Not so. The Church declared it position as early as c. AD 53–54 (early enough for you, ealgeone??) in 1 Corinthians, esp. Chapter 11, v.27-29 where it deals with eucharistic sacrilege in this way: "Whoever eats the bread or drinks the cup of the Lord in an unworthy manner will be guilty of sinning against the body and blood of the Lord."
No. The Roman Catholic understanding of transubstantiation is not supported in 1 Corinthians 11:27-29 as that came about much later as noted.
Nor is the concept of Jesus being brought down from Heaven and rendered on the altar over and over and over again not supported in the New Testament as previously demonstrated.
If by "rendered" you mean "sacrificed," this is not what the Mass is and this is not what the Church teaches. Christ's sacrifice happened ONCE at Calvary, ca. 33 AD. Christ is not re-sacrificed.
If you want to understand Catholic Doctrine, I strongly recommend your first reference should be the Catholic Catechism.
1367 The sacrifice of Christ and the sacrifice of the Eucharist are one single sacrifice: "The victim is one and the same: the same now offers through the ministry of priests, who then offered himself on the cross; only the manner of offering is different." "And since in this divine sacrifice which is celebrated in the Mass, the same Christ who offered himself once in a bloody manner on the altar of the cross is contained and is offered in an unbloody manner. . . this sacrifice is truly propitiatory."
This was very easy to locate in the Catechism, which is in searchable form online. I urge you to check it out. These are the results from using the keywords one sacrifice (LINK)
There are a number of very interesting parallel passages there.
That would be your first step.