Detecting and Amplifying an Environmental Stimulus

Question 1

List the three domains of life

Answer 1

Bacteria
Archaea
Eukarya – Photoreceptor proteins are found across all 3 domains

Question 2

Draw the chemical process of ATP production

Answer 2

:)

Question 3

How is ATP generated?

Answer 3

As H+ ions diffuse from an area of high concentration outside the membrane to a lower concentration inside the cell

Question 4

What is Retinal?

Answer 4

It is a form of vitamin A

Question 5

Where is vitamin A acquired from?

Answer 5

The diet or synthesised form beta-carotenes

Question 6

What type of molecule is retinal and what does that do?

Answer 6

Retinal is a chromophore – it absorbs certain wavelengths of light and reflects others

Question 7

Explain photoreceptors in Animals

Answer 7

In animals the light-sensitive molecule retinal is combined with a membrane protein opsin to form the photoreceptors of the eye. A cascade of proteins amplifies the signal.

Question 8

What are photoreceptors used to generate?

Answer 8

They are not used to generate ATP. Instead these photoreceptors generate nerve impulses to provide information

Question 9

What is the flatworm able to do?

Answer 9

This flatworm is able to move away from a light source by interpreting the messages generated by the photoreceptors in its eyespot

Question 10

What is a G protein?

Answer 10

Proteins that have ligand binding sites that are extracellular..

Question 11

What happens when the appropriate ligand binds to a G protein?

Answer 11

It causes a conformational change that activates the G proteins. The G proteins releases one of its subunits. This subunit then binds to another protein (an inactive enzyme) leading to its activation.