Biology Final

BIO411 with Paul Tsang

What property prevents the ligands of cell-surface receptors from entering the cell?

The molecules are hydrophilic and cannot penetrate the hydrophobic interior of the plasma membrane.

Why are ion channels necessary to transport ions into or out of a cell?

Ions are charged particles and cannot diffuse through the hydrophobic interior of the membrane.

Endocrine signals are transmitted more slowly than paracrine signals because ___________.

the ligands are transported through the bloodstream and travel greater distance

Which of the following components is not involved during the formation of the replication fork?

ligase

Which of the following does the enzyme primase synthesize?

RNA primer

In which direction does DNA replication take place?

5'-3'

Many antibiotics inhibit bacterial protein synthesis. For example, tetracycline blocks the A site on the bacterial ribosome, and chloramphenicol blocks peptidyl transfer. Tetracycline would directly affect?

tRNA binding to the ribosome

Many antibiotics inhibit bacterial protein synthesis. For example, tetracycline blocks the A site on the bacterial ribosome, and chloramphenicol blocks peptidyl transfer. Chloramphenicol would directly affect?

growth of the protein chain

How many nucleotides are in 12 mRNA codons?

36

Which pre-mRNA processing step is important for initiating translation?

7-methylguanosine cap

In any given species, there are at least how many types of aminoacyl tRNA synthetases?

20

Prokaryotic cells lack a nucleus. Therefore, the genes in prokaryotic cells are:

b and c are both true

The binding of ________ is required for transcription to start.

RNA polymerase

What will result from the binding of a transcription factor to an enhancer region?

increased transcription of a distant gene

What are the sites of translation

ribosomes