Biomolecules Flashcards
Glucose- use
- Hexose sugar (Monosaccharide)
- Oxidation of glucose provides energy to the cell
Ribose- use
- pentose sugar (Monosaccharide)
- synthesis of RNA nucleic acid
Deoxyribose- use
- Pentose sugar (Monosaccharide)
- Synthesis of DNA nucleic acid
Maltose
- Disaccharide
- Reducing sugar
- Occurs in plants as a product of starch
- Melting point is 135 degree celsius
Lactose
- Disaccharide
- Reducing sugar
- called milk sugar
- animal origin, formed as 5% in milk of mammals
Sucrose
- Disaccharide
- Non-reducing sugar
- Called table sugar. Principal disaccharide of higher plants.
- Forms colourless crystals and melting point is 160 degree celsius
Glycogen
- Polysaccharide
- Reserve carbohydrate seen in animals
- Stored in liver and muscles
Starch
- Polysaccharide
- Major fuel store in plants
- Sugar is converted to starch during photosynthesis
- Found in cereals, rice and wheat
Cellulose
- Polysaccharide
- Structural polysaccharide in plants
- Forms the cell wall in plants
Inulin
- Polysaccharide
- Muco-polysaccharide seen in plants
- Polymer of fructose and seen in tubers
Chitin
- Polysaccharide
- Structural polysaccharide
- Forms the fungal cell wall and exoskeleton of insects and shells of crustaceans
Fundamental building blocks of proteins
The fundamental building blocks of proteins are amino acids.
All proteins that exist in living beings are constructed from 20 amino acids
Primary structure (Proteins)
- It is the number and sequence of amino acids held together by peptide bonds in a polypeptide chain
- The sequence of amino acids of a protein indicated its biological function
- It is strictly controlled by the sequence of bases in a DNA.
Secondary Structure (proteins)
- It indicates the shape of the polypeptide chain
- The bonding of amino acids could lead to pleating or folding of protein chain
- The two main secondary structures exhibited by proteins are:
1. Alpha-helical structure. Example- Keratin (seen in nails, hair, claws, wool, feathers etc.)
2. Pleated structure. Example- Silk fibrion (protein used by silkworm to make their cocoon)
Tertiary structure (proteins)
- Super-folding of proteins yield intricate spheres and globules
- E.g. Myoglobin- acts as catalytic and carrier molecules
Quaternary structure (proteins)
Aggregate of multiple polypeptides to form a single functional protein
E.g. enzymes and haemoglobin
Functions of proteins
- Repair and maintenance of body, carries out transportation and storage of molecules
- Major source of energy
- Act as enzymes, antibodies and creates hormones
Essential amino acids
- They are not biosynthesized in the body
- They have to be included in the diet
Examples- the 9 essential amino acids are- Valine, Leucine, Isoleucine, Threonine, Tryptophan, Lysine, Methionine, Phenylalanine, and Histidine.
(PVT TIM HaLL)
Adults need to obtain only 8 of them. The 9th amino acid- Histidine is only essential for infants
Non-essential amino acids
- They are biosynthesized in the body
- May be included in the diet also
Examples- the 11 non-essential amino acids are ‘Almost Always All Girls Go Crazy After Getting Taken Prom Shopping’ which stands for Alanine, Asparagine, Arginine, Glutamate, Glutamine, Cysteine, Aspartate, Glycine, Tyrosine, Proline and Serine.
Lipids
- Lipids (triglycerides) have a glycerol molecule (head) and three fatty acids (tail)
- Seen in butter, vegetable oil, avocado etc.
- The enzyme lipases help in breaking down these fatty acids and energy is released
Fats
- Simple lipids
- Esters of fatty acid with glycerol
- Solid at room temperature
Oils
- Simple lipids
- Esters of fatty acid with glycerol
- Liquid at room temperature
Waxes
- Simple lipids
- Esters of fatty acids other than glycerol
- Solid at room temperature
Phospholipids
- Compound lipids
- Lipids with fatty acids, glycerol, A PHOSPHORIC ACID, nitrogen bases and certan substitutes like lecithin, cephalins etc
Glycolipids
- Compound lipids
- Lipids with fatty acids, glycerol, carbohydrates, nitrogen bases and substitutes like gangliosides etc.
Steroids
- Derived lipids
- Cholesterol is the principal sterol seen in animal tissues (nerve tissues).
- It is a precursor of bile salts, Vitamin D3 (write 3 as subscript), and hormones like testosterone and progesterone
Carotenoids
- Derived lipids
- It is exclusively of plant origin
- Due to the presence of conjugated double bonds, they are coloured red or yellow
Functions of lipids
- Lipids are very rich in calorific value
- Fats are stored as reserve food material in adipose tissues and creates heat insulation
- Lipids are structural components of membranes
- Some lipids like cholesterol maintains the fluidity of the cell membrane and also helps in the synthesis of hormones and vitamins
What are enzymes?
Enzymes:
1. act as biological catalysts.
2. accelerate the rate of a reaction but do not themselves undergo any change.
3. are active in very small quantities
4. are very specific in nature
Simple proteins
Proteins with only amino acids
Conjugated proteins
Proteins with attached non-protein groups/co-factor
- Apoenzyme (protein only)
- Holoenzyme (protein + co-factor)
Co- factor:
Inorganic- metal ion
Organic- Prosthetic group/co-enzyme
Oxidoreductases
Reaction catalysed: Transfer of hydrogen and oxygen atoms or electrons from one substrate to another
Examples: Dehydrogenases, Oxidases
Transferases
Reaction catalysed: Transfer of a specific group (a phosphate or methyl etc.) from one substrate to another
Examples: Transaminase, Kinases
Hydrolases
Reaction catalysed: Hydrolysis of a substrate
Examples: Estrases, Digestive enzymes
Isomerases
Reaction catalysed: Change of the molecular form of the substrate
Example: Phospho hexo isomerase, Fumarase
Lyases
Reaction catalysed: Nonhydrolytic removal of a group or addition of a group to a substrate
Example: Decarboxylases, Aldolases
Ligases (Synthetases)
Reaction catalysed: Joining of two molecules by the formation of new bonds
Examples: Citric acid synthetase
Factors affecting enzyme activity
- Temperature (30 degrees celsius to 50 degrees celsius)
- Substrate concentration
- pH (4 to 9)
- Competitive inhibitors
Competitive inhibition
The inhibitor molecule is structurally similar to the substrate and blocks the active site of the enzyme, thus inhibiting the formation of E + S complex.
