If by "four chemicals" you mean nucleotides, then they are as follows:
1. deoxyadenosine monophosphate or adenine
2. deoxyguanosine monophosphate or guanine
3. deoxycytosine monophosphate or cytidine
4. deoxythymine monophosphate or thymidine
The chemical bonds holding DNA molecules together are
1. phosphodiester bond in the polynucleotide strand
2. hydrogen bond between the complementary nitrogenous bases on adjacent polynucleotide strands.
Four heme groups, so I think four molecules of oxygen can be transported by one molecule of haemoglobin.
The bonds are ionic or covalent.
Within the molecule it is the covalent bonds which hold the atoms together. The facts that the molecule is polar or that the substance is in the solid state are irrelevant. If you were trying to ask what holds the molecules together to make the solid, then it is dipole-dipole forces and van der Waals forces.
Hydrogen bonds (two between adenine and thymine, and three between guanine and cytosine).
The following are the four universal forces: gravity, weak force, electromagnetic force, strong force. Out of these four, the strong force plays the largest part in holding atoms together.
Covalent bonds hold a dextrose molecule together.
True
No, they do not hold two compounds together. The forces that hold compounds together are intermolecular forces. Ionic and covalent bonds are intramolecular forces, and they hold the atoms of the molecule or formula unit together.
Covalent bonds
generally covalent bonding
intermolecular forces examples are dispersion forces
Covalent bonds
Four heme groups, so I think four molecules of oxygen can be transported by one molecule of haemoglobin.
Bonds hold atoms together. There are hydrogen bonds, ionic bonds, and covalent bonds.
s-s bridge or disulfide bond
Covalent bonds
The bonds are ionic or covalent.