Chapter 9. Cell Signaling (BIOS 1700)

3 ways to deal with ROS because of excess sunlight

1. xanthophylls 2. antioxidants 3. cyclic electron transport

Why is ROS bad?

It carries around an extra electron and adds it to other molecules causing disruption.

Which type of receptor is involved in rapid responses of muscle cells and neurons? a. ligand-gated ion channel b. receptor kinase c. intracellular receptor d. G protein-coupled receptor

a

Imagine that you've discovered a new metabolic pathway. You find that activation of this pathway leads to increased activity of the Citric Acid Cycle, but has no effect on the rate of glycolysis. Which of the following is a likely product of the new pathway you've discovered? a. glucose b. Acetyl-CoA c. NADH d. FADH2

b

In. large molecules are broken down and ATP is produced. a. Anabolism b. Catabolism c. Chemiosmosis d. Diffusion e. Active Transport

b

Microtubules and microfilaments "grow from the end to end a. plus; minus b. minus; plus c. 5'; 3' d. 3'; 5'

b

Which of the following is a type of cell communication where the signaling molecule is released by the same cell that responds to the signal? a. All of these choices are correct. b. autocrine c. endocrine d. contact-dependent e. paracrine

b

You have made an artificial leaf. In the lab, you have provided the leaf ample light for one hour so that the leaf can make glucose through the Calvin cycle. Then you turn off the light for multiple hours. What molecule of the Calvin cycle would you expect to accumulate? a. RuBP b. 3PGA c. Triose Phosphate d. Glucose

b

The energy of activation of a reaction is: a. the net change in free energy b. The difference in energy between substrate and product c. the energy input need to reach the transition state d. the difference in energy between the transition state and the product e. Equivalent to the change in Gibbs free energy of ATP hydrolysis

c

A protein on a cell surface that binds to a signaling molecule is an example of which of the following elements of cellular communication? a. a signaling molecule b. a responding cell c. a signaling cell d. a receptor protein e. None of the other answer options is correct.

d

Which of the following is NOT true about G proteins? a. G proteins become deactivated when bound GTP is hydrolyzed to GDP. b. G proteins release GDP and bind GTP when associated with an activated receptor. c. Some G proteins are composed of three subunits. d. All G proteins are a component of a signal-transduction pathway and associate with a G protein-coupled receptor.

d

Which of the following would NOT be considered a cell-surface receptor? a. a receptor that must form a dimer after binding the ligand to transmit a signal b. a receptor that causes GDP to be exchanged for GTP in a G protein c. a receptor that allows ions to enter the cell when a ligand binds d. a receptor that binds a nonpolar steroid hormone and activates transcription

d