Respiration
Each subtopic includes About section, revision page link, 10 preview questions, and practice CTAs.
Aerobic respiration
SubtopicAerobic respiration under Respiration for Grade 11 IGCSE.
Preview questions (no answers)
- 1.
Which process occurs in a living plant cell during both the day and the night?
A.Photosynthesis
B.Aerobic respiration
C.Transpiration (only when light is present)
D.Pollination
- 2.
Energy in a glucose molecule is stored in its:
A.Nucleus
B.Chemical bonds
C.Electrons only
D.Protons only
- 3.
In aerobic respiration, the glucose molecule is:
A.Reduced
B.Oxidized
C.Synthesized
D.Electrolyzed
- 4.
Which of the following happens to aerobic respiration if oxygen is completely removed from the environment of a human cell?
A.It continues normally
B.It stops
C.It speeds up
D.It produces more water
- 5.
Which statement best describes the process of aerobic respiration?
A.The use of energy to build glucose from water
B.The breakdown of nutrient molecules to release energy using oxygen
C.The exchange of gases in the lungs
D.The transport of glucose in the phloem
- 6.
What is the biological importance of the energy released during aerobic respiration for the process of cell division?
A.It is used to replicate DNA and move chromosomes
B.It is used to absorb carbon dioxide from the air
C.It is used to dissolve the cell membrane
D.It is used to turn glucose into starch
- 7.
Why is aerobic respiration considered a more efficient process than anaerobic respiration for providing energy to a cell?
A.It produces less carbon dioxide
B.It occurs faster in the cytoplasm
C.It breaks down glucose completely, releasing much more energy
D.It does not require any enzymes
- 8.
What is the consequence of the fact that aerobic respiration is not efficient?
A.Cells produce more water than they need
B.A significant portion of the energy from glucose is released as thermal energy
C.The cell must use anaerobic respiration to make up the difference
D.The produced is unusable by plants
- 9.
In an experiment, a student finds that the rate of production in a plant increases when the light is turned off. What is the most likely explanation?
A.The plant has started respiring for the first time
B.The rate of photosynthesis was previously higher than or equal to the rate of respiration, masking release
C.Respiration only occurs in the dark
D.The plant is performing anaerobic respiration to survive the darkness
- 10.
Which of these is a correct description of the 'Link Reaction' in aerobic respiration?
A.Conversion of glucose to pyruvate in the cytoplasm
B.Conversion of pyruvate to acetyl-CoA while releasing
C.The joining of oxygen and hydrogen to form water
D.The breakdown of ATP to release energy for the cell
Download the worksheet for Respiration - Aerobic respiration to practice offline. It includes additional chapter-level practice questions.
Anaerobic respiration
SubtopicAnaerobic respiration under Respiration for Grade 11 IGCSE.
Preview questions (no answers)
- 1.
What is the source of energy released during anaerobic respiration?
A.Chemical bonds in glucose
B.The surrounding heat
C.Oxygen atoms
D.Light from the sun
- 2.
Which of these is the most accurate description of lactic acid?
A.A product of plant respiration
B.A product of human anaerobic respiration
C.The main fuel for aerobic respiration
D.A gas released by yeast
- 3.
In yeast, which molecule is broken down to release energy anaerobically?
A.Ethanol
B.Carbon dioxide
C.Glucose
D.Lactic acid
- 4.
What is the primary reason why humans cannot survive on anaerobic respiration alone?
A.It produces too much water
B.It does not produce enough energy for life processes
C.It uses up too much oxygen
D.It only happens in the liver
- 5.
The provided flowchart illustrates two different pathways for the anaerobic breakdown of glucose. One pathway occurs in human muscle cells during heavy exercise, and the other occurs in yeast cells. Which statement correctly compares these pathways?
A.A molecule of the organic product in human muscle cells contains more carbon atoms than a molecule of the organic product in yeast.
B.The conversion of pyruvate to ethanol and carbon dioxide is the metabolic process used to thicken milk into yogurt.
C.The majority of the cell's ATP is generated during the stage where pyruvate is converted into lactic acid.
D.In both yeast and human muscle cells, the final stages of these pathways take place inside the mitochondria.
- 6.
Which of these substances is not a product of any form of anaerobic respiration mentioned in the IGCSE syllabus?
A.Lactic acid
B.Ethanol
C.Water
D.Carbon dioxide
- 7.
In an experiment, if the temperature of a yeast culture is increased from to , the rate of anaerobic respiration doubles. Why?
A.The yeast cells reproduce twice as fast
B.The enzymes involved have more kinetic energy and collide more frequently
C.The glucose dissolves more easily at higher temperatures
D.The ethanol produced evaporates faster, allowing the reaction to proceed
- 8.
Which of these graphs would correctly represent the concentration of lactic acid in the blood over time, starting from the beginning of a 400m race through 10 minutes of rest?
A.A steady decrease from the start of the race.
B.A rapid increase during the race, followed by a slow decrease during rest.
C.A constant horizontal line throughout the entire period.
D.An increase during rest and a decrease during the race.
- 9.
In a situation where a cell has a limited supply of NAD+ (a coenzyme), how does the conversion of pyruvate to lactic acid help the cell continue to produce energy?
A.It produces more NAD+ to allow glycolysis to continue.
B.It uses up the excess NAD+ that would otherwise be toxic.
C.Lactic acid can be directly converted into NAD+.
D.The reaction does not involve NAD+ at all.
- 10.
What is the primary difference in the chemical products of anaerobic respiration in a human muscle cell versus a Lactobacillus bacterium used in yogurt making?
A.The muscle cell produces lactic acid; the bacterium produces ethanol.
B.The muscle cell produces ethanol; the bacterium produces lactic acid.
C.Both produce lactic acid as their primary metabolic byproduct.
D.The muscle cell produces ; the bacterium does not.
Download the worksheet for Respiration - Anaerobic respiration to practice offline. It includes additional chapter-level practice questions.