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Biology / ch. 8 Study Guide

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What are organisms which must obtain energy from consuming food?
heterotrophs
What kind of organisms use ATP to perform cellular work?
All organisms
When ATP becomes ADP...
it releases energy
What is the location within the chloroplast where the light-dependent reactions take place?
thylakoids
How do CAM plants photosynthesis under bright, hot conditions without drying out?
Seal pores in their leaves trapping CO2
Which of the following carries high energy electrons?
NADPH
The wavelength of light least effective for plants is
Green
The process within a chloroplast that produces sugar
Light-independent reactions
Proteins within the thylakoid membranes that
contain chlorophyll pigment molecules are called
Photosystems
In the Light-Independent Reactions (Calvin Cycle),
NADPH and ATP provide energy to
Build high-energy sugars
What is one of the most important compounds that cells use to store and release energy?
ATP
What does ATP consist of?
Ribose (5-carbon sugar) and three phosphate groups
How many phosphate groups does ADP have?
2 phosphate groups
What is like a rechargeable battery that powers the machinery of the cell?
ADP
How can cells release the energy stored in ATP?
by the controlled breaking of the chemical bonds between the second and third phosphate groups
Which of the following would require ATP?
Pumping ions into the cell through active transport
What is the basic energy source for all cells
ATP
One way cells use the energy provided by ATP is to...
carry out active transport
Many cell membranes contain sodium potassium pumps, membrane proteins that pump ____ ions out of the cell and _____ ions into it.
sodium; potassium
Energy from ATP powers other important events such as...
The synthesis of proteins and responds to chemical signals at the cell surface.
Where do living things get the energy they use to produce ATP?
It comes from food
What are organisms that make their own food?
autotrophs
The process by which autotrophs use the energy of sunlight to produce high-energy carbohydrates that can be used as food is known as what?
photosynthesis
What happens in the process of photosynthesis?
Plants convert the energy of sunlight into chemical energy stored in bonds of carbohydrates
What role do pigments play in the process of photosynthesis?
Photo synthetic organisms capture energy from sunlight with pigments
What is the plant's principal pigment?
chlorophyll
Why do plants look green?
Because leaves reflect green light
Why are leaves red and orange during fall?
As temperatures drop later in the year, chlorophyll molecules breakdown first, Leaving the reds and oranges of the accessory pigments for all to see.
What are the saclike photosynthetic membranes?
thylakoids
Where are the chlorophyll located?
thylakoid membranes
What is the fluid portion of the chloroplast, outside the thylakoids.
stroma
What's special about chlorophyll that makes it important for photosynthesis?
Because light is a form of energy, any compound that absorbs light absorbs energy.
What happens during the light-independent reactions?
ATP and NADPH from the light-dependent reactions are used to produce high-energy sugars.
What is another name for the light-independent reactions?
Calvin cycle
Who is the Calvin cycle named after?
Melvin Calvin
What happens midcycle in a light-independent reaction?
Two of the twelve 3-carbon molecules are removed from the cycle. These molecules become the building blocks that the plant cell uses to produce sugars, lipids, amino acids, and other compounds.
What happens to the remaining ten 3-carbon molecules?
They're converted back into six 5-carbon molecules which eventually join six new carbon dioxide molecules to begin the next cycle.
What does the plant use the sugars produced for?
To build macromolecules needed for growth and development including lipids, proteins, and complex carbohydrates such as cellulose.
Summarize the light-dependent and the light-independent reactions.
The light dependent reactions trap the energy of sunlight in chemical form, and the light independent reactions use that chemical energy to produce stable, high-energy sugars from carbon dioxide and water.
What are electron carrier molecules?
A compound that can accept a pair of high energy electrons and transfer them to another molecule.
What do plants use to transfer a high-energy electrons from chlorophyll to other molecules?
electron carriers
What is a compound that serves as a carrier molecule?
NADP+
What does NADP+ do?
accepts and holds 2 high-energy electrons, along with a hydrogen ion. (this converts NADP+ into NADPH)
Why are high-energy electron carriers helpful?
They help build a variety of molecules the cell needs (ex: glucose)
What are the reactants and products of photosynthesis?
reactants: water and carbon dioxide
products: high-energy sugars and oxygen
What is released in the light-dependent reaction?
oxygen
Where do the light-independent reactions take place?
stroma
What happens during the light-dependent reactions?
Use energy from sunlight to produce oxygen and convert ADP and NADP+ into the energy carriers ATP and NADPH.
What is the role of the photosystems?
Absorb sunlight and generate high-energy electrons that are then passed to series of electron carriers embedded in the thylakoid membrane.
When do you light-dependent reactions begin?
When pigments in photosystem II absorb light.
What is a series of electron carrier proteins that shuttle high energy electrons during ATP-generation reaction?
electron transport chain
What happens to the electrons as they move down the electron transport chain?
Energy from the electrons is used by the proteins in the chain to pump hydrogen ions from the stroma into the the thylakoid space.
What do the pigments do in photosystem I?
They use energy from light to reenergize the electrons.
What happens at the end of photosystem I?
NADP+ molecules in the stroma pick up the high-energy electrons and the hydrogen ions to become NADPH.
What protein spans the membrane and allows hydrogen ions to pass through it?
ATP synthase
What are the most important factors that affect photosynthesis?
temperature(0C-35C), light intensity, and water
What are C4 and CAM plants?
have biochemical adaptations that minimize water loss while still allowing photosynthesis to take place in intense sunlight.
What is C4 photosynthesis?
Add examples.
C4 plans have a specialized chemical pathway that allows them to capture even very low levels of carbon dioxide and pass it to the Calvin cycle. ex: corn, sugar cane, and sorghum)
What are examples of CAM plants?
pineapple trees, desert cacti, and ice plants.