Biochemistry: Carbohydrates

• This chapter explains important compounds in the context of biochemistry

Carbohydrates

• Carbohydrates stand out as the most abundant type of organic compound
• General Formula: Cx(H2O)y
• Plants synthesize carbohydrates through photosynthesis
• Chemical equation: 6H2O(l) + 6CO2(g) → C6H12O6 (aq) + 6O2(g)
• Plants transforms glucose into starch and cellulose
• Carbohydrates consist of both monomers and polymers of aldehydes and ketones, featuring multiple hydroxyl groups
• World population growth increases the demand for food
• New methods and techniques are used to grow more crops
• Protein deficiency can cause physical and mental disabilities
• Excessive fat intake might trigger cardiovascular diseases, stroke, cancer, diabetes, etc
• Nutritional chemists suggest that the daily caloric intake from fat should not exceed 30%
• Healthy crops, fruits and vegetables are necessary for proper growth and health
• Agricultural and nutritional sciences are vital for us.

Carbohydrate Classification

• Carbohydrates are classified as:
• Monosaccharides
• Oligosaccharides
• Polysaccharides

Monosaccharides

• Monosaccharides are the most simple carbohydrates, which means they cannot be hydrolyzed
• General formula: (CH2O)n, where n is between 3-6 carbon atoms
• Monosaccharides contain between 3-6 carbon atoms
• Further categorized as trioses, tetroses, pentoses, hexoses, according to carbon atoms
• Two familiar monosaccharides are:
• Glucose: an aldohexose containing an aldehyde group
• Fructose: a ketohexose containing a ketone group
• Monosaccharides are glucose and fructose, both sharing the molecular formula C6H12O6
• Glucose is a pentahydroxy aldehyde, while fructose is a pentahydroxy ketone
• They are called simple sugars
• Some monosaccharide molecules can rotate plane polarized light to the right (clockwise); also called dextro-rotatory or dextrose sugars
• Glucose, mannose, and galactose are dextrose sugars
• Monosaccharides are white crystalline solids that can dissolve in water, have a sweet flavor, cannot be hydrolyzed and are reducing in nature

Oligosaccharides

• Carbohydrates undergoing hydrolysis produce 2-10 molecules of monosaccharides or simple sugars.
• Depending on the number of monosaccharide units from hydrolysis, the units are clarified as disaccharides or trisaccharides
• Prefixes like di, tri, and tetra indicate the count of monosaccharide units produced upon hydrolysis
• Oligosaccharides are white crystalline solids with a sweet flavor, and can dissolve in water
• 5%m/v aqueous solution of dextrose is used in IV drips for patients severely dehydrated or unable to eat on their own

Polysaccharides

• Hydrolysis leads to carbohydrates forming hundreds to thousands of simple sugar units and are called polysaccharides
• Starch and cellulose are polysaccharides
• Polysaccharides exist in the form of amorphous solids, are tasteless and insoluble in water, and do not have reducing properties

Sources and Applications of Carbohydrates

• Carbohydrates, the most abundant carbon based compounds, exist in varied sources
• Monosaccharides like glucose, fructose, and galactose come from fruits, vegetables, honey, and cereals
• Disaccharides like sucrose are found in sugarcane, sugar beet, and fruits, while maltose is present in cereals, and lactose is the primary sugar in milk/dairy
• Cellulose comes from plants such as cotton
• Starch is in cereals like wheat, barley, rice, maize, potato, and sweet potato
• Carbohydrates' uses include:
• Storing and transporting energy in plants and animals, providing 15.6 KJ of energy per gram
• Serving as a food source for organisms
• Acting as a structural material for plants
• Cellulose, a fiber in the human diet, supports intestinal movement, absorbs harmful food chemicals, lowers cholesterol, and regulates blood pressure
• Sucrose as common table sugar
• Storing animal muscle and liver cells as glycogen, working as a long-term energy reserve
• Storing plant energy as starch
• Producing rectified spirit through starch fermentation and dextrin as an adhesive in stamps and wallpaper glue
• Providing cow, cattle, goat, deer, sheep, and termite nutrition through cellulose

Other Uses of Carbohydrates

• Cellulose functions as wood for heat, shelter, and furniture
• Wood creates paper and wood pulp
• Cotton cellulose fiber creates rayon and cellulose acetate for the textile industry

Proteins

• Proteins is a major food class
• The body contains tens of proteins, with key functions
• Transporting oxygen and nutrients
• Catalyzing reactions
• Regulating systems in our bodies
• Proteins are high molecular weight polymers; therefore all proteins produce amino acids that generate amino acids following their complete hydrolysis

Amino Acids

• Amino acids are the building blocks of proteins that have two functional groups
• There are twenty amino acids involved in protein synthesis; only ten can be synthesized by human bodies
• Non-essential amino acids are synthesized by the body, while essential amino acids must be taken from diet
• Amino acids are joined through amino (-NH2) and carboxyl (-COOH) groups, through the elimination of water forming a peptide bond
• The linkage that joins two amino acid units is called a peptide bond
• A dipeptide is the resulting molecule with an amino group on the left and a carboxyl group on the right
• Thousands of amino acid units join to form a large protein molecule.

Protein Sources and Functions

• Animal based proteins contain all the essential amino acids in adequate amounts: meat, fish, eggs, milk, and cheese
• Plant-based proteins also provide crucial nutrients: pulses and beans
• Most growth occurs in the initial 2 years of life, with the brain nearly reaching its full size by this age
• Protein deficiency can lead to physical and mental retardation
• Proteins are essential for creating the amino acids needed for muscle growth, hair development, enzyme production, and tissue repair
• Essential for cell formation
• Essential for both physical and mental growth, particularly for children
• Gelatin, derived from heating bones and tendons in water, provides valuable applications in bakery products
• Enzymes catalyze specific biological reactions necessary for life
• Antibodies are large protein molecules that help us fight disease

Enzymes

• Enzymes are large protein molecules that are biological catalysts; as a result, they catalyze chemical reactions in organisms
• Enzymes' commercial uses range from producing sweeteners, chocolate syrup, bakery items, infant foods and detergents for stain removal
• They support cheesemaking, assist the paper and pulp sectors to eliminate stickiness and assist in textile manufacturing
• Enzymes like diastase, invertase, and zymase help ferment molasses and starch to produce ethanol
• Amylase is beneficial in baking bread
• Proteases coupled with amylase serve as cleaning agents helping remove stains from clothing
• Lactase benefits infant nutrition

Lipids

• A lipid is any component of plant or animal tissue that is insoluble in water
• Solvents that have low polarity are required: ether, hexane, benzene and carbon tetrachloride
• Lipids include:
• Fats and oils
• Cholesterol
• Sex hormones
• Components of cell membrane called phospholipids
• Some vitamins (A, D, E and K)

Fatty Acids

• Fats and oils, or simple lipids, consist of esters of fatty acids combined with glycerol, a trihydroxy alcohol
• Consequently, they are named glyceryl esters or glycerides
• Fatty acids are long chain carboxylic acids: stearic acid (C17H35COOH)
• A lipid is identified as fat if it is a solid state at room temperature
• A lipid is an oil whenever it remains in a liquid state when kept at room temperature
• Melting point differences depend on saturation levels found within individual fatty acids
• Fats contain a higher proportion of saturated fatty acid units
• Oils contain a higher amount of unsaturated fatty acid units

Lipid Sources and Applications

• Animals, plants, and marine life have abundant lipids; salmon and whales have rich sources
• Milk provides dairy animals with quality animal fats to produce butter, ghee, and cheese
• Several plant species house significant amounts of seeds with lots of sunflower, corn, cotton, groundnut/coconut and olive oils
• Cod liver oil exists within salmon and whales
• Butter, ghee, and vegetable oils allow individuals to prepare baked goods and cook/fry foods
• In mammals, a layer of fat keeps the body insulated
• Fats safeguard organs against trauma and injury
• Lipids feature essential vitamins such as A, D, and E, though these nutrients can only be soluble in lipids themselves

Important Facts About Lipids, Fats and Oils:

• Fats and oils act as key energy reserves
• They produce more energy for each unit of mass than carbohydrates
• Vegetable oils become vegetable ghee when through catalytic hydrogenation
• Fats and oils are important in the manufacture of soaps, detergents, cosmetics, varnishes and paints
• Cholesterol is important for creating stress hormones, vitamin D and bile acids
• Flax seed consumption in hens decreases cholesterol amounts in eggs
• Insulin, a protein encoded by DNA, regulates glucose utilization and is generated through bacterium

Nucleic Acids

• Nucleic acids are vital components vital to life and serve as information and control centers composed of nucleotides
• Every nucleotide houses 3 components
• A nitrogenous base
• A pentose or five carbon sugar
• A phosphate group
• Nucleic acids are of two types: deoxyribonucleic acid and ribonucleic acid
• DNA stores and shares every piece of genetic data necessary for creating organisms; humans utilize a single cell to transmit the information for developing various body parts
• J. Watson and F. Crick discovered the spiral formation of DNA in 1953
• DNA exists as two twisted strands forming into a double helix shape
• Every strand comprises deoxyribose sugars, phosphate units and a nitrogen base that get strengthened via hydrogen molecules
• DNA contains strands of base pairs that act like information codes required to synthesize proteins

RNA

• RNA remains in a form having just one strand with sugar, phosphate and nitrogen base units that are synthesized by DNA to assist the transfer of genetic data and creation of recent proteins
• Genetic information remains in the DNA found within individuals
• DNA samples can identify a sample's source, as well as trace the unique and complete blueprint
• Genetic samples from a known sample remain complete in determining individual origin

Vitamins

• C. Eijkman found that polished rice had components lacking entirely in the rice hull that lead to beriberi, or a nutritional deficiency disease
• Hopkins found that outside of minerals, etc, carbohydrates, fats and proteins also needed certain extra components to sustain a healthy lifestyle
• Funk named this new set of factors “vitamine” and later was changed vitamin due to no amines available
• Vitamins represent dietary factors that facilitate growth
• Vitamin D's deficiency causes bone softening as shown above in fig 13.5 (a) ; (b) displays vitamin B3 causing inflammation and abnormal pigment abnormalities
• Vitamins exist as compounds which our body requires and cannot personally create, though they are critical to health.
• They need to be consumed, along with minerals, etc

Importance of Vitamins

• Vitamins represent key components for our health.
• Vitamin A enables vision while chemically transmitting visual data from eye through brain. It is essential for keeping the cornea in a moist state
• Vitamin C facilitates production of blood, as well as reinforcing mechanisms to defend against ailments ranging anywhere from the prevalent cold to forms of cancer
• Vitamin B helps direct movement of impulses around various nerves, strengthens hemoglobin as well as activates over 100+ enzyme types
• Vitamin D controls blood calcium levels needed for the healthy bone/tooth development
• There are two major types of vitamins - soluble in fat or soluble in water

Fat-Soluble Vitamins

• A fat soluble vitamin dissolves in fat
• Examples are Vitamins A, D, E and K
• Overdosing through fat-soluble vitamins can have harmful effects
• Consuming too much vitamin A stimulates irritability/dry skin, as well causes pressure sensations within somebody’s head
• Overdosing with D vitamins triggers pain or weight losses inside bones, builds strong debris inside both joints and also in kidney sites

Water-Soluble Vitamins

• Water soluble vitamins are able to dissolve through water, such as with vitamins within the vitamin B complex
• If individuals over consume water soluble vitamins, the residue easily gets expelled in the body
• Some naturally produced substances stimulate life through either plants or animals
• These natural substances are known in cosmetics, various tastes, smells, supplements and various dietary choices
• The natural additives used to manufacture certain foods work to raise the colors, aromas or flavoring
• In some foods many compounds become synthesized during manufacture from fruits and other similar plant matter
• Artificial vitamins support the supply for Vitamin C and eliminate instances regarding scurvy and eliminates risks regarding rickets
• Vitamin additives contribute a safeguard to the risks associated to night blindness

Other Information

• Natural products stimulate medicinal production through e.g digitalis, quinone, nicotine Many facilitate the process for effective medication for synthesis purposes
• Chemical structures within microorganisms enhance syntheses with either cephalosporin and various other antibacterial agents
• These products represent important resources to combat diseases
• Sources for Vitamin A include butter or even fish oils
• The origin for various B vitamins stands as a liver product
• Origins for vitamin C derive from tomatoes
• Sources used to obtain vitamin E encompass eggs or grains
• Sources providing vitamin K are known as vegetables
• Monosaccharides are components such as glucose or fructose
• Disaccharides have components of cellulose

An overview of carbohydrates in biochemistry. Includes their general formula and synthesis via photosynthesis. Covers the importance of carbohydrates, proteins, and fats in diet and health. Touches on the role of agricultural and nutritional sciences.