How does a T-cell recognize a cell infected by a virus? Select one:

Binding of _______ to _______ in DNA can increase the rate of transcription of specific genes. a. activators; repressors c. repressors; operators b. activators; enhancers d. repressors; enhancers

Control of gene expression in eukaryotic cells occurs at which level(s)? a. only the transcriptional level b. epigenetic and transcriptional levels c. epigenetic, transcriptional, and translational levels d. epigenetic, transcriptional, post-transcriptional, translational, and post-translational levels

Figure 15.16 Many antibiotics inhibit bacterial protein synthesis. For example, tetracycline blocks the A site on the bacterial ribosome, and chloramphenicol blocks peptidyl transfer. What specific effect would you expect each of these antibiotics to have on protein synthesis? Tetracycline would directly affect: tRNA binding to the ribosome ribosome assembly growth of the protein chain Chloramphenicol would directly affect tRNA binding to the ribosome ribosome assembly growth of the protein chain

What property prevents the ligands of cell-surface receptors from entering the cell? The molecules bind to the extracellular domain. The molecules are hydrophilic and cannot penetrate the hydrophobic inferior of the plasma membrane. The molecules are attached to transport proteins that deliver them through the bloodstream to target cells. The ligands are able to penetrate the membrane and directly influence gene expression upon receptor binding.

Which of the following is an example of positive control? (a) transcription occurs when a repressor binds to an inducer (b) transcription cannot occur when a repressor binds to a corepressor (c) transcription is stimulated when an activator protein binds to DNA (d) a and b (e) a and c

The Adaptive Immune Response Is a Specific Defense Against Infection Describe the genetic basis of antibody diversity.

A binding site for RNA polymerase is called a ________. a. gene c. codon b. promoter d. protein

Complement proteins function in defense by _______. a. neutralizing toxins b. enhancing resident bacteria c. promoting inflammation d. forming pores that cause pathogens to disintegrate e. both a and b f. both c and d

The binding of _____ is required for transcription to start. a protein DNA polymerase RNA polymerase a transcription factor