4 Energy from respiration Flashcards
What is the aerobic respiration equation?
glucose + oxygen –> carbon dioxide + water (+energy)
What happens during aerobic respiration?
- glucose reacts with oxygen
- reaction releases energy which your cells can use
- the energy is vital for everything which goes on in your body (one of the most important enzyme-controlled processes in living organisms)
- carbon dioxide and water are produced as waste products
What does aerobic respiration involve and where do they occur?
- involves lots of chemical reactions (controlled by different enzymes)
- most take place in the mitochondria of your cells
What are mitochondria?
tiny rod-shaped parts (organelles) that are found in all plant and animal cells
they have a folded inner membrane which provides a larger surface area for the enzymes involved in aerobic respiration
the number of mitochondria in a cell shows you how active the cell is
What are the reasons for respiration?
releases energy from the food we eat so that our cells can use it:
- living cells need energy to carry out the basic functions of life, they build up large molecules from smaller ones to make new cell material, much of the energy released is used for these synthesis reactions e.g. in plants, the sugars, nitrates and other nutrients are built up into amino acids which are built up into proteins
- in animals, energy from respiration is used to make muscles contract which are working all the time in the body, all requiring energy e.g. even when you sleep, your heart beats, you breather etc
- mammals and birds also keep their bodies at a constant temperature regardless of surroundings e.g. cold days = energy to keep warm, warm days = energy to sweat and keep body cool
What is muscle tissue made up from?
protein fibres
What happens when you use your muscles?
- they contract and are supplied with energy from respiration (also relax to allow other muscles to work)
- they need a lot of energy
- they need more glucose and oxygen and so produce more CO2 (which must be removed to keep muscles working effectively)
What do muscles store and why?
- store glucose as the carbohydrate glycogen
- glycogen can be converted rapidly back into glucose during exercise
What are the main ways in which the body responds to exercise?
- an increase in heart rate, in breathing rate and in depth of breathing (allows more oxygen to be brought into the body to be picked up by red blood cells and it’s carried to exercising muscles allowing more CO2 to be removed with its increased rate)
- glycogen stores in the muscle are converted to glucose for cellular respiration
- the blood flow to muscles increases (caused by increased heart rate and dilated arteries)
Why does the body respond to exercise?
to increase the supply of glucose and oxygen to muscle and remove carbon dioxide to keep the muscles able to work effectively
What are the benefits of regular exercise?
- heart and lungs become larger
- they both develop a bigger and more efficient blood supply
- they function as effectively as possible, exercising or not
What is a good way to test fitness?
by measuring resting and working heart rates
lower = more fit
When does anaerobic respiration occur?
when there is not enough oxygen being supplied to muscles
due to muscles working hard for a long time becoming fatigued and not contracting efficiently
What is anaerobic respiration?
respiration without oxygen
glucose is incompletely broken down to form lactic acid
Why is anaerobic respiration less efficient than aerobic respiration?
the glucose molecules are not broken down completely
far less energy is released
the end product is lactic acid which only releases a small amount of energy and causes muscle fatigue
