Nutrients and Nutrition

• Nutrition is one of the 7 characteristics of living organisms

  Nutrition is the taking in of nutrients (organic substances and mineral nutrients) that contain the raw materials or energy needed by the organism. It also includes absorption and assimilation of these nutrients into new body tissue during growth and tissue repair.

Plant nutrition does not include taking in organic substances because plants make their own carbohydrates using photosynthesis. However, plants need to take in mineral ions through their roots to make other substances needed for healthy growth and tissue repair.

Carbohydrates, Proteins, and Lipids

Most molecules found in living organisms fall into three main groups:

• carbohydrates

• proteins

• lipids

Which are commonly called fats and oils.

All these molecules contain carbon (C), Hydrogen (H), and Oxygen (O). All proteins contain Nitrogen (N) and some also contain Sulfur (S).

Carbohydrate molecules are made up of small basic units called simple sugars. These are formed from carbon, hydrogen, and oxygen atoms, sometimes arranged in a ring-shaped molecule. E.g. glucose.

Simple sugar molecules can link together to form larger molecules. They can join in pairs, such as sucrose (the sugar we use in our food). They can also form much larger molecules called polysaccarides, such as starch and glycogen, which are both chains of glucose molecules.

Protein molecules are made up of long chains of amino acids linked together. There are 20 diff. kinds of amino acids in plant and animal cells. These can join in long chains, in any order, to make all the diff. proteins within the plant or animal body. E.g. the structural proteins in muscles as well as enzymes that help control cell reactions.

A lipid is what is commonly know as a fat or oil. Fats are solid at room temp, whereas oils are liquid, both they both have similar structure. Both are made from basic units called fatty acids and glycerol. There are 3 fatty acids in each lipid, and the acids differ in different lipids. Lipid are important in forming cell membranes and many other molecules such as fats in storage cells.