Transcript Nutrition and Metabolism PPT

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 from smaller
ones.
– Dehydration synthesis
• Joining monosaccharide to form polysaccharides
(glycogen).
• Joining glycerol and fatty acids to form fat
molecules.
• Joining amino acids to form proteins.
2 Types of Metabolic Reactions
Continued
• Catabolism - (catabolic metabolism) Metabolic process that breaks down large
molecules into smaller ones.
– Hydrolysis
• Breaking down complex carbohydrates into
monosaccharides.
• Breaking down fats into glycerol and fatty acids.
• Breaking down proteins into amino acids.
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
https://sites.google.com/site/biologymolecules/dehydration-sythesis-vs-hydrolysis
http://www.bcconline.com/biol10rs/PearsonAnimations/monomers_and_polymers.swf
Enzyme Action
• Enzymes are special
proteins that
catalyze chemical
reactions in the
body.
– They are highly
specific.
– The substances that
they work on are
called substrates.
– Substrates bind at
the enzymes active
site.
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, substrate
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 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.
Lactose Intolerance
http://www.dsm.com/le/en_US/maxilact/html/how_it_works.htm
http://www.youtube.com/watch?v=w_KR6k6YIIs
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.
ATP
To release the stored energy, the last
phosphate is removed and ADP (adenosine
diphosphate) + a phosphate group is formed.
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)
3 Stages of Cellular
Respiration
• Glycolysishappens in the
cytoplasm. (1st
stage for aerobic
and anaerobic
reactions.)
• The 6-carbon glucose is
broken down into 3-carbon
pyruvic acid molecules.
3 Stages of Cellular
Respiration
• Citric Acid Cycle
(Kreb’s Cycle)happens in
mitochondria.
(aerobic only)
• The 3-carbon pyruvic acids
enter the mitochondria and
lose a carbon generating
CO2 and is combined with a
coenzyme to form 2-carbon
acetyl coenzyme A. Each of
those combines with a 4carbon oxaloacetic acid to
form a 6-carbon citric acid.
3 Stages of Cellular
Respiration
• Electron
Transport chainhappens in the
mitochondria.
(aerobic only)
• The high energy electrons
that were released during
two previous cycles are
carried and combined with
enzymes that convert most
of the remaining energy to
ATP.
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
Aerobic vs. Anaerobic
Respiration
• http://www.youtube.com/watch?v=Gb2EzF_XqA
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.
Nutrition Lectures
• http://oyc.yale.edu/psychology/psyc123/lecture-3#ch4
lecture 3, part 5
• http://www.thegreatcourses.com/tgc/special/N
utritionFreeLecture.aspx