Photosynthesis and Cellular Respiration Flashcards
1
Q
What is the cell membrane?
A
A boundary that separates the internal environment of the cell from its external environment
2
Q
What are the three ways molecules and ions transport through the cell?
A
- passive transport
- facilitated diffusion
- active transport
3
Q
What is passive transport?
A
It does not require energy; molecules pass through the semi-permeable membrane
4
Q
What are the two types of passive transport?
A
- diffusion
- osmosis
5
Q
What is diffusion?
A
Natural movement of molecules/ions from regions of high concentration to low concentration through the cell membrane
6
Q
What is osmosis?
A
Diffusion of water across a semi-permeable membrane
7
Q
What is facilitated diffusion?
A
Doesn’t require energy (still passive); specialized proteins help different substances move in and out of the cell
8
Q
What are channel proteins?
A
Transports charged particles across the concentration gradient through the cell membrane
9
Q
What are carrier proteins?
A
Help movement of larger molecules (ex. glucose) which cannot naturally fit through the membrane
10
Q
What is active transport?
A
uses energy to enable a cell to take in a substance that is mroe concentrated inside the cell than out
11
Q
What is ATP?
A
Adenosine Triphosphate; usable form of chemical energy within cells
12
Q
What is metabolism?
A
All chemical reactions that occur within a cell to support and sustain its life function
13
Q
What are the two types of metabolism?
A
- anabolic metabolic pathways
- catabolic metabolic pathways
14
Q
What are anabolic pathways?
A
synthesizes large molecules from smaller ones and require energy (ex. photosyntehsis)
15
Q
What are catobolic pathways?
A
Break down large molecules into smaller ones and release energy (ex. cellular repiration)
16
Q
What is photosynthesis?
A
Autotrophs trap the sun’s energy and convert it to chemical energy
17
Q
Where does photosynthesis occur?
A
In the chlorophyll which is stored in chloroplasts
18
Q
How many membranes does a chloroplast have?
A
two (an inner and outer)
19
Q
What is the stroma?
A
Fluid in the innerspace of a chloroplast (contains a mix of proteins and other chemicals used to synthesize carbohydrates)
20
Q
What are thylakoids?
A
Interconnected flattened sacs
21
Q
What are lumen?
A
Inside of thylakoids
22
Q
What are granum?
A
Stacks of thylakoids
23
Q
What are the two main groups of photosynthesis?
A
- light dependent reactions
- light independent reactions
24
Q
What are light dependent reactions?
A
- solar energy is trapped and used to generate two high-energy compounds (ATP and NADPH)
- occurs in thylakoids
25
What are light independent reactions?
- also called the calvin cycle)
- energy of ATP and reducing power of NADPH is used to reduce CO2 to make glucose
- occurs in the stroma
26
What are redox reactions:
oxidation- an atom/molecule loses an electron
reduction- an atom or molecule gains an electron
27
What is reducing power?
Compounds contain more energy in their reduced form
28
What are photosystems?
Arrangements of photosynthetic pigments (clusters); act like light-gathering "antenna complexes"
- chlorophyll is found in clusters in the thylakoids in photosystem one and two
29
What colour is chlorophyll?
Appears green as it reflects greenlight and absorbs the blue and red light
30
What colour is chlorophyll A?
blueish-green
31
What colour is chlorophyll B?
yellowish-green
32
What colour are cartenoids?
Orange
33
What is the first step of light dependent reactions?
- light hits electrons in the pigments and become "excited"
- the electrons rise to a high energy level adn are passed onto specialized reaction centres in PSII
- leaves an electron hole which is later filled by electrons extracted from water molecules
- water is split with light (photolysis) and the byproduct O2 is created
34
What is the second step of light dependent reactions?
- the electron acceptor transfers the energized electron to crytochromes (electron carrying protein molecules)
- the series of crytochromes makes up the ETS
- with each transfer along the ETS, the high energy electron releases a small amount of energy
35
What is the third step of light dependent reactions?
- the energy created in the ETS is used to push hydrogen ions from the stroma into the thylakoid lumen
- ATP synthase in the membrane creates a path for the Hydrogen ions
- as the hydrogen ions move down their concentration gradient through ATP synthase, the energy produced is used to bond a phosphate group to an ADP molecule to make ATP (chemiosmosis)
35
What is the fourth step of light dependent reactions?
- at the same time, PSI is also absorbing light
- an electron is released, transferred to a reaction centre, passed to an electron acceptor
- this electron is replaced by the electron arriving down the ETS from PSII
- in plants the released electron from the PSI is used to reduce NADP+ to make NADPH (reducing power of NADPH is used in light independent reaction)
36
What are the steps of light independent reaction?
- carbon dioxide fixation
- reduction
- replacing RuBP
37
What is carbon dioxide fixation?
- first step
- carbon atom in CO2 is bonded to RuBP in the stroma (five carbon compound, reibulose biphosphate)
- enzyme rubisco catalyszes this reaction
- resulting six carbon compound is unstable and immediately breaks down into two 3-carbon compound PGA (3-phosphoglycerate)
38
What is reduction?
- second step
- PGAs are low-energy when formed, then activated by ATP, and reduced by NADPH
- results in two PGAL
- some PGAL leaves cycle to make glucose, others move onto third stage
39
What is replacing RuBP?
- third step
- remaining PGAL make RUBP to continue the cycle
- ATP provides energy to make 5-carbon RuBP from 3-carbon PGALs
- cycle starts again
40
How many times does the calvin cycle need to happen?
- six CO2 molecules are needed to make one glucose
- so the cycle repeats six times
- produces 12 PGAL molecules (10 to regenerate RuBP and 2 to make glucose)
41
What is cellular respiration?
Cells break down glucose to generate ATP
42
What are the three ways organisms release energy?
- aerobic cellular respiration (requires oxygen)
- anaerobic cellular respiration (doesn't require oxygen)
- fermentation (anaerobic, but much simpler)
43
What is Glycolysis?
- all cathabolic pathways in cellular respiration start with glycolysis
- occurs in cytoplasm of all cells
- anaerobic
- ATP is formed by splitting a glucose molecule into 2 molecules of pyruvate
44
What are the net products of glycolysis?
- two ATP
- two NADH
45
Can glycolysis be used by all organisms?
- yes
- when oxygen isn't available or for species that can't use oxygen, glycolysis is the only way the cell can extract energy
46
What is the mitochondria?
Where aerobic cellular respiration occurs
47
What is the outer membrane of the mitochondria?
the outermost membrane
48
What is the inner membrane of the mitochondria?
the inner membrane
49
What is the cristae in a mitochondria?
The folds of the inner membrane to gain surface area
50
What is the matrix of the mitochondria?
the liquid-like substance filling the mitochondria
51
What is pyruvate oxidation?
- two pyruvate molecules formed by glycolysis have to do into the matrix of the mitochondria
- pyruvate undergoes pyruvate oxidation to be used in aerobic cellular respiration
- pyruvate loses a carbon atom to CO2 and the other two are bonded to coenzyme A (CoA)
- creates acetyl CoA and another NAD+ is reduced to NADH
52
What are the steps of the Krebs cycle?
*occurswa in the matrix of the mitochondria*
- Acetyl CoA loses its two carbon atoms to a pre-existing four carbon starting molecule
- it loses a carbon to CO2, meanwhile NAD+ is converted to NADH by the reducing power
- it is now a five carbon molecule
- it loses a carbon to CO2 and NAD+ is converted to NADH by the reducing power
- ADP is converted to ATP by the energy released when the carbon breaks off
- it is now a four carbon molecule
- FAD is converte4d to FADH2
- the four carbon molecule is rearragned
- NAD+ becomes NADH again on the side
- the four carbon starting molecule cycles again
53
What are the net products of the Krebs Cycle?
- six CO2
- two ATP
- six NADH
- six FADH2
54
What is the ETS in cellular respiration?
*occurs in the innermembrane of the mitochondria*
- produces majority of ATP in aerobic cellular respiration
- high energy electrons from the NADH and FADH2 produced in the Krebs cycle are passed onto electron carrying moelcules
- as the electrons are passed from one carrier to another, energy is released in small amounts
- this energy pumps hydrogen ions across the membrane from the matrix to the intermembrane space
- creates a hydrogen-ion concentration gradient
- chemiosmosis occurs to bind a phosphate group to ADP, creating ATP (26-34 molecules of ATP)
55
What does oxygen do in cellular respiration?
the final electron acceptor in the ETS, accepts electrons adn hydrogen ions to form water. If this didn't occur the ETS would fail (NADH and FADH2 wouldn't lose electrons)
56
What is fermentation?
anaerobic; includes glycolysis and one or more reactions where NADH is oxidized to NAD+ by reducing pyruvate to other components (only produce as much ATP generated in glycolysis)
57
What is lactate fermentation?
- occurs in muscle cells when working strenously and tehre is not enough oxygen available
- pyruvate is converted to lactate/lactic acid in the abscence of oxygen to replenish NAD+ that was converted to NADH during glycolysis
- if lactate builds up too much, the muscle fatigues and cramps
- when oxygen is present again, the lactate is converted back to pyruvate and processed as usual through aerobic pathways
58
What is ethanol fermentation?
- some organisms (bacteria and yeast) convert pyruvate to ethanol and CO2
- pyruvate is converted to ethanol via a two-step irreversible process which also recycles a NAD+ for glycolysis
- brewer's yeast is used to make baked goods and alcoholic beverages
59
What is chromotagraphy?
separation of pigments; the different solubilities, size, masses, etc of pigements are used to isolate them on special paper (the more soluble, the further up the paper it travels)
60
What is Rf value?
Describes how soluble a substance is
61
How do you calculate Rf value based off of a chromotagraphy lab?
Rf = distance travelled by solute (ink from baseline) / distance travelled by solven from baseline
