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?

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).

How do the systems of your

body work together to

provide energy?

• 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.

• At least 3 body systems are involved in making

cellular respiration possible:

Circulatory System: (heart, blood vessels, etc.) carries materials/molecules 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

?

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 low- carbohydrate 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.