Autotrophs vs. Heterotrophs

 What is the purpose of nutrition?

 Nutrition provides energy for life activities for ALL living things.

 Autotroph – organisms that make their own food  Examples: multicellular plants and unicellular algae.

 Heterotroph: organism that needs to take in its food from the environment.  Example: Humans, all animals, fungi, etc.

 How does nutrition vary among heterotrophs?

 Herbivore – eats only plants  Carnivore – eats only meat  Omnivore – eats both meat and plants

 Why do humans need a variety of nutrients?

 Humans are complex organisms. There are 6 essential nutrients needed for the human body to function properly.

6 Essential Nutrients

 Main source of energy

 Bread, pasta, rice, vegetables, fruits

- Turns into fat or stored energy

 Why are fats essential in a diet?

 Stored energy  Structure of the cell membrane  Protects organs  Insulation from the cold  Synthesize hormones

 Saturated fats are solids at room temperature (ie: butter, fat found on/in meat)  Mostly from animals  Increases bad cholesterol  Unsaturated fats are liquids at room temperature. (ie: different types of oils)  Mostly from plants  Increases good cholesterol

 Nuts, meat, dairy products, oils.

 Why do body builders eat a diet high in protein?

 Build muscle and tissue  Structure of the cell membrane  Enzymes, hormones, antibodies  Last source of energy

 Amino acids are the building blocks of proteins  Human body needs 20 different amino acids  12 can be made by the body  8 are essential – must be taken in through diet

 Meat, beans, whole grains, eggs, soy, nuts

 Up to 75% of your total body mass is water  Water is necessary for  Chemical reactions  Movement of materials into and out of cells  Breakdown of foods during digestion

 Why do we need to take in water every day?

 We lose 2.5L of water a day through exhalation, sweat and urination

 Used for building body parts  Involved in many body functions such as nerve and muscle action  Examples:  Calcium, phosphorus, zinc, sodium, iodine, iron, potassium

 Vitamins are coenzymes (help enzymes to function) that are found in food

 Cellulose – indigestible part of the cell wall of a plant (fiber)  Helps to push food through the digestive tract  Examples – fruits, vegetables, bran cereals, nuts