Chapter 15- Autotrophic Nutrition

Question 1

Autotroph

Answer 1

An organism that manufactures its own organic molecules such as glucose, amino acids, and fats

Question 2

Organic molecules contain potential energy in form of:

Answer 2

organic bonds

Question 3

Photosynthesis

Answer 3

A metabolic process where solar energy is trapped, converted to chemical energy, and then stored in the bonds of plant organic nutrient molecules.

Question 4

Plants use Co2 and water to make:

Answer 4

glucose and oxygen

Question 5

Chloroplast

Answer 5

Specialized organelle in plants where photosynthesis takes place. Highly organized plastid containing the chlorophyll pigment

Question 6

Do photosynthetic bacteria have chloroplasts?

Answer 6

No, but they have membranes that function in a similar manner.

Question 7

Chloroplast is bounded by:

Answer 7

Two membranes and contains a network of membranes called thylakoid membranes.

Question 8

Chlorophyll resides within the:

Answer 8

thylakoid membranes

Question 9

Grana

Answer 9

Stacks of thylaoid membranes

Question 10

Stroma

Answer 10

fluid matrix of the chloroplast

Question 11

Cofactor of chlorophyll?

Answer 11

Magnesium

Question 12

Why is chlorophyll green?

Answer 12

It absorbs light in red and blue wavelengths

Question 13

Two types of chlorophylls?

Answer 13

A and B

Question 14

Photosystem

Answer 14

light-capturing unit of the thylakoid membrane.

Question 15

What is each photosystem composed of?

Answer 15

A number of chlorophyll molecules. In the center is a single chlorophyll molecule coupled to other proteins that is ultimately excited by the absorbed photon.

Question 16

Photosystem I: Chlorophyll A molecule is called because—

Answer 16

it absorbs best at 700 nm

Photosystem II= 680 nm

Question 17

Net reaction of photosynthesis:

Answer 17

6CO2 + 12 H2O + light energy —-> C6H12O6+ 6O2+ 6H20

Question 18

Light reactions

Answer 18

Convert solar energy into chemical energy in the form of ATP (photophosporylation) and NADH. Must take place in light.

Question 19

Dark reactions

Answer 19

Coupled to light reactions. They incorporate Co2 into organic molecules in a process called carbon fixation.

Carbohydrates are produced by reducing CO2

Question 20

Cyclic electron flow

Answer 20

Photons of light excite electrons in P700 PSI. the high energy electrons are transferred to NADP+ and forms NADH

P700 is left with electrol hole and is a powerful oxidizing agent

Question 21

What happens when light strikes P680 in PSII

Answer 21

Electrons are excited and travel down the same electron carrier chain used by cyclic electron flow until they reach P700 and fill in the electron holes– this is NONCYCLIC photophosphorylation

Question 22

How does P680 fill its electron holes

Answer 22

P680 is a strong enough oxidizing agent to oxidize water and fill its holes. Water is split into two hydrogen ions and an oxygen atom, and the electrons produced reduce P680. Oxygen atoms combine to form O2

Question 23

What is the net result of noncyclic electron flow?

Answer 23

Productin of NADPH and ATP and the photolysis of water

Question 24

Photoionization

Answer 24

Escape of high energy electrons from chlorophyll molecules.

Question 25

What do dark reactions use? What do they produce?

Answer 25

They use ATP and NADPH produced by the light reactions to reduce CO2 to carbohydrates, primarily glucose.

Question 26

When do dark reactions take place?

Answer 26

During days when light reactions are replenishing supply of ATP and NADPH. Doesn't need direct light.

Question 27

What is the source of carbon for carbohydrates production in the Calvin Cycle?

Answer 27

CO2

Question 28

What is the product of the calvin cycle?

Answer 28

Three-carbon sugar phosphoglyceraldehyde (PGAL)

Question 29

What must happen to produce three-carbon sugar from the calvin cycle?

Answer 29

It must take place 3 times

Question 30

What happens during the calvin cycle?

Answer 30

CO2+ ribulose biphosphate (5 c sugar) which produuces an unstable six-carbon intermediate which splits to two 3-carbon molecules of 3-phosphoglyceric acid. Acid phosphorylated by ATP and reduced by NADPH to give PGAL (glycealdehyde-3-phosphate) Two molecules of PGAL can be converted into glucose, which can then be oxidize to provide usable energy.

Question 31

What is the Calvin cycle similar to?

Answer 31

The Krebs cycle in revese

Question 32

What happens to most of the PGAL?

Answer 32

It is recycled to RBP by a complex series of reactions

Question 33

In 6 turns of the Calvin cycle, what is formed?

Answer 33

12 PGAL from 6 CO2 and 6RBP | The 12 PGAL recombine to form 6 RBP and 1 molecule of glucose, the net product.

Question 34

Prime end product of photosynthesis

Answer 34

PGAL

Question 35

What can PGAL be used as?

Answer 35

An immediate food nutrient combined and rearranged to form monosaccharide sugars (such as glucose) which can be transported to other cells It can also be packaged for storage as insoluble polysaccharides such as starch.

Question 36

Waxy cuticle of lead

Answer 36

Adaptation to reduce transpiration and conserve water. Leaves have no openings on the upper surface

Question 37

Palisade

Answer 37

Adaptation of leaf. Layer of elongated, chloroplast-containing cells spread over a large surface area. Directly under the upper epidermis and are well exposed to light.

Question 38

Spongy layer.

Answer 38

Adaptation of leaf. Stomata open to air spaces that contact internal moist surface called spongy layer cells. Necessary for diffusion of gases into and out of cell, for photosynthesis and respiration. Contain chloroplasts

Question 39

Guard cells

Answer 39

of leaves. Surround each stomata on the lower surface of the leaves. Regulate the size of the opening. Open stomata during day to admit CO2 for photosynthesis and clsoe them at night to limit the loss of water vapor by transpiration

Question 40

Stomata

Answer 40

Openings in the lower epidermis of a leaf that permit diffusion of carbon dioxide, water vapor, and oxygen between the leaf and the atmosphere.

Question 41

What do guard cells do during the day?

Answer 41

Produce glucose

Question 42

What does the presence of high glucose content in the cells do?

Answer 42

They swell up by osmosis (turgor). Because the inner wall of the guard cell is thickened, the swelling produces a curvature of the opening between the guard cells and the stomata opening the increases.

Question 43

What happens at night?

Answer 43

Cell turgor decreases and turgor pressure decreases.

Question 44

What will happen in the stomata during a drought?

Answer 44

The stomata will close even during the day time to prevent loss of water by transpiration. Photosynthesis will cease because of a lack of CO2.

Question 45

Vascular bundle

Answer 45

Veins containing xylem and phloem bring water to the leaf from roots (x) and carry manufactured food out of the leaf (p)

Question 46

Specialized epidermal cells with thin-waled root hair are found in the: What do they do?

Answer 46

Root. They provide an increased surface for absorption of water and minerals by diffusion and active transport.

Question 47

Chemosynthesis

Answer 47

Use of chemical energy by bacteria to form carbohydrates. Use chemical energy rather than radiant energy from the sun.

Question 48

What do nitrifying cateria do?

Answer 48

Oxidize ammonia and nitrites into mitrates. The plants use this nitrate to make proteins. The bacteria use the energy obtained from this oxidation to make glucose.

Question 49

Nitrogen, sulfur and iron bacteria

Answer 49

Bacteria that oxidize these elements-- use the small amount of energy from this oxidation to form glucose and preform vital organs.