chapter 4 Flashcards
biofuels
produced from plant and animal products
fossil fuels
gasoline, cars run on this
oils and fats, like gasoline, contain chains of carbon and hydrogen atoms bound together. Breaking these bonds are forming new, lower energy bonds releasing large amounts of energy, and and
water and carbon dioxide
the production of biofuels requires what
plant or animal sources, sunlight, air, water, and a short amount of time
production of fossil fuels requires
plant and animal remains, and millions of years
biofuels are or are not a renewable source
they are
photosynthesis
process by which plants captures energy from the sun and stores it in the chemical bonds of sugars
cellular respiratrion
process in which all living organisms release the energy stored in the chemical bonds of food molecules and use it to fuel their lives
the energy from sunlight is stored in the chemical bonds of molecules, and when these bonds are broken, what is released
energy, even if the bond is made of a fossil fuel, biofuel, or molecule of food, energy is released
energy
capacity to do work
kinetic energy
energy of motion;
ex legs pushing a bike pedals
birds flapping wings
heat
potential energy
an object doesn’t have to be moving to have the capacity to do work, stored energy that results from an object’s location or position
-doesn’t involve movement
ex water behind dam, water can flow through and spin a waterwheel
concentration gradient, moving from a high to low concentration
chemical energy
storage of energy in chemical bonds (a type of potential energy)
how is the sun’s energy divided?
less than 1%: captured and transformed into usable chemical energy by organisms through photosynthesis
30% space/absorbed by land and oceans
70% atmosphere and heat
kinetic energy to potential energy
light energy from the sun, to energy transformed into heat, to chemical energy stored in plants
potenetial energy to kientic energy
chem energy stored in muscles and liver
energy transformed into heat
kinetic energy of forward motion
thermodynamics
the study of transformation of energy from one type to another, such as potential energy to kinetic energy
first law of thermodynamics
energy can never be created or destroyed, can only change from one form to another
second law of thermodynamics
every conversion of energy is not perfectly efficient and invariably includes the transformation of some energy into heat
-quantity of energy in the universe isn’t changing, the quality is; little by little, the amount of energy that is available to do work decreases
adenosine triphosphate ATP
free floating molecule found in cells that act like a rechargeable batterys, temporarily storing energy that can be then used for cellular work in plants, animals, bacteria, and all other organism on earth
-will be available when neded
describe the structure of atp
three components:
center has two of the components: small sugar molecule attached to adenine
third component: attached to the sugar and adenine is a chain of there negatively charged phosphate groups, three negative charges that repel one another, bc they store a large amount of energy that is stressed and unstable
cells temporarily store energy in the bonds of
atp molecules
potential energy can be converted to what and used for what
kinetic energy and used to fuel life sustaining chemical reactions
or k energy can be converted to p energy
when plants grow where does the new tissue come from
carbon dioxide
what else can photosynthesize?
some bacteria, and many other unicellular organisms such as kelp and other multi cellular algae
three inputs for photosynthesis
light energy from the sun, carbob]n dioxide from the atmosphere, and water from the ground
products of photosynth
sugar and oxygen
chlorpolasts
light harvesting organelles that hold the process of photosynthesis
stroma
sac-shaped organelle filled with fluid
thlakoids
floats in the stroma
interconnected membranous structures, look like pancakes
where does the conversion of light energy to chemical energy (“photo”) part of photosynth occur?
inside the thylakoids
where does the production of sugars (place where “synthesis” occurs) part of photo synth occur?
within the stroma
chlorophyll
molecule in chloroplasts that make the capture of light energy possible
light energy
type of kinetic energy that is made up of photons
photons
energy packets organized into waves
can heat things
the shorter the wavelength the ___ energy the photon carries
more
electromagnetic spectrum
a range that extends from extremely short, high energy gamma rays and x rays with wavelengths as short as one nanometer
pigments
light absorbing molecules
how do pigments work?
the absorb wavelengths of light within a visible range, and the energy in stimulating these nerves in our eyes then transmit electrical signals to our brains. We perceive different wavlengths within the visible spectrum as different colors
where is chlorophyll located
thylakoid membrane
chlorophyll a
primary photosynthetic pigment
absorbs red and blue violet wavelengths of light
which color does chlorophyll a not absorb?
green and instead reflects those wavelengths
chlorophyll b
absorbs blue and red-orange wavelengths, and reflects yellow-green wavelengths
carotenoids
type of pigment that absorbs blue-violet and blue-green wavelengths and reflects yellow, orange, and red wavlengths
an electron in a photosynthetic pigment that is in the excited state has two fates:
1) electron returns to its resting, unexcited state, releasing energy in the process, which may bump other electrons in a nearby molecule
2) excited electron is passed to another molecule
where does the reactions of the calvin cycle occur?
stroma of the leaves’ of chlorplasts
how do plants carry out the calvin cycle?
with energy stored in the ATP and NADPH molecules that are built in the “photo” part of photosynth
How is the calvin cycle like magic
it takes individual molecules of co2 from the air and uses them to assemble visible, edible molecules of sugar
what are the three steps to the calvin cycle
fixation, sugar creation, and regeneration
Why is evaporation a problem for plants
bc water is essential to photosynth, growth, and the transport of nutrients; without water, plants can’t live long without water
stomata
small pores on the underside of leaves; they’re primary sites for gas exchange in plants: carbon dioxide enters, and oxygen is generate as a by product and exits
when open stomata also allow water to evaporate from the plants
why do plants close their stomata
to prevent too much water from evaporating
how does closing the stomata cause problems
oxygen from the “photo” reactions of photosynth can’t be released from the chloroplasts, and carbon dioxide can’t enter
length of a wave:
amount of energy the photon contains
plant pigments do what to specific wavelengths?
absorb
chlorophyll is the main pigment molecule in plants that
absorb light energy from the sun
“photo” in photosynthesis is when
sunlight hits the chloroplasts of a plant’s leaves and some of the energy in this sunlight is captured and stored in ATP and in another molecule, NADPH
NADPH
stores energy by accepting high-energy electrons
How is the chlorophyll a molecule different from the rest of the pigments?
when its electrons are boosted to an exctied state, they do not return to their resting, unexcited state; they continually lose they’re excited electrons to a nearby molecule (primary electron acceptor)
primary electron acceptor
acts like an electron vacuum; passes high energy electrons from chlorophyll a to another molecule, who passes it to another molecule, etc
electron transport chain steps
1) electrons move through the etc, releasing a little energy and falling to a lower energy state
2) the released energy powers proton pumps that move hydrogen ions from the stroma and pack them inside the thylakoid
3) protons rush out of the thylakoid with great kinetic energy, which can be used to build ATP
what happens in each step in the ETC sequence of electron handoffs?
electrons fall to a lower sequence of electron handoffs, the electrons then fall to a lower energy state, and then a little bit of energy is released; these bits of energy are then used to power pump the thylakoid membrane that move protons from the stroma to the inside of the thylakoid
summary of the “photo” reaction components
1) water splitting photosystem
2) 1 ETC
3) NADPH producing photosystem
4) 2 ETC
What happens during the water splitting photosystem during the “photo” reaction components of photosynthesis
light energy is used to transfer electrons to the primary electron acceptor, electrons are donated by water, releasing oxygen and hydrogen ions as the products
what happens during the first etc in the “photo” reaction component of photosyntheis
High energy electrons are used to pump hydrogen ions into the thylakoid. The KE from the release of these ions are used to build ATP
What happens during the NADPH-Producing photosystem during the “photo” reaction component of photosynthesis?
light energy is used to transfer electrons to the primary electron acceptor, electrons are donated by the ETC
what happens during the 2 ETC of the “photo” components of photosynthesis?
High energy electrons are passed to NADP+ creating a NADPH
fixation
plants take carbon from the air in the form of carbon dioxide and then attach/”fix” it to a visible organic molecule within the chloroplast, using an enzyme called rubisco
what enzyme is used in fixation
rubisco
sugar creation
organic molecule is modified into a small sugar (G3P) using energy from ATP & NADPH
Regeneration
g3p molecules are rearranged to regenerate the original five carbon molecule in the cholorpolast
-clavin cycle can continue to fix teh carbon and produce molecules of g3p
c4 photosynthesis
these types of plants produce an enzyme that function like sticky tape; the enzyme ahs a tremendously strong attraction for carbon dixoxide, and can find/bind carbon even when co2 is very low;
as a consequence, the plant’s stomata can be opened just a tiny bit, and let in just a little CO2.
c3 advantage/disadvantage vs c4 advantage/disadvantage
c3: energy efficient//water lost to evaporation in hot climates
c4: water loss minimized in warm climates//requires more energy
CAM photosynthesis
night: open stomata and let co2 into the leaves, where it binds temporarily to a holding molecule then during the day, when a carbon source is needed to make sugars int he calvin cycle, the co2 is needed to make sugars in the calvin cycle, the co2 is graudually released from the holding molecule, enabling photosynthesis to proceed while keeping the stomata closed to reduce water loss
CAM advantage/disadvantage
water loss minimized in hot climates//requires more energy, slow growth
cellular respiration
chemical bonds of sugar and other energy rich food molecules are broken down to release the energy that went into creating them
input/output of cellular respiration
sugar and oxygen//atp molecules (energy), water, and carbon dioxide
first step of cellular respiration
glycolysis
to generate energy such fuels and glucose and other carbohydrates, such as proteins and fats, what three steps are used?
1) glycolysis,
2) krebs
3) etc
glycolysis
splitting of sugar;
glucose is broken down, resulting in two molecules of a substance called pyruvate
where does glycolysis occur
cytoplasm, and uses energy released from breaking chemical bonds in food molecules to produce ATP and NADH
second step of cellular respiration
krebs cycle
-extracts energy from sugar
kreb cycle
produces additional molecules of ATP, and captures a huge amount of chemical energy by producing high energy electron carriers
when a chlorophyll molecule absorbs light, exciting an electron, the chlorophyll molecule
gains potential energy
where do replacement electrons for chlorophyll a come from?
water molecules
What is the outcome of the flow of protons across the thylakoid membrane into the stroma?
the generation of ATP from the differences in photon concentration
why must plants get water for photosynthesis to occur
water replaces electrons used during the “photo” reactions
what links the “photo” reactions with the “synthesis” reactions
atp and nadph
what is regenerated in the calvin cycle
organic molecule
why does feeding sugars to cut flowers help keep them alive longer?
sugar provides an energy source for cellular molecules
A plant whose leaves are reddish yellow is NOT absorbing light from which wavelengths of the visible light spectrum?
red and yellow
What is the source of the electrons that replace those lost by chlorophyll a in the photosystems?
water
Which of the following statements most accurately depicts the relationship between the light reactions and the Calvin cycle in photosynthesis?
The light reactions provide ATP and NADPH to the Calvin cycle and the Calvin cycle returns ADP, NADP+, and a phosphate group to the light reactions.
NAD+ vs NADH
NADH carries one additional proton and two additional high-energy electrons
outcome of glycolysis?
breakdown of a glucose molecule into two smaller pyruvate molecules
glycolysis net worths what
2 atp and 2 nadh per molecules of glucose
Which metabolic processes results in the production of ATP in the absence of oxygen?
glycolysis
If ATP is being generated in the cytosol, which of the following processes is responsible?
glycolysis
Where are the molecules of the mitochondrial electron transport chain located?
within the inner membrane
What happens to electrons as they are passed down the photosynthetic electron transport chain from the primary electron acceptor?
they fall to a lower energy state and some energy is released
