Chapter 8- Photosynthesis

Question 1

ATP

Answer 1

Adenosine Triphosphate, consists of adenine, a 5-carbon sugar called ribose, and three phosphate groups
One of the most important compounds that cells use to store and release energy

Question 2

Difference between ATP and ADP

Answer 2

adenosine triphosphate vs adenosine diphosphate, meaning the difference is in one phosphate group. When ATP- stored energy
When ADP- already used energy

Question 3

How is ATP like a battery?

Answer 3

ATP can easily release and store energy by breaking and re-forming the bonds between its phosphate groups, very useful as a basic energy source for all cells

Question 4

Name a variety of uses for ATP?

Answer 4

1) provides energy for sodium potassium pumps across a cell membrane
2) used to power flagella and cilia which are motors
3) provide energy to proteins
4) used to produce light (like in the butt of fireflies)

Question 5

What is a heterotroph?

Answer 5

Organisms that obtain food by consuming other living things

Question 6

What is an autotroph?

Answer 6

Organisms that make their own food

Question 7

Short description of phosynthesis

Answer 7

plants convert the energy of sunlight into chemical energy stored in the bonds of carbohydrates

Question 8

What is a pigment?

Answer 8

light-absorbing molecules

Question 9

What is chlorophyll?

Answer 9

the plants primary pigment. appears in two forms:

1) chlorophyll A
2) chlorophyll B

Question 10

What light does chlorophyll have a hard time absorbing?

Answer 10

Green-thats why plants are green

Question 11

What role do pigments play in the process of photosynthesis?

Answer 11

photosynthetic organisms capture energy from sunlight with pigments

Question 12

What is a thylakoid?

Answer 12

interconnected sac-like photosynthetic membranes inside of a chloroplast (contain clusters of chlorophyll and proteins called photosystems)

Question 13

Why does a cell only make a small amount of ATP

Answer 13

ATP is efficient for short term energy in quick situations like maintaining a concentration gradient (Na K pumps). Glucose is used for long term storage, having 90x the amount of energy than ATP in a stable complex

Question 14

What is NADP+ ?

Answer 14

(nicotinamide adenine dinucleotide phosphate) Can accept and hold 2 high-energy electrons along with a hydrogen ion (H+) to make it NADPH. This is another way the energy from the sun can be converted to chemical form.

Question 15

What are the reactants and products of photosynthesis?

Answer 15

carbon dioxide + water = (Light)= sugars + oxygen

6CO2 + 6H2O =(Light)= C6H12O6 + 6O2

Question 16

What are the light-dependent reactions?

Answer 16

depend on photons of light. Both PS I and PS II use light captured by pigments to energize electrons.

These reactions release oxygen as a byproduct and make energy rich compounds ATP and NADPH

Question 17

What are the light-independent reactions?

Answer 17

(USE CALVIN CYCLE) ATP and NADPH molecules made from Light-dependent reactions are used in light-independent reactions to make sugars from carbon dioxide. Reactions take place outside of thylakoids in the stroma

Question 18

What is an electron transport chain?

Answer 18

(ETC) - a series of electron carrier proteins that shuttle high-energy electrons during ATP-generating reactions. These electrons come from water molecules.

(this means water is a limiting factor in the process of photosynthesis)

Question 19

What is ATP synthase?

Answer 19

a protein that spans the thylakoid membrane and allows H+ ions to pass through it. Powered by the H+ gradient, H+ ions rotate the protein on its route to the other side which adds a Phosphate (P) to ADP to produce ATP.

The trans-membrane protein that makes ATP

Question 20

What are 3 factors affecting photosynthesis?

Answer 20

Temperature- enzymes involved work best between 0-35d C
Light intensity- positive correlation with an upper limit
Water- need electrons from H20, water is a big limiting factor to photosynthesis

Question 21

How does photosynthesis work under extreme conditions?

Answer 21

C4 Photosynthesis- have specialized chemical pathway that allows them to capture CO2 for the calvin cycle by first producing a compound to fixate carbon, storing it to be used during times of intense heat and light.
Examples include sugar cane, corn, and sorghum

CAM Plants- adapted to dry climates to obtain carbon dioxide while minimizing water loss. Close stomata during day, open at night. At night, they turn CO2 into Crassulacean Acid. (CAM stands for Crassulacean Acid Metabolism). They metabolize the acid to free up carbon for the calvin cycle during the day instead of having to open the stomata during the day to get CO2. This reduces water lost through transpiration