Chapter 5 - Photosynthesis

Question 1

photoautotroph

Answer 1

an organism capable of undertaking photosynthesis

Question 2

photosynthesis

Answer 2

the process of capturing light energy to power the production of glucose and oxygen from carbon dioxide and water
6CO2 + 12H2O -> C6H12O6 + 6CO2 + 6H2O

Question 3

mesophyll cell

Answer 3

a plant cell type found in leaves that contain large amounts of chloroplasts

Question 4

chloroplast

Answer 4

a membrane-bound organelle only found in plant and photoautotroph cells that is the site of photosynthesis

Question 5

chlorophyll

Answer 5

a chemical found in the thylakoids of chloroplasts. It is responsible for absorbing light energy in photosynthesis

Question 6

stoma (pl. stomata) 

Answer 6

a small pore on the leaf’s surface that opens and closes to regulate gas exchange

Question 7

xylem

Answer 7

vascular tissue in plants responsible for transporting water and minerals from the roots to the leaves

Question 8

light-dependent stage

Answer 8

the first stage of photosynthesis, where light energy splits water molecules into oxygen and hydrogen inside the thylakoid membranes. Also known as the light-dependent reactions
12H2O + 12NADP(+) +18ADP & Pi = 6O2 + 12NADPH + 18ATP

Question 9

thylakoid

Answer 9

a flattened sac-like structure housed inside the chloroplast. Each thylakoid is made up of a chlorophyll-containing membrane enclosing a lumen. Thylakoids are the location of the light-dependent stage of photosynthesis

Question 10

granum (pl. grana)

Answer 10

a stack of thylakoids

Question 11

NADPH

Answer 11

a coenzyme that is a proton (H+) and electron carrier in photosynthesis (transfers hydrogen ions)

Question 12

ATP

Answer 12

adenosine triphosphate, a high energy molecule that, when broken down, provides energy for cellular processes

Question 13

photolysis

Answer 13

the process in which molecules are broken down by the action of light

Question 14

light-independent stage 

Answer 14

the second stage of photosynthesis where carbon dioxide is used to form glucose in the stroma of a chloroplast. Also known as the Calvin cycle, the dark stage, or the light-independent reactions
6CO2 + 12NADPH + 18ATP = C6H12O6 + 6H2O + 12NADP(+) + 18ADP &Pi

Question 15

stroma

Answer 15

the fluid substance that makes up the interior of chloroplasts. It is the site of the light-independent stage of photosynthesis

Question 16

enzyme

Answer 16

an organic molecule, typically a protein, that catalyses (speeds up) specific reactions

Question 17

Rubisco 

Answer 17

a pivotal enzyme involved in initial carbon fixation during the light-independent stage of photosynthesis

Question 18

carbon fixation

Answer 18

the process in living organisms where inorganic carbon, typically within carbon dioxide, is converted into organic compounds such as glucose. Carbon fixation is a central part of the light-independent stage of photosynthesis

Question 19

inorganic 

Answer 19

a compound that does not contain a carbon-hydrogen bond, e.g. carbon dioxide

Question 20

organic 

Answer 20

a compound containing a carbon-hydrogen bond, e.g. glucose

Question 21

substrate

Answer 21

the reactant of a reaction catalysed by an enzyme

Question 22

photorespiration

Answer 22

a wasteful process in plants initiated by Rubisco that limits photosynthesis

Question 23

affinity

Answer 23

the tendency of a molecule/atom to bind or react with another molecule/atom

Question 24

C3 plants 

Answer 24

plants with no evolved adaptation to minimise photorespiration

Question 25

C4 plants

Answer 25

plants that minimise photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over space

Question 26

bundle-sheath cell

Answer 26

a plant cell type that is the site of most of the Calvin cycle in C4 plants

Question 27

CAM plants 

Answer 27

plants that minimise photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over time

Question 28

plateau

Answer 28

to reach a state where no further change occurs

Question 29

saturation point

Answer 29

the point at which a substance (e.g. an enzyme) cannot receive more of another substance (e.g. a substrate)

Question 30

limiting factor

Answer 30

a factor that prevents the rate of reaction from increasing

Question 31

limiting reagent

Answer 31

a reactant that prevents the rate of reaction from increasing

Question 32

optimal

Answer 32

the point at which for a given condition (e.g. temperature), the maximum function of an enzyme occurs. Also known as optimum

Question 33

denature

Answer 33

the disruption of a molecule’s structure by an external factor such as heat

Question 34

enzyme inhibitor

Answer 34

a molecule that binds to and prevents an enzyme from functioning

Question 35

competitive inhibitor

Answer 35

a molecule that hinders an enzyme by blocking the active site and preventing the substrate from binding

Question 36

non-competitive inhibitor

Answer 36

a molecule that hinders an enzyme by binding to an allosteric site and changing the shape of the active site to prevent the substrate from binding

Question 37

allosteric site 

Answer 37

a region on an enzyme that is not the active site

Question 38

reversible inhibition

Answer 38

enzyme inhibition that involves weaker bonds that can be overcome

Question 39

irreversible inhibition

Answer 39

enzyme inhibition that involves stronger bonds that cannot be broken

Question 40

CRISPR

Answer 40

short, clustered repeats of DNA found in prokaryotes which protects them against viral invasion

Question 41

CRISPR-associated protein 9 (Cas9)

Answer 41

an endonuclease that creates a blunt end cut at a site specified by guide RNA (gRNA)

Question 42

genetic modification

Answer 42

the manipulation of an organism’s genetic material using biotechnology

Question 43

genetically modified organism (GMO)

Answer 43

an organism with genetic material that has been altered using genetic engineering technology

Question 44

arable land

Answer 44

land that is suitable for growing crops

Question 45

yield 

Answer 45

the amount of agricultural product harvested per area of land