EXAM 2

Which of the following statements is TRUE? Another name for the fertilized egg cell is the zygote Diploid organisms reproduce only sexually Gametes have only one chromosome. All sexually reproducing organisms must have two copies of every chromosome

Another name for the fertilized egg cell is the zygote

Which of the following statements is TRUE? To function, all extracellular signal molecules must be transported by their receptor across the plasma membrane into the cytosol Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior A cell-surface receptor capable of binding only one type of signal molecule can mediate only one kind of cell response. Any foreign substance that binds to a receptor for a normal signal molecule will always induce the same response that is produced by that signal molecule on the same cell type.

Extracellular signal molecules that are hydrophilic must bind to a cell-surface receptor so as to signal a target cell to change its behavior.

Acetylcholine is a signaling molecule that elicits responses from heart muscle cells, salivary gland cells, and skeletal muscle cells. Which of the following statements is FALSE? Active acetylcholine receptors on salivary gland cells and heart muscle cells activate different intracellular signaling pathways. Heart muscle cells, salivary gland cells, and skeletal muscle cells all express an acetylcholine receptor that belongs to the transmitter-gated ion channel family Heart muscle cells, salivary gland cells, and skeletal muscle cells all respond to acetylcholine within minutes of receiving the signal Heart muscle cells decrease their rate and force of contraction when they receive acetylcholine, whereas skeletal muscle cells contract

Heart muscle cells, salivary gland cells, and skeletal muscle cells all express an acetylcholine receptor that belongs to the transmitter-gated ion channel family

Mendels pea plants (P: RRxrr, F1: Rr, F2: RR Rr Rr rr) which is true If you crossed the round-seeded pea plants from the F2 generation with the wrinkle-seeded pea plants from the F2 generation, you should get 100% round-seeded pea plants If you crossed all the round-seeded pea plants from the F2 generation with true-breeding wrinkle-seeded pea plants, you would get more round-seeded pea plants in the next generation than if you crossed all the round-seeded pea plants from the F1 generation with true-breeding wrinkle-seeded pea plants The gene for round-seeded pea plants is on a different chromosome from the gene for wrinkle-seeded pea plants, which is why you get 25% wrinkle-seeded pea plants in the F2 generation The reason you do not see wrinkle-seeded pea plants in the F1 generation is because the round-seeded pea plants used to create the F1generation were not true-breeding strains

If you crossed all the round-seeded pea plants from the F2 generation with true-breeding wrinkle-seeded pea plants, you would get more round-seeded pea plants in the next generation than if you crossed all the round-seeded pea plants from the F1 generation with true-breeding wrinkle-seeded pea plants

Give an example of a 2nd messengers are produced in cell and can pass through membrane

NO

There are organisms that go through meiosis but do not undergo recombination when forming haploid gametes. Which of the following statements correctly describes the gametes produced by such an organism? (Assume that these organisms are diploid, that each of the two homologous chromosomes are genetically distinct as typically found in the wild, and that these organisms have more than one chromosome.) Due to the random assortment of homologs, each of the gametes formed during a single meiosis will be different All gametes formed during a single meiosis will be identical This organism could potentially produce 2n genetically distinct gametes, where n is its haploid number of chromosomes The fusion of any two gametes produced by such an organism that does not undergo recombination during meiosis will create a cell that is genetically identical to that individual

This organism could potentially produce 2n genetically distinct gametes, where n is its haploid number of chromosomes

The growth factor Superchick stimulates the proliferation of cultured chicken cells. The receptor that binds Superchick is a receptor tyrosine kinase (RTK), and many chicken tumor cell lines have mutations in the gene that encodes this receptor. Which of the following types of mutation would be expected to promote uncontrolled cell proliferation? a mutation that destroys the kinase activity of the receptor a mutation that prevents dimerization of the receptor a mutation that inactivates the protein tyrosine phosphatase that normally removes the phosphates from tyrosines on the activated receptor a mutation that prevents the binding of the normal extracellular signal to the receptor

a mutation that inactivates the protein tyrosine phosphatase that normally removes the phosphates from tyrosines on the activated receptor

where are the ligand binding domains on transmembrane proteins

cell surface

During nervous-system development in Drosophila, the membrane-bound protein Delta acts as an inhibitory signal to prevent neighboring cells from developing into neuronal cells. Delta is involved in __________ signaling endocrine paracrine contact-dependent neuronal

contact-dependent

what do enzyme coupled receptors usually regulate 4 things "GPDS"

growth proliferation differentiation survival

Somatic cells... are not necessary for sexual reproduction in all eukaryotic organisms. do not contain sex chromosomes. leave no progeny are used to produce germ-line cells when organisms reach sexual maturity

leave no progeny

are enzyme coupled receptor responses fast

no

do enzyme coupled receptors associate with G proteins

no

Organisms that reproduce sexually create zygotes that are genetically identical to each other must be haploid, unlike organisms that reproduce asexually undergo a sexual reproductive cycle that involves an alternation of haploid cells with the generation of diploid cells can reproduce only with a partner that carries the same alleles

undergo a sexual reproductive cycle that involves an alternation of haploid cells with the generation of diploid cells

are enzyme coupled receptors often multistep

yes

can some enzyme coupled receptor responses lead to changes in shape and movement

yes

do enzyme coupled receptor responses usually lead to gene transcription

yes