1.2. (8/28) Properties for Life Flashcards
(water, energy, nutrients, light)
What makes water an excellent solvent?
polar: positive charge on one side, negative charge on the other
- dissolves stuff
Why is water’s ability to dissolve most substances important to life?
facilitates chemical reactions, good medium for molecular processes
What is a property that is only unique to water?
it is the only thing that keeps its liquid form over a range of temperatures
Why is water’s ability to stay in liquid form important to life?
it is everywhere and available
What is water resistant to?
changes in internal temperature and state
- slower
- stable
How do we know water resists changes in state?
- it takes 500x energy to evaporate
- you need to remove 80x heat to freeze it
- easier to raise temperature 1 degree celcius
Why is this stability and resistance important to life?
it allows life to exist at many different temperatures and facilitates homeostasis
What is unique about water when it comes to density?
It is at its most dense at 4 degrees Celsius
Why is this density characteristic important to life?
water retains its liquid form even when there is ice on top
How many times denser is water compared to air?
800x
How do aquatic organisms achieve neutral density?
- reduced hard skeletal components
- bladders filled with gas
- accumulate lipids
How do organisms combat the viscosity of water?
to be fast: streamlined
to be suspended: parachutes
Why is water’s fluidity, buoyancy, and viscosity properties important to life?
developed different kinds of mechanisms for movement
How do animals maintain equilibrium when the external pH is different?
with energy
What two elements are important to the biological transfer of energy (multicellular level)?
carbon and oxygen
How does life obtain energy?
moving electrons
What is oxidation?
removes electrons, releases energy, breaks bonds
What is reduction?
Builds bonds, adds electrons, requires energy
What are heterotrophs?
require organic rich food
- oxidize carbon bonds
What are autotrophs?
Get energy from inorganic sources (non-carbon)
- reduce carbon, store carbon energy
What are photoautotrophs?
light energy
What are chemoautotrophs?
oxidize inorganic compounds
- hydrogen sulfide
- ammonium
What methods do prokaryotes (bacteria and archaea) use to acquire energy?
all three methods: heterotrophy, photosynthesis, and chemosynthesis
- only ones with all three groups
What is an example of a heterotrophic plant?
American cancer-root
Which groups are the most limited in terms of biochemically obtaining energy?
fungi and animals require organic matter (are heterotrophs)
What is a mixotroph?
obtain energy more than one way (within the same organism)
What kind of relationship do photosynthesis and aerobic respiration have?
complementary
- they are opposites
What does photosynthesis do to carbon?
reduces it
- water is oxidized (loses electrons)
What does aerobic respiration do to carbon?
oxidizes carbohydrate
oxygen is reduced (gains electrons)
What do ecologists mean by nutrients?
elements other than H, C, and O
What is living biomass composed of? how much? (%)
C, O, N, P
- 93-97%
Which nutrients are required by organisms, and some of their primary functions
Sulfur, potassium, calcium, magnesium, iron, sodium, silicon
What limits growth in ecological systems?
nutrients
What is tied to growth and biomass generation?
the rate at which nutrients are becoming available
How does light function?
wavelength
What is the photosynthetically active region?
visible light 400-700 nm (red)
- region of light used for photosynthesis
What is ultraviolet (UV) wavelength?
less than 400 nm
- shorter ones
What is infrared (IR) wavelength?
greater than 700
- longer ones
What kind of relationship do light and energy have?
inversely proportional
- short-wavelength = more energetic light
What is the relationship between IR and the greenhouse gas?
IR wavelengths (heat) absorbed by GHGs
- doesn’t escape to space
How do the seasons come into play? (greenhouse effect)
Summer: plants suck CO2
Winter: photosynthesis slows down, increased CO2
