chapter 1
A scientist is observing that people who take echinacea appear to have fewer or shorter colds. What step of scientific thinking (scientific method) comes next if this scientist wants to transform his observation into an explanation that can potentially be tested?
What are the three domains of life?
Bacteria, Archaea, and Eukarya
An atom has an atomic mass of 23 and an atomic number of 11. How many neutrons does it have?
12 neutrons.
During a chemical reaction, what happens to matter and energy?
It is rearranged. (Reactants into products).
What property allows water to adhere to the walls of a graduated cylinder?
Adhesion
You're a researcher who hypothesizes that echinacea reduces the likelihood and duration of colds. What specific type of statement would you make to determine what results should potentially occur if your hypothesis is totally correct?
Testable prediction.
Grab A makes group A appear dramatically different from B and C, but the different becomes much smaller when the y-axis begins at zero. What specific practice is responsible for creating the misleading impression and why does it affect the data?
Omitting the baseline. Starting the y-axis at a value other than zero exaggerates the differences.
Why do valence electrons have such a major influence on an element's chemical reactivity?
They determine the atom's bonding abilities.
When a radioactive isotope decays, what determines whether it becomes a different element of if it remains the same element?
whether the decay changed the number of protons in the nucleus.
Why does water have a high specific heat?
it can absorb large amounts of energy before temp increases.
A virus can have characteristics associated with living organisms; however, as seen in lecture, it is not classified as a living organism. What does this demonstrate about identifying an object as living?
A combination of characteristics that are extremely necessary such as metabolisms; a single characteristic is not usually sufficient.
You're working with your team and you hear a person say, "People with strong religious beliefs live more meaningful lives." You automatically thing that this would be a problematic idea. Why would it be?
It is not testable by the scientific method as stated.
Two atoms have identical atomic numbers but different atomic masses. What differs between them?
neutrons. Isotopes.
What property causes water molecules to attract one another?
cohesion.
Which changes during evaporative cooling: heat or temperature?
Temperature decreases as higher energy molecules evaporate.
A biological structure has a particular shape and organization that allows it to perform a specific task efficiently. According to one of the central themes of biology, what can these structures tell us?
Structures provide clues about function.
Why can’t a single characteristic of life reliably define an organism as living?
living organisms require a combination of characteristics to set them apart from non-life.
What distinguishes a polar covalent bond from an ionic bond?
polar covalent bonds unequal sharing of electrons.
Ionic bonds involve electron transfer.
Why does sweating cool the body?
removes heat as liquid becomes gas.
What two components make up a solution?
solute and solvent.
An organism's internal temperature and chemical concentrations constantly change from moment to moment. However, this organism is still able to maintain an appropriate internal environment. What characteristic of life is demonstrated?
Homeostasis and regulation.
Which biological level includes both organisms and their physical environment?
Ecosystem.
Why does NaCl form an ionic bond rather than a covalent bond?
Because Sodium transfers an electron to chlorine, producing oppositely charged ions that attract each other.
A solution's pH begins changing rapidly after an acid is added. What does this suggest about its buffer capacity?
The solution has little or insufficient capacity to absorb the added hydrogen (H+) and resist pH change.
A substance that changes from gas to liquid, has gone through?
Condensation