final exam Flashcards
you have been hired to run a trial to see if a new anxiety medication works. Even though you are collecting the data, you won’t know who gets the drug and who gets the placebo. The people taking the drug or placebo also don’t know. This type of an experiment is:
double blind
The group that receives the placebo is known as
control group
In the study described in chapter 1, cell phone use is the _________ and cancer is the _________
independent variable: dependent variable
what is the last step in the scientific process
drawing a conclusion
a statement that is a good hypothesis:
is testable and refutablew
what is a theory?
a widely-accepted explanation for an observation, that is testable and well-supported by evidence
when scientists carry out an experiment, they are testing a
hypothesis
true or false: a placebo is a fake treatment that mimics the treatment of the experimental group
true
in a controlled experiment, the control and experimental groups differ in that
the independent variable is applied to only one group
which substance is most likely to dissolve in water
a hydrophilic molecule
which type of chemical bond is the weakest
hydrogen
the bond that attaches two hydrogens to an oxygen in an H2) molecule is a(n) _______ bond
covalent
an acidic solution has _______ hydrogen ions compared to water
more
an acidic solution has a _______ pH value compared to water
lower
your friend makes instant coffee by mixing coffee powder in hot water. the coffee is the ________, the powder is the ______ and the water is the ________
solution, solute, solvent
olive oil is _______ because it _________
hydrophobic; doesn’t interact with water
human’s ability to shive is an attempt to increase the body’s internal temperature and maintain ________
homeostatis
which characteristic is not present in all types of living organisms?
obtain energy directly from sunlight
when an atom loses an electron, what happens?
it becomes positively charged
the nucleus of an atom contains ______ while the _______ surrounds the nucleus
protons & neutrons; electrons
which is not one of the four types of organic molecules that make up all living things on earth
atoms
what is atomic mass
the mass of an atom indicated the number of protons plus neutrons
what is true about organic molecules
an organic molecule contains at least one carbon-hydrogen bond
an atom of oxygen has 8 protons, 8 electrons, and 8 neutrons. what is the atomic number of oxygen
8 because oxygen has 8 protons
what property of water molecules leads to surface tension of liquid water
formation of hydrogen bonds between water molecules
what is an monomer
a small molecule that can react with similar molecules to form a polymer
why does water have a pH of seven
water dissociates to form an equal amount of H+ ions and OH- ions
the octet rule states that many atoms will share, donate, or accept ______ to have eight in the outer shell
electrons
what is homeostasis
the body’s maintenance if a relatively stable internal environment even when the external environment changes
which chemical bond forms when an atom accepts an extra electron or donates an electron
ionic bond
which type of fatty acid is usually found in lipids that are liquid at room temperature
unsaturated cis-fat
the monomers that make up proteins are
amino acids
simple diffusion occurs when molecules move from _______ using ________
high to low concentration; no energy
facilitated diffusion occurs when molecules move through _____ in the cell membrance
proteins
which lipid molecule is part hydrophobic and part hydrophilic, allowing it to make the selectively-permeable cell membrane
phospholipid
which organelle could cause the most damage to the rest of the cell by leaking its digestive enzymes into the cytoplasm
lysosome
fungi are eukaryotic organisms. scientists have found it more difficult to develop treatments for fungal infections such as yeast infection and athlete’s foot. why are fungal infections harder to treat than bacterial infections
fungi are eukaryotes like humans, so their cellular components are similar
penicillin interferes with ______, causing bacteria to die from _____
cell walls; osmosis