C1 Flashcards
1
Q
True or False
Diffusion and osmosis are forms of active transport
A
False
2
Q
True for False
Xylem in plant cells transports water to different parts of plants
A
True
3
Q
True or False
Humans produce oxygen through cellular respiration
A
False
4
Q
True or False
Chlorophyll is the only pigment in plant cell
A
False
5
Q
Photosynthesis
A
A process that converts solar energy into chemical energy
6 CO2 + 6 H2O → C6H12O6 + 6 O2
6
Q
___ energy is the ultimate source of energy for mostliving things
A
Solar energy
7
Q
Organisms use energy indirectly from _____ organisms at first trophic levels
A
Photosynthetic
8
Q
As our populations grow, rates of ____ grow, and we become ______ dependent on photosynthesis
A
- Consumption
- More
9
Q
What does light travel in
A
Waves called photons (small units of energy)
10
Q
Short vs. Long wavelenghts
A
- Short wavelenghts have high energy
- Long wavelenghts have low energy
11
Q
What type of radiation is light
A
Electromagnetic
Includes X-rays, radiowaves
12
Q
What colors is visible light composed of
A
White light is a mixture of all visible light/colors
13
Q
What wavelenght is light from the sun
A
Light from the sun is a mixture of different wavelenghts
13
Q
What energy is required for photosynthesis
A
Light energy
14
Q
Chlorophyll
A
- Green coloured pigment
- Found in plants, algae, protists, cyanobacteria
- Absorbs photons and begins photosynthesis
15
Q
Different types of Chlorophyll found in photosynthetic organisms
A
- Chlorophyll-A (blue-green) is the primary light absorbing pigment
- Chlorophyll-A and B absorb photons with energies in the blue-violet and red regions of the spectrum and reflect/transmit those wavelenghts
16
Q
Accessory Pigments
A
- Chlorphyll B (yellow-green)
- Carotenoid (orange)
17
Q
Role of accessory pigments
A
Accessory pigments abosrb other photon wavelenghts and pass the energy to chlorophyll A
18
Q
Spectrophotometer
A
Can determine the absorption spectrum of pigments, shows which pigments absorb which wavelenghts of colors
19
Q
Chromatography
A
Technique used to seperate pigments
- Pigments dissolved in fluid
- Fluid passes through material
- Pigments move at different speeds (distances)
20
Q
Chloroplast Structure
Stroma
A
Gel-like enzyme-rich substance filling chloroplast
Protein-rich semilquid material. This is where chemical reactions and synthesis of carbs occurs
21
Q
Chloroplast Structure
Thylakoids
A
A system of membrane-bound sacs that stack on top of each other to form columns
21
Q
Plant cell requirements to undergo photosynthesis
A
- Chlorophyll
- Be able to obtain CO2 and H2O
- Be able to capture solar energy from the environment
22
Q
Chloroplast Structure
Membranes
A
2 limiting membranes: Inner and Outer
23
# Chloroplast Structure
Grana Stacks
* Stacks of thylakoid discs
* One chloroplast may have 60 grana; each containing 30-50 thylakoids
24
Lamellae
Unstacked thylakoids that connect adjacent grana
25
# Chloroplast Structure
Thylakoid Membrane
Contains light gathering pigment molecules and other molecules and complexes essential to the process.
## Footnote
Enclose an interior (water filled) thylakoid space
26
# Chloroplast Structure
Lumen
A fluid-filled space inside thylakoid
27
# Leaf Structure
Where are chloroplasts found
In the palisade mesophyll
28
# Leaf Structure
How does sunlight reach the palisade mesophyll layer
Sun passes through waxy cuticle, through the upper epidermis into the palisade mesophyll layer
29
# Leaf Structure
Palisade Tissue Cells
* Long, narrow cells packed with chloroplasts.
* Under the uppper surface of the leaf
* Where most photosynthesis occurs in the leaf
30
# Leaf Structure
Vascular Tissue Cells
* Xylem tubes carry water and minerals from the roots to the leaves
* Phloem tubes carry sugars to various parts of the plant
31
# Leaf Structure
Spongy Tissue Cells
* Round and more loosely packed than palisade cells, with many air spaces between them
* These cells have chloroplasts so they perform some photosynthesis
* Their structure helps the cells to exchange gasses and water with the environment
32
# Leaf Structure
Stomata
* Small opening in the outer (epidermal) layer that allow CO2 into the leaf and O2 out of the leaf
* H2O also diffuses out of the leaf through stomata
33
# Products of Photosynthesis
ATP
* High energy molecule used by all living cells
* Provides an immediate source of energy for cellular processes
* Formed by addition of ADP and Pi
34
ADP
* A molecule containing 2 high-energy phosphate bonds that may be formed by breaking one of the phosphate bonds in ATP
* ADP + Pi + Energy → ATP
* Energy comes from the chemical potential energy in the bonds of glucose molecules during cell resp.
35
# Products of Photosynthesis
NADPH
* During photosynthesis NADP+ accepts 1 H atom and 2 e- to form NADPH
* NADPH is an electron donor, thus it becomes NADP+ again
* Involved in energy transfers
36
# Products of Photosynthesis
Glucose
* Transport Molecule (blood sugar)
* Medium-term energy storage (bonds)
37
Light dependent reactions
* Directly energized by light
* Require chlorophyll
* Occur in thylakoid membrane
38
# Stages of Photosynthesis
Light independent reaction (dark reaction)
Calvin Cycle
39
# Light-Dependent Reactions
Photosystems
Membrane proteins; cluster of photosynthetic pigments responsible for capturing light
## Footnote
Photosystems are named in the order they were discovered. Photosystem I was discovered first but actually comes second in this process
40
# Light-Dependent Reaction
Reduction + Oxidation Reaction
| LEO the lion goes GER
* Lose Electrons → Oxidation
* Gain Electrons → Reduction
| Occurs with NADP+ and NADPH
## Footnote
When electrons transfer between two substances, both oxidation and reduction reactions occur simultaneously
41
What type of reaction is photosynthesis
Photosynthesis is a redox reaction
* CO2 & C6H12O6 is reduced
* H2O & O2 is oxidized
42
# Light-Dependent Reaction
Step 1
**Photo-excitation:**
1. Photon from the sun strikes a molecule of chlorophyll inside of PS II (wavelenght of 680)
2. That electron absorbs the energy from the photons and gets excited (low energy to high energy due to the photon)
3. It leaves photosystem II to travel down the ETC towards PS I
| The missing electron will be replaced by step 3
43
# Light-Dependent Reaction
ETC
A series of progressively stronger electron acceptors; each time an electron is transferred energy is released
43
# Light-Dependent Reaction
Step 2
**ETC (PS II → PS I):**
* Electrons move through the proteins in the ETC
* As it moves through the ETC, the electron releases energy (decreased potential energy)
* The chain uses energy released from the electron to bring hydrogen ions into thylakoid
## Footnote
Occurs at the same time as step 3
44
# Light-Dependent Reaction
Step 3
**Photolysis:**
* Occurs within the thylakoid
* Water is split into Hydrogen, Oxygen and an electron
* 2 H2O + solar energy → 4 H+ + 4 e- + O2
* Oxygen: released from leaf back into air
* Hydrogen: continue to build up hydrogen ions in the thylakoid
* Electron: replaces the missing electron from PS II
## Footnote
Occurs simultaneously with step 2
45
# Light-Dependent Reaction
Step 4
**Chemiosmosis:**
* Hydrogen is pumped into thylakoid lumen and the resulting energy helps generate ATP through a REDOX reaction
* ATP Synthase Complexes: Protein complexe embedded in thylakoid membrane that allows H+ ions to escape from lumen and uses the resulting energy to generate ATP
46
# Light-Dependent Reaction
Step 5
**Reduction ADP → ATP:**
* Once the hydrogen ions pass through ATP synthase a reduction reaction occurs
47
# Light-Dependent Reaction
Step 6
**ETC (PS I → Stroma):**
* Occurs within the thylakoid membrane
* Electron absorbs the energy from the photons (photoexcitation)
* Once it absorbs a lot of energy, it leaves PS I to head towards the stroma
48
# Light-Dependent Reaction
Step 7
**Reduction NADP+ → NADPH:**
* NADP+ + H+ + 2e- → NADPH → Calvin Cycle
* NADP+ is reduced
* NADPH is oxidized
* NADPH had reducing power because it can donate an electron
49
4 Main Steps in ETC
1. e- from PS II are transferred along an ETC and across the thylakoid membrane to inner surface
2. Some of their energy is uised to pull H+ ions across the membrane = positive charge building in lumen
3. e- that have lost lots of original energy are transferred to chlorophyll molecules in PS I where they absorb energy again and reach excited state
4. High-energy e- from PS I are transferred to NADP+ to form NADPH
50
# Light Independent
Calvin Cycle
* Does not require en energy from photons
* Occurs in the stroma (empty space in chloroplast)
* Mechanism: Carbon fixation - forms high-energy organic molecules from CO2
51
# Calvin Cycle
Step 1
**Carbon Fixation:**
* Inorganic carbon is turned converted into organic compounds (carbs)
* CO2 + RuBP → 6 Carbon Molecule → 3-PGA + 3-PGA
* CO2 + RuBP → 6 Carbon Molecule → 3-PGA + 3-PGA
* CO2 + RuBP → 6 Carbon Molecule → 3-PGA + 3-PGA
An ezyme called rubisco is required in order to make this reaction happen
## Footnote
* 6 carbon molecule is unstable and breaks into 2 3-PGA molecules immediately
52
# Calvin Cycle
Step 2
**Activation and Reduction:**
* Requires 6 NADPH and 6 ATP molecules (from light dependent reaction)
* 3-PGA + ATP → active 3-PGA + NADPH → G3P
* 3-PGA + ATP → active 3-PGA + NADPH → G3P
* 3-PGA + ATP → active 3-PGA + NADPH → G3P
* 3-PGA + ATP → active 3-PGA + NADPH → G3P
* 3-PGA + ATP → active 3-PGA + NADPH → G3P
* 3-PGA + ATP → active 3-PGA + NADPH → G3P
## Footnote
ATP "activates" 3-PGA and NADPH donates electrons to or reduces, a three-carbon immediate to make G3P
53
# Calvin Cycle
Step 3
**Replacement of RuBp:**
* Requires 5 G3P molescules; 3 ATP (9 total now)
* Production: regenerates RuBP molecules; makes ½ glucose molecule
## Footnote
* ATP activates 3-PGA
* G3P is the building block of glucose; it is still a 3 carbon compound
54
# Calvin Cycle
Molecules Used
* 3 ATP and 2 NADPH consumed for every 1 CO2 that enters
* 18 ATP and 12 NADPH produces 1 glucose
* 6 H2O consumed for every glucose formed
55
Where does the Calvin Cycle occur
In the stroma of the chloroplast
56
How does CO2 enter plant leaf cells
CO2 doffises directly into the photosynthesizing plant leaf cells and chloroplasts from air spaces within the leaves
## Footnote
The air spaces are connected to the outside environment via tiny openings in the surface of the leaves
57
Effect of temperature on Rubisco
| IB
* Rubisco (enzyme) has an optimal temperature
* Increasing temp. increase the likelihood of a collision between Rubisco, RuBP and CO2 until the enzyme denatures because temp. is too high
* Optimal temp. is at which photosynthesis rate is at its fastest
58
Effect of light intensity on chlorophyll
| IB
* As light intensity increases, more chlorophyll becomes photo-activated until all of it is activated in which photosynthetic rate will plateau
* This is because there are a limited number of chlorophyll molecules
