Science 3.1 "How Do Plants Capture Energy?"

simple sugar

a sugar that cannot be broken down into small carbohydrate units

ex: glucose

vascular tissue

the tissue in plants that make up the vascular system (w/ phloem + xylem)

phloem

carries food/glucose up + down the vascular system

* food made in leaves needs to travel throughout the plant to create energy for cellular activities
* roots use this for energy or starch

xylem

carries water + minerals in the vascular system in one direction

* water is important to photosynthesis + needs to travel to the leaves

vascular cambium

a layer in a stem/trunk that surrounds the sapwood + produces new xylem + phloem cells

transpiration

the loss of water from a plant through the stomata in the leaves, triggering the xylem to pull water upward.

* similar to perspiration (sweating) cause they both involve the loss of water from an organism

meristem

a growth region of a plant

cork cambium

a meristem located outside the phloem that produces cork tissue and is responsible for secondary growth in stems

photosynthesis

the process of how plants make food through the chemical reaction of:

* 6CO2 + 6H2O + light energy

(6 atoms of carbon dioxide from breathed out air, 6 atoms of water from soil, + light energy from the sun)

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* the chemical reaction will make sugar: C6H12O6

the sugar will get stored in ATP molecules made from ADP + oxygen

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* the chemical reaction will also make oxygen: 6O2

the oxygen will be released as air used to breathe

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* the process takes 2 steps that depend on each other: light + dark reactions

chloroplast

forms the products glucose + molecular oxygen

molecular oxygen

a molecule w/ 2 oxygen atoms (O2)

light reactions

the 1st step of photosynthesis when light hits the leaves + is absorbed by chlorophyll in the chloroplasts

4 steps of light reactions

1. light energy is absorbed by chlorophyll in the leaf
2. light energy splits the water molecules into hydrogen (H2) + one oxygen atom (O)
3. created H2 gets added to NADP+ to make NADPH and the oxygen is released by the leaf into the air
4. absorbed light energy is used to add to a phospate group (ADP to create ATP)

products of light reaction

NADPH, ATP, + oxygen

dark reactions

aka the Calvin Cycle + occurs in other part of the chloroplast.

it does not need light energy, hence its name

5 steps of dark reactions

1. Carbon dioxide (CO2) from atmosphere enters plant

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2. CO2 fixation occurs by when its molecules combine into 3-carbon molecules in the chloroplast

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3. the reduction phase occurs by chemical reactions, causing the ATP + NADPH to give electrons + change back to ADP + NADP+, which results in PGAL molecules.

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4. some PGAL molecules are reused to keep the cycle going

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5. some PGAL molecules leave the cycle + are used to build organic molecules that make up the cell

NADP+

nicotinamide adenine dinucleotide phosphate

NADPH

Nicotinamide Adenine Dinucleotide Phosphate plus an electron from Hydrogen

* a product by light reactions
* made from hydrogen + Nicotinamide Adenine Dinucleotide Phosphate (NADP+) during the light reaction cycle


* an energy-rich compound reaction for dark reactions in photosynthesis

ADP

adenosine diphosphate

ATP

adenosine triphosphate

* a product of light reactions
* made by light energy getting absorbed into Adenosine Diphosphate (ADP) during light reaction
* its molecules are where sugar made by the plant gets stored
* an energy-rich compound reaction for dark reactions in photosynthesis

PGAL

glyceraldehyde 3-phosphate

starch

one larger molecule made by many glucose molecules that is formed by the glyceraldhyde 3-phosphate (PGAL) molecules during the Calvin Cycle

cellulose

the fibrous material in plants that can be formed by PGAL molecules during the Calvin Cycle

cellular respiration

a process in which cells obtain the energy they need to survive where they use oxygen to break down glucose to store its energy in ATP molecules.

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* 40% of glucose goes to ATP, while the rest give power to the plant + is later released as heat
* this is critical for plant survival because cells use ATP to power the plant

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sugar (stored in photosynthesis) + oxygen (from air)

= ATP, and water (a by-product)

heartwood

a layer in the darker center of a trunk made of old nonfunctioning xylem cells

sapwood

layer that surrounds heartwood made of active xylem that moves water + minerals without using energy

bark

aka cork cambium

* outer layer of a tree trunk that protects the living cells inside

roots

* part of a plant that removes sugar in the phloem to use for energy or make starch to store it
* the increase of concentration of sugar/starch causes the shape of this part of a plant to change

stoma

an opening on the leaf’s surface that allows gases in + out during photosynthesis

* when light is present, this opens + increases the rate of photosynthesis + transpiration

General Sherman

a sequoia + the largest tree ever

plant growth

when the roots + shoots’ tips grow longer

primary growth

growth at the tips of plants

* apical + intercalary meristems use this type of plant growth

secondary growth

growth where the stems thicken

* vascular + cork cambium meristems use this type of plant
* growth

plant hormone

part of a plant that sends signals to specific cells to “switch on” certain genes

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ex:

* Auxins, Abscisic acid, Ethylene, Gibberellins, Cytokinins