Chapter 5 - Photosynthesis Flashcards
photoautotroph
an organism capable of undertaking photosynthesis
photosynthesis
the process of capturing light energy to power the production of glucose and oxygen from carbon dioxide and water
6CO2 + 12H2O -> C6H12O6 + 6CO2 + 6H2O
mesophyll cell
a plant cell type found in leaves that contain large amounts of chloroplasts
chloroplast
a membrane-bound organelle only found in plant and photoautotroph cells that is the site of photosynthesis
chlorophyll
a chemical found in the thylakoids of chloroplasts. It is responsible for absorbing light energy in photosynthesis
stoma (pl. stomata)
a small pore on the leaf’s surface that opens and closes to regulate gas exchange
xylem
vascular tissue in plants responsible for transporting water and minerals from the roots to the leaves
light-dependent stage
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
thylakoid
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
granum (pl. grana)
a stack of thylakoids
NADPH
a coenzyme that is a proton (H+) and electron carrier in photosynthesis (transfers hydrogen ions)
ATP
adenosine triphosphate, a high energy molecule that, when broken down, provides energy for cellular processes
photolysis
the process in which molecules are broken down by the action of light
light-independent stage
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
stroma
the fluid substance that makes up the interior of chloroplasts. It is the site of the light-independent stage of photosynthesis
enzyme
an organic molecule, typically a protein, that catalyses (speeds up) specific reactions
Rubisco
a pivotal enzyme involved in initial carbon fixation during the light-independent stage of photosynthesis
carbon fixation
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
inorganic
a compound that does not contain a carbon-hydrogen bond, e.g. carbon dioxide
organic
a compound containing a carbon-hydrogen bond, e.g. glucose
substrate
the reactant of a reaction catalysed by an enzyme
photorespiration
a wasteful process in plants initiated by Rubisco that limits photosynthesis
affinity
the tendency of a molecule/atom to bind or react with another molecule/atom
C3 plants
plants with no evolved adaptation to minimise photorespiration
C4 plants
plants that minimise photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over space
bundle-sheath cell
a plant cell type that is the site of most of the Calvin cycle in C4 plants
CAM plants
plants that minimise photorespiration by separating initial carbon fixation and the remainder of the Calvin cycle over time
plateau
to reach a state where no further change occurs
saturation point
the point at which a substance (e.g. an enzyme) cannot receive more of another substance (e.g. a substrate)
limiting factor
a factor that prevents the rate of reaction from increasing
limiting reagent
a reactant that prevents the rate of reaction from increasing
optimal
the point at which for a given condition (e.g. temperature), the maximum function of an enzyme occurs. Also known as optimum
denature
the disruption of a molecule’s structure by an external factor such as heat
enzyme inhibitor
a molecule that binds to and prevents an enzyme from functioning
competitive inhibitor
a molecule that hinders an enzyme by blocking the active site and preventing the substrate from binding
non-competitive inhibitor
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
allosteric site
a region on an enzyme that is not the active site
reversible inhibition
enzyme inhibition that involves weaker bonds that can be overcome
irreversible inhibition
enzyme inhibition that involves stronger bonds that cannot be broken
CRISPR
short, clustered repeats
of DNA found in prokaryotes
which protects them against
viral invasion
CRISPR-associated protein 9 (Cas9)
an endonuclease that creates a blunt end cut at a site specified by guide RNA (gRNA)
genetic modification
the manipulation of an organism’s genetic material using biotechnology
genetically modified organism (GMO)
an organism with genetic material that has been altered using genetic engineering technology
arable land
land that is suitable for growing crops
yield
the amount of agricultural product harvested per area of land
