Honours Biology: Photosynthesis Quiz and Test

light-harvesting complexes

proteins with molecules bound to them that function as a light-gathering antenna

The Calvin Cycle

occurs in the stroma of the chloroplast and is a series of reactions that assembles sugar using CO2 and products of the light reaction

CAM plants

only admit CO2 at night and saves it so the plant can use it during the day, when the stomata are closed

Rubisco

thought to be the most abundant protein on Earth and is the enzyme that attaches CO2 to RuBP during carbon fixation

C4 Plants

fixes CO2 into a 4 carbon compound during carbon fixation, the Calvin Cycle happens in a different kind of cell to conserve CO2

RuBP

a five-carbon sugar and is the starting material needed for the Calvin Cycle

The Calvin Cycle

like the sugar factory of the cell and occurs in the stroma, produces NADP+, ADP, G3P, and RuBP. The reactants are NADPH, ATP, CO2 and RuBP and it

Light Reactions

the reactions that convert light energy to chemical energy and occurs in the thylakoid membranes

carbon fixation

The incorporation of carbon from CO2 into organic compounds and is a step in the Calvin Cycle

Chlorophyll a

a pigment in the chloroplasts that absorbs mainly blue-violet and red light, and reflects green light

Chlorophyll b

absorbs mainly blue and orange light and reflects yellow and green light. It also broadens the range of light a plant can use

carotenoids

other pigments found in chloroplasts and are various shades of yellow and orange

photoprotection

a function of carotenoids, where they absorb and dissipate excess light that would otherwise damage the chlorophyll

photosynthesis equation

6CO2+6H20 →C6H12O6 +6O2

photosynthesis

the process of converting light energy to chemical energy

autotrophs

plants that make their own food and sustain themselves without consuming organic molecules derived from other organisms

photoautotrophs

plants that catch light energy and convert it to chemical energy and are the ultimate source for all other organisms

endosymbiotic theory

states chloroplasts originated from a photosynthetic prokaryote that took up residence in a eukaryotic cell

chlorophyll

the light absorbing pigment in the chloroplast

mesophyll

the green tissue in the interior of the leaf where the chloroplasts are found

stomata

the “pores” of a cell that allows CO2 and O2 to enter and exit the cell

veins

how water and sugar are moved within the plant

30-40

the amount of chloroplasts in one mesophyll cell

stroma

the thick liquid between the inner and outer membrane

thylakoid space

an internal compartment inside of thylakoids

thylakoid

a system of interconnected membraneous sacs found in the stroma, that looks like a pancake

grana/granum

the name of the stacks of thylakoids

photosystem

a number of light-harvesting complexes and a reaction-center complex

fluoresence

the photons of light that are given off during photosynthesis

chemiosmosis

the energy given off from the ETC causes the H+ gradient to form, and drives cellular work

photophosphorylation

the production of ATP during photosynthesis

heterotrophs

consumes other plants/animals/decomposed organic material

Chemical bonds of sugar molecules

where plants store their chemical energy

C3 plants

a plant that takes CO2 from the atmosphere and fixes it into a 3 carbon compound

photorespiration

when O2 builds up in a leaf and Rubisco adds O2 to RuBP instead of CO2 and yeilds no sugar

G3P

a product of the Calvin Cycle needed to make glucose and other organic compounds, and is 1/2 of a glucose molecule

reaction-center complex

contains the pair of special chlorophyll a molecules and the primary electron acceptor which accepts an electron from a split up water

What happens during the first step, carbon fixation, of the Calvin Cycle?

the enzyme rubisco attaches CO2 to RuBP, which splits into two molecules of 3-PGA

What is NADPH used for in the Calvin cycle?

NADPH provides the electrons for the further reduction of carbons in the Calvin Cycle

What is oxidized in photosynthesis?

6 H2O

How do the reactant molecules of photosynthesis reach the chloroplasts in leaves?

O2 and CO2- the stomata

H20- the roots

Where is chlorophyll found? (be specific)

the thylakoid membranes

Why would you expect photorespiration on a hot, dry, day to occur less in C4 and CAM plans than in C3 plants?

Because C4 and CAM plants have their carbons fxed in a way that would ensure they have enough for photosynthesis without having to take in more through their stomata

To synthesize one glucose molecule, the Calvin Cycle uses __CO2, ATP, and NADPH.__

6 CO2

18 ATP

12 NADPH

What happens during the third step of the Calvin Cycle?

1 G3P leaves the cycle, which is the net product of photosynthesis. The remaining 5 G3P are brought to RuBP regeneration

For every 3 CO2 that enters the cell how much 3-PGA is made?

For every 3 CO2 that enters 6 3-PGA are made

What’s the difference between oxidative phosphorylation in cellular respiration and photophosphorylation in photosynthesis?

The electrons used for oxidative phosphorylation are from oxidised organic molecules and passed down the ETC and for photophosphorylation the electrons come from the splitting of water

What is an advantage of the light reactions producing NADPH and ATP on the stroma side of the thylakoid membrane?

NADPH and ATP are reactants of the Calvin Cycle, which occurs in the stroma

Which redox process is endergonic, photosynthesis or cellular respiration?

photosynthesis

What is ATP used for in the Calvin Cycle?

ATP produced in the light reactions is used to power several steps of the Calvin Cycle

What do self-feeding photoautotrpohs require from the environment in order to make their own food?

Light, CO2, and H2O

What are the other names of the Calvin Cycle?

The light-independent reaction or dark reaction

For Chloroplasts to produce sugar from CO2 in the dark, they would need to be supplied with __ __and__ ___

NADPH and ATP

What is oxidized in cellular respiration?

C6H12O6

Why is the Calvin Cycle called a “Cycle”?

Because the starting material is regenerated with every turn of the cycle

What is reduced in cellular respiration?

6 O2

What are the products of the light reactions?

NADPH, ATP, and O2

What happens during step four of the Calvin Cycle?

RuBP is regenerated through a series of chemical reactions that use ATP to rearrange the atoms in the 5 G3P