Intro to Biochem Flashcards
What are the three main components of feedstuffs?
Carbohydrates, proteins and fats
Define CARBOHYDRATES
A carbohydrate is a group of substances used as both energy sources and structural materials in organisms. All carbohydrates contain carbon, hydrogen and oxygen.
General formula:
Cn(H2O)n
What are the three main groups of carbohydrates?
Monosaccharides (simple sugars)
Disaccharides (double sugars, formed of two monosaccharides)
Polysaccharides (large molecules formed of many monosaccharides)
Define GLUCOSE
A monosaccharide. It is the major energy source for most cells.. Highly soluble and the main form in which carbohydrates are transported around the body.
Two types: alpha and beta
Define FRUCTOSE
A monosaccharide. The second most important one after glucose.
Define MONOSACCARIDES
A monosaccharide is the simplest type of carbohydrate. Can serve alone or as part of a larger structure (di or polysaccharides)
Molecular formula: CH2O
Examples: glucose, fructose
Define DISACCHARIDES
A disaccharide is a double sugar, formed of two monosaccharides joined by dehydration synthesis.
The stronger the link between the two single units, the harder it is to break down/digest.
Examples: lactose, sucrose, maltose
Define POLYSACCHARIDES
A polysaccharide is a polymer of up to one thousnad monosaccharide molecules, formed by dehydration reactions.
Examples: storage; starch and glycogen
structural; cellulose
Define RESPIRATION
Respiration is the process of converting stored energy. The bonds in glucose are broken down the form carbon dioxide and water. The break down of glucose occurs in steps and each step is driven by enzymes. Plants and animals are only able to break down alpha glucose, and therefore it is the one used in respiration.
Define GLYCOGEN
Glycogen is an extensive branched glucose storage molecule found in the muscle and liver of animals. Broken down more rapidly than starch.
What is cellulose? How is it broken down in the horse?
Celluose is a polysaccharide that is the main component of plant cell walls. Contains long chains of beta glucose molecules. Cannot be broken down by the horse - instead it is broken down by microbiota in the caecum that are able to produce cellulase.
What is the general structure of an amino acid?
- a basic amino group
- an acidic carboxyl group
- organic R group
How many natural amino acids are there?
20 natural amino acids
Define an INDISPENSIBLE AMINO ACID
An indispensable amino acid is one that cannot be synthesised from scratch and therefore must be supplied in its diet.
Name the 3 key amino acids and describe them
- lysine - promotes bone growth in foals and enhances growth and nitrogen balance. Often in shortest supply in horse feeds.
- phenylalanine - produces both adrenaline and noradrenaline. It is an antidepressant.
- valine - regulates protein turnover and energy metabolism. Vital for muscle coordination
Define DEAMINATION
Deamination is the removal of the amine group in the liver, as the horse cannot store excess amino acids. Too much protein = too much excretion.
Define POLYPEPTIDES
Polypeptides are long chains of many amino acids linked together by peptide bonds.
Define PROTEASES
Proteases are enzymes that catalyse the reaction that breaks down peptide bonds. An example is trypsin.
Define LIPIDS
Lipids are fats. They are an excellent energy reserve due to many carbon-hydrogen bonds.
What is the composition of a fatty acid?
- have a carboxyl group at one end
- rest of the molecule is a hydrocarbon
- the hydrocarbon chain can be anywhere from 15-18 carbons long
- they may be saturated (no double bonds) or unsaturated (double bonds)
How are fats used in respiration?
- first comes the hydrolysis of the ester bonds holding the fatty acid and the glycerol together
- this hydrolyses the lipid to its glycerol and fatty acid components
- releases energy which is used to generate ATP
What is formed when alpha glucose molecules join together?
They form long, coiled chains. Amylose is formed from chains of alpha glucose.
What is formed when beta glucose molecules join together?
They form long, straight chains, used in the structural roles of plants. Cellulose is formed from chains of beta glucose.
Define AMINO ACIDS
An amino acid is an organic molecule possessing both carboxyl and amino groups. Amino acids are the monomers of proteins. May be positively or negatively charged and may be hydrophilic or hydrophobic.
