Download Humans as Consumers– Day 1

Humans as Consumers– Day 1
Consumers
3 Main Nutrients
Enzymes
Mechanical vs. Chemical
Digestion
Consumers

Rely on other organisms for food (eat other
things to survive)
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Herbivore
Omnivore
Carnivore
Detritivore
I am eukaryotic.
(Each cell in my body has a nucleus.)
I am multicellular.
(My body is made of many cells.)
My cells do not have a cell wall.
(My cells only have a cell membrane.)
I am generally motile.
(I am able to move voluntarily.)
I have specialized sensory organs for recognizing and
responding to stimuli in the environment.
I am generally heterotrophic.
(I depend on other organisms for energy.)
I generally digest food in an internal
chamber. (I have a digestive tract.)
Well then, you’re an ANIMAL!
The 3 Main Nutrients
(this is a label from a Kellogg’s Froot
Loops box)

Calorie:
–

A measure of energy
released from digested
foods.
The 3 main nutrients:
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–
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Carbohydrates
Fat (lipids)
Proteins
The 3 Main Nutrients
Starch
Cellulose
(a.k.a. fiber)
The 3 Main Nutrients

Carbohydrates:
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Molecule
composed of
carbon,
hydrogen, and
oxygen.
Ex) sugars,
starches, etc.
The 3 Main Nutrients

Proteins:
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–
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Molecule
composed of
amino acids linked
by peptide bonds.
Amino acids are
made of carbon,
hydrogen, oxygen,
and nitrogen.
Ex) structural,
enzymes, muscle
proteins, etc.
The 3 Main Nutrients

Fats:
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a.k.a. Lipids
molecule
consisting of
carbon,
hydrogen, and
oxygen.
Ex) oils, butter,
lard, animal fat.
Enzymes are…
special proteins in our
digestive system that
speed up the chemical
breakdown of food
Why enzymes are necessary

Reactions in organisms need to occur at low
temperature (body temperature), with low
concentrations of reactants, and at a high rate.
Important factors in enzyme structure

The order of the amino acids determine the structure
of an enzyme.
How structure affects function

If the structure changes, then substrates will not be
able to bind to the enzyme’s active site.
Lock and key model

Only certain substrates bind to an enzyme’s active
sites; when bound to the enzyme, the chemical
reaction can occur.
1. How do enzymes weaken the bonds in
substrates?


The enzyme’s shape changes slightly, which strains
the bonds inside the substrate.
The strain on the bond weakens them.
http://www.kscience.co.uk/animations/anim_2.htm
2. How are substrates like keys and
enzymes like locks?

Specific substrates fit exactly into the active sites for
specific enzymes
–
ANALOGY: in a similar way that only a certain key will open
any given lock.
Substrate
3. What does the enzyme do in the
demonstrations?

Enzymes speed up the breakdown of the substrate.
Mechanical vs. Chemical Digestion

Mechanical
Digestion:
Food is physically
broken down into
smaller parts

Chemical
Digestion:
Enzymes change food
into simpler substances
Mechanical vs. Chemical Digestion
•Simply crunches
food into smaller
more manageable
pieces.
•Creates more
surface area for
chemical digestion
•Both break
down food
into smaller
Pieces.
•Enzymes break
chemical bonds
between
building blocks.
•The products are
not the same as
the reactants.