Bio 20 review Exam Questions And
Answers
Photosynthesis vs chemosyntheis - ANS is the process by which producers use solar
energy to convert carbon dioxide into glucose vs deep-sea producers uses chemical energy to
make organic molecules.
Photosynthesis: - ANS is an important mechanism for capturing and storing energy. Plant
cells have organelles called chloroplasts, containing the pigment chlorophyll, which are able to
capture the solar energy. The solar energy excites electrons in the chlorophyll, triggering a
series of reactions that convert carbon dioxide and water into glucose and oxygen.
Photosynthesis occurs mainly in the leaves of plants.
Photosynthetic Bacteria - ANS Some photoautotrophs are not plants, but special bacteria
capable of performing photosynthesis. The bacteria in this image are called cyanobacteria and
are usually found in fresh water environments, but they can also be found in areas such as
oceans, damp rocky areas, damp soil and even the fur of sloths.
Chemosythesis: - ANS The northernmost hydrothermal vent fields in the world were
discovered in late July 2005 on a research expedition northwest of Norway. Hydrothermal vents,
also called "smokers" or "chimneys", form along the Mid-Ocean Ridge, an area along the ocean
floor where the Earth's crust splits apart and new crust bubbles up in the form of lava from the
mantle. The ridge is the Earth's largest geologic feature; it zips up and down the middle of the
world's ocean basins like seams on a baseball, and is considered one of the most extreme
environments on Earth. "There is also a vast low-temperature field that supports a diverse
community of life, including large sea-lilies that sit atop mineral-bacterial chimney-like structures
that look like pineapples. That is a particularly strange form of vent, because the fluids come out
at a temperature only a fraction of a degree above the temperature of the background seawater,
and that is very cold-below zero Celcius-which is only possible in the Arctic." Much of the Arctic
Ridge system is unexplored, and prior to this discovery, a vent field on the shelf of Iceland was
the only one scientists had ever laid eyes upon. In marked contrast to that Icelandic field, the
new fields are replete with animal life.
Earth's Solar Budget - ANS Only 2% of the Sun's radiation is used in photosynthesis and
passed on to consumers. The fate of the other 98% of the Sun's energy is depicted in the
image. Although the energy absorbed by the Earth's atmosphere and the Earth's surface is not
available for food energy, it is important in maintaining a temperature on Earth that allows
organisms to survive. The albedo of a given surface describes the percentage of energy that is
,reflected away from the Earth's biosphere. The albedo of certain surfaces can help explain the
climate in a given area. For example, sand has a much lower albedo than snow, meaning that
sand-covered surfaces will absorb more of the Sun's radiant energy than a snow-covered one.
The first law of thermodynamics states that energy can neither be created nor destroyed;
however, life on Earth depends on a continual supply of solar energy. This continual supply of
energy is required because as energy is transferred, a portion of it is converted into a form of
energy that is not usable to organisms, like heat. This is known as the second law of
thermodynamics and has important implications for consumers.
Cellular Respiration - ANS Consumers are not able to harness energy from the Sun, so
depend on the energy stored by producers or other consumers. Consumers release the energy
stored in the chemical bonds of glucose through the process of cellular respiration. Cellular
respiration occurs in the mitochondria of both plant and animal cells to produce ATP, the
chemical compound that supplies energy to cells. Plants and animals use ATP to drive cellular
functions.
trophic levels - ANS describe feeding relationships in an ecosystem. Organisms can be
identified in many ways, such as through feeding relationships, and organisms can be organized
into trophic levels. These levels also indicate the amount of energy available to organisms. Food
webs and food chains are used to represent the feeding relationships in an ecosystem. You
should be able to identify the trophic level of an organism given a food web or food chain for an
ecosystem..
As energy is transferred, a large percentage is lost and not transferred to the next trophic level.
rule of 10 - ANS As organisms go about their daily activities of growth, movement,
reproduction etc., much of the energy that they captured is lost as heat and other waste
products. The amount of energy lost varies, but is usually around 90%, meaning that 10% of the
energy captured by an organism is available to be passed on to the next trophic level. This is a
generalization rather than a rule but is referred to as the Rule of 10.
Energy Flow in Ecosystems - ANS The solar radiation budget helps to explain the
distribution of the Sun's energy. The amount of solar energy absorbed by a surface depends on
its albedo. Albedo is a measure of the percentage of solar energy that is reflected from a given
surface. The higher the albedo, the less energy that is absorbed by that surface. The albedo of
features within an ecosystem have an impact on the type and number of organisms that will
reside in that ecosystem. For example, the albedo of ice and snow is much higher than the
albedo of a forest, resulting in less absorbed energy in frozen environments. If soil begins to be
uncovered, more energy will be absorbed, warming the climate Energy flows one way through
an ecosystem. It is not recycled. Matter cycles through an ecosystem. Only producers are able
to capture the Sun's energy. Consumers then use the energy captured by producers. Due to the
second law of thermodynamics, energy is lost to less usable forms as it flows through the
ecosystem. Producers provide energy directly to primary consumers (herbivores), who are then
consumed by secondary consumers (omnivores or carnivores) and so on until an apex predator
dies and decomposing organisms use the remaining energy in the carcass.
,The pyramid of Biomass - ANS Represents the mass of organisms at each trophic level is
the dry mass of living organisms per area, usually measured in g/m2.
Bioaccumulation - ANS is the build-up of a substance in an organism over time. If a fish
feeds on plankton in polluted waters, they accumulate more of the toxin as they consume more
plankton. The toxin is never excreted.
Biomagnification - ANS is the magnification of a toxin as it moves up the food chain. If a
predatory bird feeds on fish that have stored toxins, the concentration of toxins in the bird will be
higher than in the fish due to the quantity of fish that the bird eats.
Pyramid of Energy vs Pyramid of Numbers - ANS Represents the available energy at each
trophic level and reflects the flow of energy through an ecosystem with loss of energy (about
90%) at each trophic level. are upright as the most energy is always available to the first trophic
level, decreasing as it moves up the trophic level Represents the number of organisms at each
trophic level Though most have an upright shape, the shape can vary for some ecosystems. For
example, if the size of one organism is very large, it can feed a number of consumers. Also,
organisms that reproduce very quickly can feed a larger number of consumers as they are
always replenishing their numbers.
conservationist - ANS someone who advocates saving and/ or conserving natural
resources ,
biodiversity - ANS a variety in the number and kind of species in a given area
food web - ANS a diagram or model that shows the connections among food chains
(food/energy transfer) in an ecosystem
food chain - ANS a diagram or model that uses a straight line to show how food (energy)
transfers from producers to primary consumers to higher trophic levels
Properties of Water - ANS Hydrogen bonding gives water special properties . A water
molecule is made up of two hydrogens and one oxygen molecule. Each water molecule has a
slightly positive charge near the hydrogen and a slightly negative charge by the oxygen. This
causes water molecules to be strongly attracted to other water molecules. This attraction is so
strong, it is called a hydrogen bond, and is what gives water its special properties like cohesion,
adhesion and a high specific capacity. It is also what allows ionic compounds and polar
compounds to dissolve easily in water, which is why water is often called the universal solvent.
Universal Solvent - ANS Polarity makes water a good solvent for ionic compounds or polar
covalent molecules. Since water is a polar molecule, the negatively charged oxygen end of the
molecule is highly attracted to the positive ion in ionic compounds. This attraction allows the
, positive and negative ions to be pulled apart and dissolved in water. The same attraction occurs
with the negative ion and the positive hydrogen end of the water molecule.
cohesion vs adhesion - ANS is the attraction of water molecules to other water molecules.
Surface tension is a result Since water molecules are charged, they are also strongly attracted
to each other. This results in water forming droplets more easily than other liquids. It is also
responsible for the high surface tension of water. is the attraction of water molecules to other
charged particles. Glass is slightly charged. is what allows you to fill a glass over the top. Since
some surfaces are slightly charged, water is attracted to them. Adhesion is important in the
transport of water from roots to leaves through the xylem.
Specific Heat Capacity - ANS Water has a high specific heat capacity. is the amount of
energy required to raise 1g of a substance by 1 degree Celcius. Water uses a large amount of
energy to be warmed and releases a large amount of energy as it is cooled. This property of
water moderates climates, especially those close to a large body of water. heat capacity: the
amount of heat energy (J) required to change the temperature of one gram of a substance by
1°C Water has a high heat capacity of 4.19 J/g °C.
Pollution in the Great Lakes - ANS "Today roughly one-quarter of Canada's population
drink from the Great Lakes" (Walker, 2013) Pollution in the Great Lakes has been a concern
since the 60s when high levels of phosphates were found in the lakes due to household
detergents. Water is the universal solvent and does not distinguish between good and bad
solutes. Once pollutants have been dissolved in water, it can be difficult to impossible to remove
them from bodies of water. Click the link below to find out more about the dissolved pollutants in
the Great Lakes.
Nutrient cycling - ANS the dark green lines represent the movement of nutrients and the
dashed lines represent the movement of energy. Nutrients are not depleted, whereas energy is
depleted, so a constant supply of solar radiation is required to sustain the biosphere. The
biosphere is a closed system in relation to the matter The biosphere is an open system in
relation to energy Since nutrients are not replenished in the biosphere, they are finite and cycle
through the biosphere. The biogeochemical cycles are the pathways through which all nutrients
cycle. cycle through both slow and rapid cycling. When nutrients move relatively quickly
between organisms or abiotic components, this is called rapid cycling. Photosynthesis and
cellular respiration are rapid cycles. When nutrients become unavailable for long periods of time
(e.g., deep in the ocean or deposited in rocks) they are slow cycling.
Carbon - ANS composes almost 20% of the human body. It is also important in
carbohydrates, fat, proteins, hormones, and vitamins. Life on Earth is -based since provides the
framework for all molecules important in biological systems. Photosynthesis and cellular
respiration are important processes in the carbon cycle The movement of carbon through the
carbon cycle is highly affected by carbon being stored in a variety of reservoirs, including fossil
fuels and the vast reserves of calcium carbonate in the oceans. Reservoirs of carbon are called
carbon sinks. Boreal forest ecosystems are now recognized as significant carbon sinks, not only
