Final answer:
The TATA box and promoter-proximal elements like the CAAT and GC boxes are found near eukaryotic transcription start sites, important for binding of transcription factors and RNA Polymerase II.
Step-by-step explanation:
The two elements that appear near eukaryotic transcription start sites are the TATA box and promoter-proximal elements such as the CAAT box and GC box. The TATA box is a DNA sequence motif typically located around 25-35 bases upstream of the transcription start site. This sequence is crucial for the binding of transcription factors and the initiation of transcription by RNA Polymerase II. The box aids in unwinding the DNA due to the low thermostability of A-T bonds. Promoter-proximal elements, including the CAAT box with consensus sequence 5'-CCAAT-3' and the GC box with consensus sequence 5'-GGGCGG-3', are usually found within a few hundred base pairs upstream of the transcriptional start site and bind specific transcription factors that regulate gene transcription.