2.1 Flashcards
Cell elements
Water
Inorganic Ions
Organic molecules
Water
70% of cell mass
Polar molecule
Allows hydrogen bonds to form with each other and with polar molecules or interact with charged ions.
Inorganic ions
1% of cell mass.
Involved in cellular metabolism and play function in cellular function.
Organic molecules
Lipids, carbohydrates, proteins and nucleic acids. (Formed by polymerisation.
90% of dry weight of most cells.
Carbohydrates
Monosaccharides - Main nutrients of cells
Polysaccharides - Energy storing sugars, structural components of cell.
Monosaccharides
(CH20)n is formula.
It is a 3-7 sugar, with most common being a 3-5 sugar.
Sugars with more than 5 can be cyclised form a ring. Exist in alpha or beta.
Linked through dehydration reactions, water is removed. Two sugars linked by glycosidic bond.
Oligosaccharide is few sugars attached, polysaccharides hundreds of thousands.
Polysaccharides
Glycogen and starch.
Composed of glucose molecules in alpha configuration.
Glycogen branching occurs in alpha 1-6 bond.
Starch is made up of amylose (1-4) and amylopectin (1-6) branch.
Function to store glucose
Cellulose
Main structural component of cell wall of plant cells.
Composed of glucose molecules.
Beta confirmation - not branched polysaccharide.
B(1-4) bonds
Other functions of carbohydrates
Cell signaling
Markers of the cell surface
Lipids
Simplest lipid are fatty acid. Non polar.
Hydrophobic nature responsible for behaviour of complex lipids.
Fatty acids stored in form of triglycerides - 3 fatty acids, 1 glycerol.
Triglycerides accumulate as fat drop in cytoplasm.
More efficient storage than carbohydrates.
Phospholipids
Made up of 2 fatty acids and a polar head group contains a phosphate group.
Phospholipids are amphipathic molecules.
Membrane phospholipids are typically phosphoglycerides.
Cell membranes ( glycolipids and cholesterol.
Glycolipids are composed of hydrocarbon chains linked to polar heads.
Cholesterol consists of 4 hydrophobic hydrocarbon rings.
Both are amphipathic.
Nucleic acids
DNA and RNA are polymers of nucleotides.
Nucleotide = nitrogenous base, sugar and a phosphate.
Purines = adenine, guanine
Pyrimidines = cytosine, thymine, uracil
Polymerisation of nucleotides to form nucleic acids involves formation of phosphodiester bond between 5’ phosphate and 3’ OH of next.
Different nucleotides
Oligonucleotides -small polymers that contain few nucleotides.
Polynucleotides - contains multiplied nucleotides.
Proteins
Polymers of amino acids.
Every amino acid has carboxyl group and amino group.
Channel properties are defined by nature of R.
Non polar amino acids - located inside proteins.
Polar amino acids - hydrophilic and outside of protein
Basic and acidic - very hydrophilic - surface of proteins.
Amino acids linked by peptide bonds - polypeptides are linear chains.
