Restriction enzymes: weld together fragments of dna attach to dna molecules at specific sites and cut both strands of dna at that place only cut rna molecules at specific sites and cut both strands of dna at that place are chemical machines that make parts of the cell membrane.

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.