Download 5.1 Tracing the Processes of Cows Growing: Digestion and

Carbon: Transformations in Matter and Energy
Environmental Literacy Project
Michigan State University
Animals Unit
Activity 5.1: Tracing the Processes
for Cows Growing: Digestion and
Biosynthesis
Unit Map
You
are
here
2
Connecting Questions about Processes
at Different Scales: Digestion
Scale
Unanswered Questions
Macroscopic
Scale
How to cows get food to all of
their cells?
Microscopic
Scale
How do food molecules get
into a cow’s blood?
AtomicMolecular
Scale
How are molecules in food
changed chemically so that
cow cells can use them?
3
Food
molecules
are in the
grass
Place two
nickels here:
large food
molecules
(grass).
4
What happens to the food cows eat?
Food
Digestion
Energy:
Cellular
respiration
5
Food is mostly water and large
organic molecules
CARBOHYDRATES:
STARCH
LIPIDS (FAT)
GLUCOSE
(SUGAR)
PROTEINS
CELLULOSE (FIBER)
6
These large organic molecules cannot
enter the cells
LIPIDS (FAT)
PROTEINS
How do animals digest, or
break down, these
molecules into smaller
molecules the cells can use
to do work?
Digestion occurs
in stomach and small
intestines
Put nickels here:
Large food
molecules break
into small
molecules in
intestines
Exchange one nickel for 5 pennies (small organic molecules)
Note: digestive
cells produce
molecules
(enzymes) that
can break large
organic
molecules up
into small
organic
molecules.
8
During digestion, large organic molecules are broken
down into small organic molecules
STARCH
GLUCOSE
(SUGAR)
9
Animals don’t digest all the food that
they eat
Our digestive
systems cannot
break down some
large organic
molecules (such as
fiber).
Have the remaining nickel leave the cow as
feces
These molecules
leave our bodies as
feces.
10
What happens to carbon
atoms and chemical
energy in digestion?
Chemical change
Large organic molecules
(+ water)
Reactants
11
Small organic molecules
Products
What happens to carbon
atoms and chemical
energy in digestion?
Chemical change
Large organic
molecules (+ water)
Reactants
12
Carbon atoms stay in
organic molecules with
high-energy bonds
Small organic
molecules
Products
Small molecules move from intestines to blood, and the heart
pumps blood and small molecules to all parts of the body.
Move Pennies:
Small molecules
move through
circulatory
system
13
Where do the small molecules go?
glucose
glycerol
fatty acid
amino acid
14
Connecting Questions about Processes
at Different Scales: Biosynthesis
Scale
Unanswered Questions
Macroscopic
Scale
How do cows grow?
Microscopic
Scale
How do cows’ cells use small
organic molecules to grow?
AtomicMolecular
Scale
How do cells make their large
organic molecules?
15
How do cows’ cells use food to grow?
Materials
for growth:
Biosynthesis
Food
Digestion
Energy:
Cellular
respiration
16
What happens during biosynthesis?
Chemical
change
Small organic molecules go into
cells, but don’t come out. What
happens inside the cells?
Biosynthesis is the
process of small
organic molecules
becoming large
organic molecules
in individual cells.
Place your
pennies here:
Large
molecules are
built here
Exchange your 5 pennies (small organic molecules) for a nickel
(large organic molecule)
18
During biosynthesis, small organic molecules are built
into large organic molecules
GLUCOSE
(SUGAR)
STARCH
19
What happens to carbon
atoms and chemical
energy in biosynthesis?
Chemical change
Small organic
molecules
Reactants
20
Large organic molecules
(+ water)
Products
What happens to carbon
atoms and chemical
energy in biosynthesis?
Chemical change
Small organic
molecules
Reactants
21
Carbon atoms stay in
organic molecules with Large organic molecules
(+ water)
high-energy bonds
Products
How do animal cells use glucose?
• The diets of most animals—including
mealworms, cows, and humans—include lots
of carbohydrates (starch, fiber, sugar)
• This means that lots of glucose travels to
animal cells in the blood.
• BUT animal cells don’t make starch or
cellulose.
• How do they use the glucose?
22
Animal cells use glucose in two ways
1. Animal cells can combine glucose molecules
with oxygen to release chemical energy in
cellular respiration.
– This is how all cells get the energy they need for their
functions.
2. Animal cells can make fat molecules from
glucose molecules.
– Glycerol and fatty acids are made of the same
atoms—C, H, and O—as glucose molecules
– Animals use fats to store chemical energy in C-C and
C-H bonds
23
Where do the atoms in animals come
from?
Work with a
partner to
complete the
first chart about
atoms.
Remembering Nutrition Labels
Animal cells are made of:
• Water: around 60% (H2O)
• Large organic molecules: less than 40%
– Fats: Made of CHO atoms
– Proteins: Made of CHON atoms
– (Some other large organic molecules such as DNA,
made from CHONP)
• Minerals: around 1%
– Many kinds of atoms: sodium, calcium,
magnesium, etc.
25
Where does the energy in animals
come from?
Work with a
partner to
complete the
second chart
about energy.
Chemical Energy
• Chemical energy is stored in C-C and C-H
bonds.
• Does water have chemical energy?
• Does air have chemical energy?
• Does food have chemical energy?
Additional Metabolic Pathways
There are many more small organic molecules
and ways they can be changed other than the
ones in this lesson. Look at the Metabolic
Pathways poster to see some of them.
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