Photosynthesis and Respiration Flashcards
1
Q
What do plants use energy for?
A
- Photosynthesis
- AT
- DNA replication
- Cell division
- Protein synthesis
2
Q
What do animals use energy for?
A
- Muscle contraction
- Maintenance of body temperature
- AT
- DNA replication
- Cell division
- Protein synthesis
3
Q
Define photosynthesis
A
Process where energy from light is used to make glucose from water and carbon dioxide
4
Q
What is the overall equation for photosynthesis?
A
6CO2 + 6H2O + Energy => C6H12O6 + 6O2
5
Q
Define respiration
A
Process of releasing energy from glucose
6
Q
What is the overall equation for aerobic respiration?
A
C6H12O6 + 6O2 => 6CO2 + 6H2O + Energy
7
Q
What are the products of anaerobic respiration in plants and yeast?
A
- Ethanol
- CO2
- Releases energy
8
Q
What are the products of anaerobic respiration inhumans?
A
- Lactate
- Releases energy
9
Q
What makes ATP a good energy source?
A
- Releases small manageable amount of energy so no energy is wasted as heat
- Small + soluble so can easily be transported
- Quickly re-made
- Can make other molecules more reactive by transferring its phosphate group (phosphorylation)
- Can’t pass out cell so always has immediate supply of energy
10
Q
Define metabolic pathway
A
Series of small reactions controlled by enzymes
11
Q
Define phosphorylation
A
Adding phosphate to a molecule
12
Q
Define photophosphorylation
A
Adding phosphate to a molecule using light
13
Q
Define photolysis
A
Splitting a molecule using light energy
14
Q
Define photoionisation
A
- Light energy excites e- in an atom/molecule, giving them more energy + causing them to be released.
- Release of e- causes atom/molecule to become +ve-charged ion
15
Q
Define decarboxylation
A
Removal of CO<strong>2</strong> from molecule
16
Q
Define dehydrogenation
A
Removal of H+ from molecule
17
Q
Define coenzyme
A
Molecule that aids the function of an enzyme
18
Q
Give an example of a coenzyme used in photosynthesis
A
- NADP
- Tranfers H<strong>+</strong> from one molecule to another
- Can reduce/oxidise molecule
19
Q
Give examples of a coenzyme used in respiration
A
- NAD and FAD - tranfers H+ from one molecule to another
- Coenzyme A - tranfers acetate btw molecules
20
Q
Where does photosynthesis take place?
A
Chloroplast
21
Q
What do chloroplasts contain?
A
- Photosynthetic pigments
- eg. chlorophyll a, chlorophyll b + carotene
- Coloured substances that absorb light energy needed for photosynthesis
- Found in thylakoid membranes - attached to proteins
- Pigment + protein = photosystem
22
Q
What are the wavelengths used by both photosystems for absorbing light energy?
A
- Photosystem I - absorbs light at wavelength of 700nm
- Phtosystem II - absorbs light at 680nm
23
Q
What does the stroma conatin?
A
- Enzymes
- Sugars
- Organic acids
24
Q
How are carbs produced by phtosynthesis stored as and where?
A
- Starch grains
- Stroma
25
Where does the light-dependent reaction take place?
**Thylakoid membrane**
26
Where does the light-independent reaction take place?
**Stroma**
27
In the light-dependent reaction, what is the energy from the photoionisation of chlorophyll used for?
* Making **ATP** from **ADP** + **inorganic phosphate** (photophosphorylation)
* Making **reduced NADP** from **NADP**
* **Splitting water** into **protons**, **e**- + **O2 **(photolysis)
28
What are electron carriers?
**Proteins** that **transfer electrons**
29
What do photosystems and electron carriers form?
* **Electron transport chain**
* **Chain** of **proteins** where **excited e- flow** through
30
Outline the light-dependent reaction
* **Light absorbed** by PSII
* **Excites e-** to **higher energy level**
* High Ee- **released** from **chlorophyll** + **move down ETC** to PSI, **e- **must be **replaced**
* **Light splits water** to **H+, e- + O2**
* Ee- **lose energy** as they **move down ETC**
* Energy used to **transport H**+ to **thylakoid** so has a **higher conc** of H+ than stroma- forms **proton gradient**
* **Protons move** down **conc gradient** into **stroma** via **enzyme ATP Synthase**
* Energy released **forms ATP**
* Light energy absorbed by PSI exciting e- to even higher energy level
* **E- transferred** to **NADP** along w/ **H+ **from stroma forming **reduced NADP**
31
Define chemiosmosis
Process of e- flowing down ETC and creating proton gradient across membrane to drive ATP synthesis
32
What are the products of non-cyclic photophosphorylation
* **ATP**
* **Reduced NADP**
* **O2**
33
What are the products of cyclic photophosphorylation and why is it called cyclic?
* **ATP**
* **Only** uses **PSI**
* E- from **chlorophyll** **aren't passed** to **NADP** but **passed back** to **PSI** via **e- carriers** - **e- recycled**
34
Where does the light-independent (calvin cycle) reaction take place?
**Stroma**
35
Outline the light-independent reaction
* **CO2 **enters leaf + **diffuses** into **stroma**
* CO2 **combines** w/ **ribulose biphosphate** (**5C**) catalysed by **rubisco**
* Gives **unstable 6C breaking** into **2 glycerate 3-phosphate** (**3C**)
* **Hydrolysis** of **ATP** provides **energy** turning **GP** to **triose phosphate** (**3C**), also requires **H+ **from **reduced NADP** (both from **LDR**)
* **Some TP** coverted to **useful compounds** (**glucose**) + some continue to **regenerate RuBP**
* **5/6** of TP aren't used to make hexose but to **regenerate RuBP** - uses rest of ATP produced by LDR
36
Name the substance triphosphate and glycerate 3-phosphate are converted to
* **Carbs** - **hexose sugars**: **join 2 TP** together, **larger carbs**: join **hexose sugars** in **diff ways**
* **Lipids** - made using **glycerol synthesised** from **TP** + f**atty acids** **synthesised** from **glycerate 3-phosphate**
* **AA** - made from **glycerate 3-phosphate**
37
How many calvin cycle turns, ATP and reduced NADP does there need to be to make a one hexose sugar
* **6 cycles**
* **18 ATP**
* **12 reduced NADP**
38
What are the optimum conditions for photosynthesis?
* **High light intensity** w/ **certain wavelength** - light provides **energy**. **Photosynthetic pigments** only **absorb red** + **blue light** (reflect green)
* **Temp 25oC** - involves enzymes, below **10oC** enzymes **inactive**, above **45oC** enzymes **denature** + **stomata close** to **avoid losing water** - photosynthesis **slows** down bc **less CO2 enters**
* **CO2 **at **0.4%** - **higher rate** of photosynthesis, higher: stomata closes
39
Name the factors limiting photosynthesis
* **Light intensity**
* **Temp**
* **CO2 conc**
40
Define the saturation point
Where **factor** is **no longer limiting** the reaction - **something else** becomes the **limiting factor**
41
How do growers manage glasshouses to create optimum conditions for plants to grow?
* **CO2 conc** - added to air by **burning propane** in **CO2 generator**
* **Light** - **LED lights**
* **Temp** - **heaters and coolers**. **Air circulation systems** makes sure **temp** is **even** throughout glasshouse
42
What process can you use to determine what pigments are present in the leaves of a plant?
* **Thin layer chromatograph**y:
* **Mobile phase** - molecules can **move**, **liquid solevent**
* **Stationary phase** - molecules **can't move**, **solid plate** w/ **thin layer** of **gel** ontop
43
Describe how you carry out a TLC to compare pigments in diff. plants
* **Grind up leaves** w/ **anhydrous sodium sulfate**, add drops of **propanone**
* **Transfer** liquid to test tube, **add petroleum ether** and shake. **2** distinct **layers** form - top is pigments mixed w/ PE
* **Transfer top** layer to another test tube **w/ anhydrous sodium sulfate**
* Draw pencil line at bottom of TLC plate. **Build up conc** spot - point of origin
* Place plate in **glass w/ solvent** just below line.
* When solevent has nearly reached the top, mark w/ pencil
* **Calculate** the **Rf value**
44
What's the equation to work out the Rf value?
**Rf value = distance travelled by spot / distance travelled by solvent**
45
In the photosystem I, during the light-dependent stage of photosynethesis, NADP acts as e- acceptor + is reduced. What is this reaction catalysed by?
**Dehydrogenase enzyme**
46
Describe how to investigate the effect of light intensity on dehydrogenase activity in extracts of chloroplasts
* **Add redox indicator dye** (**DCPIP**) to extract **chloroplast**. **Dye** acts as **e- acceptor** + when **reduced**, goes **blue** to **colourless**
* If **dehydrogenase activity** is taking place, **absorbance dec** in **colorimeter** as **DCPIP** gets **reduced** + **loses blue colour**
* **Stronger light intensity**, **faster absorbance dec**, faster rate of dehydrogenase activity
47
What are the stages in aerobic respiration?
* **Glycolysis**
* **Link reaction**
* **Krebs cycle**
* **Oxidative phosphorylation**
48
Where does glycolysis occur?
**Cytoplasm**
49
Outline the 2 stages in glycolysis
* **Phosphorylation:**
* **Glucose** is **phosphorylated** using **phosphate** from **ATP**, creates **1 glucose phosphate** (6C) + **1 ADP**
* **ATP** used to add **phosphate** forming **hexose biphosphate** (6C)
* Hexose biphosphate **split** into **2 triose phosphate** (3C)
* **Oxidation:**
* **TP** is **oxidised** forming **2 pyruvate**
* **NAD** **collects H+ **forming **2 reduced NAD**
* **4 ATP produced**
50
Does glycolysis require oxygen?
**No**, it's an **anaerobic** process
51
During aerobic respiration, what happens to the products after glycolysis?
* **2 reduced NAD** go to **oxidative phosphorylation**
* **2 pyruvate AT** into **matrix** of **mitochondria** for **link reaction**
52
What is the net gain after glycolysis?
* **2 ATP**
* **2 reduced NAD**
53
During anaerobic respiration, what is the pyruvate converted into in animals and some bacteria?
* **Lactate**
* **Oxidises reduced NAD** to NAD
54
During anaerobic respiration, what is the pyruvate converted into in plants and yeast?
* **Ethanal**, **releasing CO2**
* Converted into **ethanol**
* **Oxidises reduced NAD** to NAD
55
During anaerobic respiration, how can glycolysis continue in the presence of v. little oxygen?
* **Production** of **ethanol/lactate regenerates oxidised NAD**
* **Small amount** of **ATP produced**
56
Where does the link reaction and the kreb cycle occur?
**Matrix** of **mitochondria**
57
Outline what happens during the link reaction
* **Pyruvate** (3C) is **decarboxylated** (C atom is **removed** in form of **CO2**)
* Pyruvate **oxidised** to form **acetate** (2C) and **NAD** is **reduced**
* **Acetate** **combines** w/ **coenzyme A forming acetyl coenzyme A**
* **No ATP produced**
58
What happens for every glucose molecule that enters glycolysis?
* **2 molecules** of **acetyl coA** go into **krebs cycle**
* **2 CO2 released** as waste product
* **2 reduced NAD formed** + go to **oxidative phosphorylation**
* **Link reaction + kreb cycle occur twice**
59
Outline the krebs cycle
* **Acetyl coA** from link reaction **combine** w/ **4C** molecule to **form 6C** molecule
* **Coenzyme A** goes **back** to **link reaction**
* **6C citrate converted** to **5C**
* **Decorboxylation** (CO2 removed) + **dehydrogenation** occurs, **H+ used** to produce **reduced NAD** from NAD
* **5C converted** to **4C**
* **Decorb + dehyd** occurs producing **1 reduced FAD** + **2 reduced NAD**
* **ATP produced** by **direct transfer** of **phosphate group from intermediat**e to **ADP**
60
Define substrate-level phosphorylation
**Phosphate group transferred** from **1 molecule** to **another**
61
What are the products of the krebs cycle and where does it go?
* **Coenzyme A** - **Link reaction**
* **Oxaloacetate** - **regenerated** for **next KC**
* **2 CO2 **- **Waste** product
* **1 ATP** - **energy**
* **3 reduced NAD** - **oxi phosph**
* **1 reduced FAD** - **oxi phosph**
62
What does oxidative phosphorylation involve?
* **e- transport chain**
* **Chemiosmosis**
63
Where does oxidative phosphorylation occur?
**Inner mitochondrial membrane**
64
Outline oxidative phosphorylation
* **H atoms released** from **reduced NAD** + **FAD**. H **split** into **H+** and **e-**
* **e-** **move down e- transport chain** **losing energy** at **each carrier**
* Energy used by **EC** to **pump H**+ from **mitochondrial matrix into intermembrane space**
* **Conc** of **H+ higher** in **intermembrane space** than matrix - **forms electrochemical gradient**
* **H+ move down electrochemical gradient** via **ATP synthase**. **Movement synthesise ATP** (**chemiosmosis**)
* In matrix **H+**, **e- **+ **O2** (**final e- acceptor**) combine to **form water**
65
How much ATP can be made from 1 glucose molecule?
**32**
66
Outline how ATP production can be affected by mitochondrial diseases and it's effects
* Mitochondrial diseases **affect protein** involved in **oxi phosph/Krebs cycle function**, **reducing ATP** production
* May cause **inc anaerobic respiration**, results in **lots of lactate** being produced leading to **muscle fatigu**e + **weakness**. Lactate will **also diffuse** into **bloodstream**, **high lactate conc** in **blood**
67
What other substrates, aside from glucose, can be used in aerobic respiration?
* **Fatty acids** from lipids
* **AA** from proteins
* Able to **enter Krebs cycle**
68
Outline the procedure needed when investigating how temperature affects respiration in single-celled organisms during aerobic respiration
* Put **known vol** + **conc** of **substrate sol** in **test tube**. Add **known vo**l of **buffer** sol
* Place in **water bath** to 1 of the temp. Leave for 10 mins to a**llow temp** of **substrate** to **stabalise**
* **Add known mass** of **dried yeast** to tube + stir
* Put **bung** w/ **tube attached** to **gas syringe** set to 0
* **Start stop watch**
* As **yeast respire**, **CO**2 formed will **travel** into **gas syringe**. **Record** at **regular intervals**
* **Compare** w/ **control** (**w/o yeast)**
69
Outline the procedure needed when investigating how temperature affects respiration in single-celled organisms during anaerobic respiration
* Same 1-3 steps as aerobic respiration experiment
* **After yeast dissolved**, **add liquid parffin** to **cover whole SA** of substrate to **stop O2 entering** (yeast will respire anaerobically)
* Follow last steps from aerobic respiration experiment
