02. Chemical and Cellular Basis of Life [DEFINITIONS] Flashcards
Polarity
polarity is an uneven charge distribution within a molecule.
Hydrogen Bonds
Weak attractions between the slightly polar hydrogen atom of one water molecule and the slightly polar oxygen atom of the adjacent water molecule are known as hydrogen bonds.
Cohesion
Attraction between water molecules due to hydrogen bonding is known as cohesion
Adhesion
Attraction between water molecules and other substances
Carbohydrates
Carbohydrates are the most abundant group of organic compounds on earth with a major elemental composition of C, H, and O.
Hydrates of carbon contain the same proportion of H:O which equals to 2:1 as in water.
The general formula of carbohydrates is Cx(H20)y
Monosaccharides
The simplest form of carbohydrates having the general molecular formula of (CH2O)n are monosaccharides.
Disaccharides
They are the sugars formed by joining two monosaccharides by a glycosidic bond
Glycosidic Bond
A glycosidic bond is formed by the removal of a water molecule from two adjacent monosaccharides by a condensation reaction.
Polysaccharides
They are macromolecules and biopolymers made up of a few hundred to a few thousand monosaccharide subunits.
Lipids
Lipids are a diverse group of large hydrophobic molecules which are biological molecules but not considered as polymers or macromolecules.
They consist of C,H,O and H:O ratio is not 2:1. Comparatively more H is present.
Saturated Fats
Fats are made up of saturated fatty acids (fatty acids with hydrocarbons having no double bonds)
Unsaturated Fats
Fats are made up of unsaturated fatty acids (fatty acids with hydrocarbons having one more more double bonds)
Phospholipids
Phospholipids are major components of cells membranes composed of two fatty acids and one phosphate group attached to one glycerol molecule.
Proteins
Proteins
Proteins are made up of amino acids and has an elemental composition of C, H, O, N and S
Primary Structure of Proteins
The unique sequence of linearly arranged amino acids linked by peptide bonds is the primary structure of proteins.
Secondary Structure of Proteins
When the primary structure of a single polypeptide chain coils and folds, as a result of intra molecular hydrogen bonds between the oxygen atoms and hydrogen atoms attached to the nitrogen atoms of the same poly peptide chain backbone to form the secondary structure.
Tertiary Structure of Proteins
Usually the secondary polypeptide chain bends and golds extensively forming a precise compact unique, functional and three-dimensional shape resulting from the interactions between the side chain/R-group of amino acids.
Quaternary Structure of Proteins
The aggregation of two or more polypeptide chains involve in the formation of one functional protein. Separate chains are called sub units which were held together by inter and intra-molecular bonds.
Denaturation of Proteins
Denaturation of proteins is the loss of its specific chemical three dimensional shape due to the alteration of weak chemical bonds and interactions.
Nucleic Acids
Nucleic acids are polymers that exist as polynucleotides made up of monomers called nucleotides containing C,H,O,N and P
Base Pair Rule
Always a purine base, pairs with a specific pyrimidine base
RNA
This is normally a single stranded nucleic acid composed of ribonucleotides containing the bases Uracil (U), Cytosine (C), Guanine (G), Adenine (A)
Messenger RNA
Messenger RNA is a linear molecule and is the least abundant type of RNA in a cells comparatively.
Transfer RNA (tRNA)
This is the smallest RNA molecule which is linear, but forms a three-looped structure.
Ribosomal RNA (rRNA)
It is the most abundant type of RNA. rRNA has a complex irregular structure and provides a site where polypeptide chains are assembled.
Magnification
Magnification is the ration of an object’s image size to its actual size.
Resolution
Resolution power is the minimum distance between two points that can be distinguished as separate points. It is a measure of the clarity of the image.
Total Magnification
Total magnification is the product of the magnification of each lens.
Transmission Electron Microscope
It’s used to study the internal structures of cells. In this microscope, a beam of electrons is passed through a thin, especially prepared slice of material.
Scanning electron microscopes
In this instrument, a fine beam of electrons is reflected from the surface of specimen.
Scanning electron microscopes
In this instrument, a fine beam of electrons is reflected from the surface of specimen.
Cell Theory
- All organisms are composed of one or more cells
- The basic structural and functional unit of organisms is the cells.
- All cells arise from pre-existing cells.
Plasma Membrane
The plasma membrane is the outer limit of the cytoplasm.
It is mainly composed of 1. phospholipids (the most abundant type of lipid in plasma membrane)
2. protein
Peripheral Proteins
Some proteins are not embedded in the lipid bilayer at all, and are loosely bound to the inner surface of the membrane, called peripheral proteins.
Subcellular Components
There are many subcellular components in the cell. Some of them are organelles, which are bound by membranes and suspended in the cytosol of eukaryotic cell to perform specialized functions.