Chapter 4 - Energy & Life Flashcards
every living thing metabolizes _______.
energy
define energy
the capacity to do work.
work
the movement of an object after the application of force, expenditure of energy
converting energy from one form to another drives _____________________
all of life’s processes
kinetic energy
the energy of motion (like a child moving down a slide)
potential energy
the energy an object has due to its location or structure, such as the energy contained by a child sitting atop of a slide
describe how potential energy and kinetic energy are converted to each other?
a child releases/lowers potential energy built up from sitting high on the slide as he slides down. the energy is converted into kinetic energy of motion. Potential energy from food converts into the kinetic energy required to climb the stairs of the slide.
chemical energy
potential energy that is stored in the bonds that hold atoms together. Breaking the bonds releases useful energy. When ATP chemically reacts and turns into ADP, chemical energy is released and turned into kinetic energy
the law of conservation of energy
energy cannot be created or destroyed, only converted.
about how much of the calories we consume are dissipated back into the environment as body heat?
60%
heat
a form of kinetic energy stored in the random motions of atoms and molecules.
T or F. Within living systems, energy conversion is perfectly efficient.
False. There is always some waste expelled as heat.
entropy
the amount of disorder in a system
what happens to entropy every time energy is converted within a system?
Entropy (randomness) increases.
it requires significant effort to decrease disorder in real life. How does this relate to entropy and heat?
Heat is chaotic and hard to recapture. It takes a lot of energy to do so, which in turn creates its own entropy.
what energy conversions are taking place by pressing a spring?
compressing the spring converts kinetic energy into potential energy. releasing the spring converts potential energy into kinetic energy.
Explain how life processes are powered by the sun’s energy.
sun energy enters the system as light. Sun energy is converted into chemical energy by producers via photosynthesis. Consumers use the chemical energy in food to power bodily functions. Heat is released from the system.
producers
organisms that absorb the sun’s energy and convert it into chemical energy. They can produce their own food.
consumers
These organisms can’t produce their own food (energy). They obtain food by eating plants or by eating animals that have eaten plants.
name organisms that are consumers.
animals, fungi, and some microscopic protists.
name organisms that are producers.
plants, aquatic protists (such as seaweed, a form of algae) and certain bacteria.
what is a mutual means of obtaining energy that producers and consumers use?
breaking down sugars through cellular respiration
production of what is the goal of photosynthesis?
sugar
what is the by-product of photosynthesis?
oxygen
what is the process that provides food to nearly all life on earth?
photosynthesis
what are the structures of the chloroplast?
inner membrane, outer membrane, thylakoid, granum, grana, stroma
where do the inputs of photosynthesis come from?
CO2 comes from the AIR and H2O comes from the GROUND.
what is the product of photosynthesis?
glucose
what parts of the plant usually have the most chloroplasts?
The leaves
T or F. Photosynthesis NEVER occurs in the stems of plants.
False.
how do grana aid in photosynthesis?
provide lots of surface area for reactions to take place
how does carbon dioxide reach the chloroplasts?
Through tiny pores called stomata on the undersides of leaves.
pigment
a light-absorbing molecule
what is the primary pigment in chloroplasts?
chlorophyll
what light ranges do chlorophyll absorb?
blue-violet light and orange-red light
what light ranges does chlorophyll not absorb?
green-yellow light
why do plants appear green to us?
The reflected light is the light that reaches the eye.
What produces the brilliant colors of fall foliage?
Different pigments become visible in autumn and reflect different types of lights.
Through what structure is oxygen by-product released?
stomata
IN what chloroplast structure is chlorophyll located?
the thylakoid membranes
what are the two stages of photosynthesis?
light reactions stage and the the Calvin cycle
light reaction stage
light reactions capture sunlight and store it in high-energy molecules
the Calvin cycle
uses the high-energy sun-baked molecules to make sugar from carbon dioxide.
what are the high energy molecules that energy in sunlight is stored in?
ATP and NADPH
NADPH
a molecule that acts as a high-energy electron shuttle, produced from lower-energy form NADP+
ATP
adenosine triphosphate, a high-energy molecule that acts as an energy shuttle
where in the chloroplast does the Calvin cycle take place?
the stroma
where do the electrons and energy needed for the Calvin cycle come from?
NADPH and ATP
What molecules would accumulate if the light reactions proceeded but the Calvin cycle did not? What molecules would not be made?
NADPH and ATP would accumulate and sugar would not be made.
what are the two ways plants store glucose (sugar)?
As cellulose and as starch.
what process releases the chemical energy stored in sugars?
cellular respiration
aerobic respiration
cellular respiration requiring oxygen. Takes place in the mitochondria, and occurs in both producers and consumers
what is a calorie?
the amount of energy required to raise 1 gram of water 1 degree Celsius.
how is energy in food measured?
in kilocalories (kcals)
how many calories in are in one kcal?
1,000
How can we measure the amount of kilocalories in food?
By combusting the chemical energy in food and using the energy released to heat water.
what is basal metabolic rate (BMR)?
the amount of energy required to maintain minimum bodily functions to stay alive. Any additional energy needed for movement, thinking, exercise, etc. will increase caloric needs.
