What happens if glycoproteins are absent?

Solution:

Glycoproteins refer to proteins that have sugar attached to them. They are always found on the outside of the plasma membrane. 

Glycoproteins are involved in many processes of the cells. They play a role in our immune system, protection of our body, communication between cells, and reproductive system. So, if glycoproteins are absent, our immune system will get weakened. There would be no protection of the body from invading foreign bodies. Cell miscommunication will happen.