Unit 1.4c

Question 1

Is hydrophilic non-polar or polar?

Answer 1

Polar

Question 2

Can hydrophilic signals pass through the hydrophobic part of the membrane?

Answer 2

No, they cannot

Question 3

Do hydrophilic signals enter the cytosol?

Answer 3

They don’t

Question 4

What do hydrophilic signalling molecules bind to?

Answer 4

They bind to transmembrane receptor

Question 5

What are two examples of hydrophilic extracellular signalling molecules?

Answer 5

Peptide hormones and neurotransmitters

Question 6

What are hydrophilic signalling molecule sometimes referred to as?

Answer 6

Ligands

Question 7

What binds to the extracellular face of receptor proteins?

Answer 7

Hydrophilic signalling molecules

Question 8

When does the receptor protein change conformation?

Answer 8

Once the hydrophilic signal on molecule binds to its extracellular face

Question 9

What is caused due to the conformational change of the receptor protein?

Answer 9

A signal is transduced across the plasma membrane

Question 10

So, in summary, what happens when a hydrophilic signalling molecule binds to the extracellular face of a protein receptor?

Answer 10

An intracellular signal occurs

Question 11

What do intracellular signals cause?

Answer 11

They cause the cells behaviour to alter

Question 12

What process causes a chemical or physical signal to transmit through a cell by series of molecular events?

Answer 12

Transduction

Question 13

What does transduction result in?

Answer 13

A cellular response

Question 14

So what do transmembrane receptor proteins do?

Answer 14

They convert an extra cellular hydrophilic binding event into a specific intercellular response

Question 15

How do transmembrane receptor proteins create intracellular responses?

Answer 15

Signal transduction pathways

Question 16

What do transduced hydrophilic signals involve in the signal transduction pathways?

Answer 16

G-proteins or phosphorylation cascades caused by kinase enzymes

Question 17

What do G-proteins do?

Answer 17

Relay signals from activated receptors to target proteins like enzymes and ion channels

Question 18

What do phosphorylation cascades allow?

Answer 18

They allow the activation of multiple intracellular signalling pathways

Question 19

How does phosphorylation cause multiple proteins to be phosphorylated?

Answer 19

Because to allow the cascade to activate the signalling pathways a series of events where one kinase must activate the next sequence occurs.

Question 20

What type of enzyme is the catalyst for phosphorylation?

Answer 20

Kinase

Question 21

What is phosphorylation?

Answer 21

It’s the transfer of 1 phosphate group form ATP to a different protein

Question 22

In blood, what level must glucose be kept be kept within?

Answer 22

3.9-6.1 mmol per litre

Question 23

When would pancreas cells produce insulin?

Answer 23

Insulin will be produced when there was an increase in blood glucose concentration (that was detected by the pancreas)

Question 24

What is insulins job in the body?

Answer 24

It helps fat tissue and skeletal muscles absorb glucose from the bloodstream

Question 25

How does glucose travel into the cell?

Answer 25

It travels into the cell by facilitated diffusion in transporter proteins

Question 26

What is insulin?

Answer 26

Insulin is a peptide hormone

Question 27

What happens when insulin binds to the receptor?

Answer 27

The receptor undergoes a conformational change that triggers its phosphorylation

Question 29

When insulin causes a phosphorylation cascade in a cell what is transported and where?

Answer 29

GLUT4 containing vesicles are transported to the fat and muscle cell membranes

Question 30

What do GLUT4 proteins allow?

Answer 30

The passing of Glucose across the plasma membrane into the cell

Question 31

What is the cause of type one diabetes?

Answer 31

Failure of insulin production in the pancreas

Question 32

What is the treatment of type one diabetes?

Answer 32

Regular insulin injections throughout the day

Question 33

What is the cause of type two diabetes?

Answer 33

Loss of insulin receptor function

Question 34

What are the three treatments of type two diabetes?

Answer 34

• medication that lowers blood glucose levels
• Lifestyle changes
  -Exercise, which triggers GLUT4 recruitment so improves glucose uptake in fat and muscle cells

Question 35

What is type two diabetes associated with?

Answer 35

Obesity