M5 C17: Energy for Biological Processes

Question 1

what is the law of energy?

Answer 1

energy cant be created or destroyed

Question 2

where does energy come from for metabolic reactions in producers?

Answer 2

radiation from the sun is converted into chemical energy

Question 3

what is the respiration equation?

Answer 3

C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 4

what is the photosynthesis equation?

Answer 4

6CO2 + 6H20 → C6H12O6 + 6O2

Question 5

What is the purpose of photosynthesis?

Answer 5

to make glucose by converting inorganic substances to organic substances

Question 6

what is the purpose of respiration?

Answer 6

to produce atp for metabolic processes
converts organic substances to inorganic

Question 7

when is energy released?

Answer 7

when bonds are formed

Question 8

when is energy absorbed?

Answer 8

when bonds are broken

Question 9

what is an exothermic reaction?

Answer 9

overall reaction releases more energy (more bonds made)

Question 10

what is an endothermic reaction?

Answer 10

overall reaction absorbs more energy (more bonds broken)

Question 11

autotrpohic?

Answer 11

organism that can produce own food using inorganic materials

Question 12

heterotrophic?

Answer 12

cant make its own food rely on other organisms

Question 13

photosynthesis?

Answer 13

where plants make glucose out of CO2 and light

Question 14

chlorophyll?

Answer 14

makes a plant green captures light in photosynthgesis

Question 15

chloroplast?

Answer 15

site of photodynthesis

Question 16

what is a pigment?

Answer 16

natural coloring matter of animals or plant tissue absorb wavelengths of light. Molecules that absorb specific wavelengths of light.

Question 17

where does the light dependent reaction occur in the chloroplast?

Answer 17

occurs in the thylakoid membranes and the thylakoid spaces (the spaces inside the thylakoids)

Question 18

photosystems

Answer 18

Protein complexes involved in the absorption of light and electron transfers in photosynthesis.

Question 19

Non-cyclic photophosphorylation

Answer 19

The synthesis of ATP and reduced NADP involving photosystems I and II.

Question 20

Cyclic photophosphorylation

Answer 20

The synthesis of ATP involving only photosystem I.
No reduced NADP produced .

Question 21

what do photosystems contain?

Answer 21

Location of other pigments such as chlorophyll b, xanthophylls and carotenoids. Also called a light harvesting system
reaction centre

Question 22

what pigment is in the reaction system?

Answer 22

Location of chlorophyll a

Question 23

what is another name for the pigments not in the reaction centre?
(in the light harevesting system)

Answer 23

accessory pigments
antenna pigments

Question 24

what wavelength of light does chlorophyll absorb?

Answer 24

mainly blue and red light and reflects green (why plants appear green).
Different combinations of pigments are the reason for different shades and colours of leaves.

Question 25

what happens in the light dependent reaction? (briefly)

Answer 25

energy from sunlight is absorbed and is used to form ATP. Hydrogen from water is used to reduce coenzyme NADP to reduced NADP.

Question 26

what is the first step of the light dependent reaction

Answer 26

light absorbed by PSII excites electrons that are released from the reaction centre of the photosystem. ATP is then produced by chemiosmosis.

Question 27

what is chemisosmosis?

Answer 27

diffusion of protons from a region of high concentration to a region of low concentration through a partially permeable membrane due to energy from electrons moving down electron carriers. protons then move back through atp synthase to releases energy to attach an inorganic phosphate to ADP as they do, forming ATP.

Question 28

what happens after chemiosmosis in PSII?

Answer 28

ligh excited electrons which are then released from the reaction centre at PSI these are passed to another electron transport chain, again producing ATP by chemiosmosis. Electrons leaving this electron transport chain are accepted by the coenzyme NADP along with a hydrogen ion to form reduced NADP.

Question 29

how are electrons replaced in PSII

Answer 29

replaced by the splitting of water into hydrogen ions, electrons andoxygen molecules using energy from the sun-photolysis.

Question 30

how are electrons replaced in PSI?

Answer 30

replaced by electrons that have just travelled along the first electron transport chain after being released from PSII.

Question 31

what is a waste product of the light dependent reaction?

Answer 31

O2

Question 32

what substances from the light dependent reactions reduce NADP?

Answer 32

excited electrons from PSI and hydrogen ions from photolysis of water combine to reduce NADP

Question 33

what happens in the light independent stage?

Answer 33

takes place in the stroma and uses carbon dioxide and the products from the light-dependent stage (ATP and reduced NADP).

Question 34

what does carbon dioxide do when entering the calvin cycle?

Answer 34

CO2 and RuBP (5C) join together making an unstable intermediate 6C compound

Question 35

what catalyses the reaction between CO2 and RuBP?

Answer 35

RuBisCO (ribulose bisphosphate carboxylase)

Question 36

what happens after the unstable intermediate has been formed in the calvin cycle?

Answer 36

This breaks down to form X2 3C molecules called GP

Question 37

what happens once GP is formed in the calvin cycle?

Answer 37

GP is turned into TP, using energy from NADPH and ATP

Question 38

What is TP used for?

Answer 38

1 TP is used to make glucose; 5 TPs are recycled to regenerate RuBP, which requires ATP

Question 39

what happens in carbon fixation/

Answer 39

carbon is 'fixed' to RuBP from carbon dioxide

Question 40

what happens in reduction?

Answer 40

GP is reduced to form TP due to ATP and NADPH

Question 41

what happens in regeneration?

Answer 41

5/6 of the TP molecules are used to regenerate RuBP which requires ATP releasing energy

Question 42

what are some examples of biological molecules TP can syntheise/

Answer 42

glucose sucrose amino accids

Question 43

when does photorespiration happen?

Answer 43

Photorespiration occurs when carbon dioxide levels fall and oxygen levels increase.

Question 44

what is photorespiration?

Answer 44

when plants consume oxygen and release carbon dioxide during photosynthesis, resulting in a decrease in photosynthetic output. caused by the enzyme RuBisCO adding oxygen to a sugar instead of carbon dioxide during normal photosynthesis reducing efficiency

Question 45

how does light intensity affect photosynthesis?

Answer 45

light is needed as an energy source as it increases ATP and NADPH is produced quicker therefore it can be used in calvin cycle less light= less atp and nadph so more GP

Question 46

how does carbon dioxide concentration affect photosynthesis?

Answer 46

increase in CO2 means carbon fixation can happen faster and more GP can be produced? TP

Question 47

What effect does temperature have on photosynthesis?

Answer 47

increases rate of enzyme activity until they denature. this can include carbon fixation

Question 48

what is a negative effect of high temperatures?

Answer 48

when plants undergo dry spells, closure of stomata stops CO2 coming in, so carbon fixation can't occur