Health Science 20 Nutrition Notes Nutrition Basics

A nutrient is any substance in food that is used by the body to promote normal growth, maintenance, and repair.

There are different types of nutrients: o Major nutrients (macromolecules)

Carbohydrates Lipids Proteins

o Minor nutrients Vitamins Minerals

o Water Importance of Chemical Reactions

In a chemical reaction, matter is rearranged and new materials are made. o Ex: 2H2 + O2 ---> 2H2O

In a chemical reaction reactants are the starting materials (left side of the arrow), while products are the materials that remain after the reaction (right side of the arrow).

There are two major types of chemical reactions in our bodies o Dehydration Synthesis (a form of synthesis reaction)

A process that links monomers (monosaccharaides) together to form polymers (disaccharides, etc.)

This is an anabolic process – simpler substances make more complex substances.

During this process, water is released as a product

o Hydrolysis (Decomposition) The reverse reaction of dehydration. Used to break down polymers into their component monomers This is a catabolic process – complex substances broken down into simpler

substances.

Macromolecules

These are large complex organic molecules that form the basis of all living functions

Built around carbon atoms – but also include many hydrogen and oxygen atoms

Macromolecules are also called polymers

Polymers are large molecules consisting of many identical or similar units strung together via bonds

The building blocks of polymers are called monomers

Cells link monomers together through dehydration synthesis (removal of water to make a covalent bond) and break apart polymers through hydrolysis (addition of water to break covalent bonds)

There are four macromolecules: o Nucleic acids: made from monomers called nucleotides – takes the form of either DNA

or RNA (store and communicate genetic info) o Lipids: found in butter, oil, seeds, dairy products (stores function in the body and

provides barriers) o Proteins: found in meat, milk, cheese, avacado (transport substances, speed up

reactions (catalysts), provide structural support, make antibodies) o Carbohydrates: found in breads, etc. – made of monomers, that make polymers –

found in (main source of energy, provide structural support) Carbohydrates

the main elements in a carbohydrate are carbon, hydrogen and oxygen

general formula: (CH2O) n, where n = number of CH2O units in a chain

simplest carbs are called monosaccharides; n = 3-7 o example: the chemical formula for glucose is C6H12O6

small chains of sugars are for short bursts of energy

monosaccharides (mainly glucose) are the main fuel for cellular respiration (to make ATP) o Note: Many names for sugars end in “ose” (lactose, fructose, glucose, sucrose...)

Structure of Glucose

or… Structure of Fructose

or… Carbohydrates: Disaccharides

A combination of two or more monosaccharides is a disaccharide. (Dehydration synthesis)

Example: Sucrose

Energy is needed to connect these monomers. (Energy gets stored in the bonds.)

Carbohydrates: Polysaccharide (Complex Carb)

When there are a few hundred to a few thousand monosaccharides linked together via dehydration synthesis reactions, these are polysaccharides.

These molecules store a lot of energy that can be broken down to obtain sugars when needed.

They serve as building materials for structures – protect cells and support the organism

Examples of polysaccharides: o Starches o Glycogen o Cellulose

Starch: o Used for storing energy and raw building materials in plant roots and other tissues o Consists entirely of glucose monomers o Humans and other animals are able to use plant starch as food for hydrolyzing the

bonds between glucose monomers (to get energy) This happens in our digestive tracts

Glycogen:

o Starches in animals are called glycogen – the way that animals store energy o Mainly located in the muscle cells and liver o Glycogen identical to starch, except that it is more high branched o Humans can hydrolyze glycogen that is found in the meat we eat

Cellulose:

o Very long chain of carbohydrates that are very strong o Very hard to digest (hydrogen bonds exist between

chains) o Plant cell walls made up of cellulose o Humans can’t hydrolyze the links between glucose and

monomers o Known as fiber in our bodies (helps with digestive

system health) o Can be hydrolyzed by some microorganisms

Lipids

These molecules are mainly C and H atoms linked by nonpolar covalent bonds

They are not a true polymer

Lipids have greater hydrogen to oxygen ratio than carbohydrates

Greater ratio means lipids can provide or store more energy than other organic substances

A gram of fat can produce twice as much energy as a gram of proteins

Lipids are a source of fuel for the liver (gets metabolized to acetic acid) Lipids: Saturated vs. Unsaturated Fats

Saturated fats contain the max number of hydrogen atoms o Solids at room temperature

Unsaturated fats contain less than the max number of hydrogen atoms o Liquids are room temperature

High levels of saturated fats in animals create high blood pressure

Build up can happen in the walls of blood vessels and lead to cardiovascular problems such as atherosclerosis

Importance of Lipids

Fats and oils store energy and vitamins (fat soluble vitamins)

Waxes help plants and animals reduce water loss due to they hydrophobia (repel water)

Phospholipids are one of the major components of cell membranes – without these life would cease to exist as we know it.

Steroids (like cholesterol) are important in cell membranes and the production of some hormones (ex: human sex hormones)

Lipoproteins help with lipid transport in the blood – two types o Low-Density Lipoproteins (LDL) transport cholesterol to body

cells An excess of LDLs can lead to build up in the walls of

blood vessels and cause cardiovascular issues o High-Density Lipoproteins (HDL) transport cholesterol from

body cells to the liver

Proteins

Very complex types of compounds

Consist of very long chains called polypeptides that are usually folded into a unique 3D structure

Important to the structures of cells and organisms – participate in every activity they do

Proteins make up large portions of body tissues and body parts o Structural proteins: hair, nails, muscles o Functional proteins: antibodies, hemoglobin o Chromosomes contain proteins o Can be used for energy if lacking glucose/fats o Make up enzymes (catalysts)

Protein Structure

Proteins are made up of monomers called amino acids

Two amino acids can be joined by establishing a bond between them called a peptide bond

(happens through dehydration synthesis)

There are 20 different amino acids that make up proteins (8 of these amino acids cannot be made by humans)

Note: lose H2O during this process

3D Protein Structure

A protein’s shape determines its function – different species have very different protein arrangements.

If the structure of the protein is damaged, the function becomes lost o If the temperature is altered, or the pH of a protein’s environment is changed, this will

cause the molecule to denature (change shape) and this can alter the protein’s effectiveness.

Minor Nutrients: Vitamins

Vitamins are organic nutrients of various forms that the body will require in small amounts.

Can be found in a variety of food groups.

No one food group contains all the required vitamins.

Most vitamins function as coenzymes.

Minor Nutrients: Minerals

These are inorganic substances

Minerals we need include: calcium, phosphorus, potassium, sulphur, sodium, chloride, and magnesium.

Need trace amounts of other minerals (selenium, fluoride, iodine, iron, copper, zinc, etc.) Homeostatic Imbalances

Macromolecules are vital for our body to function properly. What happens when the nutrients aren’t present and can’t do what they should?

Missing Carbs

Hypoglycaemia (low blood sugar) is caused by no carbs

Includes headaches, confusion, trembling, weakness, hunger, anxiety

Leads to poor coordination, numbness, passing out, and eventually, coma Issues with Lipids

High cholesterol OR Low cholesterol Issues with Proteins

Denaturation – leads to loss of muscle mass, fatigue, loss of colour/texture of hair and skin pigmentation, rashes, swelling, etc.