Cellular and molecular engineering

Primary structure of DNA is represented by the:

• single chain resulting from nucleotides polymerization

• double chains linked by hydrogen bonds    

• single chain resulting from amino acids polymerization

• double chains linked by disulfide bonds    

The double helix DNA is:

•  polycationic

• polyanionic

• neutral

• not electric charged

Secondary DNA structure is represented by:

• association of the 2 chains by hydrogen bonds

• association of the 2 chains by disulfide bonds    

• association of the 2 chains by phosphodiester bound

• association of the 2 chains by covalent bonds

DNA can be denatured using:

• temperature

• pH

• urea

• all the statements

In eukaryotes, DNA is associated with:

• histone and form chromatin fiber

• glucose and form chromatin fiber

• collagen and form chromatin fiber

• is not associated with proteins

Protein are composed from:

• fatty acids

• nucleotides

• carbohydrates

• amino acids

Amino acid is an amphoteric substance ( ampholyte), that means:

• can behave either as an acid or as a base

• can behave only as an acid

• can behave only as a base

• amino acids are not ampholytes

⍺-helix and β-sheet are elements corresponding to:

• primary structures

• secondary structures

• tertiary structures

• quaternary structures

Identical or different polypeptide chains (subunits) assemble through non-covalent interactions to form a supramolecular structure with biological function is the definition for:

• primary structures

• secondary structures

• tertiary structures

• quaternary structures

Enzymes are:

• proteins

• carbohydrates

• nucleotides

• lipids