chap 7&8 test Flashcards
What is the electromagnetic spectrum?
consists of all the radiation that is emitted by stars in the solar system. high frequency wavelengths in the EM spectrum contain more energy than low frequency wavelengths. The EM spectrum includes (from highest to lowest energy) gamma rays, x-rays, ultraviolet rays, visible light, infrared waves, microwaves, and radio waves.
Most high-energy radiation is stopped from reaching Earth’s surface by the ozone layer which is made up of three oxygen atoms bonded together. Low energy radiation are often shielded from Earth by water vapor and carbon dioxide.
Over the years, living organisms have adapted to use the primary source of EM radiation that reaches Earth: visible light. Most animals have eyes that are used to detect visible light. Pants use the energy from visible light to photosynthesize. The various colors of visible light can be remembered using the mnemonic device “ROY G BIV”
the process by which plants use the energy from visible light, carbon dioxide, and water to produce carbohydrates (glucose) and oxygen
photosynthesis
What is the chemical reaction for photosynthesis?
CO2 + H2O + Visible Light —–> C6H12O6 + O2
What is the glucose from photosynthesis used for? How about oxygen?
Glucose is a monomer of polysaccharides (carbohydrates). They are used for food (plants), building materials (wood), fabrics (cotton), paper, fuel, pharmaceuticals, and energy (fossil fuels)
oxygen is used for breathing and ultimately for cellular respiration. Oxygen also makes up a protective layer of ozone that covers the Earth and protects us from much higher energy electromagnetic radiation
organisms that can make their own food
autotrophs
How do autotrophs get water and carbon dioxide?
Vascular plants get water from their roots
organisms that cannot make their own food
Heterotrophs
In what organelle does photosynthesis occur? Why?
chloroplasts. Because they have pigments which are capable of absorbing visible light and capturing its energy to use in photosynthesis
Why do green plants look green?
they don’t absorb wavelengths of green light; instead, they reflect wavelengths of green light and thus appear green
describe the structure and function of a chloroplast
they have double membranes surrounding then. Inside is a fluid-filled interior called the stroma. Membranes within the stroma form flattened sacs called thylakoids. Thylakoids are stacked in some areas to form grana. Chlorophyll and other pigments that absorb visible light are a part of the thylakoid membranes. Water is oxidized to form oxygen in the thylakoid membranes. Carbon dioxide is reduced to form glucose in the stroma
What are the three most important photosynthesis pigments?
Chlorophyll a and Chlorophyll b- absorb violet, blue, and and red light best
Carotenoids absorb violet, blue, and green light best
How does an absorption spectrum differ from an action spectrum?
An absorption spectrum shows the visible light wavelengths that various pigments can absorb. An action spectrum shows the visible light used to perform a function
What are the reactants of photosynthesis? the products?
Reactants: carbon dioxide and water
Products: glucose and oxygen
From which reactant does the oxygen from photosynthesis originate?
Water
Photosynthesis is an oxidation-reduction reaction. What does this mean?
Carbon dioxide is reduced while water is oxidized. OIL RIG
Photosynthesis has two sets of reactions. What are they and how do they differ?
light reactions take place in the thylakoid membranes and involve the oxidation of water to produce oxygen.
Calvin cycle reactions take place in the stroma and involve the reduction of carbon dioxide to produce glucose
Why are the Calvin cycle reactions so important?
They produce G3P which can be converted to all sorts of organic molecules. The hydrocarbon skeleton of G3P can be used to synthesize three of the four major macromolecules: carbohydrates, lipids, and proteins.
What are the three types of photosynthesis?
C3, C4, and CAM
- Used in most common plants like maple trees, azaleas, wheat, and kentucky bluegrass
- mesophyll cells in the leaves contain chloroplasts where both carbon dioxide fixation and other Calvin cycle reactions occur
- this type of photosynthesis requires photorespiration
- a drawback is that since the stomata open only during the day, water is also lost
C3
- Used in plants like corn, sugarcane, Bermuda grass, and crab grass
- both mesophyll cells and bundle sheath cells around the leaf veins contain chloroplasts
- carbon dioxide fixation occurs in the mesophyll cells and other Calvin cycle reactions occur in the bundle sheath cells
- this type of photosynthesis does not require photorespiration, so they can be more productive than c3 plants in hot, dry climates
- their stomata can open during the day or the night
C4
- used by flowering succulents living in warm, dry regions like pineapples, cacti, and orchids
- this type of photosynthesis fixes carbon dioxide into four carbon molecules during the night. I then releases carbon dioxide to the Calvin cycle reactions during the day
- this means that stomata only have to open at night, which allows them to conserve water
CAM
- the process by which cells break down glucose to produce energy in the form of ATP
- it takes place in he cell cytoplasm and in cellular organelles called mitochondria
- cellular respiration requires oxygen and produces carbon dioxide and water as waste products
- you can refer to it as the “flip side” of photosynthesis since the products are the reactants are the products of photosynthesis
cellular respiration
What is the chemical reaction for cellular respiration
C6H12O6 + O2 —->H2O + CO2 + energy to make ATP
Where did the energy captured in the chemical bonds of glucose originally come from?
visible light from the EM spectrum during photosynthesis
