential for aerobic respiration, the process by which most organisms, including animals, obtain energy from food.

Chloroplast

Chloroplast is the location where photosynthesis takes place, furthermore, it contains chlorophyll that gives off the green pigment in plants

How is chlorophyll necessary for photosynthesis to occur

Photosynthesis is the process by which plants transform light energy into chemical energy, and it is dependent on the light that is absorbed by chlorophyll. Using this energy, glucose, a type of sugar that is the plant's main energy source, is created from carbon dioxide and water. Photosynthesis is dependent on light absorption; without it, glucose cannot be produced, which ultimately makes a plant incapable of surviving.

Discuss limiting factors that affect the rate of photosynthesis.

1. Carbon Dioxide concentration

lants are unable to photosynthesize if there is an insufficient supply of Carbon Dioxide.

2.Light intensity

Without light or without sufficient light, a plant would not be able to photosynthesize effectively even if there is a sufficient supply of water or Carbon Dioxide.

3.Temperature

If the temperature gets too low (it gets too cold),the rate of photosynthesis will decrease.

Predict what happens to the process of photosynthesis at night? Explain your answer.

At night, when there is no sunlight available, the process of photosynthesis stops. Without the sun's energy to power the reactions, plants cannot produce glucose through photosynthesis. Instead, plants switch to a process called respiration, where they consume oxygen and release carbon dioxide, the opposite of photosynthesis.

Describe what happens to light energy once it enters a plant.

The energy from light causes a chemical reaction that breaks down the molecules of carbon dioxide and water and reorganizes them to make the sugar (glucose) and oxygen gas. After the sugar is produced, it is then broken down by the mitochondria into energy that can be used for growth and repair.

Discuss how this knowledge would be of use to someone who's job is dependent on plant growth.

For someone whose job is dependent on plant growth, understanding how plants absorb energy can lead to better changes to optimize plant growth and sustainability. This understanding helps these individuals attune the growth of a plant, enabling them to understand how factors such as the light intensity, temperature and water availability, affect the plant, and adjust them accordingly to promote plant growth.

Define catalyst

A substance that increases the rate of a chemical reaction without itself undergoing any permanent chemical change.

Kinetic energy

The energy of motion possessed by an object. It's not directly involved in enzyme activity, but enzymes can influence the movement of atoms during reactions.

Energy transfer

The movement of energy from one form to another. Chemical reactions involve energy transfer, with enzymes can influence the movement of atoms during reactions.

Enzyme

A complex protein molecule that acts as a biological catalyst. Enzymes are highly specific and only bind to certain molecules known as substrates.

Active site

A specific region within an enzyme that binds the substrate and facilitates the chemical reaction. The active site has a unique shape and chemical properties complementary to the substrate.

Substrate

The molecule an enzyme acts upon. The substrate binds to the active site of the enzyme, where it undergoes a chemical change.

Product

The molecule formed after the enzyme acts on the substrate. The product is typically different from the substrate in structure and properties.

Enzyme-substrate complex

A temporary complex formed when the enzyme and its substrate bind together at the active site. This complex allows the enzyme to work its catalytic magic and convert the substrate to the product.

Denatured

A process in which the structure of an enzyme is altered due to exposure to certain chemical or physical factors (e.g. heat, acid, etc.), causing the enzymes to become permanently inactive.

Immobilised enzyme

An immobilized enzyme is an enzyme that has been physically confined or attached to an inert carrier material. This restricts the enzyme's movement but allows it to retain its catalytic activity. In simpler terms, it's an enzyme that's been attached to a scaffold, allowing it to work but not move freely.

Enzyme action:

Enzyme action occurs when an enzyme and substrate collide, in which the substrate slots into the active site of the enzyme.

When the substrate and enzyme join together, the entire structure is known as the 'enzyme-substrate complex' or the 'lock and key structure'.

In this action, the substrate becomes changed, and is then released as the product in which the enzyme is free to join with another substrate.

Binding of enzymes and substrates:

Simple explanation:

Step 1 The enzyme and the substrate are in the same area

Step 2 The enzyme grabs on to the substrate at a special area called the active site. The combination is called the enzyme/substrate complex. The active site is a specially shaped area of the enzyme that fits around the substrate.

Step 3 The enzyme to exerts pressure on the substrate bonds, causing the activation energy to lower and resulting in them breaking bonds in the substrate and making new bonds in the product.

Step 4 The enzyme releases the product. When the enzyme lets go, it returns to its original shape. It is then ready to work on another molecule of substrLSate.

Lock and Key Theory:

• Active Site: Rigid and pre-formed, perfectly matching the shape of a specific substrate (like a key fitting a lock).

• Substrate Binding: No change in the active site's shape upon substrate binding.

• Specificity: Explains why enzymes only bind to specific substrates due to perfect shape complementarity.

Induced Fit Model (more widely accepted):

The induced fit theory states that once the active site makes contact with the substrate, the enzyme would mold itself to the shape of the substrate to allow the substrate and enzyme to bind.

The induced fit model is more accepted, considering that it was a development of the lock and key theory/mechanism by suggesting that the active site does change slightly to better suit the shape of the substrate, whereas the lock and key theory fails to mention any changes that the active site could undergo.

Examples of Enzymes:

1. Amylase - Breaks down starch (amylose) to maltose. Secreted by the salivary glands, pancreas, and small intestine.

2. Maltase - Breaks down maltose to glucose.

3. Protease - Breaks down proteins. Found in the stomach, pancreas, and small intestine.

4. Lipase - Breaks down fats. Secreted by the pancreas and the small intestine.

5. Lactase - Breaks down lactose (milk).

6. Sucrase - Digests sucrose.

Summarize the General Effects of Enzymes:

• Enzymes lower the activation energy, enabling the reaction to occur with expending/utilizing less energy.

• Activation energy is the energy input required to carry out a reaction.

• The activity of the cell is determined by which enzyme is active in the cell at that time.

• Enzymes regulate thousands of different metabolic reactions.

Temperature: 

Raising temperature generally speeds up a reaction, and lowering temperature slows down a reaction. However, extreme high temperatures can cause an enzyme to lose its shape (denature) and stop working.

pH: 

Each enzyme has an optimum pH range. Changing the pH outside of this range will slow enzyme activity. Extreme pH values can cause enzymes to denature.

Enzyme concentration:

Increasing enzyme concentration will speed up the reaction, as long as there is substrate available to bind to. Once all of the substrate is bound, the reaction will no longer speed up, since there will be nothing for additional enzymes to bind to.

Substrate concentration: 

Increasing substrate concentration also increases the rate of reaction to a certain point. Once all of the enzymes have bound, any substrate increase will have no effect on the rate of reaction, as the available enzymes will be saturated and working at their maximum rate.

It can be used in the following industries:

Food industry: Immobilised enzymes are used in food processing for tasks like the production of high-fructose corn syrup, brewing beer, and clarifying fruit juices.

Pharmaceutical industry: They are employed in pharmaceutical production for synthesizing specific drug compounds and in diagnostic tests to detect biomarkers.

Textile industry: Immobilised enzymes are utilised in the textile industry for processes such as denim finishing and fabric softening.

Environmental biotechnology: They play a role in environmental remediation by breaking down pollutants in wastewater treatment plants and soil bioremediation processes.