unit 5 vocab.

autotroph

organisms that can make their own food (glucose/sugar) by using light energy from the sun. includes all green plants, some bacteria, and some protists.

heterotroph

organisms that cannot make their own food, so they consume plants or other animals. includes all animals and all fungi.

ATP (adenosine triphosphate)

a chemical compound in a living cell that serves as its basic energy source. consists of adenine (nitrogen base), ribose (5-C sugar), and a chain of three phosphate groups. used to power photosynthesis, protein synthesis, muscle contraction, and active transport across the cell membrane.

pigments

any substance that absorbs light. different variations absorb light of different wavelengths and some reflect certain wavelengths of light.

chlorophyll

the green pigment contained in chloroplasts and principal photosynthetic pigment. absorbs all colors except green. two main kinds: A (blue) and B (yellow) but both are green in color.

photosynthesis

process by which plants use light energy to convert water and carbon dioxide into high-energy sugar molecules. oxygen is given off as a waste product.

light-dependent reactions

one stage of photosynthesis. takes place within the thylakoid membrane. reactants are sunlight and H2O. products are ATP, NADPH, and O2.

light-independent reactions

one stage of photosynthesis. takes place in the stroma (the area inside the chloroplast that is outside the thylakoids). reactants are CO2, NADPH, and ATP. products are glucose, NADP+ and H2)

calvin cycle

another term for light independent reaction.

electron carrier molecules

a compound that can accept a pair of high-energy electrons and transfer them along w/ most of their energy to another molecule. EX: NADP+

chloroplast

organelle found in plant cells containing chlorophyll

thylakoid

interior of the chloroplast and structural unit of photosynthesis. disc like structures in stacks (grana) that contain chlorophyll and are the site of photosynthesis.

stroma

a dense solution within chloroplast that surround the thylakoids. site of light independent reactions.

NADP+

electron carrier that accepts and holds 2 high-energy electrons along with a hydrogen ion. carry electrons to chemical reactions elsewhere in the chloroplast.

photosystems

clusters of pigments embedded in the thylakoid membrane. the light collecting units of the chloroplast.

electron transport chain

electron carriers taking electrons from one reaction to another

ATP synthase

a protein enzyme that hydrogen flows through, rotating the enzyme. as it rotates, it binds a phosphate to ADP, forming ATP

roots

how water is absorbed in the ground and brought into the plant.

stomata

pores/openings in a leaf through with CO2 enters and O2 exits. anytime these are open, there will be excessive water loss.

stem

supports the plant and allows for transportation of material from roots to leaves and vice versa via the vascular bundle.

xylem

one component of the vascular bundle. carries water up into the plant and brings water to the leaf.

phloem

one component of the vascular bundle. carries food down the plant. glucose made will exit the leaf through this and will be carried to other parts of the plant.

guard cell

found on either side of a stoma. function is to open and close the stoma.

palisade mesophyll

one component of the central middle area of the leaf. this layer is the primary photosynthetic layer of the leaf as it includes many chloroplasts.

spongy mesophyll

one component of the middle area of the leaf. contains chloroplasts, though not nearly as many as the palisade mesophyll.

transpiration

the process of water movement through a plant and its evaporation from parts such as leaves, stems and flowers. it’s a passive process that requires no energy expense by the plant.

monocot

plants that have one cotyledon or a seed leaf after germination

dicot

plants that have two cotyledons or a seed leaves after germination