quiz 6 bio 100
Humans can see only a fraction of this solar energy (also known as electromagnetic radiation), which is referred to as ______________ ______________
"visible light."
The photon causes an electron in the chlorophyll to become ____________________
"excited."
When carbon dioxide dissolves in water it forms an acid called _____________ acid.
carbonic
A photon of light energy travels until it reaches a molecule of __________________
chlorophyll
Where is chlorophyll located?
chloroplast
chlorophyll b
reflects green and absorbs blue and red-orange light
Which color(s) of light does chlorophyll a reflect? A. red and blue B. green C. red D. blue
B. green
The movement of mineral nutrients through organisms and their environment is called a ________ cycle. A. biological B. bioaccumulation C. biogeochemical D. biochemical
C. biogeochemical
Which molecule absorbs the energy of a photon in photosynthesis? A. ATP B. glucose C. chlorophyll D. water
C. chlorophyll
The majority of water found on Earth is: A. ice B. water vapor C. fresh water D. salt water
D. salt water
Discuss how the human disruption of the carbon cycle has caused ocean acidification.
Human activity has greatly increased the amount of carbon dioxide gas in the Earth's atmosphere. The oceanic and atmospheric levels of carbon dioxide are linked so that when atmospheric carbon dioxide levels increase, the amount of dissolved carbon dioxide in the ocean also increases (partial pressure of oxygen). When carbon dioxide dissolves in water it produces the weak acid bicarbonate. Since the Industrial Revolution the pH of the ocean has dropped 0.1 pH units, a 30% increase in acidity.
biogeochemical cycle
Because geology and chemistry have major roles in the study of this process, the recycling of inorganic matter between living organisms and their nonliving environment is called a biogeochemical cycle.
Why are carnivores, such as lions, dependent on photosynthesis to survive?
Because lions eat animals that eat plants.
Has rain and snowfall increased or decreased as the result of a warmer climate?
Both have actually increased, on average, when the entire world is taken into account. Some places, however, have become much drier due to climatic shifts.
What are some things that you can do to reduce your carbon dioxide emissions?
Buy a more fuel efficient car, drive less, use energy efficient bulbs, and adopt the lifestyle that includes reusing things, recycling whenever you can, and producing less waste, including not using throw-away plastic bottles and bags. Anything that you can do to burn less fossil fuel and use less energy will not only help the climate change problem, but also many other environmental problems that have been around for decades, and are only getting worse.
Why are drinking water supplies still a major concern for many countries?
Most of the water on Earth is salt water, which humans cannot drink unless the salt is removed. Some fresh water is locked in glaciers and polar ice caps, or is present in the atmosphere. The Earth's water supplies are threatened by pollution and exhaustion. The effort to supply fresh drinking water to the planet's ever-expanding human population is seen as a major challenge in this century.
ATP and _______________ carry their energy to the Calvin cycle, where glucose will be made.
NADPH
As the electron from the electron transport chain arrives at photosystem I, it is re-energized with another photon captured by chlorophyll. The energy from this electron drives the formation of ___________ from NADP+ and a hydrogen ion (H+).
NADPH
What two nutrients are most limiting to plants?
Nitrogen (N) and phosphorus (P)
After the energy is released, the "empty" energy carriers return to the light-dependent reactions to obtain more _________________.
energy
A major effect from fertilizer runoff is saltwater and freshwater ______________________________
eutrophication
Other organisms, such as animals, fungi, and most other bacteria, are termed ____________________ ("other feeders"), because they must rely on the sugars produced by photosynthetic organisms for their energy needs.
heterotrophs
In what way can the oceans help to reduce the effects of climate change.
They are a huge reservoir of both carbon dioxide and heat. This allows them to absorb some of the excess carbon and heat, but not enough to prevent climate change from occurring over the long term.
According to NASA, how much has the world warmed, on average, over the last 100 years or so?
They found that it had warmed 0.5 degrees Celsius, or 1 degree Fahrenheit, by the beginning of the 21st century. Some places, such as the poles and southwestern U.S., have warmed by much more.
What is the overall purpose of the light reactions in photosynthesis?
To convert solar energy into chemical energy that cells can use to do work.
True or False: A warmer climate leads to both abiotic (non-living) and biotic (living) changes.
True
True or False: Autotrophs only use a specific component of sunlight.
True
True or False: Most of the solar radiation from the sun that reaches the Earth is absorbed at its surface
True
True or False: The carriers that move energy from the light-dependent reactions to the Calvin cycle reactions can be thought of as "full" because they bring energy to the Calvin cycle
True
______________ ___________ constitutes only one of many types of electromagnetic radiation emitted from the sun.
Visible light
What are the most common greenhouse gas emissions that humans are adding to the atmosphere? Which is the most abundant emission and where does it mostly come from?
We are adding carbon dioxide (the most abundant; mainly from fossil fuel use), methane, nitrous oxide, and chlorofluorocarbons to the atmosphere through various activities.
light is
a form of energy
It takes a lot of energy to heat water because of the ____________________bonds that it forms, and thus it can moderate the Earth's temperature to a certain extent.
hydrogen
chlorophyll a
reflects green, and absorbs wavelengths from either end of the visible spectrum (blue and red)
violet and blue have______________ wavelengths
shorter
The more greenhouse gases, the greater the atmosphere's ability to trap reflected ________________ __________________. It is a direct relationship.
solar radiation
What are the two stages of Photosynthesis
the light-dependent reactions and the Calvin cycle (light-independent reactions)
carotenoids
reflect red, orange, or yellow and absorb blue-green and violet light
What does chlorophyll do?
absorb red and blue light (reflects green and yellow light)
greenhouse effect
keeps the earth warm
Carbon is present in the atmosphere as ________. A. carbon dioxide B. carbonate ion C. carbon dust D. carbon monoxide
A. carbon dioxide
The average time a molecule spends in its reservoir is known as ________. A. residence time B. restriction time C. resilience time D. storage time
A. residence time
Plants produce oxygen when they photosynthesize. Where does the oxygen come from? A. splitting water molecules B. ATP synthesis C. the electron transport chain D. chlorophyll
A. splitting water molecules
Which statement correctly describes carbon fixation? A. the conversion of CO2 to an organic compound B. the use of RuBisCO to form 3-PGA C. the production of carbohydrate molecules from G3P D. the formation of RuBP from G3P molecules E. the use of ATP and NADPH to reduce CO2
A. the conversion of CO2 to an organic compound
Now that the solar energy is stored in energy carriers, it can be used to make a sugar molecule. That is the purpose of the Calvin cycle. When these molecules release energy into the Calvin cycle, they each lose atoms to become the lower-energy molecules _________ and NADP+.
ADP
In the light-dependent reactions, energy absorbed by sunlight is stored by two types of energy-carrier molecules: ______ and ____________. The energy that these molecules carry is stored in a bond that holds a single atom to the molecule. For ATP, it is a phosphate atom, and for NADPH, it is a hydrogen atom.
ATP and NADPH
What is the molecule that leaves the Calvin cycle to be converted into glucose? A. ADP B. G3P C. RuBP D. 3-PGA
B. G3P
Which of the following approaches would be the most effective way to reduce greenhouse carbon dioxide? A. Increase waste deposition into the deep ocean. B. Plant more environmentally-suitable plants. C. Increase use of fuel sources that do not produce carbon dioxide as a by-product. D. Decrease livestock agriculture.
B. Plant more environmentally-suitable plants.
Which statement about thylakoids in eukaryotes is not correct? A. Thylakoids are assembled into stacks. B. Thylakoids exist as a maze of folded membranes. C. The space surrounding thylakoids is called stroma. D. Thylakoids contain chlorophyll.
B. Thylakoids exist as a maze of folded membranes.
What is the energy of a photon first used to do in photosynthesis? A. split a water molecule B. energize an electron C. produce ATP D. synthesize glucose
B. energize an electron
The process whereby oxygen is depleted by the growth of microorganisms due to excess nutrients in aquatic systems is called ________. A. dead zoning B. eutrophication C. retrofication D. depletion
B. eutrophication
From where does a heterotroph directly obtain its energy? A. the sun B. the sun and eating other organisms C. eating other organisms D. simple chemicals in the environment
C. eating other organisms
What two products result from photosynthesis? A. water and carbon dioxide B. water and oxygen C. glucose and oxygen D. glucose and carbon dioxide
C. glucose and oxygen
The process whereby nitrogen is brought into organic molecules is called ________. A. nitrification B. denitrification C. nitrogen fixation D. nitrogen cycling
C. nitrogen fixation
Where in plant cells does the Calvin cycle take place? A. thylakoid membrane B. thylakoid space C. stroma D. granum
C. stroma
In ___________ a more efficient use of CO2 allows plants to photosynthesize even when CO2 is in short supply, as when the stomata are closed on hot days.
C4
Which of the following statements about the nitrogen cycle is false? A: Ammonification converts organic nitrogenous matter from living organisms into ammonium (NH4+). B. Denitrification by bacteria converts nitrates (NO3−) to nitrogen gas (N2). C. Nitrification by bacteria converts nitrates (NO3−) to nitrites (NO2−). D. Nitrogen fixing bacteria convert nitrogen gas (N2) into organic compounds.
C: Nitrification by bacteria converts nitrates (NO3−) to nitrites (NO2−).
Cacti and other water-storing succulents belonging to the plant family Crassulaceae can perform ________________, otherwise known as crassulaean acid metabolism.
CAM
___________ plants can perform preliminary reactions of the Calvin cycle at night, because opening the stomata at this time conserves water due to cooler temperatures.
CAM
We have also contributed extra greenhouse gases to the atmosphere by adding _______________________________ from the use of refrigerants, aerosols, and solvents,
CFC's (chlorofluorocarbons)
In the _________________ ____________________________, which takes place in the stroma, the chemical energy derived from the light-dependent reactions drives both the capture of carbon in carbon dioxide molecules and the subsequent assembly of sugar molecules.
Calvin Cycle (light-independent reactions)
This chemical energy produced in the light-dependent reactions will be used by the ______________ _____________ to fuel the assembly of sugar molecules.
Calvin cycle
What is the pigment plants use for photosynthesis?
Chlorophyll
What are two examples of C4 plants
Corn and sugar cane are C4 plants. They both thrive in hot environments receiving abundant sunshine.
How would loss of fungi in a forest effect biogeochemical cycles in the area? A. Nitrogen could no longer be fixed into organic molecules. B. Phosphorus stores would be released for use by other organisms. C. Sulfur release from eroding rocks would cease. D. Carbon would accumulate in dead organic matter and waste.
D. Carbon would accumulate in dead organic matter and waste.
What is eutrophication? What causes it and what does it do to the oxygen supply where it occurs?
It involves the excessive growth of algae in aquatic habitats, mainly freshwater ones, such as lakes. Both nitrogen and phosphorus from fertilizers in runoff can lead to this problem. As algae blooms take over, oxygen is depleted from the environment, causing huge die offs of fish and other organisms.
What are three things light can do?
Like all energy, light can: travel change form be harnessed to do work.
What are the factors that cause dead zones? Describe eutrophication, in particular, as a cause.
Many factors can kill life in a lake or ocean, such as eutrophication by nutrient-rich surface runoff, oil spills, toxic waste spills, changes in climate, and the dumping of garbage into the ocean. Eutrophication is a result of nutrient-rich runoff from land using artificial fertilizers high in nitrogen and phosphorus. These nutrients cause the rapid and excessive growth of microorganisms, which deplete local dissolved oxygen and kill many fish and other aquatic organisms.
Describe nitrogen fixation and why it is important to agriculture.
Nitrogen fixation is the process of bringing nitrogen gas from the atmosphere and incorporating it into organic molecules. Most plants do not have this capability and must rely on free-living or symbiotic bacteria to do this. As nitrogen is often the limiting nutrient in the growth of crops, farmers make use of artificial fertilizers to provide a nitrogen source to the plants as they grow.
Is the greenhouse effect a human-caused phenomenon?
No. It has been around ever since the Earth formed and there were greenhouse gases, such as carbon dioxide and methane, in the air. Humans have added greenhouse emissions, however, which has made the greenhouse effect more dramatic, thus making the climate warmer.
Have Republicans always been completely skeptical of "global warming?"
No. When he was president, George W. Bush, along with Newt Gingrich and other high ranking Republicans were actually working collaboratively with many Democrats in congress to begin addressing the climate change problem. However, by 2012, members of both political parties were avoiding the issue altogether. Although nothing had changed in terms of the science, with the vast majority of the world's climate scientists still finding overwhelming evidence pointing at climate change, well-funded skeptics made it a political liability to even talk about the subject.
Which part of the Calvin cycle would be affected if a cell could not produce the enzyme RuBisCO?
None of the cycle could take place, because RuBisCO is essential in fixing carbon dioxide. Specifically, RuBisCO catalyzes the reaction between carbon dioxide and RuBP at the start of the cycle.
In what form is most phosphorus in nature?
Phosphate (PO4 3-)
Explain the reciprocal nature of the net chemical reactions for photosynthesis and respiration.
Photosynthesis takes the energy of sunlight and combines water and carbon dioxide to produce sugar and oxygen as a waste product. The reactions of respiration take sugar and consume oxygen to break it down into carbon dioxide and water, releasing energy. Thus, the reactants of photosynthesis are the products of respiration, and vice versa.
What organisms can fix nitrogen and where are they found?
Some bacteria in the soil and bacteria living in root nodules of legumes (e.g. beans, peanuts, and pea plants) can do this.
Plants produce oxygen when they photosynthesize. Where does the oxygen come from?
Splitting water molecules
Where does the Calvin cycle (also called: light-independent reactions) take place?
Stroma (of the chloroplasts)
In what ways have humans altered the carbon cycle, leading to higher amounts of carbon dioxide in the atmosphere?
The combustion of fossil fuels, including coal, oil, and gas, and burning of plant biomass (e.g. trees) has added large amounts of carbon dioxide to the atmosphere, while at the same time the loss of plants (e.g. through deforestation) has reduced the amount of photosynthesis that removes carbon dioxide from the atmosphere.
Describe the pathway of energy in light-dependent reactions.
The energy is present initially as light. A photon of light hits chlorophyll, causing an electron to be energized. The free electron travels through the electron transport chain, and the energy of the electron is used to pump hydrogen ions into the thylakoid space, transferring the energy into the electrochemical gradient. The energy of the electrochemical gradient is used to power ATP synthase, and the energy is transferred into a bond in the ATP molecule. In addition, energy from another photon can be used to create a high-energy bond in the molecule NADPH.
Each type of pigment can be identified by the specific pattern of wavelengths it absorbs from visible light, which is its __________________ _______________
absorption spectrum.
Excess phosphorus and nitrogen that enter the ecosystems from fertilizer runoff and from sewage cause excessive growth of ___________.
algae
Carbohydrate molecules made will have a backbone of carbon atoms. Where does the carbon come from? The carbon atoms used to build carbohydrate molecules comes from carbon dioxide, the gas that animals exhale with each breath. The Calvin cycle is the term used for the reactions of photosynthesis that use the energy stored by the light-dependent reactions to form glucose and other carbohydrate molecules.
calvin cycle
Autotrophs
can capture light energy from the sun, converting it into chemical energy used to build food molecules.
In the case of photosynthesis, light energy is transformed into chemical energy, which autotrophs use to build _______________ ______________.
carbohydrate molecules.
What are the three main nutrients plants require
carbon (C), nitrogen (N), and phosphorus (P).
Greenhouse gas molecules, such as _______________ _______________, absorb much of the reflected radiation, sending it in all directions. This results in a warming of the Earth's surface and lower atmosphere.
carbon dioxide (CO2)
What absorbs energy from sunlight and then converts it into chemical energy with the use of water
chlorophyll
Photosynthesis vs Cellular Respiration: Water is consumed instead of being produced, and oxygen is produced instead of being ________________________
consumed
A __________ ___________ is an area in lakes and oceans near the mouths of rivers where large areas are periodically depleted of their normal flora and fauna; these zones can be caused by eutrophication, oil spills, dumping toxic chemicals, and other human activities.
dead zone
The sun emits an enormous amount of _________________ ________________________
electromagnetic radiation (solar energy)
The ___________________________ ____________________ is the range of all possible wavelengths of radiation
electromagnetic spectrum
The energy given to the electron allows it to break free from an atom of the chlorophyll molecule. Chlorophyll is therefore said to "donate" an ______________________
electron
Technically, each breaking of a water molecule releases a pair of electrons, and therefore can replace two donated electrons. The replacing of the electron enables chlorophyll to respond to another photon. The oxygen molecules produced as byproducts find their way to the surrounding environment (and oxygen breathers, like us!). The __________________ ions play critical roles in the remainder of the light-dependent reactions.
hydrogen
The overall purpose of the light-dependent reactions is to convert ________ energy into _________________energy.
light , chemical
The ___________________ _____________________________reactions release oxygen from the hydrolysis of water as a byproduct.
light-dependent
However, it should also be noted that ____________ is about 20 times more potent than CO2 when it comes to the ability to trap solar radiation. _________________ released by the melting of permafrost in the polar regions could have an even greater impact on climate change in the future.
methane
Are most plants C3, C4, or CAM
most are C3: examples: example, soybeans, rice, and wheat are C3 plants.
In _____________________ feedback, the effect is to move in the opposite direction.
negative
In what form do plants need nitrogen?
nitrate (NO3-)
A _________________________ resource is either regenerated very slowly or not at all.
non-renewable
The ______________serve as the Earth's largest carbon dioxide and heat reservoir.
oceans
This splitting releases an electron and results in the formation of _____________________ and hydrogen ions (H+) in the thylakoid lumen.
oxygen (O2
A pigment molecule in the photosystem absorbs one _____________, a quantity or "packet" of light energy, at a time
photon
The light-dependent reactions begin in a grouping of pigment molecules and proteins called a ______________________.
photosystem
Light energy enters the process of photosynthesis when ____________ absorb the light.
pigments
As the polar ice melts, the polar region loses its reflectiveness, making warming more dramatic at the poles. Is this positive or negative feedback
positive feedback
Where do light dependent reactions occur?
thylakoid membrane (of the chloroplasts)
Photosystems exist in the membranes of ________________________
thylakoids
photoautotrophs
use light to manufacture their own food (Plants, algae, and a group of bacteria called cyanobacteria) (literally, "self-feeders using light").
To replace the electron in the chlorophyll, a molecule of _________ is split.
water
Scientists can determine the amount of energy of a wave by measuring its ______________________, the distance between two consecutive, similar points in a series of waves, such as from crest to crest or trough to trough
wavelength
The wavelength of a single wave is the distance between two consecutive points along the wave. The distance between the crests (shown as the uppermost part, in contrast to the trough at the bottom) is the __________________________.
wavelength
The manner in which solar energy travels can be described and measured as ____________.
waves