Biology Chapter 7

Fill-in-the-Blanks(1) __________obtain carbon and energy from the physical environment; their carbon source is(2)___________. (3) ____________ autotrophs obtain energy fromsunlight. T. (4) ___________demonstrated that aerobic bacteria moved to the regions of a strand

2of Spirogyra where red and (5) __________light was falling on the strand; O was producedhere. (6) _________________ feed on autotrophs, each other, and organic wastes;representatives include (7) _________________, fungi, many protistans, and most bacteria.Although energy stored in organic compounds such as glucose may be released by severalpathways, the pathway known as (8) ___________________________ releases the most energy.9. In the space below, supply the missing information to complete the summary equation forphotosynthesis:

2 2 6 12 6 12 ________ + CO —> + O + C H O

10. Supply the appropriate information to state the equation for photosynthesis (above) in words:(a) _____________________ molecules of water plus six molecules of(b)____________________ (in the presence of pigments, enzymes, and sunlight) yield sixmolecules of (c)______________________ plus one molecule of (d) ____________________plus (e)_________________________ molecules of water.The two major sets of reactions of photosynthesis are the (11)________________ reactions andthe (12) ________________________ reactions. (13)______________________and (14) ________________________ are the reactants of photosynthesis, and the end product isusually given as (15) _________________. The internal membranes and channels of thechloroplast form the (16)________________________ membrane and are organized into stacks,called (17) ____________________________. Spaces inside the thylakoid disks and channelsform a continuous compartment where (18) _______________________ions accumulate to beused to produce ATP. The semifluid interior area surrounding the thylakoid is known as the (19) ___________________________ and is the area where the products of photosynthesis areproduced. Although glucose is commonly listed as the end product of photosynthesis, littleglucose is actually found in the cells, since the glucose phosphate produced is quickly convertedinto (20) ________________________, (21) _____________________, and (22) ________________.

a. thylakoid membrane b. stroma23. ____ Light-independent reactions24. ____ Sugars are assembled25. ____ Light-dependent reactions26. _____ ATP production27. _____ Carbon dioxide provides the carbon

28. _____ Sunlight energy is absorbed 29. _____ Water molecules are split30. _____ NADPH delivers the hydrogen received from water31. _____ Oxygen is formed

Fill-in-the-BlanksThe light-capturing phase of photosynthesis takes place on a system of (1) _________

membranes. A(n) (2) _______________ is a packet of light energy. Thylakoid membranes

contain (3) ______________________, which absorb photons of light. The principal pigments

are the (4) __________________, which reflect green wavelengths but absorb (5) ____________

and (6) _____________________ wavelengths. (7)__________________ are pigments that

absorb violet and blue wavelengths but reflect yellow, orange, and red.A cluster of 200 to 300 of

these pigment proteins is a(n) (8) __________________________.

Matching Choose the most appropriate answer.

9. ____ Chlorophyll 10. ____ accessory pigments 11. _____ carotenoids 12. ____ violet—blue—green—yellow—red 13. ____ photons 14. ____ Chloroplast15. ____ phycobilins 16. ____ thylakoid17. ____ pigments

A. Packets of energy that have an undulating motion

through space

B. The two stages of photosynthesis occur here

C. Molecules that can absorb light

D. Absorb violet and blue wavelengths but transmit

red, orange, and yellow

E. Visible light portion of the electromagnetic spectrum

F. Pigments that transfer energy to chlorophyll a

G. Absorb violet-to-blue and red wavelengths; the

reason leaves appear green

H. Red and blue pigments

I. The site of the first stage of photosynthesis

LabelingThe following diagram illustrates noncyclic photophosphorylation. Identify each numbered part of the illustration.

2.__________________________

3.__________________________

4.__________________________

5._______________________________

6._______________________________

7._______________________________

8._______________________________

Fill-in-the-Blanks

ATP forms in both the cyclic and noncyclic pathways. When (9)___________________ flow

through the membrane-bound transport systems, the systems also pick up hydrogen ions (H )

outside the membrane and shunt them into the (10)___________________ . compartment. This

sets up Hf-concentration and electric (11) ___________________ across the membrane.

Hydrogen ions that were split away from (12)___________________ molecules increase the

gradients. The ions respond by flowing out through the interior of (13) ___________________

proteins that span the membrane. Energy associated with the flow drives the binding of unbound

phosphate (F1) to ADP, the result being (14) ___________________ . The above description is

known as the (15)___________________ theory of ATP formation. The noncyclic pathway also

produces (16) __________________ by using (17) ___________________ from water and H

ions from the thylakoid compartment to reduce NADP.

Label and Match Identify each part of the following illustration. Complete the exercise bymatching and entering the letter of the proper function description in the parentheses followingeach label.

1. ________________________( )

2. ________________________( )

3. ________________________( )

4. ________________________( )

5. ________________________( )

6. ________________________( )

7. ________________________( )

8.________________________ ( )9.________________________ ( )

A. A three-carbon sugar, the first sugar produced; goes on to form sugar phosphate and RuBPB. Typically used at once to form carbohydrate end products of photosynthesis

2C. A five-carbon compound produced from PGALs; attaches to incoming COD. A compound that diffuses into leaves; attached to RuBP by enzymes in photosynthetic cellsE. Includes all the chemical reactions that “fix” carbon into an organic compoundF. Three-carbon compounds formed from the splitting of the six-carbon intermediate compoundC. A molecule that was reduced in the noncyclic pathway; furnishes hydrogen atoms to construct sugar moleculesH. A product of the light-dependent reactions; necessary in the light-independent reactions to energize molecules in metabolic pathways

2I. Includes all the chemistry that fixes CO converts PGA to PGAL and PGAL to RuBP and sugar phosphates

Self-Quiz

_____ 1. The electrons that are passed to NADPH

during the noncyclic pathway of photo synthesis were

obtained from

2a. water b. CO d. sunlightc. glucose

_____ 2. The cyclic pathway of the light- dependent

reactions functions mainly to _______________ .

a. fix CO2

b. make ATP

c. produce PGAL

d. regenerate ribulose bisphosphate

____ 3. Chemosynthetic autotrophs obtain en

ergy by oxidizing such inorganic sub

stances as ________________ .

a. PGA b. PGAL c. sulfur d. water

_____ 4. The ultimate electron and hydrogen acceptor

in noncyclic photophosphorylation is

_______________ .

2 2a. NADP b. ADP c. O d. H O

____ 5. C4 plants have an advantage in hot, dry

conditions because _______________

a. their leaves are covered with thicker wax layers than

those of C3 plants

b. their stomates open wider than those of C3 plants,

thus cooling their surfaces

c. they have a two-step CO2 fixation that reduces

photorespiration

d. they are also capable of carrying on photo-respiration

_____ 6. Chlorophyll is

a. on the outer chloroplast membrane

b. inside the mitochondria

c. in the stroma

d. in the thylakoid membrane system

_____ 7. Which of the following is applicable to C3

plants?

a. At the end of carbon fixation, the intermediate

compound is PGA.

b. At the end of carbon fixation, the intermediate

compound is oxaloacetate.

c. They are more sensitive to cold temperatures than are

C4 plants.

d. Corn, crabgrass, and sugarcane are examples of C3

plants.

2____ 8. Plant cells produce 0 during

photosynthesis by .

2a. splitting CO

b. splitting water

c. degradation of the stroma

d. breaking up sugar molecules

_____ 9. Plants need and _______________ to carry on

photosynthesis.

a. oxygen; water

2b. oxygen; CO

2 2c. C0 H 0

d. sugar; water

_____ 10. The two products of the light-dependent

reactions that are required for the light-independent

chemistry are _____________ and

2 2a. C0 ; H 0 b. 02; NADPH

2 c. 0 ; ATP d. ATP; NADPH