Week 1

Question 1

What are cell surface receptors?

Answer 1

Receptors that are embedded in the plasma membrane of cells.

Question 2

What are the general features of cell signalling?

Answer 2

There are four basic categories of chemical signaling found in multicellular organisms: paracrine signaling, autocrine signaling, endocrine signaling, and signaling by direct contact. The main difference between the different categories of signaling is the distance that the signal travels through the organism to reach the target cell.

Question 3

What are the four main signalling messages delivered?

Answer 3

• Survive
• Divide
• Differentiate
• Die

Question 4

What are the three main diverse responses to cell signalling?

Answer 4

• Decreased rate of firing
• Secretion
• Contraction

Question 5

What does the signal transduction pathway involve?

Answer 5

The binding of extracellular signaling molecules and ligands to receptors located on the cell surface or inside the cell that trigger events inside the cell, to invoke a response.

Question 6

What are the four distinct molecular mechanisms for transmembrane signalling?

Answer 6

I: Ligand-gated ion channels.

II: Receptors which possess intrinsic guanylyl cyclase activity.

III: Receptors with intrinsic tyrosine kinase activity.

IV: G protein—coupled receptors

Question 7

What are the two major classes of cell receptors?

Answer 7

Intracellular receptors, which are found inside of the cell (in the cytoplasm or nucleus), and cell surface receptors, which are found in the plasma membrane.

Question 8

What are the two main types of ligands in cell signalling?

Answer 8

Ligands that bind to receptors inside the cell, called intracellular ligands, and ligands that bind to receptors outside the cell, called extracellular ligands.

Question 9

What are the major families of cell surface receptors?

Answer 9

G protein-coupled receptors (GPCRs), enzyme-coupled receptors, and ion channels.

Question 10

What is the process intracellular signal transduction?

Answer 10

A chain of reactions transmitting signals from the cell surface to a variety of intracellular targets

Question 11

What are enzyme-coupled receptors?

Answer 11

The receptors for many growth factors, cytokines and hormones and have a major role in regulation of cell growth, proliferation and differentiation.

Question 12

What are receptor tyrosine kinases?

Answer 12

A group of membrane-bound receptors that play an important role in the normal function of cells.

Question 13

What are GTP binding proteins?

Answer 13

Transmitting signals outside the cell which cause changes within the cell. They act as molecular switches which are on when binding GTP and off when binding GDP. GTP-binding proteins belong to two families: heterotrimeric G proteins see Transducin and small GTPases

Question 14

What is the function of G protein-coupled receptors?

Answer 14

Forming a large group of evolutionarily-related proteins that are cell surface receptors that detect molecules outside the cell and activate cellular responses.

Question 15

What is the most important family of the intracellular receptors?

Answer 15

The nuclear receptors (also known as ‘nuclear hormone receptors’), which includes receptors for steroid hormones, thyroid hormones, retinoids and vitamin D

Question 16

What is a key characteristic of intracellular nuclear receptors?

Answer 16

Such hormones are lipophilic to facilitate their movement across the cell membrane.

Question 17

What are the ligands of intracellular receptors?

Answer 17

Small, hydrophobic (water-hating) molecules, since they must be able to cross the plasma membrane in order to reach their receptors.

Question 18

How are nuclear receptors activated?

Answer 18

By lipid-soluble signals (e.g., steroid hormones) that cross the plasma membrane.

Question 19

What is cancer?

Answer 19

A disease caused when cells divide uncontrollably and spread into surrounding tissues.

Question 20

What are the two RAS signalling pathways prominently associated with cancer?

Answer 20

MAP kinase pathway regulating cell proliferation and the phosphoinositide 3-kinase (PI3K) pathway that regulates cell metabolism and survival

Question 21

What is the tumour microenvironment?

Answer 21

the environment around a tumor, including the surrounding blood vessels, immune cells, fibroblasts, signaling molecules and the extracellular matrix.

Question 22

What does metastasis mean?

Answer 22

The spread of cancer cells from the place where they first formed to another part of the body.

Question 23

What is angiogenesis?

Answer 23

The formation of new blood vessels

Question 24

What do the hallmarks of cancer constitute?

Answer 24

An organizing principle for rationalizing the complexities of neoplastic disease. They include sustaining proliferative signaling, evading growth suppressors, resisting cell death, enabling replicative immortality, inducing angiogenesis, and activating invasion and metastasis.

Question 25

What underlies the hallmarks of cancer?

Answer 25

Genome instability, which generates the genetic diversity that expedites their acquisition, and inflammation, which fosters multiple hallmark functions.

Question 26

What are the two newest emerging hallmarks of cancer?

Answer 26

Energy metabolism and evading immune destruction