Download Cells and Your Health

How is energy
important to humans?
Humans require
energy to function. The
total energy used by an individual
depends on the activities you do
(sports? Couch potato?),
but you also
need energy for
basic
life functions
(beating your
heart, breathing,
digesting, etc.).
The amount of energy required to
power basic life functions is called
basal metabolic rate, or BMR.
Humans obtain the energy required
to carry out basic life processes from
the food they consume.
Food energy is
measured in
calories. The amount of
food energy (calories) a
person requires varies
with body weight, age,
sex, activity level, and
natural body efficiency.
What is a balanced
diet?
Your body needs a
variety of nutrients
to survive and function
properly. You need food
(carbohydrates, proteins,
and lipids), water, and
vitamins and minerals
(vitamin A, B, C, D, E, folic
acid, etc.). Without these
your body cannot function
properly, leading to serious
health issues (scurvy= low
vitamin C, anemia= low
iron).
• For the body to use food
(proteins, lipids,
carbohydrates) for
energy and building
materials, the food must
first be digested into
molecules that are
absorbed and
transported to cells.
How do the
•
systems of your
body work together
to provide energy?
At least 3 body systems
are involved in making
cellular
respiration
possible:
Circulatory System:
(heart, blood
vessels, etc.)
carries
materials/molec
ules to and from
your cells. It
works with your
lungs to supply your
cells with oxygen
and remove carbon
dioxide.
Digestive System:
(stomach, liver,
intestines, etc.) breaks
down food into
smaller molecules,
which is then
absorbed into
your bloodstream
(circulatory system) and
carried to cells.
Some molecules are
used for building
materials, while
other molecules (sugars)
go through cellular
respiration (react with
oxygen to make energy).
Respiratory System: (lungs,
nose, etc.) Oxygen is
breathed in through your
respiratory system, then
transported through your
circulatory system (red blood
cells) to your body’s cells,
where it can then take part
in cellular respiration.
Your lungs also
get rid of the
carbon dioxide
produced from
cellular
respiration.
Test your knowledge:
What is
metabolism?
Metabolism is the set of
chemical reactions
involved in storing fuel
(food) molecules and
converting fuel (food)
molecules into energy. In
order for the body to use the
energy stored in food, the food
must first be digested and
combined with oxygen
(oxidized). This is cellular
respiration, and it’s how our
body converts food into energy
(ATP).
What is metabolic
rate?
• Metabolic rate is how much
energy your body needs to
function.
• 3 factors contribute to the overall
metabolic rate of the body:
– The Basal Metabolic Rate
(BMR) accounts for about 60% of
all energy used by the body.
– Daily physical activities such
as walking and moving around
account for another 30% of the
energy used by the body.
– Finally, 10% of the energy used
by the body is used to digest and
process (oxidize) food.
How is weight gained
or lost?
If you consume
more calories
than the body
uses, the excess is
stored and weight
is gained. Weight
loss occurs when
fewer calories are
taken in
than the body
needs.
What
happens to
food you
eat?
In order for energy balance to occur, Energy
In = Energy Out. This means that caloric
intake equals caloric output, or you use all
the energy you take in.
Food components (protein, fat,
and carbohydrate) taken into
the body have one of the
following fates:
–they can be used
to fuel metabolic
activities and
physical activities
–they can be
incorporated into
growing body
tissues
–they can be stored
as fat
How can you
keep your
body healthy?
In order for systems to work properly, energy from food must be
transformed into a useable form for cells and ultimately, organs, to
perform work. Your body systems work together in order for the
body to function properly and maintain a balance. Regular exercise
is important to maintain a healthy heart/lung system, good muscle
tone, and bone strength. Regular exercise and physical activity
increases the heart rate providing more oxygen for the body to use
for processing food. A healthy body requires a delicate balance
between a healthy diet and physical activity.
Questions:
1. Why is it important to have a balanced
diet?
2. Why is it important to exercise?
3. What does oxidize mean?
4. Explain how your body systems work
together to provide your body with the
energy it needs.
5. Evaluate your own eating and exercise
habits. Do you think you are healthy? What
could you do to improve your health?
Homework
Research the science behind lowcarbohydrate diets and explain why these
diets might lower blood cholesterol more
than a low-fat diet would.
Answer #3: The respiratory system brings in
oxygen, the digestive system breaks down
food into sugars, and the circulatory system
transports the oxygen and sugars to cells to
be used in cellular respiration.