Unit 4 Questions Flashcards
1
Q
What is energy?
A
Ability to do work
2
Q
What is energy NOT?
A
Matter
3
Q
What do all cells need to carry out their activities?
A
Energy
4
Q
Where does all energy ultimately come from?
A
The Sun
5
Q
What are the two states of energy?
A
- Kinetic energy
- Potential energy
6
Q
What is kinetic energy?
A
The energy of motion
7
Q
What is potential energy?
A
Stored energy
8
Q
What forms can energy take?
A
- Heat
- Electrical
- Light
- Sound
9
Q
What form of energy comes from the sun?
A
Radiant energy
10
Q
What does the First Law of Thermodynamics state?
A
Energy can be transferred but not created or destroyed
11
Q
What is the Second Law of Thermodynamics?
A
Entropy law; loss of usable energy as heat during energy transfer
12
Q
What does the law of conservation of mass state?
A
Matter is neither created nor destroyed by chemical reactions or physical transformations
13
Q
What must equal in a chemical reaction according to the conservation of mass?
A
The mass of the products must equal the mass of the reactants
14
Q
Fill in the blank: Energy flows, but ______ is recycled.
A
Matter
15
Q
What is energy from the sun used for?
A
To build molecules that possess potential energy for cellular work.
16
Q
What are autotrophs?
A
Organisms that can synthesize organic molecules for food.
17
Q
What are heterotrophs?
A
Organisms that consume organic molecules for energy.
18
Q
What are photoautotrophs?
A
Organisms that use photosynthesis to make organic molecules from sunlight.
19
Q
Examples of photoautotrophs?
A
Plants, bacteria, and some protists.
20
Q
What are chemoautotrophs?
A
Organisms that use chemosynthesis to obtain energy.
21
Q
Example of a chemoautotroph?
A
Sulfur bacteria.
22
Q
What are endergonic reactions?
A
Reactions that require energy inputs.
Example: Photosynthesis (6H2O + 6CO2 + light energy → 6O2 + glucose).
23
Q
What are exergonic reactions?
A
Reactions that release energy.
Example: Cellular Respiration (C6H12O6 + 6O2 → ATP energy + 6H2O + 6CO2).
24
Q
What is metabolism?
A
The total of the chemical reactions in all cells.
25
What are metabolic pathways?
Series of connected chemical reactions that feed eachother. Processes that include catabolic and anabolic pathways.
26
What do catabolic pathways do?
Break down large molecules and release energy.
27
What do anabolic pathways do?
Use energy from catabolic pathways to build larger molecules from smaller ones.
28
What is the relationship between catabolic and anabolic pathways?
There is a continual energy flow between the two.
29
What is photosynthesis?
An metabolic (anabolic) pathway that transforms light energy into chemical energy.
30
What is cellular respiration?
A metabolic (catabolic) pathway that transforms chemical energy into usable energy (ATP).
31
What is one special adaptation that leaves have to help them trap as much sunlight as possible?
The structure of the leaf, particularly the bottom and sides, is adapted to maximize sunlight absorption.
32
What are the two functions of the stomata?
1. Allow gas exchange (CO2 in, O2 out)
2. Regulate water loss through transpiration.
33
What is an important function of the waxy cuticle that relates to photosynthesis?
The waxy cuticle helps to reduce water loss, allowing the leaf to maintain moisture for photosynthesis.
34
Describe the path of water from the environment to the leaf's palisade mesophyll.
Water is absorbed by the roots, travels through the xylem, and reaches the palisade mesophyll in the leaf.
35
What are the two types of tissues found inside plant veins?
Xylem and phloem.
## Footnote
Xylem carries water and minerals up from the roots, while phloem carries nutrients away from the leaf.
36
What is the role of chloroplasts in plants?
Chloroplasts are organelles where photosynthesis occurs.
37
What structures are indicated on the chloroplast?
The thylakoid membranes and stroma are key structures within the chloroplast.
38
What is photosynthesis?
Photosynthesis is the process by which plants convert sunlight, water, and carbon dioxide into oxygen and glucose.
39
What enters the leaf during photosynthesis?
Carbon dioxide, sunlight, and water as a liquid.
40
What substances leave the leaf during photosynthesis?
Water as a gas, oxygen, and sugary substances.
41
Which substance is both entering and leaving the leaf?
Water (as a gas and liquid).
42
What is the role of veins in a leaf?
Veins are important structures that carry materials through the leaf.
43
Why is a leaf compared to a factory?
A leaf is like a factory because it processes sunlight, water, and carbon dioxide to produce food.
44
Which part of a leaf is exposed to the most light?
The top of the leaf.
45
What are the cells that contain chlorophyll?
Palisade mesophyll cells.
46
What are the two types of molecules that plants are made up of?
Plants are made up of water and organic molecules (e.g. sugars, cellulose, starch, and proteins).
47
What is the typical mass composition of a small plant?
For a typical small plant, more than half of the total mass is organic molecules and the rest is water.
48
How does a plant obtain or produce organic molecules?
A plant obtains or makes organic molecules from soil, into roots, into stems, and through photosynthesis.
49
What is the process of photosynthesis?
During photosynthesis, light energy is converted to chemical energy stored in the bonds of sugar molecules.
50
What is the chemical equation for photosynthesis?
6 CO2 + 6 H2O + sunlight → 6 O2 + C6H12O6
51
What are some organic molecules produced from glucose?
Some organic molecules produced from glucose include cellulose, starch, proteins, and amino acids.
52
What is cellulose and how is it formed?
Cellulose is a polymer made from multiple glucose molecules joined together.
53
What is the goal of photosynthesis?
To produce glucose for cellular respiration.
54
Where does the process of photosynthesis occur?
In the chloroplasts of plant cells.
55
What are the reactants of photosynthesis?
Carbon dioxide (CO2) and water (H2O).
56
How does each reactant get to the site of photosynthesis?
CO2 diffuses in through stomata; H2O is absorbed through roots.
57
What happens to each product of photosynthesis?
Oxygen (O2) is released as a byproduct; glucose is used for energy.
58
What are the three energy transformations in photosynthesis?
Light energy is converted to chemical energy through light-dependent reactions.
59
Why do parts of a plant look green in color?
Special pigments in chloroplasts absorb certain wavelengths of light.
60
What are the best wavelengths of light for photosynthesis?
The blue range (425-450 nm) and red range (600-700 nm).
61
What is a pigment?
A substance that absorbs light at specific wavelengths.
62
What does a green leaf do with light?
It reflects green light and absorbs other wavelengths.
63
Where is chlorophyll found in plants?
In the thylakoid membranes of chloroplasts.
64
What is a key feature of chlorophyll?
It has a central magnesium atom.
65
What are the two forms of chlorophyll?
Chlorophyll a and chlorophyll b.
66
What are the best colors for growing plants?
Blue and red light are the best for photosynthesis.
67
What are the worst colors for growing plants?
Green and yellow light are the least effective.
68
How is red light different from blue light?
Red light has a lower frequency and longer wavelength than blue light.
69
What is a pigment?
A substance that absorbs light, typically found in plants.
70
Describe chlorophyll's structure.
Chlorophyll consists of a porphyrin ring with a central magnesium atom.
71
Why is chlorophyll green?
Because it absorbs blue and red light best, reflecting green light.
72
What are the two phases of photosynthesis?
The light-dependent reactions and the light-independent reactions.
73
Where do the Light Dependent Reactions (LDR) happen?
The Light Dependent Reactions occur in the thylakoid membranes of chloroplasts.
74
When do the Light Dependent Reactions take place?
The Light Dependent Reactions take place during daylight.
75
What is the first step of the Light Dependent Reactions?
Step 1: PHOTOLYSIS (splitting water)
76
What is a waste product of photosynthesis?
Oxygen is a waste product of photosynthesis.
77
What happens during the Electron Transport Chain (ETC)?
Electrons from Photosystem II are passed through a series of protein carriers in the thylakoid membrane.
78
What is Chemiosmosis?
Chemiosmosis is the movement of H+ ions down their concentration gradient through ATP synthase to produce ATP.
79
What happens to the ATP made during the LDR?
ATP takes its energy to the stroma to help in the light independent reactions.
80
What is the role of NADP+ reductase?
NADP+ reductase takes electrons and H+ to form NADPH.
81
What happens to NADPH after it is formed?
NADPH takes its energy to the light independent reactions in the stroma.
82
What are the reactants of the Light Dependent Reactions?
The reactants are water and sunlight.
83
What are the products of the Light Dependent Reactions?
The products are ATP, NADPH, and oxygen.
84
Role of P680
Captures light energy
85
Role of P700
Captures light energy
86
Role of Photolysis
Splits into hydrogen atoms
87
Role of NADP Reductase
Bonds H+ and electrons with NADP
88
Role of ATP Synthase
Protons out of thylakoid
89
What is the free energy?
The usable energy captured from sunlight and then is stored within the chemical bonds on glucose molecules.
90
What is chemiosmosis?
Process of moving ions (protons) across membrane
91
Use of electrochemical gradient in light reactions
To build up energy in the thylakoids
92
Effect of Photosystem I inhibitors
Process to create NADPH is halted
93
Photosystem I summary
Captures light energy
## Footnote
What goes in: Light energy; What comes out: NADPH
94
Photosystem II summary
Captures light energy
## Footnote
What goes in: Light energy; What comes out: Oxygen
