Chapter 10: Photosynthesis

Question 1

Chloroplasts

Answer 1

organelle found in plants and photosynthetic protists of that absorbs light and uses it to drive the synthesis of organic compounds from carbon dioxide and water

Question 2

photosynthesis

Answer 2

conversion of light energy to chemical energy that is stored in sugars or other organic compounds

Question 3

Autotrophs

Answer 3

an organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. Use energy from the sun or oxidation of inorganic substacnes to make organic molecules from inorganic ones.

makes own food

Question 4

Heterotrophs

Answer 4

An organism that obtains organic food molecules by eating other organisms or substances derived from them
finds food and consumes it

Question 5

Mesophyl

Answer 5

Leaf cells specialized for photosynthesis*. In c3 plants, located between the upper and lower epidermic. In c4 plants, located between the bundle-sheath cells and the epidermis

Question 6

Stomata

Answer 6

microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant

Question 7

Xylem

Answer 7

vascular plant tissue consisting mainly of tubular* dead cells that conduct most of the water* and minerals upward from the roots to the rest of the plant

*vascular tissue that transports water up the stem from the roots

Question 8

Phloem

Answer 8

Vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar* and other organic nutrients throughout the plant

*vascular tissue that transport sugar through the plant

Question 9

Thylakoids

Answer 9

*flattened membranous sac inside the chloroplast.
often exist in stacks called grana that are interconnected. their membranes contain molecular machinery used to convert light energy to chemical energy

Question 10

Grana (granum)

Answer 10

stack of membrane bounded thylakoids in the chloroplast. grana function in the light reactions of photosynthesis

Question 11

Chlorophyll

Answer 11

green pigment located in membranes within the chloroplasts of plants and algae and in the membranes of certain prokaryotes

Question 12

Light Reactions

• What are these reactions?
• Where do they occur?
• What are the major products?

Answer 12

Light dependent reaction:
*Light and H20 taken in by thylakoids, and transformed into ATP and NADPH

Light Independent Reaction:

• Happens in the chloroplast, in the stroma (not thylakoid)
• CO2 is fixed, and ATP and NADPH (from Light dependent reactions) are added to make glucose

Question 13

Calvin Cycle

• What is this reaction?
• Where does it occur?
• What are the major products?

Answer 13

• Anabolic reaction that builds glucose
• occurs in the chloroplast (in the thylakoids and the stroma)
• Produces glucose, ATP, NAPH, and O2

Question 14

Wavelength

Answer 14

distance between crests of waves

Question 15

Electromagnetic Spectrum

Answer 15

the entire spectrum of electromagnetic radiation, ranging in wavelength from less than a nanometer to more than a kilometer

Question 16

Visible Light Range

Answer 16

380-750 nm, wavelengths of color that we can see

Question 17

Spectrophotometer

Answer 17

an instrument that measures the proportions of light of different wavelengths absorbed and transmitted by a pigment solution

Question 18

Pigments

Answer 18

light-absorbing molecules

Question 19

Chlorophyll (A & B)

Answer 19

A. photosynthetic pigment that participates directly in the light reactions, which convert solar energy to chemical energy
B. an accessory photosynthetic pigment that transfers energy to chlorophyll a

Question 20

Carotenoids

Answer 20

an accessory pigment, yellow or orange, in the chloroplasts of plants. absorb wavelengths of light that chloroplasts cant, broadening the spectrum of colors that drive photosynthesis

Question 21

Photoprotection

Answer 21

absorbs excessive light that would damage chlorophyll or react with oxygen

Question 22

Photosystems (II & I)

Answer 22

II

I

Question 23

RuBP

Answer 23

Ribulose Biphosphate

Question 24

Rubisco

Answer 24

the enzyme that normally catalyzes the first step of the calvin cycle (adding co2 to RuBP). When excess O2 is present or Co2 levels are low, rubisco can bind oxygen, resulting in photorespiration

Question 25

G3P

Answer 25

g3p is the product of the reduction phase of the calvin cycle. It was 3-phosphoglycerate. But ATP donated a phosphate group, and NAPH donated electrons. Making Glyceraldehyde 3 -phosphate. AKA G3P.

A high energy, 3 carbon compound that plants can turn into any carbohydrate that it needs

Question 26

C3 plant

Answer 26

Plant that uses the Calvin Cycle for the initial steps that incorporate CO2 into organic material, forming a 3-carbon compound as the first stable intermediate

Question 27

C4 plant

Answer 27

Plant in which the calvin cycle is preceded by reactions that incorporate co2 into a four-carbon compound, the end product of which supplies co2 for the calvin cycle

Question 28

Photosynthesis consists basically of two major processes. What are those processes? (Look on slide 18, but elaborate a little more beyond the slide. Incorporate other information that you learned about the two major processes.

Answer 28

Light Dependent Reaction:
Chloroplasts absorb photons. Light energy, water, ADP, and NADP+ form ATP and NADPH which are released into the stroma (and O2 as a waste product).

Calvin Cycle:
Occurs in the stroma, CO2 combines with RuBP and becomes fixed. ATP and NADPH from the light reaction enter into the cycle, synthesizing glucose (c6h12o6) (which is released into the cell), adp and nadp+ which is returned to the thylakoid to be used again

Question 29

What does P680 and P700 mean? Why is this important to know about photosynthesis? Why are leaves green if plants use other wavelengths to gain energy?

Answer 29

Plants are green because the chlorophylls reflect that wavelength. It is the only wavelength on the visible spectrum that is NOT accepted into the plant. The other colors/wavelengths are absorbed.

Question 30

Compare and Contrast the Calvin cycle to the Krebs cycle. (Discuss location, substrates, outputs, and how they generally work—hint: both work in cycles)

Answer 30

Krebs Vs Calvin
TCA: Happens in all aerobic organisms (plants, animals, etc.), in the mitochondrial matrix.
Calvin: Happens in only plants and some protists and bacteria, in the stroma of chloroplasts

TCA: Uses Glucose and Oxygen to make Co2, NADPH, and ATP
Calvin: Uses light, CO2, and Water to make Glucose

TCA: Catabolic reaction (breaks glucose)
Calvin: Anabolic reaction (makes glucose)

TCA: Aerobic process (oxygen is the final receptor at end of ETC)
Calvin: Anaerobic process (molecule –not oxygen– is final receptor)

Question 31

What are the three steps of the Calvin Cycle? Of the three steps, select one that you understand best and describe it.

Answer 31

Reduction (making glucose byproduct), Regeneration (sending adp and nadp+ into thylakoid)

6 CO2 become fixed by RuBP into 2 3-carbon chain compounds, ATP and NADPH (synthesized from the light reaction portion of photosynthesis) donate a phosphate and electrons to the fixed CO2 compounds and form G3P molecules. G3P molecules then form C6H12O6 (glucose)