Respiration & Photosynthesis (mitochondria, Aerobic respiration, Anaerobic respiration, Chloroplasts, Light-dependant & Light-Independant reactions/phases

Question 1

Photosynthesis

Answer 1

Photosynthesis is the process by which green plants synthesis (make) food using sunlight. They use sunlight, carbon dioxide, and water to produce glucose and oxygen.

• Energy from sunlight is used to convert carbon dioxide & water into glucose.

Question 2

Photosynthesis chemical equation & word equation

Answer 2

Photosynthesis Word Equation:
Carbon dioxide + Water (sunlight)→ Glucose + Oxygen

Photosynthesis Chemical Equation:
6CO2+6H2O→C6H12O6+6O2.

Question 3

What are the factors that affects photosynthesis?

Answer 3

• Light intensity
• Carbon dioxide concentration
• Temperature
• Increase in reactants

Question 4

What are the TWO stages of photosynthesis

Answer 4

1. Light dependent Reaction
2. Light Independent Reaction

Question 5

What is the DETAILED version of photosynthesis process

Answer 5

STEP 1 - Light Dependent
CO2 and H2O enter the leaf

STEP 2 - Light Dependent
Light hits the pigment in the membrane of a thylakoid, splitting the H2O into O2

STEP 3 - Light Dependent
The electrons move down the enzymes

STEP 4 - Light Dependent
Sunlight hits the second pigment molecule allowing the enzymes to convert ADP to ATP and NADP+ gets converted to NADPH

STEP 5 - Light Independent
The ATP and NADPH is used by the Calvin cycle as a power source for converting carbon dioxide from the atmosphere into simple sugar glucose

STEP 6 - Light Independent
The Calvin cycle converts 3CO2 molecules from the atmosphere to glucose.

STEP 7 - Calvin Cycle
The second of two major stages in photosynthesis (following the light reactions), involving atmospheric CO2 fixation and reduction of the fixed carbon into carbohydrate.

Question 6

Chloroplast

Answer 6

Within plants there are chloroplasts. These chloroplasts have many flat thylakoid stacks (granum) surrounded by the stroma. Within thylakoids there is a lumen. Photosynthesis happens in the membrane between the lumen and stroma. This is where light energy is turned into ATP.

Question 7

Parts of a chloroplast

Answer 7

• Inner membrane
• Outer membrane
• Grana/granum,
• Stroma
• Thylakoid stacks

Question 8

Chloroplast - Outer membrane

Answer 8

The outer membrane of a chloroplast is the chloroplast membrane facing the cytoplasm

Question 9

Chloroplast - Inner membrane

Answer 9

The inner membrane of the chloroplast forms a border to the stroma. It regulates passage of material in and out of the chloroplast.

Question 10

Chloroplast - Grana/Granum

Answer 10

These are green - they absorb light energy and use it in a light-dependant reaction which starts photosynthesis.

Question 11

Chloroplast - Stroma

Answer 11

A clear Jelly-like liquid inside the chloroplast. It’s clear so it allows light to pass through the thylakoid. The stroma is the site of the light-independant reaction.

Question 12

Chloroplast - Thylakoid Stacks

Answer 12

Thylakoids are a stack of grana. This maximises the surface area available for the reaction.

Thylakoids contain chlorophyll that is necessary for a plant to go through photosynthesis

Each thylakoid is flat so it can absorb maximum sunlight and are located on flat leaves

Question 13

Chloroplast - Chlorophyll

Answer 13

Chlorophyll, a green pigment found in chloroplasts, is an important part of the light-dependent reactions.

Chlorophyll soaks up the energy from sunlight. It is also the reason why plants are green.

Question 14

Mitochondria

Answer 14

Cell respiration takes place in the mitochondria.
- Site of aerobic respiration
- Glucose is broken down to H20 and Co2 and produces a lot of ATP

Question 15

Why are thylakoid stacks arranged the way they are?

Answer 15

When stacked, each thylakoid is able to increase their total surface area which allows more electron transport chains to be embedded into each thylakoid membrane

Question 16

Role of Mitochondria

Answer 16

The role of mitochondria is to produce ATP. ATP is used by all cells for energy.
- Active transport
- Protein synthesis
- Movement: muscles, flagella, phagocytosis

Cells with high energy demand (e.g muscle cells, secretory cells, sperm) have many more mitochondria.

Mitochondria in these cells have more folded Cristae, to allow more reactions and more ATP production.

Question 17

Parts of a Mitochondria

Answer 17

Outer membrane, Inner membrane, matrix, cristae

Question 18

Mitochondria - Outer Membrane

Answer 18

Contains the mitochondria, regulates molecules entering and exiting the mitochondria.

Question 19

Mitochondria - Inner Membrane

Answer 19

Folded up into Cristae, which increases the surface area for the respiration reactions.

Question 20

Mitochondria - Matrix

Answer 20

Jelly-like filling of the mitochondria that contains many enzymes. The site of the krebs cycle.

Question 21

Mitochondria - Cristae

Answer 21

Site of the electron transfer chain reactions.

Question 22

Define Anaerobic Respiration

Question 23

Define Aerobic Respiration

Question 24

Explain the purpose of Aerobic Respiration

Question 25

Three stages of Aerobic Respiration

Answer 25

The three stages of Aerobic respiration is
- Glycolysis
- Krebs cycle
- Electron Transfer chain

Question 26

Aerobic Respiration Equation

Answer 26

glucose + oxygen = carbon dioxide + water (+ATP+Heat)

C6H12O6 + 6O2 = 6CO2 + 6H20 (+36ATP+Heat)

Question 27

Explain why the inner membrane of mitochondria forms the wiggly Cristae

Question 28

Define Anaerobic respiration

Question 29

Explain why anaerobic respiration takes place

Question 30

Aerobic Respiration - Glycolysis

Answer 30

Occurs in the cytoplasm. A molecule of glucose is broken down to pyruvate,

• 2 ATP produced

Question 31

Aerobic Respiration - Krebs Cycle

Answer 31

Occurs in the Matrix of the mitochondria. Through the complex series of enzyme reactions, pyruvate is broken down to produce CO2 waste, and hydrogen atoms.

• CO2 waste products released
• Hydrogen atoms passed to the cristae

Question 32

Aerobic Respiration - Electron Transport Chain

Answer 32

Occurs on the cristae. Hydrogen atoms are ionised to H+, and their electrons are passed back and fourth between molecules on the cristae. Their energy is used to turn ADP into ATP.

• Water is produced as a waste product.
• 36 ATP

Question 33

Cellular Respiration - where does the ANAEROBIC respiration occur in a cell?

Answer 33

Takes place in a cytoplasm

Question 34

Cellular Respiration - Advantages & Disadvantages of ANAEROBIC respiration

Question 35

Cellular Respiration - where does the AEROBIC respiration occur in a cell?

Question 36

Cellular Respiration - Advantages & Disadvantages of AEROBIC respiration

Question 37

WHERE does Anaerobic Respiration takes place?

Answer 37

Anaerobic respiration takes place in the cytoplasm
- no mitochondria needed!
- Only produces 2 ATP for each molecule of glucose

Question 38

5 Factors affecting Respiration

Answer 38

Temperature
pH
Concentration of substrates
Inhibitors
Demand

Question 39

Respiration factor - Temperature

Answer 39

Too cold - respiration slow
optimum - respiration ideal
Too hot - the enzymes will denature. Respiration will stop.

Question 40

Respiration factor - pH

Answer 40

Can denature the enzymes

Question 41

Respiration factor - Concentration of Substrates

Answer 41

Shortage of glucose & oxygen will slow down respiration.

Question 42

Respiration factor - Inhibitors

Answer 42

Substances that prevent the enzymes from catalysing a reaction

Question 43

Respiration factor - Demand

Answer 43

In animals, the demand for energy will cause an increase in respiration, up to a maximum.

Question 44

What are the TWO main chemical reactions of photosynthesis?

Answer 44

Light dependant & Light Independent reaction

Question 45

Light - Dependant Reaction

Answer 45

Light - Dependent reaction takes place on the grana/thylakoids in the chloroplast.

Chlorophyll absorbs light energy from the sun, exciting electrons in the thylakoid membrane.

Highly excited electrons are used to make ATP from ADP

Water is split into hydrogen and oxygen gas

Oxygen is released as a waste product

Hydrogen is picked up by a carrier molecule called NADP, and NADPH transfers the hydrogen to the stroma of the chloroplast.

Question 46

What is difference between ATP & ADP?

Question 47

2017 NCEA Q1)
Describe osmosis and explain how it occurs in root cells of a plant

Question 48

EXAM QUESTION
Discuss how photosynthesis occurs, and the factors that affect it. In your answer:
- Explain light-dependent & Light independent reactions
- Discuss how water AND one other factor can affect the rate of photosyntheiss

Answer 48

Photosynthesis is the process by which plants synthesis (make) food using sunlight. Sunlight is used twice in the process of photosynthesis. This is where light dependent and light independent process comes into the frame. Light dependent reactions in the plant are reactions which require sunlight to function, unlike the light independent reaction which does not require sunlight.

Water can affect the rate of photosynthesis because it is a reactant in the reaction. Plant’s require H2O molecules from the ground in order to split and bind hydrogen with carbon dioxide, and release O2 to form the glucose (food) and energy they require. If there is abundant sunlight and carbon dioxide but no water, the reaction cannot take place. Water is often the most limiting factor in photosynthesis reaction. Therefore, limiting the rate of ATP energy production & the energy for life processes. Water abundance can heavily influence the photosynthesis reaction as it is necessary. Without water, the plant cannot perform the reaction & it will die.

Another factor influencing the rate of photosynthesis is temperature. Enzyme is necessary in carrying out the reaction. One key aspect is temperature and light intensity will raise the temperature. As the temperature rises, the number of collisions between enzymes and substrate will also rise which increases the rate of photosynthesis. In colder temperatures, the collision rate and photosynthesis rate will fall. There will be an optimum temperature for the enzymes in the plant to function, optimising the rate of photosynthesis. Past this point, the enzyme will denature, unraveling the the proteins and disfiguring the active site rendering the enzyme unable to bond to substrate and react. If this occurs, the rate of photosynthesis will slow, and likely come to a stop altogether.

Question 49

Where does cell respiration take place?

Answer 49

Mitochondria

Question 50

Aerobic Respiration - Glyco

Question 51

Anaerobic Respiration

Answer 51

• Does not require oxygen
• Cytoplasm
• Chemical Equation:
• Word Equation:

Question 52

Aerobic Respiration

Answer 52

Aerobic respiration requires oxygen to perform/complete. It again begins with glycolysis in the cytoplasm of the cells, however this process then moves inside the mitochondria where the krebs cycle occur on the cristae - inner membrane of the organelle.

Word Equation: Oxygen + glucose = Water + carbon dioxide + ATP
Chemical Equation: 6O2 + C6H12O2 = 6H20 + 6CO2 + ATP