Transcript Cellular Metabolism and Nutrition notes

Ch. 4 and 18
Cellular Metabolism and
Nutrition
Metabolism
• Metabolism - Sum total of chemical
reactions within a cell.
– All of the chemical reactions within your
body.
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……. water
2.Something is being made…
• 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
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
• 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
Anabolism
Building
molecules
EX:
Dehydration
Synthesis
Forms
molecules while
releasing Water
Molecules made or
broken down by
these processes
Glycogen,
Catabolism
Breaking down
molecules
Ex: Hydrolysis
Fat molecules
Proteins
Breaks down
molecules while
splitting or
using water.
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/dehydration-sythesis-vshydrolysis
http://apchute.com/dehydrat/dehydrat.html
http://resource.rockyview.ab.ca/t4t/bio20/mm/m7/hydrolysis/Bio20_Hydrolysis_Fina
l.swf
http://www.goldiesroom.org/Shockwave_Pages/Make%20and%20Brake%20Em.htm
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.
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’.
Enzyme catalysis
• Substrate + enzyme 
Enzyme substrate complex 
Product (changed substrate) 
Enzyme (unchanged)
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.
Metabolic Pathways
• Sequences of enzyme-controlled
reactions that lead to the synthesis
(making) or breakdown of particular
biochemicals.
Coenzymes
• Coenzymes are
non-protein
substances (such
as vitamins) that
either aid in
enzyme activity,
or are required
for the enzyme
to function
properly.
Factors that Affect Enzyme
Activity
• Excessive temperatures (too hot
or too cold)
• Radiation
• Electricity
• Certain Chemicals
• Extreme pH values
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/labbench/lab2/im
ages/phact.gif
At high temperatures the enzyme changes
shape (denatures) and cannot function anymore.
https://lpscience.fatcow.com/jwanamaker/animations/Enzyme%20activity.html
Energy for Metabolic Reactions
• Energy - the capacity for doing work.
• ATP - energy rich molecule in cells
that powers cellular activities.
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.
Energy is stored in the ATP molecule
•ATP: adenosine triphosphate
Adenosine
Phosphate
Phosphate
Phosphate
High-energy bond: Stores much energy
*This energy is released when the bond is
broken*
Adenosine
Phosphate
Phosphate
Energy
ATP
To release the stored energy, the last
phosphate is removed and ADP (adenosine
diphosphate) + a phosphate group is formed.
ATP
P + Energy
Phosphate
Energy stored
released
ADP
Energy ‘cycle’
ATP
• Energy from cellular respiration is used to
synthesize more ATP by adding the
phosphate group back to ADP • This is known as phosphorylation.
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.
3 Stages of Cellular
Respiration
• Glycolysis - happens in the cytoplasm. (1st
stage for aerobic and anaerobic reactions.)
• Citric Acid Cycle (Kreb’s Cycle) - happens
in mitochondria. (aerobic only)
• Electron Transport chain - happens in the
mitochondria. (aerobic only)
Cellular Respiration…
3 main stages
1
Glycolysis – in the cytoplasm
2.
Krebs Cycle
In the
mitochondriol
matrix
3.
ETC
On the inner
membrane
3 Stages of Cellular
Respiration
• Glycolysishappens in the
cytoplasm. (1st
stage for aerobic
and anaerobic
reactions.)
3 Stages of Cellular
Respiration
• Citric Acid Cycle
(Kreb’s Cycle)happens in
mitochondria.
(aerobic only)
Will go through
2x
3 Stages of Cellular
Respiration
• Electron
Transport chainhappens in the
mitochondria.
(aerobic only)
Aerobic vs. Anaerobic Respiration
Characteristic
Aerobic Respiration
Anerobic Respiration
Glucose
Glucose
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
Starting materials
1st step
http://www.sumanasinc.com/webcontent/animations/content/cellularrespiration.html
(Aerobic)
ATP
Glucose
Oxygen
Carbon
dioxide
Water
Read through this section and complete the writing prompt for today
Nutritional Requirements
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.
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.
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.