Respiration: Release of Energy
Life Science
Respira on
Each cell in org needs energy perform normal life func ons.
Energy obtained through metabolic breakdown process where organic compounds mainly carbohydrates broken down
gradually to release energy in small quan es. This series reac ons known cellular respira on, occur all living cells.
Oxygen needed usually together with organic molecule, apart from energy also produces water, CO2 as waste products.
Water go en rid of:
- Urine.
- Sweat.
- Breathing out water vapour.
Plant cells also respire to provide their energy needs.
Cellular Respira on compared to combus on:
- Both processes need fuel.
- Both need Oxygen.
- Both release CO2 and water.
- Both processes release energy.
ATP( adenosine triphosphate). Means 3 phosphate bonded to adenosine.
Cellular Respira on
Most eukaryo c, prokaryo c orgs respire aerobically, process needs oxygen.
Orgs can also respire in absence oxygen called anaerobic respira on(oxygen independent respira on).
Most cells use aerobic respira on to obtain energy, more efficient than anaerobic respira on.
C6H12O6 + 6O2 6CO2 + 6H2O + energy(form of ATP)
Aerobic respira on occurs mainly in mitochondria cells. Four stages are iden fied in this process.
Aerobic respira on
1. Glycolysis in the Cytoplasm:
Glucose(6C compound) broken down into 2 molecules of pyruvic acid(3C compound).
During this phase 2 ATPs are produced.
Hydrogens (energy rich) removed, bind temporarily with hydrogen carrier NAD. NADH used last stage.
Glycolysis does not need oxygen. This stage is anaerobic.
2. Forming of Acetyl Co-enzyme A(2 C compound):
A CO2 is removed and released.
The 2 C-compound is carried into mitochondrion by co-enzyme A as Acetyl co-enzyme A.
Although oxygen not involved in this process, will not start without sufficient oxygen available for rest of process(type of
control mechanism.
1 Glucose= 2x Krebs Cycle.
3. Krebs cycle(also citric acid cycle):
Process occurs in mitochondrion.
CO2 released.
Energy-rich hydrogen is released.
These hydrogens temporarily bind with hydrogen carriers NAD and FAD.
2 ATPs are produced.
Glucose is now broken down.
,4. Hydrogen Transfer System(electron transfer system or oxida ve phosphoryla on):
Process occurs in mitochondrion.
Energy of hydrogens is removed step-by-step to form ATP.
Exhausted hydrogens bind with oxygen to form water.
Each hydrogen has enough energy form 3 ATPs. So one glucose molecule can provide 36(12x3)+2(glycolysis)=38 ATPs.
Anaerobic Respira on
Respira on in absence oxygen, can occur in plant and animal cells.
Many unicellular orgs, o en pathogens, have ability to respire anaerobically.
Animal cells: lac c acid fermenta on. Plant cells: Alcoholic fermenta on.
Anaerobic respira on also uses glucose as fuel, delivers less energy per reac on.
Lac c Acid Fermenta on:
C6H12O6 Pyruvic acid Lac c acid + 2ATP
When muscle cells experience oxygen deficiency e.g., run long me, large amounts of pyruvic acid builds up in cells.
Krebs cycle can’t start, as not enough oxygen available. Pyruvic acid now converted to lac c acid.
This remains cells. It is lac c acid responsible for s ff, sore feeling when want to move next day.
Bets way to get rid of s ff, sore feeling do light exercise. Blood flow to muscle increases, more oxygen taken to cells lac c
acid can be converted into pyruvic acid so respira on can con nue normally.
Even during normal exercise lac c acid produced when oxygen provision to muscle cells not quite sufficient. About 80% of
this lac c acid taken liver, used form glucose can serve as source energy. Other 20% returned normal respira on process.
Humans can only rely ATP released by lac c acid fermenta on for few minutes, Many animals not need that much energy.
Red-ear turtle can remain under water 2 weeks without breathing air. Respire aerobically under normal condi ons, but
under water are rela vely inac ve, do not need much energy.
Bacteria causes milk go sour, are orgs that use this type respira on sa sfy their energy needs.
Alcoholic Fermenta on:
Yeast cells(type fungus) respire anaerobically to produce alcohol, CO2, ATP. Type alcohol produced ethanol(ethyl alcohol).
This process especially important in beer, wine, spirits industry.
C6H12O6 CO2 + ethanol + 2 ATP
Yeast cells also used bake bread.
Sweet smell of baking bread is because of ethanol(all of it evaporates in heat), texture bread( ny cavi es) caused by carbon
dioxide bubbles. Large hole in bread occurs when dough and yeast not mixed properly.
Both Lac c acid fermenta on, alcoholic fermenta on not energy effec ve processes at all.
Combus on glucose not complete only 2 molecules of ATP produced during each of these reac ons.
In contrast aerobic respira on delivers 36 to 38 ATPs per glucose molecule.
Fact fermenta on is so ineffec ve means large quan es glucose needed.
To preform same amount of work anaerobic cells need 20 mes as much fuel per second as aerobic cell.
This why muscle cells store so much glucose as glycogen-cells can respire anaerobically for short periods.
A (cellular fuel) Glucose
B (end product) Lac c acid
C (end products) CO2, ethanol
D (end product) CO2, H2O
E (molecule formed) ATP
1 Lac c acid fermenta on
2 Alcoholic fermenta on
3 Cellular respira on
,Prac cal Inves ga ons
Heat Energy Released During Respira on
Use enough seeds ensure both flasks will be at least ¾ full.
Soak seeds approximately 24 hours water allow them to stand for 48 hours to
germinate.
Place half seeds in boiling water to kill them.
Soak both dead, living seeds in formaldehyde-solu on for about 5 min
(Solu on: 1 part formaldehyde with 10 parts water).
Rinse seeds thoroughly with boiled cooled down water.
Set up apparatus as in picture.
Thermos flasks placed upside down to trap heat as heat rises.
Flask with live seeds Flask with dead seeds
Temp at start experiment 24 °C 24 °C
Temperature a er 48 hours 32 °C 24 °C
Carbon Dioxide Released During Respira on
Set up apparatus as in picture.
Soak seeds for about 24 hours in water.
Ensure lime water is clear.
Remember clean test tubes, may not be any other chemical substances present that
might react with lime water.
Place apparatus in warm place 24 hours.
Test tube A clear lime water will turn milky(as CO2 present).
Test Tube B clear lime water will stay clear (no CO2 present).
, Nutrition in the Human Body
Life Science
Nutri on in the Human Body
3 Biological reasons why nutri on necessary:
- Provision energy for day-to-day ac vi es, on cellular level.
- Availability material growth, healing wounds, replacement damaged/worn
ssues.
- Regula on processes in body.
Processes involved in nutri on:
1. Inges on: Intake food.
2. Diges on: Breakdown insoluble polymers(macromolecules)-smaller, soluble
monomers(building blocks).
3. Absorp on: Absorp on nutrients. Absorbed nutrients used variety
process body. Known as assimila on nutrients.
4. Eges on: Undigested food residues expelled. Solid waste=faeces,
process defaeca on.
5. Excre on: Waste products produced during metabolic reac ons
expelled. In liquid form.
Human body’s diges ve system highly specialised involve all steps nutri on.
Diges ve system consists diges ve tract, associated organs(glands).
Mouth Teeth. Tongue and Salivary Glands
Adult human 32 teeth.
Human=heterodont, teeth have diff structures, func ons. Teeth dolphin all look same, dolphin is homodont.
Human=difiodont, have 2 sets teeth, set milk teeth, permanent set. Animals not lose baby teeth= monofiodont.
Teeth
Types of Teeth and their Func ons:
Incisors (i): 4 in upper, lower jaw cut, bite off food. Sharp, chisel-shaped. 1 Root.
Eye teeth/canines(c): 2 top, bo om used bite off/tear food/hold on to it. NB
predators, use canines kill prey. 1 Root.
Premolars(pm): 4 top, bo om. Grind food. 2 roots.
Molars(m): 6 top, bo om. Grind food. 2 roots.
General Structure of a Tooth:
Tooth consist den ne(substance similar bone, with higher mineral content. Ensures
den ne harder bone.
Part protrudes above gum(crown of tooth) covered tooth enamel(hardest substance
body).
Dental cavity filled so type connec ve ssue containing blood, lymph vessel, nerves.
Tooth embedded with cement in socket(cavity in jaw).
Part embedded socket called root.
Nerves, blood vessels, lymph vessels enter tooth from jaw through root canal.
Life Science
Respira on
Each cell in org needs energy perform normal life func ons.
Energy obtained through metabolic breakdown process where organic compounds mainly carbohydrates broken down
gradually to release energy in small quan es. This series reac ons known cellular respira on, occur all living cells.
Oxygen needed usually together with organic molecule, apart from energy also produces water, CO2 as waste products.
Water go en rid of:
- Urine.
- Sweat.
- Breathing out water vapour.
Plant cells also respire to provide their energy needs.
Cellular Respira on compared to combus on:
- Both processes need fuel.
- Both need Oxygen.
- Both release CO2 and water.
- Both processes release energy.
ATP( adenosine triphosphate). Means 3 phosphate bonded to adenosine.
Cellular Respira on
Most eukaryo c, prokaryo c orgs respire aerobically, process needs oxygen.
Orgs can also respire in absence oxygen called anaerobic respira on(oxygen independent respira on).
Most cells use aerobic respira on to obtain energy, more efficient than anaerobic respira on.
C6H12O6 + 6O2 6CO2 + 6H2O + energy(form of ATP)
Aerobic respira on occurs mainly in mitochondria cells. Four stages are iden fied in this process.
Aerobic respira on
1. Glycolysis in the Cytoplasm:
Glucose(6C compound) broken down into 2 molecules of pyruvic acid(3C compound).
During this phase 2 ATPs are produced.
Hydrogens (energy rich) removed, bind temporarily with hydrogen carrier NAD. NADH used last stage.
Glycolysis does not need oxygen. This stage is anaerobic.
2. Forming of Acetyl Co-enzyme A(2 C compound):
A CO2 is removed and released.
The 2 C-compound is carried into mitochondrion by co-enzyme A as Acetyl co-enzyme A.
Although oxygen not involved in this process, will not start without sufficient oxygen available for rest of process(type of
control mechanism.
1 Glucose= 2x Krebs Cycle.
3. Krebs cycle(also citric acid cycle):
Process occurs in mitochondrion.
CO2 released.
Energy-rich hydrogen is released.
These hydrogens temporarily bind with hydrogen carriers NAD and FAD.
2 ATPs are produced.
Glucose is now broken down.
,4. Hydrogen Transfer System(electron transfer system or oxida ve phosphoryla on):
Process occurs in mitochondrion.
Energy of hydrogens is removed step-by-step to form ATP.
Exhausted hydrogens bind with oxygen to form water.
Each hydrogen has enough energy form 3 ATPs. So one glucose molecule can provide 36(12x3)+2(glycolysis)=38 ATPs.
Anaerobic Respira on
Respira on in absence oxygen, can occur in plant and animal cells.
Many unicellular orgs, o en pathogens, have ability to respire anaerobically.
Animal cells: lac c acid fermenta on. Plant cells: Alcoholic fermenta on.
Anaerobic respira on also uses glucose as fuel, delivers less energy per reac on.
Lac c Acid Fermenta on:
C6H12O6 Pyruvic acid Lac c acid + 2ATP
When muscle cells experience oxygen deficiency e.g., run long me, large amounts of pyruvic acid builds up in cells.
Krebs cycle can’t start, as not enough oxygen available. Pyruvic acid now converted to lac c acid.
This remains cells. It is lac c acid responsible for s ff, sore feeling when want to move next day.
Bets way to get rid of s ff, sore feeling do light exercise. Blood flow to muscle increases, more oxygen taken to cells lac c
acid can be converted into pyruvic acid so respira on can con nue normally.
Even during normal exercise lac c acid produced when oxygen provision to muscle cells not quite sufficient. About 80% of
this lac c acid taken liver, used form glucose can serve as source energy. Other 20% returned normal respira on process.
Humans can only rely ATP released by lac c acid fermenta on for few minutes, Many animals not need that much energy.
Red-ear turtle can remain under water 2 weeks without breathing air. Respire aerobically under normal condi ons, but
under water are rela vely inac ve, do not need much energy.
Bacteria causes milk go sour, are orgs that use this type respira on sa sfy their energy needs.
Alcoholic Fermenta on:
Yeast cells(type fungus) respire anaerobically to produce alcohol, CO2, ATP. Type alcohol produced ethanol(ethyl alcohol).
This process especially important in beer, wine, spirits industry.
C6H12O6 CO2 + ethanol + 2 ATP
Yeast cells also used bake bread.
Sweet smell of baking bread is because of ethanol(all of it evaporates in heat), texture bread( ny cavi es) caused by carbon
dioxide bubbles. Large hole in bread occurs when dough and yeast not mixed properly.
Both Lac c acid fermenta on, alcoholic fermenta on not energy effec ve processes at all.
Combus on glucose not complete only 2 molecules of ATP produced during each of these reac ons.
In contrast aerobic respira on delivers 36 to 38 ATPs per glucose molecule.
Fact fermenta on is so ineffec ve means large quan es glucose needed.
To preform same amount of work anaerobic cells need 20 mes as much fuel per second as aerobic cell.
This why muscle cells store so much glucose as glycogen-cells can respire anaerobically for short periods.
A (cellular fuel) Glucose
B (end product) Lac c acid
C (end products) CO2, ethanol
D (end product) CO2, H2O
E (molecule formed) ATP
1 Lac c acid fermenta on
2 Alcoholic fermenta on
3 Cellular respira on
,Prac cal Inves ga ons
Heat Energy Released During Respira on
Use enough seeds ensure both flasks will be at least ¾ full.
Soak seeds approximately 24 hours water allow them to stand for 48 hours to
germinate.
Place half seeds in boiling water to kill them.
Soak both dead, living seeds in formaldehyde-solu on for about 5 min
(Solu on: 1 part formaldehyde with 10 parts water).
Rinse seeds thoroughly with boiled cooled down water.
Set up apparatus as in picture.
Thermos flasks placed upside down to trap heat as heat rises.
Flask with live seeds Flask with dead seeds
Temp at start experiment 24 °C 24 °C
Temperature a er 48 hours 32 °C 24 °C
Carbon Dioxide Released During Respira on
Set up apparatus as in picture.
Soak seeds for about 24 hours in water.
Ensure lime water is clear.
Remember clean test tubes, may not be any other chemical substances present that
might react with lime water.
Place apparatus in warm place 24 hours.
Test tube A clear lime water will turn milky(as CO2 present).
Test Tube B clear lime water will stay clear (no CO2 present).
, Nutrition in the Human Body
Life Science
Nutri on in the Human Body
3 Biological reasons why nutri on necessary:
- Provision energy for day-to-day ac vi es, on cellular level.
- Availability material growth, healing wounds, replacement damaged/worn
ssues.
- Regula on processes in body.
Processes involved in nutri on:
1. Inges on: Intake food.
2. Diges on: Breakdown insoluble polymers(macromolecules)-smaller, soluble
monomers(building blocks).
3. Absorp on: Absorp on nutrients. Absorbed nutrients used variety
process body. Known as assimila on nutrients.
4. Eges on: Undigested food residues expelled. Solid waste=faeces,
process defaeca on.
5. Excre on: Waste products produced during metabolic reac ons
expelled. In liquid form.
Human body’s diges ve system highly specialised involve all steps nutri on.
Diges ve system consists diges ve tract, associated organs(glands).
Mouth Teeth. Tongue and Salivary Glands
Adult human 32 teeth.
Human=heterodont, teeth have diff structures, func ons. Teeth dolphin all look same, dolphin is homodont.
Human=difiodont, have 2 sets teeth, set milk teeth, permanent set. Animals not lose baby teeth= monofiodont.
Teeth
Types of Teeth and their Func ons:
Incisors (i): 4 in upper, lower jaw cut, bite off food. Sharp, chisel-shaped. 1 Root.
Eye teeth/canines(c): 2 top, bo om used bite off/tear food/hold on to it. NB
predators, use canines kill prey. 1 Root.
Premolars(pm): 4 top, bo om. Grind food. 2 roots.
Molars(m): 6 top, bo om. Grind food. 2 roots.
General Structure of a Tooth:
Tooth consist den ne(substance similar bone, with higher mineral content. Ensures
den ne harder bone.
Part protrudes above gum(crown of tooth) covered tooth enamel(hardest substance
body).
Dental cavity filled so type connec ve ssue containing blood, lymph vessel, nerves.
Tooth embedded with cement in socket(cavity in jaw).
Part embedded socket called root.
Nerves, blood vessels, lymph vessels enter tooth from jaw through root canal.
