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Flashcards in Animals detecting light Deck (12)
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1
Q

For humans what is visible light spectrum?

A

390-700nm (peak of solar radiation spectrum)

2
Q

What is the opsin gene family?

A

Gene family which receptors in animal eyes are based on, has 7 transmembrane helices

3
Q

Why do photoreceptor cells have extensive membrane?

A

To accomodate as much rhodpsin as possible (the opsin in rods conserved from jellyfish to humans)

4
Q

What type of photoreceptors are vertebrate rods and cones?

A

ciliary photoreceptors

5
Q

What are the other type and where are they found?

A

microvillar photoreceptors, found in molluscs, stacks of microvilli form rhabdoms

6
Q

Draw both

A

see internet – better than notes

7
Q

Draw how retinaldehyde reacts to light

A

see notes

8
Q

How does rhodopsin achieve amplification of the signal?

A

see diagram in notes

9
Q

How does adaptation occur?

A

guanylate cyclase resynthesises cGMP

10
Q

How does invertebrate phototransduction work?

A

activated rhodopsin acts through different Gprotein, Phospholipase c activated, cation channel opens(called TRP channel), depolarisation

11
Q

What is exciting about opsin?

A

Can make opsins mechanically (requiring a retinal-based cofactor) which control an ion channel which can be opened or closed, controlled by photoabsorption, can be expressed in neurons where they control neural activity by shining a light on nerve cell –> optogenetics

12
Q

in plants what is difference in light response?

A

No GCPRs instead direct electron transfer