Ch. 4 and 18

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Ch. 4 and 18

• Cellular Metabolism and Nutrition

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Metabolism

• Metabolism - Sum total of chemical reactions
  within a cell.
• All of the chemical reactions within your body.

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2 Types of Metabolic Reactions

• Anabolism - (anabolic metabolism) - Metabolic
  process by which larger molecules are
  synthesized/made from smaller ones.
• Dehydration synthesis

1. Something is being removed.
2. Something is being made

water
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• Joining monosaccharides (glucose) to form
  polysaccharides (glycogen).
• Joining glycerol and fatty acids to form fat
  molecules.
• Joining amino acids to form proteins.

Monomers smaller molecules Polymers larger
molecules
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2 Types of Metabolic Reactions Continued

• Catabolism - (catabolic metabolism) - Metabolic
  process that breaks down large molecules into
  smaller ones.

• Hydrolysis

Something is being broken down
Water is added
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• Breaking down complex carbohydrates into
  monosaccharides.
• Breaking down fats into glycerol and fatty acids.
• Breaking down proteins into amino acids.

Monomers Smaller molecules/building
blocks Polymers Bigger molecules
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Anabolism Molecules made or broken down by these processes Catabolism
Building molecules Glycogen, Fat molecules Proteins Breaking down molecules
EX Dehydration Synthesis Glycogen, Fat molecules Proteins Ex Hydrolysis
Forms molecules while releasing Water Glycogen, Fat molecules Proteins Breaks down molecules while splitting or using water.
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Metabolism Animation

• Dehydration and Hydrolysis
• Remember dehydration forms or releases water to
  build molecules and Hydrolysis splits or uses
  water to break molecules down.

https//sites.google.com/site/biologymolecules/deh
ydration-sythesis-vs-hydrolysis
http//apchute.com/dehydrat/dehydrat.html
http//resource.rockyview.ab.ca/t4t/bio20/mm/m7/hy
drolysis/Bio20_Hydrolysis_Final.swf
http//www.goldiesroom.org/Shockwave_Pages/Make20
and20Brake20Em.htm
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Enzyme Action

• Enzymes are special proteins that catalyze
  chemical reactions in the body.
• They are highly specific.Work only
• on specific substrates
• The substances that they work on are called
  substrates.
• Substrates bind at the enzymes active site.

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The enzyme and the substrate fit together like 2
puzzle pieces or like a lock and a key often
referred to as the lock and key complex.
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Enzyme catalysis

• Substrate enzyme ?
• Enzyme substrate complex ? Product (changed
  substrate) ? Enzyme (unchanged)

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Enzyme Catalysis

• Speed of the enzyme action depends on the
  concentration of the enzyme and substrate.
• As enzyme concentration increases, enzyme
  activity will increase to a point.
• As substrate concentration increases, enzyme
  activity will increase to a point.

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Metabolic Pathways

• Sequences of enzyme-controlled reactions that
  lead to the synthesis (making) or breakdown of
  particular biochemicals.

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Coenzymes

• Coenzymes are non-protein substances (such as
  vitamins) that either aid in enzyme activity, or
  are required for the enzyme to function properly.

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Factors that Affect Enzyme Activity

• Excessive temperatures (too hot or too cold)
• Radiation
• Electricity
• Certain Chemicals
• Extreme pH values

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Factors that Affect Enzyme Activity Continued

• If the enzyme becomes denatured, it will no
  longer work.
• Ex. Frying an egg
• The active site is no longer functional.

http//www.phschool.com/science/biology_place/labb
ench/lab2/images/phact.gif
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At high temperatures the enzyme changes shape
(denatures) and cannot function anymore.
https//lpscience.fatcow.com/jwanamaker/animations
/Enzyme20activity.html
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Energy for Metabolic Reactions

• Energy - the capacity for doing work.
• ATP - energy rich molecule in cells that powers
  cellular activities.

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ATP

• ATP consists of 3 parts
• a sugar (ribose)
• a base (adenine)
• 3 phosphate groups

Energy is stored in the bonds that hold the
phosphates together.
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• Energy is stored in the ATP molecule
• ATP adenosine triphosphate

High-energy bond Stores much energy This
energy is released when the bond is broken
Energy
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ATP

• To release the stored energy, the last
• phosphate is removed and ADP (adenosine
• diphosphate) a phosphate group is formed.

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ATP
P Energy released
Phosphate Energy stored
ADP
Energy cycle
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ATP

• Energy from cellular respiration is used to
  synthesize more ATP by adding the phosphate group
  back to ADP -
• This is known as phosphorylation.

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Cellular Respiration

• The process that releases energy from molecules
  of glucose and makes it available for cellular
  use. (In the form of ATP).
• Includes 2 pathways
• Aerobic - requires oxygen.
• Anaerobic - no oxygen required.

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3 Stages of Cellular Respiration

• Glycolysis - happens in the cytoplasm. (1st stage
  for aerobic and anaerobic reactions.)
• Citric Acid Cycle (Krebs Cycle) - happens in
  mitochondria. (aerobic only)
• Electron Transport chain - happens in the
  mitochondria. (aerobic only)

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Cellular Respiration 3 main stages
1
Glycolysis in the cytoplasm
Krebs Cycle In the mitochondriol matrix
2.
3.
ETC On the inner membrane
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3 Stages of Cellular Respiration

• Glycolysis- happens in the cytoplasm. (1st stage
  for aerobic and anaerobic reactions.)

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3 Stages of Cellular Respiration

• Citric Acid Cycle (Krebs Cycle)- happens in
  mitochondria. (aerobic only)

Will go through 2x
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3 Stages of Cellular Respiration

• Electron Transport chain- happens in the
  mitochondria. (aerobic only)

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Aerobic vs. Anaerobic Respiration
Characteristic Aerobic Respiration Anerobic Respiration
Starting materials Glucose Glucose
1st step Glycolysis Glycolysis
Uses oxygen Yes No
Cell location Cytoplasm then mitochondria Cytoplasm only
Products Water and CO2 Lactic Acid
Number of ATP produced 38 ATP 4 ATP
Net Gain 36 ATP 2 ATP
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http//www.sumanasinc.com/webcontent/animations/co
ntent/cellularrespiration.html
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(Aerobic)
ATP
Glucose
Carbon dioxide
Oxygen
Water
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Nutritional Requirements
Read through this section and complete the
writing prompt for today

• Carbohydrates
• Energy stored in their chemical bonds used to
  power cellular processes.
• Sources include
• Polysaccharides - grains, vegetables, meat.
• Disaccharides - milk sugar, cane sugar, molasses.
• Monosaccharides - fruit and honey.
• Requirements - at least 125-175 grams daily.
• Will differ based upon activity level.

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Nutritional Requirements

• Lipids
• Supply energy and help build cellular structures.
• Sources include
• Triglycerides plant and animal based foods.
• Saturated fats - mainly animal origin - meat,
  eggs, milk, lard, (coconut and palm oil)
• Unsaturated fats - plant origin - seeds, nuts,
  and plant oils.
• Requirements - Not more than 30 of daily calorie
  intake should come from fat.

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Nutritional Requirements

• Proteins
• Amino acids from dietary proteins are used to
  form new proteins such as enzymes.
• Can be used to supply energy.
• Sources include
• Meat, fish, poultry, cheese, nuts, eggs, cereal.
• We cannot synthesize 8 amino acids needed to
  build proteins, therefore we must get these from
  our diet. These are essential amino acids.
• Requirements
• About 0.8 grams per kilogram of body weight.