Exam 5: Photosynthesis

Question 1

Photosynthesis

Answer 1

The process that converts solar energy into chemical energy. Directly or indirectly, photosynthesis powers the entire world.

Question 2

What are autotrophs?

Answer 2

They are organisms able to sustain themselves without eating anything derived from another organism.

Question 3

What kind of organisms carry out photosynthesis?

Answer 3

Most plants, algae, certain protists, and some prokaryotes.

Question 4

What are the reactants of photosynthesis?

Answer 4

Carbine dioxide and water

Question 5

What are the products of photosynthesis?

Answer 5

Glucose, oxygen and water

Question 6

What becomes CO2?

Answer 6

Glucose and water molecules.

Question 7

Where does H come from in glucose?

Answer 7

Water

Question 8

Where does oxygen come from in the products?

Answer 8

Water

Question 9

What does a plant do with its end product glucose?

Answer 9

use it for energy

Question 10

Energy

Question 11

What if the function of pigments?

Answer 11

Absorb light energy (electron become excited and move to higher energy levels and then return to their original level, releasing energy)

Question 12

Colors seen are…

Answer 12

The colors that are being reflected (not absorbed)

Question 13

Why plants are green?

Answer 13

The green lights is not absorbed, it is reflected back to our eyes.

Question 14

Chlorophyll a

Answer 14

Main pigment (the most abundant, CH3 non polar)
Bluish green color

Question 15

Accessory pigments

Answer 15

Harvest energy that chlorophyll cannot.

Question 16

Chlorophyll b

Answer 16

Olive green (CHO-polar)

Question 17

Xanthophylls

Answer 17

Found in chloroplast- red, brown; flower colors and protection from UV

Question 18

What colors of light are most used in photosynthesis?

Answer 18

Violet, blue and red.

Question 19

Epidermis

Answer 19

Protection and secretion
-protection from invading organisms and diseases
-nonfunctional and transparent

Question 20

Cuticle

Answer 20

Waxy coating and protection
-protects against water loss and evaporation

Question 21

Stomates

Answer 21

Holes for gas exchange

Question 22

Guard cells

Answer 22

Open and closed stomates
-stomates are controlled by hormone behavior

Question 23

Mesophyll

Answer 23

Where photosynthesis occurs

Question 24

Palisade

Answer 24

Top; main in photosynthesis
-long and packed

Question 25

Spongy mesophyll

Answer 25

Bottom; air spaces

Question 26

Xylem

Answer 26

Dead cells; transport water and dissolved minerals

Question 27

Phloem

Answer 27

Living; transport sugar up and down.

Question 28

Granum

Answer 28

A stack of flat sacs

Question 29

Thylakoid

Answer 29

Each flat sac, light reaction; pigment embedded in the membrane; capture light and convert to chemical energy. Where everything first begins.

Question 30

Stroma

Answer 30

Dense fluid surrounding grana; Calvin cycle (dark reaction) occurs here. Carbon dioxide with light energy to build glucose or other organic compounds.

Question 31

Photosystems

Answer 31

Clusters of pigment molecules in the thylakoid membrane

Question 32

Photosystem I

Answer 32

Special chlorophyll a molecule- P700

Question 33

Photosystem II

Answer 33

Special chlorophyll a molecule - P680

Question 34

Calvin Cycle

Answer 34

-Carbon fixation CO2 is bonded to RuBP to form PGA -ATP and NADPH are needed. ATP releases energy, and NADPH releases electrons and hydrogen from PGAL. ADP and NADP are cycled back to the light reaction. -PGAL is used to make glucose and used to regenerate RuBP

Question 35

Cyclic Photophosphorylation

Answer 35

Performed by some bacteria; and plants perform this when in short of supply of ATP. To increase ATP (it is used much more in the Calvin cycle than NADPH) to catch up with the supply of ATP. - Only photosystem I loses electrons, then the electron transport system, and then returns to P700; chemiosmotic synthesis; ATP only.

Question 36

Photorespiration

Answer 36

oxygen combines with RuBP rather than carbon dioxide, inefficiency. hot dry weather (stomas close)

Question 37

C4 plants

Answer 37

adapted to hot, dry conditions; accumulate CO2 in bundle sheath cell where Calvin cycle is run (so they can grow) Example: tropical pants; crabgrass, and corn.

Question 38

CAM (crassulacean acid metabolism)

Answer 38

Open stomates at night to accumulate CO2 but close during the day. Examples: hens&chicks; cacti; pineapple.

Question 39

Carbon cycle

Answer 39

- CO2 is trapped in photosynthesis, passed through food webs, and returned by respiration, decomposition, and burning fossil fuels.

Question 40

Greenhouse effects

Answer 40

due to layer of CO2 (and other gases); trap infrared radiation; warms earth. CO2 increases, trapping more heat = global warming.

Question 41

Causes of global warming

Answer 41

burning fossil fuels and deforestation

Question 42

Effects of greenhouse

Answer 42

Global climatic sifts; melting of polar ice caps, causing coastal flooding.

Question 43

Solutions for the greenhouse effect.

Answer 43

Reduce fossil fuel consumption and alternative fuel sources, and stop deforestation, and reforestation.