Download study guide answers except #23

1. We need food for:
• the fuel the mitochondria “burn” to produce energy
• building blocks/raw materials to make the macromolecules
we need for growth/repair/maintenance/energy storage
also:
• homeostasis molecules that act like oil in an energy to keep
our bodies working right – examples: water, elements
important to our bodies (minerals), vitamins, electrolytes
2. Why does it matter what we eat?
• To get enough of all 3 of these different types of molecules,
we need a balanced diet. But there isn’t only one balanced
diet. Many different diets can fulfill these needs, because
many foods contain these various building blocks.
• When we don’t eat the right things, we can be low on
energy, not be able to maintain and repair our bodies, or get
out of homeostasis. Even though we do not need a big
serving of some of the homeostasis molecules each day
(especially vitamins), it is very important to get enough
because the lack of them can affect many of our bodies’
systems. Eating a variety of colors of fruits and vegetables
can provide us with the full spectrum of the vitamins we
need.
3. Where does the energy in food come from if you trace it all the
way back? The sun
4. What happens to food when we eat it? We digest it.
5. We must digest our food to be able to absorb it. Our digestive
system breaks the food down into building blocks small enough to
go through our intestine walls. We also need to break down the
building blocks so we can reassemble them as the molecules we
need. (We don’t want peanut protein, so we break it down to
amino acids and reassemble it as human protein.)
6. The digestive system uses enzymes to break down the food.
Enzymes are large, reusable proteins in our bodies. They catalyze
reactions. That means they help the right reaction take place at the
right time and the right temperature.
7/8. Enzymes are extremely specific because only certain
molecules fit into the slots or grooves of the molecule, like lock
and key.
9. Synthesis of macromolecules is endothermic. It requires (and
stores) energy.
10. Synthesis of macromolecules requires enzymes so the right
reaction happens at the right temperature.
11. Major elements in living things: C H O N P S -- 1st 3 are 3
most common
12. Energy in a molecule is stored in the arrangement of its atoms.
In some reactions, the products store less energy than the
reactants and energy is released. These are called exothermic
reactions, like burning wood.
In other reactions, the products store more energy than the
reactants and energy is absorbed. These are endothermic reaction
(and they store potential energy). Photosynthesis is an example.
13. Carbon atoms can form 4 bonds. This allows for many
different shapes because carbon can add new branches in 4
different directions, not just 2 as is true for O.
14/15. Energy can be converted into another form or type, but it
cannot be created or destroyed.
16. Potential energy is stored energy.
17. Organisms convert energy from one form to another to get the
form they need at that time and for that situation.
Skip 18 and 19; 20 and 21 are extra credit
22. ATP is adenosine triphosphate. It provides short-term energy
storage, such as cash from an ATM. It is the “cash” of the cell
that all organelles will accept. Only mitochondria can convert
food (especially glucose) into ATP.
For 3 major classes of our bodies’ macromolecules (proteins,
carbs, lipids), you should know most of the chart we made:
1. Name of the building block (monomer) – amino acid,
monosaccharide/simple sugar, fatty acid
2. name of the carbohydrate macromolecules (polymer) –
polysaccharide/complex carbohydrate which has 3 major
examples: starch which plants make, glycogen which animals use
for storage, and cellulose (in cell walls – also known as fiber)
3. how to identify the structural models of the monomers and
polymers (as we drew on the charts)
4. what elements proteins, carbohydrates, and lipids contain: C H
O for all, proteins add N
5. functions: carbohydrates and lipids store energy, lipids are
needed for hormones and cell membranes, proteins serve as
enzymes and the most of our body’s structure
See the chart on my website that you can cut up and use as a
puzzle.