Quick Review Flashcards - Click to flip and test your knowledge!
Question
What is the biological definition of respiration?
Answer
The chemical breakdown of glucose to release energy for bodily activities.
Question
Which simple carbohydrate is the primary substance broken down during respiration?
Answer
Glucose.
Question
Write the overall chemical equation for aerobic respiration.
Answer
$C_{6}H_{12}O_{6} + 6O_{2} \xrightarrow{enzyme} 6CO_{2} + 6H_{2}O + \text{ATP} + \text{Heat energy}$.
Question
State the two major phases in which the breakdown of glucose occurs.
Answer
Glycolysis and the Krebs cycle.
Question
In which part of the cell does glycolysis take place?
Answer
The cytoplasm.
Question
In which part of the cell does the Krebs cycle take place?
Answer
The mitochondria.
Question
During glycolysis, glucose is broken down into _____.
Answer
Pyruvate.
Question
What role do enzymes play in the process of respiration?
Answer
They act as catalysts for each individual breakdown step in the series.
Question
What does the acronym ATP stand for?
Answer
Adenosine triphosphate.
Question
Why is ATP often described as the 'energy currency of the cell'?
Answer
It is the immediate chemical source of energy available for all cellular activities.
Question
Into what substances is ATP converted when its energy is used by the cell?
Answer
ADP (adenosine diphosphate) and phosphate.
Question
How many molecules of ATP are yielded by the complete oxidation of one molecule of glucose?
Answer
38 molecules.
Question
How does an anabolic process differ from a catabolic process?
Answer
Anabolic processes are constructive and consume energy, while catabolic processes are destructive and release energy.
Question
Is respiration classified as an anabolic or a catabolic process?
Answer
A catabolic process.
Question
Contrast the temperature at which respiration occurs versus combustion.
Answer
Respiration occurs at body temperature, whereas combustion occurs at high temperatures (ignition point).
Question
Compare the number of steps in respiration to the number of steps in combustion.
Answer
Respiration occurs in a series of chemical steps, while combustion occurs in a single step.
Question
What form of energy is liberated in combustion that is NOT produced in respiration?
Answer
Light energy.
Question
Through which three inlets do plants obtain oxygen from the atmosphere?
Answer
Stomata, lenticels, and the general surface of the roots.
Question
Where are lenticels located on a plant?
Answer
In the stem.
Question
How does tilling or ploughing the soil benefit root respiration?
Answer
It creates tiny air spaces around soil particles, providing a source of oxygen for the roots.
Question
Why does water-logging negatively affect plant respiration?
Answer
It removes air spaces in the soil, preventing the roots from obtaining oxygen.
Question
During the daytime, what is the primary source of oxygen used by leaves for respiration?
Answer
Oxygen produced as a byproduct of photosynthesis.
Question
At night, how do leaves obtain oxygen for respiration?
Answer
They obtain it from the atmosphere.
Question
Define aerobic (oxybiotic) respiration.
Answer
Respiration that proceeds in the presence of free oxygen, resulting in the complete oxidation of glucose.
Question
What are the chemical end-products of aerobic respiration?
Answer
Carbon dioxide and water.
Question
Define anaerobic (anoxybiotic) respiration.
Answer
Respiration that proceeds in the absence of oxygen, resulting in the incomplete breakdown of glucose.
Question
Write the chemical equation for anaerobic respiration in plants.
Answer
$C_{6}H_{12}O_{6} \rightarrow 2C_{2}H_{5}OH + 2CO_{2} + 2\text{ATP}$.
Question
What is the organic end-product of anaerobic respiration in plants?
Answer
Ethanol (ethyl alcohol).
Question
How many molecules of ATP are produced from one molecule of glucose during anaerobic respiration?
Answer
2 molecules.
Question
Name two types of microscopic organisms that normally respire only anaerobically.
Answer
Certain bacteria and fungi.
Question
In respiration experiments, why is 'soda lime' used in the apparatus?
Answer
To absorb carbon dioxide from the incoming air.
Question
What is the purpose of using a 'control' set-up in biological experiments?
Answer
To provide a comparison where the condition under study is missing, ensuring results are due to that specific condition.
Question
In an experiment to show oxygen consumption, what causes the rise of water level in the delivery tube of the germinating seeds flask?
Answer
The germinating seeds consume oxygen, and the carbon dioxide they produce is absorbed by soda lime, creating a partial vacuum.
Question
What chemical is used to test for the production of carbon dioxide, and what is the positive result?
Answer
Limewater (calcium hydroxide), which turns milky in the presence of carbon dioxide.
Question
When testing for carbon dioxide production in a green plant, why must the apparatus be kept in the dark?
Answer
To prevent photosynthesis from consuming the carbon dioxide released during respiration.
Question
What is used to black out a bell jar in respiration experiments involving green plants?
Answer
A piece of black cloth.
Question
In the experiment to show heat evolution, what do the thermometers in the flasks measure?
Answer
The increase in temperature caused by energy released as heat during respiration.
Question
Why is an antiseptic like carbolic acid added to dead seeds in respiration experiments?
Answer
To prevent bacterial decay, which could otherwise produce heat or gases and interfere with results.
Question
In the experiment for anaerobic respiration, why is mercury used in the test tube instead of water?
Answer
Mercury does not contain or absorb dissolved oxygen, ensuring an anaerobic environment.
Question
What substance is used to absorb carbon dioxide at the end of the anaerobic respiration experiment to confirm its presence?
Answer
Potassium hydroxide.
Question
Regarding light requirements, how do photosynthesis and respiration differ?
Answer
Photosynthesis occurs only in the presence of light, whereas respiration occurs at all times.
Question
Contrast the gas requirements and end-products of photosynthesis and respiration.
Answer
Photosynthesis uses $CO_{2}$ and releases $O_{2}$, while respiration uses $O_{2}$ and releases $CO_{2}$.
Question
How does the conversion of energy differ between photosynthesis and respiration?
Answer
Photosynthesis converts light energy into stored chemical energy; respiration converts chemical energy into heat and ATP.
Question
Which process—photosynthesis or respiration—leads to a loss in weight for the plant?
Answer
Respiration.
Question
How does gaseous transport differ between plants and animals during respiration?
Answer
In plants, gases diffuse from cell to cell with no transport system; in animals, blood transports respiratory gases.
Question
Compare the end-product of anaerobic respiration in plants vs. animals.
Answer
Plants produce ethanol, while animals produce lactic acid.
Question
Why do plants produce less heat during respiration compared to animals?
Answer
Plants generally have lower metabolic rates and do not need to maintain a constant body temperature like many animals.
Question
Concept: Glycolysis
Answer
Definition: The first stage of respiration where a glucose molecule is broken down into two molecules of pyruvate in the cytoplasm.
Question
Concept: Krebs Cycle
Answer
Definition: The second stage of aerobic respiration occurring in the mitochondria, where pyruvate is completely oxidised to $CO_{2}$ and $H_{2}O$.
Question
In respiration experiments, why are seeds often 'peeled' before being placed in mercury?
Answer
To hasten the outward diffusion of carbon dioxide.
Question
Why is it generally advised not to sleep under a tree at night?
Answer
Because trees consume oxygen and release high concentrations of carbon dioxide at night due to the absence of photosynthesis.
Question
In the experiment to prove $CO_{2}$ production, what is the role of KOH (potassium hydroxide) solution in the first conical flask?
Answer
To dissolve any $CO_{2}$ present in the incoming air.
Question
A chemical that absorbs oxygen from the air is _____.
Answer
Alkaline pyrogallol (inferred context of experiments).
Question
True or False: Carbon dioxide readily dissolves in limewater.
Answer
False (it reacts with limewater to form insoluble calcium carbonate).
Question
The rate of _____ is more than the rate of respiration in green plants during the daytime.
Answer
Photosynthesis.
Question
What is the main substrate for any kind of respiration?
Answer
Glucose.
Question
In the context of plant respiration, what are 'three inlets'?
Answer
Stomata, lenticels, and root surfaces.
Question
What is the purpose of using vacuum flasks (thermos flasks) in heat evolution experiments?
Answer
To prevent heat loss to the surroundings, allowing the internal temperature rise to be measured accurately.
Question
Why does a burning paper flame go out when introduced into a flask of germinating seeds?
Answer
Because the germinating seeds have used up the oxygen required for combustion.
Question
What is the chemical name of the white precipitate formed when $CO_{2}$ reacts with limewater?
Answer
Calcium carbonate ($CaCO_{3}$).