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B9 Respiration (Liver (an active organ that carries out many metabolic…
B9 Respiration
Liver
liver cells grow and regenerate rapidly
an active organ that carries out many
metabolic reactions
detoxifying
poisons
ethanol from alcohol
passes breakdown products into the blood to be excreted in urine via kidneys
breakdown excess
amino acids
into urea
deamination
in liver
amino group
removed from amino acid to form
ammonia
(toxic)
ammonia converted to
urea
urea passes in blood to kidneys and excreted in urine
breakdown old
red blood cells
stores iron needed to synthesise new red blood cells
removing
lactic acid
lactic acid is converted into glucose
glucose is completely broken down in aerobic respiration
oxygen debt has been repaid
excess glucose can be stored as glycogen in the liver
hepatic artery brings blood from heart to liver
hepatic vein takes adjusted food levels blood to heart
hepatic portal vein carries blood from intestines to liver
Exercise
muscle protein fibres need energy from respiration to contract
contain many mitochondria for aerobic respiration
muscles store glucose as
glycogen
converted rapidly back into glucose to use for respiration in exercise
glycogen has multibranched structure
during exercise, muscles contract harder and faster
increases cellular respiration rate needed
Responses
:<3:rate increases and arteries dilate(widen)
increases oxygenated blood flow to muscles
oxygen and glucose supplied faster to muscles
extra carbon dioxide waste removed faster from muscles
:wind_blowing_face: breathing rate and depth increases
faster and greater uptake of oxygen at the lungs
carbon dioxide is removed quicker out of the blood
fitter people have bigger and better blood supplied hearts and lungs
each time, the heart pumps more blood and the lungs take in more oxygen
more efficient
fit people have a lower breathing rate
fit people have a lower pulse rate
Rest/ Anticipation
:<3:rate is steady
:wind_blowing_face: breathing rate slightly increases from anticipation
Exercise
:<3:rate goes up immediately then continues to increase
:wind_blowing_face: breathing rate gradually increases
Recovery
:<3:rate quickly falls
:wind_blowing_face: breathing rate stays high until oxygen debt is repaid
the fitter you are, the faster you repay your oxygen debt
Aerobic Respiration
takes place all the time in plant and animal cells
glucose reacts with
oxygen
to transfer energy
an
exothermic
reaction
energy released from forming bonds is > than energy needed to break bonds
energy is transferred to the environment
needed for all living processes
enable muscle contraction for movement in animals
mammals and birds maintain constant warm body temperature
active transport
move mineral ions against concentration gradient
metabolic reactions
transmission of nerve impulses
slightly warms up the surroundings
circulation transports glucose and oxygen to cells
digested food provides glucose
lungs takes in oxygen from the air
C₆H₁₂O₆
+
6O₂ → 6CO₂
+
6H₂O
glucose
+
oxygen → carbon dioxide
+
oxygen
carbon dioxide and water are produced as waste products
different
enzymes
control the reactions in aerobic respiration
mitochondria contains the enzymes for aerobic respiration
tiny rod shaped organelles
have a
folded inner membrane
large SA for enzymes
no. of mitochondria shows how
active
a cell is
cytoplasm
produces the enzymes
where
anaerobic
respiration take place
nucleus
holds genetic code for respiration enzymes
cell membrane
allows products & reactants to move in and out of cell
Investigating Respiration
deprive living organism of food or oxygen for aerobic respiration
unethical because organism would be killed
show the waste products of aerobic respiration
using limewater to detect carbon dioxide (turns cloudy)
detect a rise in temperature with respiration
Anaerobic Respiration
when you exercise hard, oxygen is not supplied fast enough
aerobic respiration takes place
without oxygen
less efficient than aerobic respiration at transferring energy
breakdown of glucose is
incomplete
far less energy is transferred (2 vs 38 ATP)
In Animals
end product is
lactic acid
muscle used vigorously for long periods of time causes
muscle fatigue
muscles stop contracting efficiently
due to
build up
of lactic acid
creates an oxygen
debt
glucose → lactic acid
C₆H₁₂O₆ → 2C₃H₆O₃
Oxygen Debt
the waste lactic acid is removed from the muscles by the
blood
lactic acid is converted back into glucose in the
liver
glucose may be broken down into carbon dioxide and water
extra oxygen needed to break down/ oxidise lactic acid is the
oxygen debt
lactic acid
+
oxygen → carbon dioxide
+
water
2C₃H₆O₃
+
6O₂ → 6CO₂
+
6H₂O
plants and microorganisms
also respire anaerobically
plant cells and yeast produce ethanol and carbon dioxide
fermentation
is anaerobic respiration in yeast cells
used in breadmaking and brewing alcohol
glucose → ethanol + carbon dioxide
C₆H₁₂O₆ → 2C₂H₅OH
+
2CO₂
some microorganisms produce lactic acid
e.g. bacteria used in yoghurt production
Metabolism
the sum of all the chemical reactions in a cell or the body
Metabolic Reactions
are controlled by enzymes
building larger molecules from smaller ones
Synthesis Reactions
glucose into starch, cellulose (or glycogen in animals)
plants build amino acids from sugars, nitrates and other nutrients
amino acids used to synthesise protein
3 fatty acids and glycerol into lipids
photosynthesis
breaking larger molecules into smaller ones
inside cells
breakdown of excess protein into urea in the liver
respiration
in digestion (outside cells)
changing one molecule to another
converting simple sugars
converting amino acids
