Mastering biology final exam review
questions and answers
How is a community different from an ecosystem? - Answer -A community consists of
all of the interacting populations in an ecosystem. An ecosystem includes the non-living
components that affect life as well as all of the interacting populations in a given area.
Explain why methicillin resistant Staphlococcus aureus (MRSA) is more prevalent now
than it was only 30 years ago. - Answer -Frequent and inappropriate use of methicillin-
type antibiotics has provided selective pressure that has resulted in an increase in the
proportion of methicillin-resistant strains of Staphlococcus aureus.
__________ are substances that CANNOT be broken down into other substances by
chemical reactions. - Answer -Elements; By definition, elements are substances that
cannot be broken down or converted by chemical reactions.
Which four elements make up the bulk of living cells? - Answer -oxygen, carbon,
hydrogen, and nitrogen
All sodium atoms have 11 protons. The nuclei of some sodium atoms contain 12
neutrons and others contain 11. These different forms of sodium are called
__________. - Answer -Isostopes
What is responsible for the unusual chemical properties of water? - Answer -Water
molecules can form an extensive network of hydrogen bonds with one another. The fact
that water is a polar molecule allows it to form an extensive network of hydrogen bonds
between individual water molecules. These hydrogen bonds give water unusual
chemical properties.
Why are all living organisms based on molecules that contain carbon? - Answer -
Carbon atoms can form strong covalent bonds with many other carbon atoms, and the
atoms of hydrogen, oxygen, and nitrogen.
During digestion, __________ are broken down into __________ through __________
reactions. - Answer -proteins; amino acids; hydrolysis
What do you think might happen if you put a mixture of proteins and starch in a solution
containing trypsin, an enzyme that breaks down proteins? - Answer -The protein would
, be broken down into amino acids. Enzymes are specific for particular substrates.
Trypsin will digest proteins, but not starch.
How can you tell an animal cell from a plant cell? - Answer -Plant cells contain a
vacuole and have a cell wall; animal cells lack these structures.
What molecules are constituents of animal cell membranes? - Answer -phospholipids,
proteins, carbohydrates and cholesterol.
The ideal osmotic environment for an animal cell is a(n) _____________ environment.
An animal cell placed in a(n)____________ solution will gain water, swell, and possibly
burst.
There is a net diffusion of water out of an animal cell when it is placed in a(n)
_______________solution.
The ideal _____________ environment for a plant cell is a(n) hypotonic environment.
A plant cell placed in a(n) _____________ solution will lose water and plasmolyze.
A plant cell surrounded by a(n) ____________ solution will be flaccid (limp). - Answer -
Isotonic, Hypotonic, Hypertonic, Osmotic, Hypertonic, Isotonic
What is the role of producers in most ecosystems? - Answer -To capture light energy
from the sun and convert it to chemical energy
What is the role of chlorophyll in photosynthesis? - Answer -Chlorophyll captures energy
from sunlight.
What connects the two photosystems in the light reactions? - Answer -An electron
transport chain
What provides electrons for the light reactions? - Answer -Water
What provides the carbon atoms that are incorporated into sugar molecules in the
Calvin cycle? - Answer -Carbon dioxide
The light reactions take place in the _________ and the Calvin cycle takes place in the
_________. - Answer -thylakoids; stroma
During the Calvin cycle, plants use energy from ATP and NADPH to drive __________.
- Answer -the synthesis of sugar from carbon dioxide
The food you eat is processed during cellular respiration to produce stored chemical
energy in the form of __________. __________ and __________ are by products. -
Answer -ATP; CO2; water
How does yeast make bread dough rise? - Answer -The yeast cells produce CO2.
Crossing happens during __________. - Answer -meiosis
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