NUTRITION EXPEDITIONBRANDON HOLDEN

CARBOHYDRATES

CHEMICAL STRUCTURE

Carbohydrates consist of the elements carbon (C), hydrogen (H), and oxygen (O). They have a ratio of hydrogen twice that of carbon and oxygen. In a their basic form, carbohydrates are simple sugars or monosaccharides.

Glucose, fructose, ribose, and galactose are all monosaccharides.

The empirical formula of a carbohydrate is CH2O

CHEMICAL STRUCTURE CONT.

DEHYDRATION SYNTHESIS

Dehydration means to remove water. Therefore you are building something up while taking water out. In carbohydrates, an H from one carbohydrate and an OH from another are taken out, which form water. The two carbohydrates then join together and form a bond called a glycosidic linkage.

HYDROLYSIS

Hydrolysis is the exact opposite of dehydration synthesis in that instead of taking away water, it is being added. The water molecule breaks apart the bonds and creates monosaccharides from the polymer chain.

MONOMER MOLECULES

Carbohydrate’s monomer molecules include glucose, fructose, ribose and galactose.

POLYMER MOLECULES

Cellulose: One of the most prevalent polysaccharides on earth. The structure of it’s polymer chain is linear.

Starch: It is a plant reserve carbohydrate (storage form of glucose). The structure of it’s polymer chain is branched.

Glycogen: Glucose is stored as glycogen in animal liver and muscle cells. The structure of it’s polymer chain is highly branched.

POLYMER MOLECULES CONT.Cellulose

Starch

Glycogen

TYPES OF BONDING WITHIN MOLECULES

Carbohydrates are joined by a glycosidic linkage, which is a covalent bond that is formed between two carbohydrate molecules by dehydration synthesis.

FUNCTION IN LIVING ORGANISMS

Plants store glucose as starch and convert it into cellulose. (Glucose is the product of photosynthesis)

Consumers eat carbohydrates and break polysaccharides into glucose.

Glucose is converted into ATP during cellular respiration to fuel all metabolic processes. (Excess glucose is stored in liver as glycogen)

LIPIDS

CHEMICAL STRUCTURE

Lipids are non-polar organic compounds that constitute a broad group of naturally occuring molecules that include fats, waxes, sterols, fat soluble vitamins, monoglycerides, diglycerides, triglycerides, and phospholipids.

The main biological function of lipids include energy storage, as structural components of cell membranes, and as important signaling molecules.

Lipids consist of the elements carbon (C), hydrogen (H), and oxygen (O) arranged as a carbon chain skeleton with a carboxyl group (-COOH) at one end.

CHEMICAL STRUCTURE CONT.

Cis-9-octadecenoic acid (Oleic acid)

Trans-9-octadecenoic acid (Elaidic acid)

DEHYDRATION SYNTHESIS

Dehydration in proteins involves the combination of two amino acids as shown. The water molecule comes off like the carbohydrate reaction. The bond in between the two amino acid molecules that forms is called a dipeptide bond.

HYDROLYSIS

Hydrolysis is the exact opposite of dehydration synthesis in that you add water instead of removing it, once again.

MONOMER AND POLYMER MOLECULES

The class of molecules called lipids is a wide range of structurally different molecules with very different properties, but they have no repeating unit or monomer like proteins or polysaccharides. Lipids also do not have any polymers because they are not linked together in a chain, but instead are linked along side each other. To be a polymer, another molecule would have to be attached in either direction repeatedly.

FATTY ACID STRUCTURE

Fatty acids are non-polar chains of carbon and hydrogen with carboxylic acid at one end.Types of Fatty Acid

SATURATED FATTY ACIDS

Saturated fatty acids do not contain any double bonds (the carbon chain is “saturated” with hydrogen).

Saturated fatty acids tend to be produced in animal tissue and are solid at room temperature.

UNSATURATED FATTY ACIDS

Unsaturated fatty acids contain double bonds.

Unsaturated fatty acids are produced by plant tissues and tend to be liquid at room temperature.

TYPES OF BONDING WITHIN MOLECULES

The type of chemical bonds for lipids are non-polar C-H bonds. The actual bonds that attach the fatty acids to the glycerol are referred to as ester linkages.

FUNCTION IN LIVING ORGANISMS

Cell membrane structure. Constitutes a barrier for the cell. Controls membrane fluidity. Energy storage (for instance, fats

stored in adipose tissue). Signal transduction (function in the

transmission of information in cells). Lipid vitamins (required for

metabolism, usually as coenzymes).

PROTEINS

CHEMICAL STRUCTURE

Proteins are polymers of amino acids covalently linked through peptide bonds into a chain.

Most proteins have over 100 amino acids in their structure.

Proteins can have both structural and functional roles within the cell.

There are many different types of structures for proteins.

STRUCTURAL PROTEINS

These proteins form parts of structures. Keratin is a structural protein that is a

component of fingernails and hair. Collagen is a protein that is found in

connective tissue (ligaments etc).

AMINO ACIDS (MONOMER MOLECULES)

Amino acids are the monomers of proteins (there are 20 different amino acids).

Amino acids are composed of 3 groups, amino group, carboxyl group, r-group.

(POLYMER MOLECULES) Polymer molecules of amino acids are

when 2 or more amino acids are joined together through a peptide bond.

THE 20 AMINO ACIDS

DIPEPTIDE (DEHYDRATION SYNTHESIS)

When 2 amino acids undergo dehydration synthesis they form a dipeptide.

The bond between 2 amino acids is called a peptide bond.

Peptide bonds are strong covalent bonds.

DIPEPTIDE CONT,

Dehydration Synthesis

Dipeptide

PRIMARY AND SECONDARY STRUCTURE

Primary structure is a simple linear chain of amino acids.

Secondary structure – Protein molecules become twisted due to peptide bonds.

H-bonds create either a spring like shape called an alpha helix or a more linear shape called a beta pleated sheet.

TERTIARY AND QUATERNARY STRUCTURE

As an alpha helix becomes longer, some amino acids do not fit in the configuration.

This causes kinks in the spiral pattern so that portions of the helix are close together and form more H-bonds, creating a globular shape.

Quaternary structures are groups of tertiary structures (haemoglobin).

PRIMARY, SECONDARY, TERTIARY, QUATERNARY STRUCTURE

DEHYDRATION SYNTHESIS AND HYDROLYSIS

Dehydration synthesis (as seen a few slides back) is when a water molecule is removed from two amino acids and they form a peptide bond to make a dipeptide.

Hydrolysis is the exact opposite, where when water is added, the dipeptide breaks apart into two amino acids.

FUNCTION IN LIVING ORGANISMS

Proteins are used in the cell as enzymes, which catalyze chemical reactions.

Proteins are necessary in animals’ diets, since animals cannot synthesize all the amino acids, they need and must obtain essential amino acids from food.

Many proteins are involved in the process of cell signaling and signal transduction.