Download Semester 1 Final Review- Answers

Semester 1 Final ReviewAnswers
What is the goal of science?
The goal of science is to investigate and
explain the natural world.
Put the following terms in size order:
Earth, molecule, atom, individual,
population, galaxy, proton
Largest to smallest
Galaxy, Earth, population, individual,
molecule, atom, proton
List the eight characteristics of life
 a. made of cells
 b. able to reproduce
 c. based on genetic code (DNA or RNA)
 d. growth and development
 e. need for materials and energy
 f. respond to stimuli
 g. keep internal environment constant (called
homeostasis)
 h. evolve (populations, not individuals)
What element is the basis of all
organic molecules? Why is this
element so versatile?
Carbon is the basis of all organic molecules.
It is so versatile because it has four valence
electrons, so it can bond to four other atoms.
This means it can form double and triple
bonds with itself. Also, it allows carbon to
form many shapes, like rings and chains.
What is the main function of
carbohydrates?
Carbohydrates are the main source of energy
for living things, being converted to ATP
inside of cells
Carbohydrates can be stored for later use;
they are stored as glycogen in the livers of
animals, and as starch in plant roots.
Carbohydrates help with body structure; they
are found in plant cell walls and the
exoskeletons of insects.
What are two example of and two
functions of lipids?
Lipids like fats and oils are used for energy
storage; they can be converted when the
body runs out of carbohydrates.
Lipids like phospholipids make all of your cell
membranes (outer covering of cells)
What trait do all lipids share in
common?
All lipids are hydrophobic, meaning they are
repelled by water.
What is the function of nucleic acids?
DNA and RNA- they serve as the blueprint for
making new cells and overall living things.
What are two main functions of
proteins that you have seen so far this
year?
a. transport of substances into and out of
cells
b. cell structure
c. cell movement
d. immune system response (antibodies)
e. help with chemical reactions (enzymes)
Explain how enzymes work.
 Enzymes are proteins that are made to help a
specific chemical reaction take place inside of a
cell. Enzymes have an active site that fits the
substrate it wants to work on. The substrate is
the reactants of a chemical reaction. When the
substrate binds to the active site, the enzyme
changes shape, transferring its kinetic energy to
the molecules to help the reaction along. This is
called ‘lowering the activation energy, which is
the energy needed to make a reaction happen.
The molecules are either broken down or linked
together, forming the desired product.
What monomers make up carbs,
nucleic acids, and proteins?
Monomer
Amino Acid
Polymer/
Macromolecule
Protein
Simple Sugars/ Starches
Carbohydrates
Nucleotides
Nucleic Acids (DNA/RNA)
What are two differences between
prokaryotes and eukaryotes?
prokaryotes do not have compartments in
their cells; eukaryotes do
eukaryotes can be multi-cellular; prokaryotes
are only unicellular
Main source of energy for ecosystems.
The Sun
Draw a food web and label producer,
first, second, and third level
consumers
• See demo on board
Define: autotroph, heterotroph,
decomposer
 Autotroph: an organisms that makes it own food
via sunlight or chemicals in its environment
(plants)
 Heterotroph: an organism that gets its
food/energy from another organism (deer,
human)
 Decomposer: an organism that gets energy by
releasing enzymes and absorbing nutrients from
dead organisms (bacteria, fungi)
Energy- how much gets passed on
between trophic levels; where most is
located in a ecological pyramid
10% is passed
Most is located in the producers
Biomass- definition; where most is
located in an ecological
biomass: the mass of all living things at the
given trophic level
Most biomass is contained within the
producers (plants)
Importance of water, carbon, nitrogen
to living things.
Water transports key molecules like proteins
and sugars, and maintains an internal balance
in cells.
Carbon is the basis of all organic molecules,
like DNA, proteins, carbohydrates, and fats
Nitrogen is a major component of amino acids
and proteins
Difference between energy, matter
cycle through ecosystems.
Energy moves in one direction, from the sun to
producer, to consumer and into the
atmosphere.
Matter, like carbon, nitrogen, and water, is
recycled between solid, gas, and liquid forms.
Explain: greenhouse effect,
greenhouse gases, global warming
• The greenhouse effect is the trapping of heat
energy from the sun by greenhouse gases.
• These gases are carbon dioxide, methane
(CH4), and water vapor.
• Too many gases/ heat trapped can lead to
global warming, when the gases are not able
to leave the atmosphere, trapping heat inside.
Define: Niche and Competative
Exclusion Principle
• A niche is the role that an organism plays in an
ecosystem. Part of this role is the food and
shelter sources an organism uses.
• The competitive exclusion principle explains
that no two species can occupy exactly the
same niche. One will outcompete the other,
and the other will either evolve or go extinct.
(Think of musical chairs)
Draw a graph for logistic and exponential
population growth
• Logistic- birth rate= death when carrying capacity
is reached, net pop growth = 0
• Exponential- high birth, low death, net pop
growth is positive, unlimited resources
Define: carrying capacity and what
causes populations to reach it
• Carrying capacity is the maximum amount of
organisms an environment can support over
time.
• Populations can reach this when there is a
limit on resources, causing the birth and death
rate to be equal.
Biotic vs. Abiotic factors
• Biotic: predators, disease
• Abiotic: natural disasters, habitat destruction
• Biotic factors depend on density, while abiotic
factors are density-independent
Define: renewable vs. nonrenewable
resources and give an example of each
• Renewable resources will regenerate
themselves if used wisely. Ex: fish, trees
• Non-renewable resources will not regenerate
themselves; when gone, they’re gone! Ex:
fossil fuels
Define: sustainable development
• Using the earth’s renewable resources wisely,
allowing them to regenerate for use of future
generations