Biology & Evolution
What is the basic unit of structure and function in all living organisms?
the cell
What are the three domains of life?
Bacteria, Archaea, and Eukarya
What four elements make up approximately 96% of living matter?
Carbon, hydrogen, oxygen, and nitrogen (CHON)
What type of bond forms when atoms share electrons?
Covalent bond
What property describes the attraction of water molecules to each other?
Cohesion
What term describes new characteristics that arise from the arrangement and interactions of parts within a system?
Emergent properties
What mechanism did Darwin propose to explain evolution?
Natural selection
Which subatomic particle is directly involved in chemical reactions between atoms?
Electrons
What type of bond results from the attraction between oppositely charged ions?
Ionic bond
What property allows a water strider to walk across the surface of water?
Surface tension, resulting from cohesion/hydrogen bonding.
Put these in order from smallest to largest: organism, organelle, tissue, molecule, organ, cell.
Molecule → organelle → cell → tissue → organ → organism
On an evolutionary tree, what does a branch point represent?
A common ancestor from which descendant lineages diverged.
What determines an atom's atomic number?
Its number of protons.
What is electronegativity?
An atom's attraction for electrons in a covalent bond.
Why does ice float in liquid water?
Hydrogen bonds hold water molecules farther apart in ice, making ice less dense than liquid water.
What is the difference between a prokaryotic and eukaryotic cell?
Eukaryotic cells contain a nucleus and membrane-bound organelles; prokaryotic cells do not.
What two important qualities must a scientific hypothesis have?
It must be testable and falsifiable.
An atom has 6 protons, 6 electrons, and 8 neutrons. What element is it, and what is its mass number?
Carbon; mass number = 14.
Oxygen pulls shared electrons toward itself more strongly than hydrogen does. What type of bond exists between O and H in water?
Polar covalent bond
How many times more acidic is a solution with a pH of 3 than one with a pH of 5?
100 times
A body temperature rises above its normal range and sweating causes the temperature to decrease. What type of regulation is occurring?
Negative feedback
Scientists observe that snakes with a certain coloration are attacked less frequently by predators. They propose that resembling a venomous species protects the snakes. Is this an observation, hypothesis, or theory, and why?
Hypothesis — it is a proposed, testable explanation for the observations.
Two atoms of the same element contain different numbers of neutrons. What are these atoms called, and what remains the same between them?
Isotopes; they have the same number of protons/atomic number.
Put these interactions in order from strongest to weakest: van der Waals interactions, covalent bonds, hydrogen bonds, ionic bonds.
Covalent → ionic → hydrogen → van der Waals
A lake changes from pH 7 to pH 4. By what factor has its H⁺ concentration changed?
It increased 1,000-fold.