click below
click below
Normal Size Small Size show me how
Science
Chapter 3 Lessons 3 & 4
Question | Answer |
---|---|
why do all cells need energy | In order to carry out their functions, such as making proteins and transporting substances into and out of the cell. |
photosynthesis | the process by which a cell captures energy in sunlight and uses it to make food |
sources of energy | direct and indirect |
example of an organism that obtains direct energy from the sun | grass |
example of an organism that obtains indirect energy from the sun | animals |
autotroph | an organism that makes its own food |
heterotroph | an organism that cannot make its own food |
two ways that heterotrophs obtain their food | eating other organisms, absorbing their food from other organisms |
2 stages of photosynthesis | |
during photosynthesis | plants and some other organisms use energy from the sun to convert carbon dioxide and water into oxygen and sugars |
first stage of photosynthesis involves | capturing the energy from sunlight |
In plants, the first stage of photosynthesis process occurs mostly in | the leaves |
What are the green organelles inside plant cells | chloroplasts |
pigments | The green color (which are colored chemical compounds that absorb light). |
chlorophyll | main photosynthetic pigment in chloroplasts |
Chlorophyll functions similar to solar cells | uses the light energy to power in the second stage of photosynthesis. |
2nd stage of photosynthesis | cells use the captured energy to produce sugars. For this stage, plants need water (taken up by the roots) and carbon dioxide. |
stomata | Where The carbon dioxide enters the plant through small openings in the leaves . . |
chloroplasts | Once in the leaves, where the water and carbon dioxide are taken up into |
The photosynthetic Equation | Once inside the chloroplasts, water and carbon dioxide undergo a complex series of chemical reactions to produce sugar (a type of carbohydrate) and oxygen. |
What happens to the sugar produced in photosynthesis? | 1) Plants use the sugar for food. 2) Some sugar is converted to other compounds such as cellulose. 3) Can be stored in plant’s cells for later use. |
What is respiration? | Respiration is the process by which cells obtain energy from glucose. During respiration, cells break down simple food molecules and release the energy they contain. |
carbohydrates, including sugars and starches | During photosynthesis, plants capture energy from sunlight and store it in the form of |
respiration | When cells need this stored energy, they break down the carbohydrates in the process of |
The first stage of respiration takes place in the | cytoplasm of the organism’s cells. |
In this (1st stage) of respiration, molecules of glucose are broken down into | smaller molecules |
Is oxygen involved in the first stage of respiration | No |
How much energy is released in the 1st phase of respiration? | A small amount |
The second stage of respiration takes place in the | mitochondria. even smaller molecules. |
In this 2nd stage of photosynthesis, small molecules are broken down into | even smaller molecules |
Is oxygen involved in the 2nd stage of photosynthesis? | YES |
How much energy is released in the 2nd phase of respiration? | A great deal |
These products diffuse out of the cell. | carbon dioxide and water. |
Where do plants obtain the sugar they use for respiration? | From photosynthesis |
Where do animals obtain the sugar they use for respiration? | From the food they consume |
Some organisms live where there is no oxygen (such as deep in the ocean). These organisms obtain their energy through the process of | fermentation |
Fermentation provides energy for cells without using | oxygen |