Signal Squad
A cell releases a chemical that travels through the blood and affects cells in the liver. Which type of signaling is occurring?
Endocrine
A hormone is present, but a target cell has no matching receptor. Will the cell respond? Answer yes or no.
No
Put these stages in order: response, reception, signal release, transduction. Which stage comes first?
Signal release
A DNA strand reads 3′-AAATCGAATG-5′. What is its complementary strand in the correct direction.
5′-TTTAGCTTAC-3′
DNA is tightly wound ahead of the replication fork. Which protein relieves the twisting and tangling?
Topoisomerase
Cell A releases a chemical. Only nearby cells respond, while cells across the body do not. Which type of signaling is this?
Paracrine
A steroid hormone passes through the plasma membrane and binds a receptor inside the cell. What receptor type is involved?
Intracellular Receptor
A receptor activates a protein, which activates another protein, which activates another. What type of pathway is this?
Signaling cascade
A scientist replaces every adenine with guanine. Which complementary base-pairing rule is disrupted?
A–T pairing
The DNA strands separate, but their hydrogen bonds keep reforming. Which proteins should prevent them from rejoining?
Single-strand binding proteins
A cell releases a signal, then that same cell responds to it. What type of signaling is occurring?
Autocrine
A signaling molecule binds a membrane receptor, causing a nearby ion channel to open. Which receptor type directly allows ions to cross?
Ion channel-linked receptor
One activated protein causes many downstream molecules to activate. What happens to the signal?
Amplification
Two DNA strands run in opposite directions. One runs 5′ → 3′. Which direction does the other run?
3′ → 5′
DNA polymerase is ready to build a new strand, but there is no starting point. Which enzyme makes the required RNA primer?
Primase
Two cells must physically touch for one to send a signal to the other. Which type of signaling is this?
Juxtacrine
A mutation prevents a receptor from activating its G protein. Which receptor pathway is disrupted?
GPCR
A drug blocks the production of cAMP. Which type of signaling molecule is missing?
Second messenger
A mutation prevents nucleotides from linking the sugar of one nucleotide to the phosphate of the next. Which bond is affected?
Phosphodiester Bond
A drug blocks DNA ligase. DNA polymerase still makes short pieces on the lagging strand, but they remain disconnected. What are these pieces called?
Okazaki fragments
A hormone travels throughout the body, but only one organ responds because its cells have the correct receptor. What determines this selective response?
Receptor Specificity
A cell has functional receptors, but a mutation prevents the receptor from activating its associated enzyme. Which receptor type is most likely affected?
Enzyme-linked receptor
A signal binds its receptor normally, but a mutation blocks the intracellular steps before the cell can respond. Which stage is defective?
Transduction
After replication, each DNA molecule contains one original strand and one newly made strand. What is this replication model called?
Semiconservative
DNA polymerase can only synthesize in the 5′ → 3′ direction. One strand is made continuously, while the other is made in fragments. Name the continuously synthesized strand.
Leading strand