The wine doesn't turn to blood and the bread doesn't turn into the flesh of Jesus Christ. Communion is a commemoration of the sacrifice of the "Passover" Lamb. The bread is unleavened which symbolizes the escape from the way of the world. Israel had no time to wait and let the bread rise. The blood is life to the flesh, and by its shedding the fleshly desires will die. Communion then is remembrance to Jesus Christ, Him being the door that is open, allowing all who believe in Him having a way of escape enslavement.
Now the first day of the feast of unleavened bread the disciples came to Jesus, saying unto him, Where wilt thou that we prepare for thee to eat the passover? And as they were eating, Jesus took bread, and blessed it, and brake it, and gave it to the disciples, and said, Take, eat; this is my body. And he took the cup, and gave thanks, and gave it to them, saying, Drink ye all of it;For this is my blood of the new testament, which is shed for many for the remission of sins.(Matthew 26:17, 26-28 KJV)
Moreover, brethren, I would not that ye should be ignorant, how that all our fathers were under the cloud, and all passed through the sea;And were all baptized unto Moses in the cloud and in the sea;And did all eat the same spiritual meat;And did all drink the same spiritual drink: for they drank of that spiritual Rock that followed them: and that Rock was Christ.The cup of blessing which we bless, is it not the communion of the blood of Christ? The bread which we break, is it not the communion of the body of Christ? ( 1 Corinthians 10:1-4 and 16 KJV)