Unit 1: Cells and Proteins 4 Flashcards Preview

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Flashcards in Unit 1: Cells and Proteins 4 Deck (68)
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1
Q

Photoreceptor systems are found in:

A

Archaea, Prokaryota and Eukaryota

2
Q

Archaea are what?

A

Single celled organisms with no defined nucleus

3
Q

Different groups of archaea can do

A

different things

4
Q

The haloarchae can do what?

A

Photosynthesise

5
Q

Haloarchae relies on ___________ for activation of ATP synthase

A

bacterial rhodopsin

6
Q

Bacterial rhodopsin consists of:

A

a retinal and a chromophore within a bacterial opsin

7
Q

The retinal-opsin complex is known as?

A

Rhodopsin

8
Q

Bacterial Rhodopsin Process: Stage 1, sunlight strikes a bacterial rhodopsin molecule causing the retinal to undergo?

A

Photoisomerisation

9
Q

Bacterial Rhodopsin Process: Stage 2, Photoisomerisation of the retinal causes a?

A

conformational change in the opsin

10
Q

Bacterial Rhodopsin Process: Stage 3, The retinal’s conformational change causes activation of which molecule?

A

Rhodopsin molecule

11
Q

Bacterial Rhodopsin Process: Stage 4, The activated rhodopsin molecule begins to?

A

Pump protons out of the cell

12
Q

Bacterial Rhodopsin Process: Stage 5, What force causes the protons to flow back into the cell?

A

The electrochemical gradient

13
Q

Bacterial Rhodopsin Process: Stage 6, The protons flowing back into the cell due to the electrochemical gradient begin driving what?

A

ATP Synthase

14
Q

Bacterial Rhodopsin Process: Stage 7, ATP synthase begins to …

A

Synthesise Pi with ADP

15
Q

Bacterial Rhodopsin Process: Stage 8, Therefore what molecule is being generated by this whole process?

A

ATP

16
Q

In animals, retinal is combined with a

A

membrane protein opsin

17
Q

Retinal is a form of

A

Vitamin A

18
Q

When stimulated by light, the retinal undergoes

A

photoisomerisation

19
Q

During photoisomerisation the retinal goes from 11-cis-retinal into

A

all-trans-retinal

20
Q

What is the process caused by photoisomerisation that results in retinal going from 11-cis-retinal to all-trans-retinal called?

A

Bleaching

21
Q

What happens in the process of Bleaching?

A

11-cis-retinal goes to all-trans-retinal

22
Q

Bleaching of a retinal induces a ________ change

A

conformational

23
Q

Bleaching stimulates a conformational change which activates the g-protein called?

A

Transducin

24
Q

Where is the g-protein transducin located?

A

On the inside of the membrane

25
Q

Light Transduction: Stage 1, When stimulated by a photon, a rhodopsin molecule activates hundreds of

A

transducin molecules

26
Q

A rhodopsin is what type of cell?

A

Rod cell

27
Q

A photopsin is what type of cell?

A

Cone cell

28
Q

Light Transduction: Stage 2, Transducer activates what enzyme located on the intracellular side of the membrane?

A

Phosphodiesterase

29
Q

Light Transduction: Stage 3, The activation of phosphodiesterase leads to the breakdown of a 1000 of what molecule per second?

A

cGMP

30
Q

Light Transduction: Stage 4, The breakdown of cGMP causes what to become very sensitive?

A

rhodopsin-based systems

31
Q

Light Transduction: Stage 5, The decrease in cGMP levels causes what to close?

A

Ligand-gated Na+ channels

32
Q

Light Transduction: Stage 6, The close of the ion channels prevents the release of ?

A

inhibitory neurotransmitters

33
Q

Light Transduction: Stage 7, The prevention of the release of inhibitory neurotransmitters allows the sensory synapse to become stimulated and do what?

A

Transmit a nerve impulse to the visual centres of the brain

34
Q

In vertebrates retina rod cells and cone cells both contain ?

A

opsins which contain retinal

35
Q

Many rods are connected to a single

A

neuron

36
Q

Being connected to a single neutron maximises a rode cells sensitivity to

A

light

37
Q

Do rod cells detect colour?

A

No

38
Q

There are three types of cone cells, but each contains a:

A

rhodopsin analogue and photopsin.

39
Q

It is the _____ connected to the retinal that varies between the cone cells

A

opsin

40
Q

Each type of opsin in a cone cells is sensitive to a?

A

narrower range of wavelengths

41
Q

Each type of cone cells is sensitive to different ranges of

A

light wavelength

42
Q

What is it that allows the detection of colour by cone cells?

A

The specificity of the opsins to narrower range of wavelengths

43
Q

L cone cells react to

A

red

44
Q

M cone cells react to

A

green

45
Q

S cone cells react to

A

blue

46
Q

Photosynthesis is the process of converting light energy into

A

chemical energy

47
Q

One single pigment contains:

A

Chlorophyll a, chlorophyll b, phycobilins and carotenoids

48
Q

Groups of pigments are bound together in a?

A

Thylakoid membrane

49
Q

Groups of thylakoids band together in a geometric pattern to form?

A

Grana

50
Q

Within a chloroplast, Groups of Grana are joined together by a road like structure called?

A

Lamella

51
Q

The inside of a thylakoid is called the?

A

Lumen

52
Q

Surrounding the thylakoid and lamella in the chloroplast is what aqueous fluid?

A

Stroma

53
Q

A chloroplast has three parts to its membrane which are:

A

The inner membrane, the inner membrane space and the outer membrane

54
Q

The light energy trapped by the pigments in the chloroplast is used to

A

split H2O and generate ATP & NADPH

55
Q

Photolysis is the splitting of?

A

Water

56
Q

The hydrogen and electrons produced in photolysis reduce what molecule?

A

NADP to NADPH

57
Q

The reduced NADPH carries what to the next stage, carbon fixation

A

Hydrogen and Electrons

58
Q

Photophosphorylation is the conversion of:

A

ADP + Pi —> ATP

59
Q

Trapped light energy is used to pump what molecule from the stroma across into the thylakoid space?

A

H+

60
Q

H+ is pumped from the stroma into the

A

thylakoid space

61
Q

The diffusion of H+ back into the stroma drives what process?

A

ATP synthase

62
Q

Chlorophyll a channels electrons to

A

other parts of the electron transport chain

63
Q

Accessory pigments do what with their trapped energy?

A

Transfer it to chlorophyll a

64
Q

Photosystem 2 uses the energy of electrons to split

A

water

65
Q

The electrons generated by the splitting of water are passed onto other intermediaries such as

A

plastiquinones

66
Q

Electrons being passed onto intermediaries results in more H+

A

accumulating in the thylakoid space

67
Q

The large pool of thylakoid H+ leaks back across the thylakoid membrane and down the electrochemical gradient back to the

A

stroma

68
Q

H+ leaking back into the stroma drives what

A

ATP synthase to generate ATP