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Respiration
Study respiration in AQA GCSE Biology 8461 through cellular respiration, aerobic and anaerobic pathways, response to exercise, oxygen debt, fermentation and metabolic reactions.
35
Objectives
10
Flashcards
10
Questions
90 min
Study time
AqaGcseBiologyBioenergetics
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Syllabus checklist
What you need to know
35 objective pages available
Aerobic and anaerobic respiration15 objectives
- Describe cellular respiration as an exothermic reaction that occurs continuously in living cells.
- Explain that respiration transfers energy needed for living processes.
- Explain that respiration can take place aerobically using oxygen or anaerobically without oxygen.
- Compare aerobic and anaerobic respiration in terms of oxygen requirement.
- Compare aerobic and anaerobic respiration in terms of products formed.
- Compare aerobic and anaerobic respiration in terms of relative amounts of energy transferred.
- State that organisms need energy for chemical reactions that build larger molecules.
- State that organisms need energy for movement.
- State that organisms need energy for keeping warm.
- Represent aerobic respiration using the word equation glucose plus oxygen makes carbon dioxide plus water.
- Recognise the chemical symbols C6H12O6, O2, CO2 and H2O in the aerobic respiration equation.
- Represent anaerobic respiration in muscles using the word equation glucose makes lactic acid.
- Explain that incomplete oxidation of glucose in anaerobic respiration transfers much less energy than aerobic respiration.
- Represent anaerobic respiration in plant and yeast cells using the word equation glucose makes ethanol plus carbon dioxide.
- Explain that anaerobic respiration in yeast cells is fermentation and has economic importance in bread and alcoholic drink manufacture.
Response to exercise10 objectives
- Explain that during exercise the body reacts to increased demand for energy.
- Describe how heart rate increases during exercise to supply muscles with more oxygenated blood.
- Describe how breathing rate and breath volume increase during exercise to supply muscles with more oxygen.
- Explain that anaerobic respiration occurs in muscles if insufficient oxygen is supplied.
- Explain that incomplete oxidation of glucose causes lactic acid build-up and creates an oxygen debt.
- Explain that long periods of vigorous activity can cause muscles to become fatigued and stop contracting efficiently.
- Describe investigations into the effect of exercise on the body.
- Explain that (HT only) blood transports lactic acid from muscles to the liver.
- Explain that (HT only) lactic acid is converted back into glucose in the liver.
- Define (HT only) oxygen debt as the extra oxygen needed after exercise to react with accumulated lactic acid and remove it from cells.
Metabolism10 objectives
- Define metabolism as the sum of all reactions in a cell or the body.
- Explain that energy transferred by respiration is used for enzyme-controlled metabolic processes.
- Explain the importance of sugars in the synthesis and breakdown of carbohydrates.
- Explain the importance of amino acids in the synthesis and breakdown of proteins.
- Explain the importance of fatty acids and glycerol in the synthesis and breakdown of lipids.
- Describe conversion of glucose to starch, glycogen and cellulose as part of metabolism.
- Describe the formation of lipid molecules from glycerol and three fatty acid molecules.
- Describe the use of glucose and nitrate ions to form amino acids for protein synthesis.
- Include respiration as a metabolic reaction.
- Describe breakdown of excess proteins to form urea for excretion.
Key terms
cellular respirationexothermic reactionrespirationenergy transferAerobic respirationAnaerobic respirationaerobic respirationanaerobic respirationenergychemical reactionsmovementhomeostasis
Exam tips
- Understand Exothermic Reactions: Use clearly define cellular respiration as an exothermic reaction that releases energy, and explain how this process occurs continuously in living cells. Link your answer to Aerobic and anaerobic respiration in Respiration, and keep the biology specific to respiration.
- Link Respiration to Energy Needs: Use when studying respiration, always connect it back to how energy is transferred for essential living processes such as movement, growth, and maintaining body temperature. Link your answer to Aerobic and anaerobic respiration in Respiration, and keep the biology specific to respiration.
Common mistakes
- Misunderstanding Exothermic Reactions: To fix this, students should review the definitions of exothermic and endothermic reactions, focusing on how exothermic reactions release energy, which is a key characteristic of cellular respiration.
- Misunderstanding Energy Transfer: Clarify that respiration is a process that releases energy from glucose, which is then used immediately for various living processes, rather than being stored.
Practice preview
- Choose the answer that best fits the specification point: describe cellular respiration as an exothermic reaction that occurs continuously in living cells.?
- For Respiration, which option explains "describe cellular respiration as an exothermic reaction that occurs continuously in living cells" most accurately?
- Which option best explains cellular respiration within Respiration?
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