Respiration Flashcards
What is respiration?
Respiration is the process by which energy is released from glucose in cells.
Why is respiration important?
It provides energy for all life processes such as movement, growth, repair, and maintaining body temperature.
What type of energy is released during respiration?
Chemical energy, stored as ATP (adenosine triphosphate).
What are the two types of respiration?
Aerobic respiration and anaerobic respiration.
What is aerobic respiration?
Respiration that occurs in the presence of oxygen.
What is the word equation for aerobic respiration?
Glucose + Oxygen → Carbon dioxide + Water + Energy
What is the balanced chemical equation for aerobic respiration?
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy (ATP)
What is anaerobic respiration?
Respiration that occurs without oxygen.
What is the word equation for anaerobic respiration in humans?
Glucose → Lactic acid + A small amount of energy
What is the word equation for anaerobic respiration in yeast?
Glucose → Ethanol (Alcohol) + Carbon dioxide + A small amount of energy
Which type of respiration releases more energy?
Aerobic respiration releases more energy than anaerobic respiration.
What is a disadvantage of anaerobic respiration in humans?
It produces lactic acid, which can lead to muscle cramps and fatigue.
What is a use of anaerobic respiration in yeast?
It is used in baking (to make dough rise) and alcohol production (fermentation).
What does ATP stand for?
Adenosine triphosphate.
What is ATP used for in cells?
To power cell processes like active transport, muscle contraction, nerve impulses, and synthesis of molecules.
Where is ATP produced?
In the mitochondria of cells during respiration.
Which cell structure is responsible for respiration?
Mitochondria
Why are mitochondria called the “powerhouses” of the cell?
Because they produce most of the cell’s energy (ATP) through aerobic respiration.
Which cells have the most mitochondria?
Active cells like muscle cells, sperm cells, and brain cells.
What causes lactic acid buildup in muscles?
Anaerobic respiration during intense activity when oxygen is not available.
What is the effect of lactic acid on the body?
It causes muscle fatigue and cramping.
How is lactic acid removed from the body?
It is transported to the liver and broken down using oxygen after exercise (this is called oxygen debt).
Do plants respire?
Yes, all the time—day and night.
What gases do plants take in and give out during respiration?
Take in oxygen and give out carbon dioxide.
How do plants get oxygen for respiration?
From the air through the stomata.
In which organisms does respiration occur?
All living organisms—plants, animals, fungi, bacteria, etc.
What is the main difference between respiration and breathing?
Respiration is a chemical process that releases energy from glucose, while breathing is a physical process of moving air in and out of the lungs.
What is ADP?
Adenosine diphosphate – a molecule that has two phosphate groups and can be converted into ATP by gaining a third phosphate.
How is ATP formed from ADP?
Energy from respiration adds a phosphate to ADP, forming ATP (ADP + P → ATP).
What happens to ATP after it’s used for energy?
It loses a phosphate and becomes ADP again, ready to be recharged.
Why is ATP called a “packet of energy”?
Each ATP molecule carries a small, usable amount of energy for cell processes.
What are three advantages of storing energy in ATP?
1) Energy is released in small amounts to prevent damage to cells.
2) ATP is easily transported around the cell.
3) The energy can be released rapidly
4) Energy can be released wherever, whenever as required by the cell
What is oxygen debt?
The amount of oxygen needed after exercise to break down lactic acid into carbon dioxide and water.
Why does lactic acid build up in muscles?
During intense exercise, not enough oxygen reaches the muscles, so they switch to anaerobic respiration, producing lactic acid.
What happens to the body during strenuous exercise?
Muscles use more energy, oxygen supply can’t keep up, breathing and heart rate increase but can still not be enough so leading to anaerobic respiration and lactic acid buildup.
Why do muscles produce lactic acid during exercise?
Because of anaerobic respiration, when oxygen is not available, glucose is broken down into lactic acid instead of carbon dioxide and water.
Why does a person breathe heavily after exercise?
To take in more oxygen to repay the oxygen debt and remove lactic acid.
Why does the heart rate stay elevated after exercise?
To pump more oxygen-rich blood to the muscles and help remove lactic acid.
How is lactic acid removed from the body?
Oxygen is used to change it back to a chemical like glucose so that it can be broken down COMPLETELY in aerobic respiration.
Where does anaerobic respiration occur
Occurs in the cytoplasm
What is fermentation?
A type of anaerobic respiration carried out by yeast, producing alcohol and carbon dioxide from glucose.
How does yeast respire in the absence of oxygen?
They carry out anaerobic respiration called fermentation:
Glucose → Alcohol + Carbon dioxide + Small amount of energy.
What are 3 differences between aerobic and anaerobic respiration?
Oxygen: Aerobic uses oxygen; anaerobic does not.
Energy yield: Aerobic releases more energy; anaerobic releases less.
Byproducts: Aerobic produces CO₂ and water; anaerobic produces lactic acid (humans) or alcohol + CO₂ (yeast).
Why is aerobic respiration more efficient?
Because glucose is fully broken down, releasing much more energy.
When you respire a lot , heat is produced. How is heat lost?
By sweating
What is fatigue?
The build up of lactic acid in muscles causing it to ache.
Why is yeast important?
For making alcohol, beer, bread, wine
What is fermentation?
This is the anaerobic respiration in yeast where glucose is broken down to produce ethanol (alcohol) and carbon dioxide.
What is alcohol fermentation?
Anaerobic respiration in yeast and the waste products produced is ethanol (alcohol) and carbon dioxide.
What are the products of fermentation in yeast?
Ethanol (alcohol), carbon dioxide, and a small amount of energy.
How is ethanol used in everyday life?
Ethanol is used in the production of alcoholic drinks like beer and wine.
What role does carbon dioxide play in bread-making?
It causes the dough to rise by forming gas pockets that expand with heat.
What happens to the ethanol produced during bread-making?
It evaporates during baking due to the high oven temperatures.
Why does dough rise during fermentation?
Because the carbon dioxide produced by yeast accumulates and forms bubbles that expand as the dough is warmed.
Why is yeast important in the baking industry?
Yeast ferments sugar in dough, producing carbon dioxide that helps bread rise and gives it a light, airy texture.
Can bacteria respire anaerobically?
Yes, some bacteria can respire without oxygen, producing lactic acid as a waste product.
What is an example of a bacterium that respires anaerobically?
Lactobacillus bulgaricus, used in the production of yoghurt.
What is the role of lactic acid in yoghurt making?
Lactic acid thickens the milk and gives yoghurt its sour taste.
What sugar in milk is broken down during fermentation?
Lactose
What is pasteurisation in yoghurt production?
Heating the milk to 90°C to kill disease-causing microorganisms.
What is inoculation in yoghurt production?
Adding a starter culture of bacteria (like Lactobacillus) to cooled milk (around 40°C).
What happens during the incubation stage of yoghurt production?
The bacteria ferment lactose into lactic acid, turning milk into yoghurt.
Why is the yoghurt cooled after fermentation?
To stop bacterial activity and fermentation
Why is yoghurt stored at 2–4.5°C?
To keep bacteria alive but inactive, preserving the yoghurt.
What are two dairy products made using anaerobic bacterial respiration?
Yoghurt and cheese.
