21: Respiration Flashcards
(58 cards)
State the overall word equation for respiration.
Glucose + oxygen – (enzymes) –> carbon dioxide + water
State 4 differences between burning and respiration.
- Site of occurrence: Burning occurs outside cells while respiration occurs inside living cells.
- Burning does not involve enzymes while each reaction in respiration is catalysed by a specific enzyme.
- Release of energy: Burning has an uncontrolled release of energy in a single reaction while respiration has a controlled release of energy in a stepwise manner in many reactions.
- Formation of ATP: Burning releases all energy as heat while respiration uses 45% of energy to store in the form of ATP.
State 4 features of the process of respiration.
- Respiration releases energy from food through the controlled oxidative breakdown of food.
- Respiration involves many steps, each of which is catalysed by a specific enzyme.
- Respiration takes place in all living cells.
- Respiration uses glucose as the most common substrate.
Explain the meaning of oxidative breakdown.
Oxidative breakdown refers to the breaking down of a compound by oxidation.
Name the process in which ATP is formed by combining a phosphate with ADP.
Phosphorylation
Explain how ATP can supply energy to cells.
ATP can be readily broke down into ADP and a phosphate with the release of a small amount of energy. The energy is sufficient to drive individual reactions in cells.
State and provide examples of 3 main types of activities which cells require energy from ATP for.
- Movement, such as muscle contraction, movement of cilia in ciliated epithelium and movement of chromosomes during cell division.
- Synthesis, such as synthesis of proteins and DNA.
- Transport, such as pumping molecules or ions across cell membranes by active transport during mineral absorption by plant roots, and absorption of digested food across the wall of the alimentary canal in animals.
State two features of ATP as an energy carrier.
- ATP acts as an energy carrier in the cell which it is made, and it cannot be transferred from cell to cell.
- The energy released from the oxidative breakdown of one glucose molecule can be used to form many ATP molecules in the cell. In this way, the large amount of energy stored in a glucose molecule is packaged into a smaller amount in each ATP molecule.
Explain how photosynthesis and respiration contribute to the cycling of molecules in the ecosystem.
During photosynthesis, carbon dioxide and water from the surroundings are converted to organic compounds. Some of the carbon dioxide and water in the surroundings are formed from respiration.
During respiration, the organic compounds formed in photosynthesis are broken down into carbon dioxide and water, which are substrates for photosynthesis.
Explain how photosynthesis and respiration contribute to the flow of energy in the ecosystem.
During photosynthesis, light energy from the surroundings is changed to chemical energy and stored in organic food. The energy is transferred to consumers through feeding along food chains.
Through respiration, organisms break down organic food and release the energy as ATP and heat.
In photosynthesis, ATP transfers light energy captured by chlorophyll to make organic compounds. In respiration, ATP transfer the energy released by the oxidative breakdown of organic compounds to drive cellular metabolism.
State two aspects in which photosynthesis and respiration facilitates within an ecosystem.
Cycling of molecules, and flow of energy.
State the properties and functions of the outer membrane of the mitochondrion.
It controls the movement of substances into and out of the mitochondrion.
State the properties and functions of the inner membrane of the mitochondrion.
The inner membrane is highly folded to form cristae (crista). The cristae are packed with enzymes involved in the reactions of respiration, and they greatly increase the surface area for packing more enzymes.
State the properties and functions of the mitochondrial matrix.
The mitochondrial matrix is the space enclosed by the inner membrane of the mitochondrion. It contains enzymes involved in the reactions of respiration. It also provides a fluid medium for reactions to take place.
Name 4 types of cells which are abundant in mitochondria.
Liver cell, muscle cell, synaptic knob, epithelial cells of an intestinal villus.
Name the type of respiration that requires oxygen.
Aerobic respiration
State the 3 main stages of aerobic respiration.
- Glycolysis
- Krebs cycle
- Oxidative phosphorylation
State the location in which glycolysis occurs.
Cytoplasm
Describe the process of the 2 steps of glycolysis.
- Glucose is activated by phosphorylation and broken down into two triose phosphate molecules, using 2 ATP molecules.
- The two triose phosphate molecules are oxidised by NAD to form 2 pyruvate molecules, 2 NADH, and 2 ATP molecules.
State the number of pyruvate molecules formed from one glucose molecule undergoing glycolysis.
2
State the number of ATP and NADH molecules formed from one glucose molecule undergoing glycolysis.
A net amount of 2 ATP is formed (4 are formed, and 2 are used), while 2 NADH are formed.
State the location in which Krebs cycle occurs.
Mitochondrial matrix
Describe the process of bridging between glycolysis and Krebs cycle.
The pyruvate formed in glycolysis enters the mitochondrion where reactions of the Krebs cycle occur. It is converted to a 2-C compound, releasing **1 carbon dioxide molecule. After releasing 1 NADH, and combining with a molecule of coenzyme A, acetyl-CoA is formed, which carries the acetyl group into the Krebs cycle.
State the number of carbon dioxide and NADH molecules formed from one glucose molecule undergoing bridging between glycolysis and Krebs cycle.
Each pyruvate molecule produces 1 carbon dioxide and 1 NADH.
Each glucose molecule produces 2 pyruvate molecules in glycolysis.
So, 2 carbon dioxide molecules, and 2 NADH are produced.
