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Photosynthesis and Cellular Respiration

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Terms in this set (29)

  • Major parts of the chloroplast

    The thylakoid membranes (site of light reactions), stroma (site of Calvin Cycle), and grana (stacks of thylakoids).

  • Role of stomata in photosynthesis

    Stomata are pores on leaves that allow gas exchange, letting CO2 in and O2 out, essential for photosynthesis.

  • Overall equation for photosynthesis

    \(6CO_2 + 6H_2O + light \rightarrow C_6H_{12}O_6 + 6O_2\). It is the reverse of cellular respiration.

  • Why are leaves green?

    Leaves are green because chlorophyll absorbs mostly blue and red light, reflecting green wavelengths.

  • Types of chlorophyll in plants

    Plants have chlorophyll a and chlorophyll b, while other organisms may have different types like chlorophyll c.

  • Other pigments in chloroplasts

    Carotenoids are common pigments that absorb additional light wavelengths and protect chlorophyll from damage.

  • Function of Photosystem II

    Photosystem II (P680) splits water molecules, releasing O2 and electrons for the electron transport chain.

  • Function of Photosystem I

    Photosystem I (P700) produces NADPH by transferring electrons to NADP+.

  • Role of electron transport chain in light reactions

    Transfers electrons from PSII to PSI, pumping H+ into thylakoid space to generate ATP via ATP synthase.

  • Role of plastoquinone (PQ) in ETC

    Accepts electrons from PSII and moves them along the ETC while pumping H+ into the thylakoid space.

  • Role of cytochrome b6/f complex

    Transfers electrons from plastoquinone to plastocyanin and helps pump H+ across the membrane.

  • Role of plastocyanin (PC)

    Copper-containing protein that carries electrons to Photosystem I.

  • Role of ferredoxin (Fd) and ferredoxin-NADP+ reductase (FAD)

    Fd passes electrons to FAD, which helps convert NADP+ to NADPH.

  • How is ATP produced in photosynthesis?

    ATP is made by ATP synthase using the H+ gradient created by the ETC during light reactions.

  • What is ATP and its role?

    ATP (adenosine triphosphate) stores and transfers energy for cellular processes.

  • Two major stages of photosynthesis

    1. Light reactions: convert light energy to ATP and NADPH.
    2. Calvin Cycle: uses ATP and NADPH to fix CO2 into sugar.

  • Source of O2 produced in photosynthesis

    O2 is produced by splitting water molecules during the light reactions in Photosystem II.

  • Calvin Cycle inputs and outputs

    Inputs: CO2, ATP, NADPH.
    Outputs: G3P (3-carbon sugar), ADP, NADP+.

  • Role of RuBP and Rubisco in Calvin Cycle

    RuBP is a 5-carbon molecule that binds CO2; Rubisco is the enzyme that catalyzes this fixation.

  • Why is Rubisco called a two-timing enzyme?

    Because it can fix CO2 (carboxylase activity) or O2 (oxygenase activity), leading to photorespiration.

  • Photorespiration and its causes

    Occurs when Rubisco fixes O2 instead of CO2, wasting energy; influenced by O2 levels and stomata behavior.

  • C4 and CAM pathways

    Adaptations to reduce photorespiration: C4 separates steps spatially; CAM separates them temporally (day/night).

  • Difference between C3 and C4 leaf anatomy

    C4 plants have mesophyll and bundle sheath cells; C3 plants do not have this specialized anatomy.

  • Enzyme converting CO2 to 4-carbon malate in C4 and CAM plants

    PEP carboxylase fixes CO2 into a 4-carbon compound (malate).

  • Role of plants in combating global warming

    Plants absorb CO2 during photosynthesis, reducing greenhouse gases in the atmosphere.

  • Definition of autotrophs and heterotrophs

    Autotrophs produce their own food (e.g., plants); heterotrophs consume other organisms for energy.

  • Why do we breathe?

    To take in O2 needed for cellular respiration, which produces ATP in mitochondria.

  • Where does cellular respiration occur in eukaryotic cells?

    In the mitochondria.

  • Relationship between photosynthesis and cellular respiration

    Photosynthesis stores energy in glucose; cellular respiration releases energy by breaking glucose down.