Energy and Metabolism

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Energy and Metabolism
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What is energy?

• Everything in the universe is made of either
  energy or matter.
• Matter and energy cannot be created or destroyed
• They can be transformed
• They can travel through space

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What is energy?

• Energy exists in different forms
• Chemical energy energy stored in the covalent
  bonds holding molecules together
• Light energy energy traveling through space as
  particles called photons in waves.
• Kinetic energy energy present in moving matter
• Heat energy actually kinetic energy of moving
  atoms/molecules
• The faster they move the more heat they contain
• Temperature is a measurement of this heat

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What is energy?

• Energy can be defined as the ability to do work.
• Work happens whenever matter is moved or changed.
• It takes a lot of work to keep a cell alive
• It takes energy to do work

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What is energy?

• Examples of cellular work
• Building new molecules
• Taking molecules apart
• Moving organelles around inside cell
• Operating cilia or flagella
• Reproducing
• Maintaining osmotic balance
• Active transport across membrane

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What is metabolism?

• A cell or a bodys metabolism includes all the
  chemical reactions it performs to stay alive.
• When metabolism stops, the cell or the body is
  dead.
• Metabolism can be measured as a rate
• Metabolic rate can increase
• Metabolic rate can decrease

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What is metabolism?

• Metabolic activity generally divides into two
  categories
• Synthesis reactions build polymers from
  monomers.
• Digestion reactions take apart polymers to make
  monomers.

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What is metabolism?

• Examples of synthesis reactions
• Building proteins from amino acids
• Building carbohydrates from simple sugars
• Building fats from fatty acids and glycerol
• Building DNA and RNA from nucleotides

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What is metabolism?

• Examples of digestion reactions
• Also known as hydrolysis reactions
• Taking apart consumed meat in the digestive
  system to produce amino acids, lipids, and other
  monomers
• Breaking down carbohydrates in food to release
  energy.

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What is metabolism?

• Synthesis reactions generally require more energy
  than they release.
• Digestion reactions generally produce more energy
  than they require.

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Metabolism

• Synthesis
• Monomers to polymers
• Requires energy to do
• Builds bigger things from smaller pieces

• Digestion
• Polymers to monomers
• Releases more energy than it absorbs
• Breaks down larger things into smaller pieces

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Enzymes

• Enzymes are proteins shaped in a way that allows
  them to temporarily bond to other molecules
  called substrates.

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Enzymes

• Enzymes speed up chemical reactions inside cells.
• All metabolic reactions require enzymes
• Each reaction has its own specialized enzyme.

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Enzymes

• Examples of enzyme reactions
• Hydrogen peroxide catalase ? water oxygen gas
  heat catalase
• Sucrose sucrase ? glucose fructose sucrase
  energy
• Protein protease water ? amino acids
  protease

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Enzymes

• Enzymes almost always end in ase
• Enzymes often are named after the substrate they
  react with.
• Enzymes speed up the reaction but are not changed
  by reaction
• One enzyme molecule can catalyze thousands of
  reactions
• Enzymes work until they run out of substrate

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Enzymes

• Different enzymes work best under different
  conditions
• Some enzymes work best in acid solutions
• Stomach enzymes like pepsin
• Some enzymes work best at neutral pH
• Mouth enzymes like amylase

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Enzymes

• Each enzyme also has its preferred temperature
  range
• Human digestive enzymes work best at 98.6 degrees
  Fahrenheit
• Hypothermia kills because human enzymes cannot
  function well below 93 degrees
• A fever over 108 is deadly because human enzymes
  denature (change shape) and no longer function

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Enzyme Rate

• Each has its best pH

• Each has its best temperature

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ATP

• Stands for Adenosine triphosphate
• Used by all cells to do work
• Metabolism transfers energy from food molecules
  to ATP molecules.

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How is the ATP molecule built?

• ATP is built from three components
• A ribose sugar molecule
• An adenine molecule
• Three phosphate groups

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How does ATP store energy?

• ATP is like a charged battery
• ADP is like a drained battery
• Energy is stored in the covalent bond holding the
  last phosphate group on to the molecule
• ADP energy phosphate group ? ATP
• ATP ? ADP energy phosphate group

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Cellular Respiration

• Cellular respiration is a complicated pathway of
  chemical reactions that transfers energy in
  carbohydrate to ATP.
• Cellular respiration releases energy from food in
  the same way burning releases energy from paper

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Cellular Respiration

• Burning Paper
• Carbohydrate cellulose
• Energy released as heat
• Uses up oxygen
• Releases CO2
• Goes until the paper is gone or the oxygen runs
  out

• Cellular Respiration
• Carbohydrate glucose
• Energy transferred to ATP
• Uses up oxygen
• Releases CO2
• Regulated and controlled by many different
  enzymes

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Cellular Respiration

• Reactants C6H12O6 O2
• Products CO2 H2O energy

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Cellular Respiration

• Balanced chemical reaction
• C6H12O6 6O2 ? 6CO2 6H2O energy

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Cellular Respiration

• Mitochondria take in glucose and oxygen to
  convert ADP into ATP
• This is why mitochondria are called the
  powerhouses of the cell
• Cells that do a lot of work have more
  mitochondria
• Cells that are dormant or not working have few
  mitochondria

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Cellular Respiration

• Burning glucose inside mitochondria to make ATP
  is called aerobic respiration because it requires
  oxygen
• Makes a lot of ATP
• Produces CO2 as a waste gas
• Cells can also perform a different kind of
  respiration to make ATP without oxygen called
  anaerobic respiration.

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Anaerobic Respiration

• Does not require oxygen
• Also known as fermentation
• Makes a little ATP
• Produces toxic waste products
• Two types
• Lactic acid fermentation
• Alcohol fermentation

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Anaerobic Respiration

• Lactic acid fermentation
• Takes place in muscle cells that run out of
  oxygen
• Produces a small amount of ATP
• Produces lactic acid as a waste product
• Builds up in muscle cells
• Causes damage/burning

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Anaerobic Respiration

• Alcohol fermentation
• Takes place in yeast cells
• Produces a small amount of ATP
• Produces ethanol and CO2 as a waste products
• Builds up in the solution
• Eventually kills the yeast cells

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Anaerobic Respiration

• Lactic acid Fermentation
• Muscle cells
• Produces lactic acid
• Allows muscles to work a little bit longer even
  though they are not getting oxygen
• Lactic acid causes damage and burning sensation

• Alcohol Fermentation
• Yeasts
• Produces ethanol and carbon dioxide
• Used to brew beers and other distilled alcohol
  products
• Used to make bread rise

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Photosynthesis

• Photosynthesis transfers light energy from
  sunlight to molecules of carbohydrate
• Used by plants to make glucose out of CO2 and
  water
• Takes place inside chloroplasts

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Photosynthesis

• Chloroplasts are green because they are packed
  with chlorophyll
• Chlorophyll absorbs red and blue light
• Chlorophyll reflects green light

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Photosynthesis

• Balanced reaction
• 6CO2 6H2O light energy ? C6H12O6 6O2
• The same as respiration, but backwards

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Energy Flow and Ecosystems

• Energy enters ecosystems as sunlight and leaves
  as heat.
• Energy flows through ecosystems as food
• Organisms pass food energy along in food chains
• Food chains interconnect to make food webs

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Energy Flow and Ecosystems

• Plants make food, so they are called producers
• Animals eat food, so they are called consumers
• Bacteria and fungi break down plant and animal
  bodies and change them into carbon dioxide and
  water, and are called decomposers

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Energy Flow and Ecosystems

• Each time energy (in food) moves through a step
  in the food chain, 90 of the energy is lost.
• Only 10 of this food energy is captured.
• This is called the 10 rule

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Energy Flow and Ecosystems

• Biomass
• The total mass of all living and once-living
  material
• Food is biomass that can be turned into energy
  inside cells.
• Plants produce biomass by doing photosynthesis

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Energy Flow and Ecosystems

• Biomass on earth
• Living plants and animals
• Dead plants and animals
• Fossil fuels
• Coal (once living plants)
• Petroleum (once living sea organisms)

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Energy Flow and Ecosystems

• Global warming
• It is a fact that the average temperature of the
  planet is rising
• It is a fact that carbon dioxide traps heat in
  the earths atmosphere
• It is a fact that humans are burning fossil
  fuels/biomass faster than photosynthesis can fix
  it, causing CO2 levels to rise
• Scientists theorize that human activity is
  speeding up the rate of CO2 increase in the
  atmosphere.

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Energy Flow and Ecosystems

• Carbon fixation
• Plants remove carbon dioxide from the air and
  build it into biomass
• The more photosynthesis takes place, the faster
  carbon is fixed into biomass