Lecture 4 Energy

Question 1

Photons

Answer 1

Particles that move in waves from the sun to Earth

Question 2

How is energy generated?

Answer 2

By breaking bonds between atoms

Question 3

What are biofuels made from?

Answer 3

food/plant scraps

Question 4

What are fossil fuels made from?

Answer 4

Coal, oil, etc (fossilised organic matter)

Question 5

What is photosyntheis (in short)

Answer 5

Plants capture the energy from the sun and store it in the chemical bonds of sugar

Question 6

What is cellular respiration (in short)

Answer 6

Organisms release the energy in the plants they eat and use it as fuel

Question 7

What is kinetic energy

Answer 7

Motion, combustion (light, heat)

Question 8

What is potential energy?

Answer 8

Stored energy resulting from an object’s position, location, composition (can be released into kinetic energy later)

Question 9

What is chemical energy?

Answer 9

Contained in the chemical bonds between atoms (in food or else)

Question 10

How much of the energy of the sun is captured by plants?

Answer 10

1%

Question 11

How much of the energy of the sun is captured by oceans, peole, etc (for heating purposes)?

Answer 11

70%

Question 12

How much of the energy of the sun is reflected back into space?

Answer 12

30%

Question 13

What is combustion inefficiency?

Answer 13

Energy is lost in the form of heat in ANY energy transfer

Question 14

What is the first law of thermodynamics?

Answer 14

Energy is never generated nor destroyed

Question 15

What is the second law of thermodynamics?

Answer 15

An energy tranfer is never perfect, there is always a loss of energy

Question 16

How do plants fuel chemical reactions?

Answer 16

The energy of the sun cannot be used directly, so it is captured in ATP

Question 17

What does ATP stands for?

Answer 17

Adenosine Tri Phosphaste

Question 18

What is an ATP molecule composed of (3)?

Answer 18

Adenine (Nitrogen base), Ribose (sugar) and 3 Phosphate groups

Question 19

What happens to ATP when it losts a phosphate group

Answer 19

It becomes ADP (Adenosine DiPhosphate)

Question 20

Where is the energy contained in a ATP molecule?

Answer 20

In the bonds of the phosphate groups

Question 21

What is the goal of an ADP molecule?

Answer 21

Recharge into ATP by gaining a phosphate group

Question 22

Where does plant matter come from?

Answer 22

Plants use the energy of the sun to turn 6CO2 into glucose molecules, while releasing O2

Question 23

What are the input of Photosynthesis?

Answer 23

Sunlight + Water + CO2

Question 24

What are the output of Photosynthesis?

Answer 24

O2 + Sugar (glucose)

Question 25

What is the "photo" part of photosynthesis?

Answer 25

The energy from the sun is captured

Question 26

Why is water important in photosynthesis?

Answer 26

It provides electrons

Question 27

What are chloroplasts composed of?

Answer 27

Outer and innner membrane + sacks

Question 28

What are the sacks of chloroplasts named and what are they used for?

Answer 28

Thylakoid, this is where the light is converted to chemical energy

Question 29

What is the stroma of chloroplasts and what is it used for?

Answer 29

its the fluid in which thylakoids float, and on which photosystems are attached. This is where photo energy is converted into sugar "synthesis part"

Question 30

What determines the amount of energy carried by a photon

Answer 30

the length of the wave in which photons travel

Question 31

Shorter wavelenghts carry more or less energy?

Answer 31

More

Question 32

What is the main pigment in plants that absorbs energy from the sun?

Answer 32

Chlorophyll

Question 33

Which color chlorophyll does NOT absorb (and therefore reflects)?

Answer 33

Green

Question 34

Which pigment reflects orange and red pigments?

Answer 34

Carotenoids

Question 35

What happens to photons when they are absorbed by chlorophyll?

Answer 35

They enter an excited state

Question 36

What are the 2 options of excited electrons in the chloroplasts?

Answer 36

1- Returning to a resting state (which release energy) | 2- Electrons are being passed to other atoms (what will drive photosynthesis)

Question 37

Where do the electrons excited by the photons in the chloroplasts come from?

Answer 37

WATER

Question 38

Which component of water is bumped by photons and initiates the electron transport chain?

Answer 38

H+ ions

Question 39

What are the 3 output of the photo reactions?

Answer 39

ATP NADPH Oxygen

Question 40

Where do the excited electrons have to go in the first photosystem?

Answer 40

In the chlorphyll a

Question 41

What special molecule is in chlorophyll a, what does it do?

Answer 41

A primary electron acceptor grabs excited electrons from chlorophyll a and begins the electron transport chain

Question 42

Where does the oxygen released in photosynthesis comes from?

Answer 42

From WATER; H+ ions and O2 ions are separated | H+ = electron supplier for transport chain, O2 becomes by-product

Question 43

Where does the 1st electron transport chain leads to?

Answer 43

The second photosystem

Question 44

What happens at each step of the electron transport chain?

Answer 44

Electrons release energy. Therefore, after each step they are on a lowe energy state than before

Question 45

What is the energy of the 1st transport chain used for?

Answer 45

Fuelling pumps in thylakoid membranes that will move protons from the stroma to inside the thylakoid, creating a store of potential energy in the thylakoid sack

Question 46

What happens when enough electrons are stored in the thylakoid pump ? (1st transport chain)

Answer 46

The potential energy is transformed into kinetic energy when the electrons rush out with great force through an ATP molecule

Question 47

What is the energy from the thylakoid pump release used for? (1st transport chain)

Answer 47

Making ATP from ADP and free-floating phosphate groups

Question 48

How is the second photosystem supplied in electrons?

Answer 48

By the electrons from the 1st transport chain

Question 49

What is the product of the second electron transport chain?

Answer 49

Using NADP+ to create NADPH

Question 50

Where does the Calvin Cycle occurs?

Answer 50

In the stroma of the leaves (outside thylakoids)

Question 51

What part of the photosynthesis process does the Calvin Cycle corresponds to?

Answer 51

The "synthesis" part

Question 52

What happens in the first step of the Calvin Cycle (fixation)?

Answer 52

Rubisco (enzyme) plucks carbon from the air and attaches it to an organic molecule with 5C in the chloroplasts

Question 53

What happens in the second step of the Calvin Cycle (Sugar creation)?

Answer 53

The new molecule (6C) is splif in half

Question 54

What happens in the second step of the Calvin Cycle (Sugar creation) after the 6C molecule is split in half?

Answer 54

Each half is modified (added phosphate group and electrons); the result is G3P

Question 55

What are some G3P from the calvin cycle used for? If not, what are they used for?

Answer 55

To make glucose/fructose (sugars), other molecules are rearranged into the original 5C molecules

Question 56

How many turns of the Calvin Cycle does it take to synthesize 1 molecule of G3P, and how much energy does it take?

Answer 56

3 turns, and 9ATP+6NADPH

Question 57

What are the plant's stomatas

Answer 57

Small openings on the underside of their leaves, that they can open or close to let gasses through. Also prevents water loss in high temperature areas

Question 58

When happens cellular respiration, and what is this process? (big picture)

Answer 58

it happens after photosynthesis, and it transforms glucose and oxygen in energy, water and CO2

Question 59

What is the first process included in cellular respiration?

Answer 59

Glycosis

Question 60

What is the first phase of glycosis? What happens there?

Answer 60

An "uphill" preparatory phase: ATP is used to break down glucose in 2 pyruvates

Question 61

What is the second phase of glycosis? What happens there

Answer 61

A "downhill" payoff phase: Sugar bonds are broken (release energy), and are used to attach phosphate groups to ADP (creating ATP), and to bond NAD+ with H+ to form NADPH

Question 62

What is the second process of cellular respiration

Answer 62

The Krebs Cycle (or citric acid cycle)

Question 63

Where does the Krebs Cycle take place?

Answer 63

In the mitochondria

Question 64

How are the pyruvates modified before the Krebs Cycle? (3 steps)

Answer 64

1- It passes electrons to NAD+ (=NAPDH) 2- 1C and 2O are removed (releasing CO2) 3- Coenzyme A attaches to it (producing 2 acetyl-CoAs)

Question 65

What is the first possible outcome of the citric acid cycle?

Answer 65

A new molecule is formed (acetyl-CoA attaches to oxaloacetate and creates citrate)

Question 66

What is the second possible outcome of the citric acid cycle?

Answer 66

NADPH is made and CO2 is released

Question 67

What is the third possible outcome of the citric acid cycle?

Answer 67

The starting material (oxaloacetate) is reformed

Question 68

What is the third and last process of cellular respiration

Answer 68

Electron transport chain

Question 69

What is the first step of the electron transport chain in cellular respiration?

Answer 69

NADH gives electrons and returns to citric acid cycle

Question 70

What is the second step of the electron transport chain in cellular respiration?

Answer 70

The electrons move through a chain, releasing energy at each step (accumulating in the intermembrane space of the mitochondria)

Question 71

What is the third step of the electron transport chain in cellular respiration?

Answer 71

The electrons are combined with O2 to create water

Question 72

What is the last step of the electron transport chain in cellular respiration?

Answer 72

The electrons are released, and energy is used to attach phosphate groups to ADP (=ATP)

Question 73

What happens when there is no oxygen for cellular respiration? (during exercise?)

Answer 73

Glycosis is used, since it doesnt require O. It's then called fermentation and it produces little ATP and lactic acid