why proteins or glucose can be found in urine!

Usually, small amounts of glucose and proteins are present in human urine. The glucose and proteins come from blood.

In digestion, carbohydrates and proteins are broken down into monosaccharides (e.g. glucose and fructose) and amino acids. The absorbed amino acids would re-combine into proteins in human body. Human’s blood contains glucose and proteins.

The formation of urine can be divided into three processes: filtration, reabsorption, and secretion. Urine formation begins with the process of filtration, which goes on continually in the renal corpuscles. As blood courses through the glomeruli, much of its fluid, containing both useful chemicals and dissolved waste materials, soaks out of the blood through the membranes (by osmosis and diffusion) where it is filtered and then flows into the Bowman's capsule. This process is called glomerular filtration. The water, waste products, salt, glucose, proteins (a very small amount) and other chemicals that have been filtered out of the blood are known collectively as glomerular filtrate. Urine finally formed thus contains glucose and a very small amount of protein.
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ultrafilteration is better than using the word "filteration"