Metabolism Notes
Metabolism
• Metabolism is the generic term
used to describe all the chemical
reactions in the body of an
organism that either use or release
energy
• There are many chemical reactions
that make up an organism’s
metabolism, like:
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–
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–
–
Photosynthesis
Chemosynthesis
Cellular respiration
Lactic acid fermentation
Alcoholic fermentation
Chemical reactions
• A chemical reaction is a process that rearranges one set of
chemicals into a different set of chemicals
• Reactants
– Definition: the chemicals that enter into a chemical reaction
– These are written to the left of the arrow in a chemical equation
• Products
– Definition: the chemicals produced by a chemical reaction
– These are written to the right of the arrow in a chemical equation
• Catalyst
– Definition: a chemical that speeds up chemical reactions
– Many of the catalysts in organisms are proteins called enzymes
– Vitamins and minerals can greatly enhance the effects of these
Photosynthesis
• This process happens in bacteria and plants
– These organisms are called autotrophs or producers because they
can make their own food (glucose)
• It takes the energy from the sun and uses it to create the
sugar (glucose) that is the basis of most food chains
• Photosynthesis happens in the chloroplasts of plants and
protists (happens in the cytoplasm of bacteria)
Chemosynthesis
• This process happens in bacteria and archaea
– These organisms are also called autotrophs or producers because they can
make their own food (glucose)
• It is considered anaerobic because it happens without oxygen
• It takes the energy from hydrogen sulfide and uses it to create the sugar
(glucose) that is the basis of food chains in areas where there is no
sunlight
– Hydrothermal vents
– Inside the rock on the ocean floors
Cellular respiration
•
This process happens in almost all organisms
–
Both autotrophs (producers) and heterotrophs (consumers) use it
•
It is considered aerobic because it happens in the presence of oxygen
•
Cellular respiration happens in the mitochondria of plants, animals, fungi and protists
(happens in the cytoplasm of bacteria and archaea)
•
The energy released in the form of ATP runs all of the other processes in the body, like:
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Creating new cells & repairing old ones
Movement of all muscles (skeletal, smooth, and heart muscles)
Digestion
Sending nerve signals
Breathing
Lactic acid fermentation
•
This process happens in fungi, bacteria, and in the muscle cells of animals
– These organisms are called heterotrophs or consumers because they need to get
their food (glucose) from another organism
•
It is considered anaerobic because it happens without oxygen
•
Lactic acid is the chemical that makes your muscles sore after a tough workout
– Your body burns oxygen faster than you can take it in, so fermentation begins
– The more you train, the better your body gets at getting oxygen to the cells
– The better shape you’re in, the longer you can go before you produce lactic acid
•
It produces far less ATP than cellular respiration
Alcoholic fermentation
• This process happens in fungi and bacteria
– These organisms are called heterotrophs or consumers because they need to get
their food (glucose) from another organism
• It is considered anaerobic because it happens without oxygen
– Humans don’t have the right enzymes to act as a catalyst for this reaction (you’ll never
get drunk from working out)
• Ethanol and other chemicals like it are used for many different purposes
– Depending on the species doing the fermenting, different products like
cheese, yogurt, vinegar, rubbing alcohol, soy sauce, and biofuel can be
produced
Biomes
• The resources that organisms have access to for
their metabolism reactions vary greatly from one
environment to another
• A biome is an area of land or water that has a
particular climate and set of organisms
– Climate is the typical temperature and weather in an area
• Biomes are defined by their biotic and abiotic factors
– Biotic factors are the living things in an area
• Food sources and mates are some examples
– Abiotic factors are the non-living things in an area
• Oxygen, carbon dioxide, water, soil, and sunlight are examples
• Limiting factors are resources that there are not
enough of in an area for all organisms to survive
Land biomes
Name of
Biome
Temp.
Precip.
Soil
Desert
25 oC to
35 oC
Less
than
25
cm/yr
Sandy soil
Tropical
Rainforest
20 oC to
30 oC
200 +
cm/yr
Shallow topsoil
layer
Grasslands
-5 oC to
30 oC
25 –
75
cm/yr
Temperate
Forest
-5 oC to
30 oC
Taiga
Tundra
75 –
150
cm/yr
-5
to
o
5 C
25 –
75
cm/yr
Below
-5 oC
Less
than
25
cm/yr
oC
Resources that are in good supply
Limiting factors
 Lots of sunlight
 Very little water
 Very little available food
 Lots of water
 Lots of sunlight
 Lots of available food
 None
Good quality
soil
 Good sunlight in summer
 Good food availability in
summer
 Water can run short in dry
season
 Less sunlight in winter
 Less food in winter
Good quality
soil
 Good water supply
 Good sunlight in summer
 Good food availability in
summer
 Less sunlight in winter
 Less food in winter
 Good water during summer
(mostly melted snow/ice)
 Very little sunlight
 Very little available food
 Water can run short in dry
season
 None
 Very little sunlight
 Very little available food
 Very little water
Poor soil from
lack of decay
Permafrost
(soil layer that is
frozen yearround)
Water biomes
• There are two major aquatic
biomes:
– Freshwater (ponds, lakes, rivers,
streams)
– Saltwater (seas and oceans)
• The conditions in both are fairly
similar
– The deeper you go below the
surface:
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•
•
•
•
The less light reaches there
The colder the temperatures get
The less oxygen there is
The more carbon dioxide there is
The more pressure there is
Biodiversity
• Biodiversity is the variety of different types of
organisms that live in a particular area
– The more different species that live in an area, the
healthier the area is
• In case one species is wiped out, there are others to fill its niche
– All of the organisms in an area are dependent on each
other in some way
• Adding in a new species or removing an existing one can really
upset the balance
• Different types of diagrams can be used to show
the biodiversity and connections between
organisms in a biome
– They also help understand the metabolism and energy
flow of the area
Niches
• An organism’s job or role in its environment is called its niche
• Most niches revolve around how an organism gets its energy
– Producer = makes its own food (autotroph)
• Photoautotroph – uses photosynthesis to make its own food
• Chemoautotroph – uses chemosynthesis to make its own food
– Consumer = eats other organisms to get its food (heterotroph)
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Predator = chases, kills, and eats prey
Prey = the organism that gets eaten by a predator
Parasite = feeds off the body or fluids of a host without trying to kill it
Host = the organism that gets fed off of by a parasite
Scavenger = eats dead organisms that were killed by someone else
Carnivore = eats animals (or animal products)
Herbivore = eats plants (or plant products)
Omnivore = eats both plant and animal (or products)
– Decomposer = breaks down dead organisms and returns nutrients to
the soil
Food Chains
• A food chain is a diagram
that shows what organism
eats what other organism
– Only 1 organism at each level
– Diagrams are in a straight
line (chain)
– Arrows go from the organism
being eaten to the organism
doing the eating
• Arrow follows flow of energy
– Simpler to follow than food
webs
Food Webs
• A food web is a diagram
that shows what organism
eats what other organism
– Many organisms at each level
– Diagrams are highly branched
(web)
– Arrows go from the organism
being eaten to the organism
doing the eating
• Arrow follows flow of energy
– More realistic of what actually
happens in a biome
Energy Pyramids
• An energy pyramid is a diagram that
shows how the amount of energy in an
organism changes at different trophic
levels
• Each link in a food chain or food web is a
trophic level
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Level 1 = producers
Level 2 = first level consumers
Level 3 = second level consumers
Level 4 = third level consumers
Level 5 = fourth level consumers
• Wide bottom represents a lot of energy,
while narrow top means very little energy
– About 90% of the energy is lost at each
level as you go up
• This energy is lost to heat and running
body processes
– The amount of energy stored in an
organism is measured in a unit called
calories
Cycles
• According to the Laws of
Conservation of Matter and
Energy, matter and energy
cannot be created or
destroyed
– This means that within a
chemical reaction or a biome,
matter and energy are
recycled (rearranged and
shared), but not added or
removed