b9 - respiration Flashcards
define aerobic respiration
- exothermic reaction
- uses glucose and oxygen to transfer energy for all living processes
- carbon dioxide and water produced as waste products
where do chemical reactions of aerobic respiration take place?
- mitochondria
- controlled by enzymes
give equation for aerobic respiration
glucose + oxygen -> carbon dioxide + water (energy transferred to environment)
give symbol equation for respiration
C(6)H(12)O(6) + 6O(2) -> 6CO(2) + 6H(2)O
what is transferred energy in respiration used for?
- build larger molecules from smaller ones
- enable muscle contraction in animals
- maintain constant body temperature in colder surroundings in mammals and birds
- move materials such as mineral ions into cells against a concentration gradient (active transport)
- build sugars, nitrates, other nutrients into amino acids, then proteins into plants
what do investigations involving aerobic respiration use?
limewater which turns cloudy white to detect carbon dioxide produced
what else can you detect with repiration?
a rise in temperature when respiration is occuring
why do we not plan investigations with living organisms to prove that they need oxygen for aerobic respiration?
depriving a living organism of food would kills it
what does cytoplasm do wrt to aerobic respiration?
- where enzymes are made
- location of reactions in anaerobic respiration
what does nucleus do wrt to aerobic respiration?
- holds genetic code for enzymes involved in respiration
what does mitochondrian do wrt to aerobic respiration?
contains enzymes for aerobic respiration
what does cell membrane do wrt to aerobic respiration?
- allows gases and water to pass freely into and out of the cell
- controls the passage of other molecules
what happens when you exercise?
muscles need more energy so they can contract
how is rate at which oxygen and glucose reach the muscles increased?
- heart rate increases and blood vessels supplying muscles dilate to allow more blood containing oxygen and glucose to reach muscles
- breathing rate and depth of breath increases to allow greater uptake of oxygen at lungs
how is the extra waste carbon dioxide removed?
breathing rate and depth of each breath also increase to allow greater uptake of oxygen and release of carbon dioxide at lungs
what do muscles store glucose as?
glycogen which can be converted back to glucose for exercise
study tip: need to be clear about diff between rate and depth of breathing and difference between breathing rate and rate of respiration
what happens if you use muscles over a long period of time?
become fatigued and stop contracting efficiently, e.g, jogging
define anaerobic respiration
when muscles cannot get enough oxygen for aerobic respiration, they respire anaerobically without oxygen
what happens in anaerobic respiration?
- glucose is not completely broken down
- lactic acid is produced
- less energy is transferred from glucose
give equation for anaerobic respiration
glucose -> lactic acid (energy transferred to environment)
how is oxygen debt created?
created through build up of lactic acid which is a cause of muscle fatigue
how is lactic acid removed?
by blood flowing through the muscles
define oxygen debt
after excercise, lactic acid must be completely broken down to carbon dioxide and water so extra oxygen must be taken in after excercise.
- the extra oxygen needed is called oxygen debt
give equation relating to oxygen debt
lactic acid + oxygen -> carbon dioxide + water
who can pay off oxygen debt faster?
a fitter person
how do plants and microorganisms respire?
anaerobically
what do plant cells and yeast cells produce? what is the equation for this?
- ethanol and carbon dioxide
- glucose -> ethanol + carbon dioxide (energy transferred to environment)
- C(6)H(12)O(6) -> 2C(2)H(5)OH + 2CO(2)
define fermentation
anaerobic respiration in yeast cells
which microorganisms produce lactic acid in anaerobic respiration?
bacteria used in yoghurt production
define metabolism
the sum of all reactions that take place in a cell or in the body
give examples of conversion of small molecules into larger molecules
- glucose to starch, glycogen, or cellulose
- fatty acids and glycerol to lipids
- glucose and nitrate ions to amino acids
- amino acids to protein
give some other common metabolic reactions
- reactions of respiration and photosynthesis
- breakdown of excess proteins in liver to form urea
where is some of the energy transferred by respiration used?
- used to bring about movements
- used to build up or break down molecules
- mammals and birds use it to maintain constant body temperature
how are excess amino acids changed into urea in the liver?
1) amino group removed from amino acid in process of deamination
2) this forms ammonia, a toxic substance, which is the converted to urea
3) urea passes in the blood to the kidneys and is excreted (removed) in the urine
give equation relating to deamination
amino acids – deamination in liver–> ammonia –> urea – in blood to kidneys–> urine
how are poisonous substances such as ethanol detoxified in the liver?
breakdown of products are transported in the blood to the kidneys, so can be excreted in urine
how are new red blood cells made in liver?
old red blood cells are broken down and iron is stored to make new ones
what is the process of oxygen debt?
1) lactic acid produced by muscles in anaerobic respiration is transported in the blood to the liver
2) here it is converted to glucose
3) oxygen debt repaid once lactic acid –> glucose and glucose has been completely broken down in aerobic respiration to carbon dioxide and water
4) excess glucose can be stored in glycogen in the liver
