Weeks 4-5 Lecture: Plant Cell Metabolism (Diffusion, Osmosis, Photosynthesis, and Respiration)

Question 1

Refers to the net movement of particles (atoms, molecules, or ions) from a region of higher concentration to a region of lower concentration as a result of random motion.

Answer 1

Diffusion

Question 2

What are the two main types of diffusion?

Answer 2

1. Passive diffusion
2. Facilitated diffusion

Question 3

Cell membranes are made of a phospholipid bilayer that has a non-polar ___, or water fearing, middle layer that is protected on both sides by polar ___, or water-loving, surfaces. Hydrophobic molecules can freely pass through a cell membrane.

Answer 3

hydrophobic, hydrophilic

Question 3

The movement of molecules across semi-permeable membrane without the help of protein channels thus, does not require energy.

Answer 3

Passive diffusion

Question 3

The flow of molecules down a concentration gradient across a membrane through special passageways.

Answer 3

Facilitated diffusion

Question 3

__ is the assisted movement of a substance from a lower concentration to a higher concentration of that substance.

Answer 3

Active transport

Question 3

A special kind of diffusion exhibiting passive transport. It is the net movement of water (the principal solvent in biological systems) by diffusion through a selectively permeable membrane.

Answer 3

Osmosis

Question 3

__ is a movement of ions and other atomic or molecular substances across cell membranes without need of energy input.

Answer 3

Passive transport

Question 3

__ requires the expenditure of the cell’s energy to move specific substances against their concentration gradients.

Answer 3

Active transport

Question 3

What are the three types of solutions created by osmosis?

Answer 3

1. Hypertonic
2. Isotonic
3. Hypotonic

Question 3

__ and __ are passive processes that allow specific
substances to move down their concentration gradients.

Answer 3

Diffusion, facilitated diffusion

Question 3

When a cell is placed in a solution with a solute concentration equal to that inside the cell, water molecules diffuse through the plasma membrane equally in both directions. Such solutions are said to be ___ (from the Greek iso, “equal”) – that is, they have a solute concentration equal to that in the cell.

Answer 3

isotonic

Question 3

When a cell is placed in a solution with a solute concentration higher than that within the cell, the solution is said to be (from the Greek hyper, “over”) to the cell.

Answer 3

hypertonic

Question 3

When a cell is placed in a solution with a solute concentration lower than that within the cell, the solution is said to be ___ (from the Greek hypo,
“under”) to the cell.

Answer 3

hypotonic

Question 3

A __ plant cell has gaps between the cell wall and the cell membrane. This occurs when a plant cell is placed in a hypotonic solution. Water molecules move out of the cell resulting in the loss of turgor pressure.

Answer 3

plasmolyzed

Question 4

A __ plant cell is not swollen and the cell membrane does not press against the cell wall tightly. This occurs when a plant cell is placed in an isotonic solution. There would be no net movement of water molecules between the cell and the surrounding fluid.

Answer 4

flaccid

Question 4

A __ cell is a cell that has turgor pressure. A plant cell that is placed in a hypotonic solution would cause the water to move into the cell by osmosis, resulting in large turgor pressure being exerted against the plant cell wall.

Answer 4

turgid

Question 4

The chemical processes that occur in a cell are collectively referred to as its ___.

Answer 4

metabolism

Question 5

___ reactions (also called anabolism) are chemical reactions in which energy is stored in molecules.

Answer 5

Anabolic

Question 5

___ reactions (also called catabolism) are chemical reactions in which energy is released from molecules.

Answer 5

Catabolic

Question 6

___ is a chemical process in which a substance loses electrons.

Answer 6

Oxidation

Question 7

___ is a chemical process in which a substance gains electrons.

Answer 7

Reduction

Question 8

___ makes up a small portion of the electromagnetic spectrum, which is a vast, continuous range of electromagnetic radiations generated through space and matter.

Answer 8

Light

Question 8

The portion electromagnetic from of the spectrum
380 and 760 nanometers is called the ___ because humans can see it.

Answer 8

visible spectrum

Question 8

Light is composed of small
particles of energy called
___.

Answer 8

photons

Question 8

The lowest energy state an electron possesses is called the ___.

Answer 8

ground state

Question 9

When an electron is raised to a higher energy level than its ground state, the electron is
said to be ___.

Answer 9

energized

Question 10

In plants and algae, photosynthesis takes place in ___ where the photosynthetic pigment ___ captures the energy from sunlight

Answer 10

chloroplasts, chlorophyll

Question 11

A chloroplast contains:

Answer 11

• Stroma
• A fluid
• Grana
• Stacks of thylakoid containing chlorophyll

Question 12

Chloroplast pigments:

Answer 12

• Chlorophyll a
• Chlorophyll b
• Carotenoids

Question 13

This is the main pigment of photosynthesis, absorbs light primarily in the blue and red regions of the visible spectrum

Answer 13

Chlorophyll a and b

Question 14

There are several kinds of chlorophyll. The most important is __ which is the pigment that initiates photosynthesis

Answer 14

chlorophyll a

Question 15

__ is an accessory pigment that also participates in photosynthesis.

Answer 15

Chlorophyll b

Question 16

___ absorbs wavelengths of light different from those absorbed by chlorophyll, thereby expanding the spectrum of light that provides energy for photosynthesis

Answer 16

Carotenoids

Question 17

The reactions of photosynthesis occur in two stages:

Answer 17

• Light-dependent reactions
• Carbon fixation reactions

Question 18

This is the photo part of photosynthesis

Answer 18

Light-dependent reactions

Question 19

This is the synthesis part of
photosynthesis

Answer 19

Carbon fixation reactions

Question 20

Light energy is converted to chemical energy in the light dependent reactions, which are associated with the thylakoids

Answer 20

Light-dependent reactions

Question 21

The most common carbon fixation pathway is known as the Calvin cycle, Calvin-Benson Bassham (CBB) cycle, reductive pentose phosphate cycle (C3 cycle)

Answer 21

Carbon fixation reactions

Question 22

1. The light-dependent reactions of photosynthesis begin when chlorophyll a or accessory pigments absorb light.
2. Two types of photosynthetic units, designated as
   photosystem I and photosystem II, are involved in
   photosynthesis.
3. These two connected photosystems collect photons of light and transfer the energy to chlorophyll electrons.
4. The excited electrons are passed from the primary electron acceptor to electron transport chains.
5. Their energy ends up in ATP and NADPH.

Answer 22

Detailed process of photosynthesis

Question 23

• The electron transport chains are arranged with the photosystems in the thylakoid membranes and pump ___ through that membrane.
• The flow of H+ back through the membrane is harnessed by ATP synthase to make ___.
• In the stroma, the H+ ions combine with NADP+ to form ___.

Answer 23

• H+
• ATP
• NADPH

Question 24

The entire process which produces O2, NADPH, and ATP, is known as ___.

Answer 24

noncyclic electron transport

Question 25

Noncyclic electron transport is ___ because
there is a continuous, one-way flow of electrons
from water (the ultimate electron source) to
NADP+ (the terminal electron acceptor)

Answer 25

noncyclic

Question 26

The ___ of photosynthesis also include cyclic electron transport, a cyclic flow of electrons through photosystem I that produces ATP.

Answer 26

light-dependent reactions

Question 26

Most plants use the ___ to fix carbon.

Answer 26

Calvin cycle

Question 27

The reactions of the Calvin cycle, which occur in the stroma, are divided into three phases:

Answer 27

1. CO2 uptake
2. carbon reduction
3. RuBP regeneration

Question 28

CO2 combines with phosphoenolpyruvate
(PEP) in the chloroplasts of mesophyll cells,
forming a four-carbon compound that is
converted to ___.

Answer 28

malate

Question 29

___ goes to the chloroplasts of bundle sheath cells, where it is decarboxylated. The CO2 released in the bundle sheath cell is used to make carbohydrate by way of the Calvin cycle

Answer 29

Malate

Question 30

Plant cells and most other cells extract energy from fuel molecules, such as glucose, fatty acids, and other organic compounds, by ___. This process involves a sequence of 30 or more chemical reactions, each regulated by a specific enzyme

Answer 30

aerobic respiration

Question 31

The chemical reactions of of aerobic respiration are grouped into four tages:

Answer 31

1. Glycolisis
2. Formation of acetyl enzyme A
3. The citric acid cycle
4. Electron transport and chemiosmosis

Question 32

In ___, energy is released from glucose and other fuel molecules without O2; that is, oxygen is not the final electron acceptor in the electron transport chain.

Answer 32

anaerobic respiration

Question 33

___, another anaerobic pathway, also degrades glucose and other organic molecules without oxygen.

Answer 33

Fermentation