Ch. 5 - Photosynthesis & Cellular Respiration Flashcards
(100 cards)
1
Q
What is cytoplasm?
A
A gel-like material containing dissolved materials within the cell.
2
Q
What is the protoplasm?
A
All substances within a cell (nucleus + cytoplasm)
3
Q
What is the cell membrane?
A
A membrane around the cell contents that exists in a fluid state. It is made up of two layers of lipids with embedded proteins. This structure controls the movement of molecules into and out of the cell.
4
Q
What is the cell wall?
A
A tough outer wall of cellulose that provides protection and support.
This is found in prokaryotic and plant cells only.
5
Q
What is the nucleus?
A
This “control center” regulates the cell’s metabolic functions. It contains DNA which is heredity information concerning the cell’s characteristics.
DNA is organized into a threadlike mass of chromatin which separates into chromosomes when the cell is
dividing.
6
Q
What is the nucleoplasm?
A
Nuclear contents besides DNA.
- Prokaryotic cells have no nuclear membrane, like bacteria and blue-green algae
- Eukaryotic cells have a membrane-bound nucleus and organelles, like fungi, plants, and animals
7
Q
What is the nucleolus?
A
Found in the nucleus. Its function is not known, and may be involved in protein synthesis.
8
Q
What is the mitochondria?
A
The “powerhouse” of the cell, which
produces ATP (energy) by breaking down glucose during cellular respiration.
C6H12O6 (glucose) + 6O2 —–> 6CO2 + 6H2O + ~ 36 ATP.
Looks like a bean with inner membranes.
9
Q
What is the cristae?
A
Folded inner membranes within the mitochondria.
10
Q
What is the ribosome?
A
The smallest organelles of the cell, which are the site of protein synthesis (amino acids are fused together by enzymes). Proteins make up all cell structures and are necessary for growth and reproduction.
11
Q
What is the endoplasmic reticulum? What are the two types and each’s function?
A
Series of canals throughout the cytoplasm.
- Smooth ER: functions in the synthesis of lipids, and is abundant in hormone-producing organs and in seeds
- Rough ER: has ribosomes attached, and is abundant in cells producing many proteins (like the pancreas)
12
Q
What is the Golgi apparatus?
A
Pancake-like structures of membranous stacks of sacs that package RER proteins into vesicles for transport:
- either out of the cell by exocytosis
- to other parts of the cell
13
Q
What is the lysosome?
A
The “suicide bag” contains digestive enzymes that:
- join vesicles or contain damaged/worn-out cell parts to break them down
- digest food particles
Ex: UV light bursts lysosomes, releasing enzymes which kill skin cells (sunburn).
14
Q
What is the cytoskeleton?
A
A network of interconnected fibers made of proteins that maintain cell shape and allow for movement of cell parts and anchors organelles
15
Q
What is the centriole?
A
Small protein bodies, one pair found next to the nucleus in animal cells that replicate and divide before cell division.
16
Q
What are plastids and the three types?
A
Plastids are chemical factories that produce and store food and pigments (in plant cells).
- Chloroplasts, contain the green pigment chlorophyll
- Chromoplasts, store orange/yellow pigment
- Amyloplasts, colourless storing starch
17
Q
What are membranes and where can they be found?
A
Includes cell, thylakoid, and mitochondria membranes.
- Selectively permeable barrier
- Phospholipid bilayer (hydrophilic head, hydrophobic tail).
18
Q
What are membrane proteins?
A
Found in or on membrane, which allow certain substances to pass through the membrane or perform some other function (create ATP for example).
Ex: Integral (pass things through), Glycoprotein (identify)
19
Q
What is diffusion?
A
Particles moving from [high] to [low], down a concentration gradient.
Because of Brownian Motion, and requires no ATP.
20
Q
What is osmosis?
A
Diffusion of water.
21
Q
What is passive transport?
A
Movement of a particle that DOESN’T require energy. Uses a concentration gradient.
(Includes carrier proteins)
22
Q
What is active transport?
A
Movement of particles that REQUIRE energy. Move against a concentration gradient.
(Includes bulk transport)
23
Q
Where does water always move to?
A
Hypertonic (more solute).
24
Q
What is photosynthesis? What is the formula?
A
The most important chemical process on Earth.
Chloroplasts of plants and other photosynthetic organisms trap the Sun’s energy and transform it into energy-rich chemical compounds and oxygen, both essential for life on Earth.
Formula:
6CO2 (g) + 6H2O (l) + light→ C6H12O6 (s) + 6O2 (g)
25
What is cellular respiration? What is the formula?
Animals either eat the plants or eat other plant-eating animals to obtain carbohydrates. During cellular respiration mitochondria within living cells break down the high-energy carbohydrates to generate ATP energy to fuel all life functions.
Formula:
C6H12O6 (s) + 6O2 (g) → 6CO2 (g) + 6H2O (g) + ATP
26
What is ATP (adenosine triphosphate)? What type of reaction is ATP formation?
The direct source of energy for nearly all energy-requiring activities of living organisms.
Energy must be added to make ATP, thus ATP formation is an endothermic reaction. (Glucose makes ATP)
The energy comes from breaking the third bond of ATP into ATP + P.
27
What is phosphorylation?
The addition of a phosphate molecule to ADP.
Formula: ADP + P + energy -> ATP
28
What is dephosphorylation?
The removal of a phosphate molecule from ATP gives off energy.
ATP -> ADP + P + energy
29
Why are phosphorylation and dephosphorylation important?
This continuous cycle of ATP to ADP back to ATP occurs thousands of times each day.
30
Where does photosynthesis take place?
Photosynthesis occurs within the chloroplasts of plant cells (leaves have 500 000 chloroplasts/mm^2). Chloroplasts have flattened sacs of chlorophyll called thylakoids, stacked into columns called grana. Filling the chloroplast is the fluid stroma.
31
What is the chloroplast?
Contain chlorophyll, a photosensitive pigment which absorb solar energy but reflect green light.
32
What is the stroma?
Interior fluid space of the chloroplast, where the light-independent reactions takes place.
33
What are thylakoids?
Flat sacs of chlorophyll, which have a photosynthetic membrane, where the light-dependent reaction occurs.
34
What are grana?
Stacks of thylakoid disks.
35
What are carotenoids?
Accessory pigments absorb blue/green/violet light but reflect yellow (absorb light energy and transfer it to chlorophyll).
36
What are starch grains?
Made by photosynthesis.
37
What is chlorophyll?
A photosensitive pigment that absorbs solar energy but reflects green light.
Gives plants their green colour. In autumn, plants stop producing chlorophyll and thus become red/brown.
38
What is carotene?
Plant pigment that reflects yellow.
39
What is anthocyanins?
Plant pigment that reflects red.
40
What is chromatography?
- A lab technique for the separation of mixtures (for us, pigments in a plant) into its components.
- The mixture is dissolved in a solvent and travels within the solvent (up a filter paper or within a column).
- The solvent moves up the filter paper and each pigment travels with it, but due to the structures of the pigments, some travel further than others. Depends on its polarity.
- The Rf value is defined as the ratio of the distance moved by the solute (the pigment) and the distance moved by the solvent (known as the solvent front) along the paper.
41
Where does cellular respiration take place?
First step glycolysis in the cytoplasm.
The mitochondria, and in cells using a lot of ATP like liver or muscle cells, as many as 1000 mitochondria can be found.
42
What is the cristae?
Mitochondria have an inner membrane with many deep infoldings. Folds provide a large surface area for ATP production.
43
What is the matrix?
Within the cristae is a fluid-filled region.
44
What are metabolic pathways?
Chemical reactions of photosynthesis and cellular respiration take place in a series of step-by-step reactions.
45
Why are metabolic pathways important? Tie in the type of reaction cellular respiration is.
Cellular respiration is a combustion reaction and living cells could not survive the resulting high temperatures and large energy output. Metabolic pathways allows a slow release of energy. The product of one reaction becomes the reactant for another.
46
What is metabolism?
All the chemical reactions that occur within a cell to support and sustain its life functions.
47
What are the two types of metabolic pathways?
- Anabolic pathways
- Catabolic pathways
48
What are anabolic pathways?
(Make) Synthesize larger molecules from smaller ones and requires energy, like photosynthesis.
49
What are catabolic pathways?
Break down larger molecules into smaller ones and release energy, like cellular respiration.
50
What are enzymes?
Specialized proteins acting as biological catalysts that reduce the amount of activation energy needed for the reaction in metabolic pathways.
51
Why are enzymes important?
In the absence of enzymes, the reactions would require high temperatures to activate them which living organisms could not survive. Each of the thousands of reactions in living things have a specific enzyme, enabling the reaction.
52
What are the two types of REDOX reactions?
- Oxidation
- Reduction
53
What is oxidation?
Loss of electrons in a chemical reaction.
54
What is reduction?
Gain of electrons in a chemical reaction (becoming negative).
55
What is an acronym to remember the REDOX reactions?
LEO the lion says GER
- Losing electrons: oxidation
- Gaining electrons: reduction
56
How do REDOX work?
Oxidation and reduction reactions take place at the same time. When one compound loses electrons, another compound gains those elctrons.
57
What is reducing power?
Compounds contain more chemical energy in reduced form than they do in oxidized form, and are said to have this.
Ex: Phone battery charged with electrons.
58
(Characteristics of pigments) Where are photosynthetic pigments found and what do they do?
Photosynthetic pigments are in the thylakoid membrane of the chloroplast and absorb light energy.
59
(Characteristics of pigments) After photosynthetic pigments absorb light energy, what happens?
Energy is passed onto other chemicals, resulting in the synthesis of the high-energy compound: glucose.
60
(Characteristics of pigments) What is the main photosynthetic pigment?
Chlorophyll is the main photosynthetic pigment. It is green, as it reflects/transmits green light, while absorbing blue and red light.
This is why plants are green.
61
(Characteristics of pigments) What are carotenoids?
Another class of pigments---like beta carotene---which absorb blue (violet) green, but reflect yellow, orange, and red.
62
(Characteristics of pigments) Why do plants have a variety of pigments?
It enables a plant to use a greater % of the sun's light.
(Helps determine best light colours)
63
What are photosystems?
Within the chloroplasts, chlorophyll is found in clusters in the thylakoid membranes. These clusters of pigments are called photosystems.
64
What does the capture of light rely on?
Two distinct photosystems:
- Photosystem I
- Photosystem II
65
What happens as light hits the photosystem?
Energy is absorbed and electrons are promoted to an electron acceptor at a higher energy level.
66
What is the electron transport system? What is it like?
(A chemical entity accepting electrons transferred to it) The means by which ATP production occurs within cells. ADP + P <-> ATP.
It is a series of progressively stronger electron acceptors. Each time an electron's transported a small amount of energy is released.
*Think of a staircase, a ball bouncing down and releasing energy as it goes down. This energy is used for ATP/NAPDH.*
67
What are light-dependent reactions and its location?
- Solar energy is trapped and used to make ATP and NAPDH
- O2 is released by the splitting of water
- Happens in the thylakoid membrane (outside)
68
What are light-independent reactions and its location?
(aka the Calvin-Benson Cycle)
- The energy in ATP and NAPDH (from light) are used to convert CO2 into glucose. A series of reactions that synthesize carbohydrates.
- Happens in the stroma of a chloroplast
- Sunlight energy is not required.
69
(Step 1, light-dependent) What is step 1?
- Light energy excites an electron in Photosystem II.
- This electron ins transferred to an electron acceptor (ETS)
- Photolysis occurs occurs releasing H protons, H electrons, and oxygen.
- The electron from water replaces the elctron lost from photosystem II (so it can again absorb light energy)
- The oxygen from the water molecule is converted to molecular oxygen, as a waste product.
- H protons are used in chemiosmosis.
70
(Step 1, light-dependent) What is photolysis and its equation?
The splitting of water by sunlight occurs, releasing H protons, H electrons, and oxygen.
Equation: 2H2O + light -> 4H+ (aq) + 4H- + O2 (g).
Some of the H+ ions go do chemiosmosis, while others attach to NADP+ and form NADPH.
71
(Step 2, light-dependent) What is the step 2?
Electron transport and the production of ATP by chemiosmosis:
- The energized electron from photosystem II travels down an ETS.
- Energy released by the ETS will be used to create ATP by chemiosmosis.
72
(Step 2, light-dependent) What is chemiosmosis? Define photophosphorylation.
Occurs when the energy released from the ETS forces H+ ions (from water in step 1) across the thylakoid membrane (INTO INNER SPACE OF THYLAKOID):
- A concentration gradient of H+ ions is created, as a high concentration of H+ build up in the thylakoid (like water behind a dam).
- As pressure builds, H+ ions are forced down the concentration gradient and across the thylakoid membrane to the stroma.
- The H+ ions move through an enzyme called **ATP synthase complex**, which provides the only pathway out of the thylakoid, BACK to the STROMA.
- As H+ ions flood back to the stroma (like water turning a turbine), an ATP bonds ato a phosphate molecule and ATP is produced, called *photophosphorylation*.
73
(Step 3, light-dependent) What is step 3?
- Light energy excites an electron from photosystem I
- This electron is replaced by the photosystem II electron at the end of its ETS
74
(Step 4, light-dependent) What is step 4?
- The elctron acceptor send the electron through another ETS
- The resulting energy is used to reduce the oxidized **NADP+** to NAPDH**
- This reducing power of NAPDH will be used in the Calvin-Benson cycle (light-indepndent reaction)
75
(light-dependent) What does light-dependent reaction produce?
NAPDH and ATP
76
(light-dependent) What is the electron carrier?
NAPD+
77
(Step 1, light-independent) What is step 1?
Carbon dioxide fixation:
- CO2 enters the stroma of the chloroplast through the stomata (pores) of the leaves.
- CO2 then combines with a 5 carbon **RuBP** molecule forming an UNSTABLE six-carbon compound that immediately splits into two three-carbon compounds called **PGA**.
78
(Step 2, light-independent) What is step 2?
- The 2 PGA molecules are activated by ATP, then reduced by NAPDH (PGA gains an H electron); this results in two high energy molecules of **PGAL**. *The now ADP+P and (oxidized) NADP+ go back to the light-dependent reactions to be cycled.*
- Some of the PGAL molecules leave the cycle and can be used to produce glucose, starch, sucrose, glycerol, or cellulose in the plant.
- PGA can also be converted into amino acids or fatty acids in the plant, or even as just energy.
- The cycle must go around 6 times to produce (12 PGAL total) one molecule of glucose. The remaining PGAL continue through the cycle to replace RUBP:
Ex: There is 6 C's in PGAL, 1 goes to forming glucose, 5 goes to replace RUBP.
Detailed Ex: 6C from 6 CO2 + 30C from 6 RUBP -> 36C from 6 six-carbon unstable compounds -> 36C from 12 three-carbon stable compounds + (energy from ATP and NAPDH) -> 36C from 12 PGAL (three-carbon compounds) -> (6C from 2 PGAL leave to make glucose) + 30C from 10 PGAL + (energy from ATP) -> 30C from 6 RuBP
79
(Step 3, light-independent) What is step 3?
Replacing RuBP:
- Most of the PGAL molecules are used to generate RuBP, with energy from ATP.
- In 6 cycles, 12 PGAL molecules are created -> 10 reform RuBP, 2 make one glucose.
- The plantcell can manufacture ALL necessary organic compounds from the products of photosynthesis.
Ex: There is 6 C's in PGAL, 1 goes to forming glucose, 5 goes to replace RUBP.
Detailed Ex: 6C from 6 CO2 + 30C from 6 RUBP -> 36C from 6 six-carbon unstable compounds -> 36C from 12 three-carbon stable compounds + (energy from ATP and NAPDH) -> 36C from 12 PGAL (three-carbon compounds) -> (6C from 2 PGAL leave to make glucose) + 30C from 10 PGAL + (energy from ATP) -> 30C from 6 RuBP
For every 12 PGAL moelcules that are synthesized in the Calvin-Benson cycle, two leave the chloroplasts and go into the cytoplasm. There, they are used to make glucose and other high-energy compounds.
80
(Cellular respiration background information) Where do plants absorb energy from and how is it stored?
Absorb energy from the Sun, storing at glucose.
81
(Cellular respiration background information) How is glucose used in a plant?
In the form of ATP.
82
(Cellular respiration background information) How does cellular respiration take place?
In a series of reactions that releases the stored energy in glucose molecules.
83
(Cellular respiration background information) Where does cellular respiration take place?
Starting step - cytoplasm
Most - in matrix
Oxidate phosphorylation - in intermembrane space and matrix
84
(Cellular respiration background information) What is the equation for cellular respiration?
C6H12O6 (s) + 6O2 (g) -> 6CO2 (g) + 6H2O (l) + ~36 ATP
85
(Cellular respiration background information) How is glucose used?
Glucose is oxidized into CO2 (H+ and H e- are removed) -> water and energy are produced.
86
(Cellular respiration background information) How much of the energy from glucose is actually converted into ATP?
36% of energy from glucose is converted into ATP (and used within 2 seconds to 2 minutes of being made).
It is inefficient, but must be done to prevent burning.
87
(Cellular respiration background information) What is lost in the glucose to energy conversion process?
Energy is lost (64%) as heat, but is used to maintain a constant body temperature of 37 degrees (so it isn't really lost lost).
88
(Cellular respiration background information) Who carries out cellular respiration?
Cellular respiration is carried out by all organisms: producers, consumers, decomposers.
89
Different species of organisms release energy from glucose in different ways. What are three pathways for energy release?
- Aerobic Cellular Respiration
- Anaerobic Cellular Respiration
- Fermentation
90
What is aerobic cellular respiration and its four stages?
- Requires oxygen
- Carried out by animals, plants, fungi, protists, and bacteria.
- Produces 36 ATP molecules, 6 CO2 and 6 H2O
4 stages:
1. Glycolysis
2. Krebs Cycle Preparation
3. Krebs Cycle
4. Electron Transport and Chemiosmosis
91
What is anaerobic cellular respiration?
- Does not require oxygen
- Carried out by organisms in "anoxic" (lack of oxygen, rare) conditions, such as bacteria and archea.
- E.g. deep-seas chemosynthesizers, nitrogen-fixing bacteria
- Humans do not perform anaerobic cellular respiration
- Involves electron transport
(The ATP number produced varies across different organisms and conditions)
92
What is fermentation and its two stages?
- Does not require oxygen
- Occurs in yeast, bacteria, plants, and muscle cells
- Produces 2 ATP molecules and either ethanol or lactic acid (humans produce lactic acid)
2 stages:
1. Glycolysis
2. Fementation
93
(Step 1, aerobic c. respiration) What is step 1 and where is located? Is oxygen required?
Location: Cytoplasm, and NO OXYGEN is required.
- Glycosis requires the activation energy of 2 ATP to initiate glucose breakdown.
- Glucose (C6) is then split into 2 molecules of an intermediate three-carbon molecule of PGAL.
- PGAL then turns into **pyruvate.** (oxidized)
This results in two extra products:
- Transformation to pyruvate releases 4 ATP (total), or a net change of +2 ATP
- Glycolysis also produces energized electrons that combine with the electron carrier NAD+ to produce NADH (**NAD+ is reduced**) (2 total NADH total produced)
(In eukaryotic cells, if oxygen ISN'T AVALIABLE, glycosis repeats and pyruvate proceeds to fermentation)
94
(Step 2, aerobic c. respiration) What are step 2's two names and where is located? Is oxygen required?
Krebs Cycle Preparation.
Location: In the MATRIX of mitochondria, and OXYGEN is required. Also known as **pyruvate oxidation.**
The fate of pyruvate, the final product of glycolysis, depends on the avalibility of oxygen and on the type of organism. In this case, we assume yes. (If no O2, then pyruvate carries out fermentation)
When oxygen is avaliable, the 2 pyruvates enter the matrix of the mitochondria where:
1. CO2 is removed from pyruvate (2 CO2 in total as waste)
2. More NAD+ is (newly) reduced to NADH (2 NADH in total)
3. Co-enzyme A is attached to the remaining 2 ("once-pyruvate") carbon molecules to form acetyl-CoA (CoA is like a tow-truck, taking the 2C molecules to the Krebs cycle and releasing it).
*Pyruvate + CoA -> Acetyl-CoA + carbon dioxide (waste)*
95
(Step 3, aerobic c. respiration) What is step 3 and where is located? Is oxygen required?
Krebs Cycle.
Location: In the MATRIX of mitochondria, and OXYGEN is required (we don't use it, but it has to be there).
Each acetyl-CoA is turned to a 6C compound (acetyl, 2C each, enters the Krebs Cycle by combining each with 4C compounds).
Each Krebs cycle is a series of reactions in which:
1. Two carbon atoms are fully oxidized to form carbon dioxide, so 2 per 6C compound emits a total of 4 CO2.
2. NAD+ and FAD are reduced to NADH and FADH2 (will be used in an ETS to form ATP). In total, there will be 2 FADH2 and 6 NADH)
3. One molecule of ATP is produced per 6C compound (2 total ATP).
4. At the end, we return to our 2 4C starting molecules.
Krebs cycle transfers the energy once contained in glucose, into the reducing power of NADH and FADH2.
96
(Step 4, aerobic c. respiratiion) What is step 4 and where is it located? Is oxygen required?
Electron Transport and Chemiosmosis.
Location: Surface of MATRIX, and OXYGEN is necessary. This stage produces the majority of ATP molecules.
ETS:
- The NADH and FADH2 from the Krebs cycle donate their electrons to the elctron carriers in the electron transport system on the surface of the matrix. (**electron energy fuels**)
- AS electrons are passed from one carrier to the next, the energy that is released is used to pump hydrogen ions from within the matrix, out into the intermembrane space (between the inner and outer membrane), creating a concentration gradient.
- Oxygen is the **final electron acceptor** in the ETS. Without it, electrons cannot move through the chain and no energy is made.
- The resulting molecule is water.
(- Also, oxygen carries (gets) the H+ protons from the FADH2 and NADH to turn to water).
Chemiosmosis:
- H+ ions move through channels created by ATP synthase, down the concentration gradient, back to the matrix of the cristae, and ATP is produced, which is called **oxidative phosphorylation.**
**In the end, the glycolysis 2 NADH makes 4 ATP (2 ATP per), the other NADH's make 3 ATP per, and the FADH2 makes 2 ATP per. FADH2 is not as good as donating electrons as NADH, but the glycosis NADH loses some from transport from cytoplasm to mitochondria.**
97
What are some characteristics of anaerobic cellular respiration?
- Organisms that carry out anaerobic cellular respiration use inorganic chemicals other than oxygen as the final electron-acceptor (such as sulfate, nitrate, or CO2)
- Common products are sulfur, nitrite, nitrogen, or methane.
- An ETS and concentration gradient is used to produce ATP for the cell, but much fewer (inefficient) than in aerobic respiration.
98
What are some characteristics of fermentation and the two types? Where is it located?
Cell cytoplasm.
Occurs in anaerobic or aerobic organisms when oxygen is not avaliable:
- In the absence of oxygen, NADH generated from glycolysis reduces pyruvate to other compounds
- Fermentation is much less efficient than aerobic respiration because of extra conversions (to make up for lactic acid buildup, breathing converts lactate back to pyruvate, and this extra step to replenish pyruvate causes inefficiency).
Two types are:
- Lactate fermentation
- Ethanol fermentation
99
What is lactate fermentation?
In muscle that is working sternuously, oxygen debt results, so Krebs cycle cannot function. Muscle cells are functioning anaerobically, so the fermentation process occurs:
- NADH is used to convert pyruvate to lactate (also called lactic acid)
- The resulting NAD+ is recycled so that glycolysis can continue.
Lactic acid production causes:
- muscle cramps
- soreness
- stiffness
- fatigue
100
What is ethanol fermentation?
For some bacteria and in yeast, as they grow anaerobically, pyruvate is converted to carbon dioxide and ethanol.
Products of ethanol fermentation include:
- wine
- beer
- soy sauce
- bread (yeast)
- some carbonated bevrages (kombucha)
- cheese
- ethanol gas corn/wheat + yeast
