Photosynthesis

Question 1

C6H12O6 – a single sugar which is produced in photosynthesis.

Answer 1

Glucose

Question 2

ATP

Answer 2

An activated nucleotide found in all living organisms, which is produced during respiration and acts as an energy carrier. ATP is produced during the light-dependent reaction of photosynthesis.

Question 3

the chemical processes that occur within a living organism in order to maintain life.

Answer 3

Metabolism

Question 4

A complex metabolic pathway involving many intermediate reactions. Some energy in light is conserved in the form of chemical bonds. There are three main stages: capturing the light energy, the light-dependent reaction and light-independent reaction.

Answer 4

Photosynthesis

Question 5

Photolysis

Answer 5

Light energy splits 2 water molecules into 4 electrons, 4 hydrogen ions (protons) and an oxygen molecule (light-dependent reaction). These electrons replace the electrons lost from a chlorophyll molecule when light strikes it.

Question 6

Loss of electrons or loss of hydrogen or gain of oxygen with a substance

Answer 6

Oxidation

Question 7

Gain of electrons or gain of hydrogen or loss of oxygen from a substance

Answer 7

Reduction

Question 8

NADP

Answer 8

An electron carrier that is important in photosynthesis. When it takes up protons the NADP becomes reduced.

Question 9

A non-protein compound that is necessary for the functioning of an enzyme. (NOT AN ENZYME!) Play a huge role in photosynthesis and respiration where they carry hydrogen atoms from one molecule to another. E.g. NAD, FAD and NADP.

Answer 9

Co-enzyme

Question 10

The cellular organelles where photosynthesis takes place. Typically 2-10µm long and 1µm in diameter and are surrounded by a double membrane which inside it contains two distinct regions: the grana and stroma.

Answer 10

Chloroplast

Question 11

Disc like structures which make up the grana in stacks of up to 100. Where the light-dependent stage of photosynthesis takes place. They contain the photosynthesis pigment chlorophyll. Some may have tubular extensions (intergranal lamellae) which join up with thylakoids in adjacent grana.

Answer 11

Thylakoid

Question 12

Reduced NADP – it is the main product of the light-dependent stage and it enters the light-independent reaction taking with it the electrons from the chlorophyll molecules.

Answer 12

NADPH

Question 13

Fluid-filled matrix where the light-independent stage of photosynthesis takes place.

Answer 13

Stroma

Question 14

Photosynthetic pigment inside thylakoids which absorbs light energy. Can become ionisied.

Answer 14

Chlorophyll

Question 15

Stage of photosynthesis in which light energy is required to produce ATP and reduced NADP

Answer 15

Light-dependent reaction

Question 16

Photoionisation

Answer 16

Process by which a chlorophyll molecule becomes ionised. Caused by the chlorophyll molecule absorbing light energy and boosting the energy of a pair of electrons within a chlorophyll molecule, raising them to a higher energy level and they become so energetic they leave the chlorophyll molecule altogether and are taken up by an electron carrier.

Question 17

Contains a transfer chain where electrons are passed along a number of electron carriers in a series of oxidation-reduction reactions. Where chemiosmotic theory happens – ATP is made.

Answer 17

Thylakoid membrane

Question 18

A protein which actively transports protons into the thylakoid using energy from electrons from chlorophyll. They mean a concentration gradient of protons is maintained across the thylakoid membrane with a high concentration inside the thylakoid space a low concentration in the stroma.

Answer 18

Proton pumps

Question 19

How electrons are passed along a number of electron carriers in a series of oxidation-reduction reactions. Each new carrier is at a slightly lower energy level than the previous one in the chain, and so the electrons lose energy at each stage, which is used to combine an inorganic phosphate molecule with an ADP molecule to make ATP.

Answer 19

Electron carrier transfer chain

Question 20

Mechanism by which ATP is produced in the light-dependent stage of photosynthesis. How it works is that protons are pumped from the stroma using proton pumps in the thylakoid membrane. The energy to drive this process comes from electrons released when photolysis of water happens. The photolysis of water also produces protons which further increase their concentration inside the thylakoid space. A concentration gradient of protons is therefore maintained across the thylakoid membrane with a higher concentration inside the thylakoid space and lower concentration in the stroma. Protons can only cross the thylakoid membrane through ATP synthase channel proteins and when they pass through they cause changes to the structure of the enzyme which then catalyses the combination of ADP with inorganic phosphate to form ATP.

Answer 20

Chemiosmotic theory

Question 21

An enzyme which is embedded in the thylakoid membrane through which protons pass through and cause changes to the structure of the enzyme which then catalyses the combination of ADP with inorganic phosphate to form ATP.

Answer 21

ATP synthase

Question 22

Light-independent reaction

Answer 22

Stage of photosynthesis which does not require light energy directly, but does need the products of the light dependent reaction to reduce CO2 and form carbohydrate

Question 23

A biochemical pathway (part of the light-independent reaction) where CO2 is reduced to form carbohydrate. It takes 6 turns of the Calvin cycle (6 CO2, 18 ATP and 12 NADPH) to make one hexose sugar (because 1/6 molecules of TP are used to make useful substances e.g. glucose and 5/6 molecules of TP are used to make RuBP).
1 CO2 (1C) + 1 RuBP (5C)  2 GP (2 x 3C) + (2 NADPH + 2 ATP) 2 TP (2 x 3C)  Glucose (6C) or RuBP (needs 1 ATP to make RuBP) (5C)

Answer 23

Calvin cycle

Question 24

A 5 carbon sugar (in the Calvin cycle) which reacts with carbon dioxide in the stroma to produce two molecules of GP. This reaction is catalysed by rubisco (ribulose biphosphate caryboxylase).

Answer 24

Ribulose bisphosphate (RuBP)

Question 25

Glycerate 3 phosphate (GP)

Answer 25

A 3 carbon acid (in the Calvin cycle) which reduced NADP is used to reduce to TP using energy supplied by ATP.

Question 26

A 3 carbon sugar (in the Calvin cycle) which can be converted to organic substances that the plant requires such as starch, cellulose, lipids, glucose, amino acids and nucleotides, but most are used to regenerate ribulose biphosphate using ATP from the light-dependent reaction.

Answer 26

Triose Phosphate (TP)

Question 27

A variable that limits the rate of a chemical reaction

Answer 27

Limiting factor

Question 28

What is the cell wall made up of?

Answer 28

• Cellulose
• Hemicellulose
• Lignin

Question 29

What is the difference between autotrophic and heterotrophic?

Answer 29

• Autotrophs create their own food, self nourishing, plants
• Heterotrophs, feed on on other things for nutrients, animals

Question 30

Cell breaks

Answer 30

Cytolysis

Question 31

Where do plants get water from?

Answer 31

The soil

Question 32

How do we describe proteins that cut across the phospholipid bilayer?

Answer 32

• Transmembrane proteins
• Integral protein

Question 33

How do we describe proteins on the surface of the phospholipid bilayer?

Answer 33

• Peripheral proteins

Question 34

Water potential organelle in plants

Answer 34

Tonoplast