Chapter 9-10, cell signaling, cellular reproduction, mitosis, cell signaling

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

The secretion of hormones by the pituitary gland is an example of?

endocrine signaling

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 distances

Histamine binds to the H1 protein linked receptor to initiate the itchiness and airway constriction associated with an allergic response. If a mutation in the associated G-proteins alpha subunit prevented the hydrolysis of GTp how would the allergic response change?

More severe allergic response compared to normal G-protein signaling

a scientist observes a mutation in the transmembrane region of EGFR(a receptor) that eliminates during dimerization after ligand dbonding. Which hypothesis regarding the effect of this mutation on EGF signaling is most likely to be correct?

EGF signaling cascades would not occur

What is the function of a phosphate?

A phosphate removes the phosphate group from phosphorylated amino acid residues in a protein

Apoptosis can occur in a cell when the cell is?

no longer needed, infected by a virus, damaged

A doctor is researching ways to treat biofilms on artificial joints. Which approach would best help prevent colonization of the medical implants?

Inhibit quorum sensing

A diploid cell has how many number of chromosomes as a haploid cell

Twice

The first level of DNA organization in a eukaryotic cell is maintained by which molecule?

HISTONE

Identical copies of chromatin held together by cohesion at the centromere called

sister chromatids

Chromosomes are duplicated during what stage of the cell cycle

S phase

A mutation gene that codes for an altered version of CDK that is active in the absence of cyclin is an

oncogene

A gene that codes for a positive cell cycle regulator is called an

proto-oncogene

Which negative regulator molecule can trigger cell suicide if a vital cell cycle events do not occur

P53

If the M checkpoint is not cleared, what stage of mitosis will be blocked

anaphase

what is the main prerequisite for clearance at the G2 checkpoint

accurate and complete DNA replication

The fusion of Golgi vesicles at the metaphase plate of dividing plant cells forms what structure

cell plate

which type of molecule acts as a signaling molecule in unicellular Yeasts

Mating factor