From the vector labeling worksheet, how is the selectable marker identified? Is a selectable marker different from an antibiotic resistance gene?

This, unfortunately, requires a little additional knowledge of what the many abbreviations on a vector map mean. The link below has a list of antibiotic resistance genes. Note: antibiotic resistance genes are selectable markers, but not all selectable markers are antibiotic resistance genes (ex: ccdB, URA3). https://blog.addgene.org/plasmids-101-everything-you-need-to-know-about-antibiotic-resistance-genes

How do you identify a promoter on a vector map?

Usually, the feature name will include “promoter”. However, sometimes the common ones are just abbreviated. Here are two links to tables of common promoters https://blog.addgene.org/plasmids-101-the-promoter-region  https://blog.addgene.org/plasmids-101-inducible-promoters. Another way to find the promoter is to check the features upstream of the MCS and terminator sequences.

So… screenable markers are a must-have in a cloning vector and optional on an expression vector?

That is correct! Screenable markers take up space on a vector, and can have some minor deleterious effects, so it is “cleaner” to keep them off of expression vectors.

What is a feature?

(In a plasmid) A feature is a sequence of DNA that has a function – it could encode a gene, a primer binding site, a promoter, to name a few.