BIO Chapter 2 Flashcards

Front: What is matter? Back: Anything that takes up space and has mass.

Front: What are the four states of matter? Back: Solid, liquid, plasma, and gas.

Front: What are the elements important to life? Back: CHOPSTN (Carbon, Hydrogen, Oxygen, Phosphorus, Sulfur, Nitrogen).

Front: What are protons? Back: Positively charged particles found in the nucleus.

Front: What are electrons? Back: Negatively charged particles.

Front: What are neutrons? Back: Uncharged particles found in the nucleus.

Front: How do molecules form? Back: When two or more of the same elements bond together.

Front: How do compounds form? Back: When two or more different elements bond together.

Front: What is ionic bonding? Back: When electrons are transferred from one atom to another.

Front: What is covalent bonding? Back: The result when atoms share electrons.

Front: What is a nonpolar covalent bond? Back: A bond where the sharing of electrons between two atoms is fairly equal.

Front: What is electronegativity? Back: The attraction of an atom for electrons in a covalent bond.

Front: What is a polar covalent bond? Back: A bond where the sharing of electrons between atoms is unequal, as seen in water between oxygen and hydrogen.

Front: What are hydrophilic molecules? Back: Molecules that attract water.

Front: What are hydrophobic molecules? Back: Molecules that do not attract water.

Front: What is soap also called and why? Back: Amphipathic, because it is both hydrophilic and hydrophobic.

Front: What are fats, grease, and oil classified as? Back: Hydrocarbons.

Front: What happens when water ionizes? Back: It releases an equal number of hydrogen ions (H+) and hydroxide ions (OH-).

Front: What causes hydrogen atoms in one water molecule to be attracted to the oxygen atom in other water molecules? Back: Polarity within a water molecule.

Front: What is a hydrogen bond? Back: The attraction between partially negative oxygen and partially positive hydrogen.

Front: Describe the strength of hydrogen bonds. Back: They are weak individually but strong collectively.

Front: What do broken lines in a chemical diagram indicate? Back: That the bond is unstable.

Front: Where did the first cells evolve? Back: In water.

Front: What percentage of organisms is composed of water? Back: 70-90%.

Front: Why is water considered a polar molecule? Back: Due to its unequal sharing of electrons.

Front: What causes water molecules to cling to one another? Back: Hydrogen bonds.

Front: What property does water have due to hydrogen bonds? Back: High heat capacity.

Front: What is a calorie in terms of water? Back: The amount of heat energy needed to raise the temperature of 1g of water by 1°C.

Front: How do hydrogen bonds help water absorb heat? Back: They link water molecules, allowing water to absorb heat without a great change in temperature.

Front: How does water's temperature regulation benefit organisms? Back: Because the temperature of water rises and falls slowly, organisms are better able to maintain their normal internal temperature.

Front: What is water's high heat of vaporization? Back: Converting 1g of the hottest water to gas requires an input of 540 calories of heat energy.

Front: How does water's heat of vaporization help animals? Back: It provides an efficient way for animals in a hot environment to release excess body heat. It also helps moderate temperatures along coasts.

Front: Why is water considered a solvent? Back: Due to its polarity, water facilitates chemical reactions both outside and within living systems.

Front: What does a solution contain? Back: Dissolved substances, which are called solutes.

Front: What does it mean that water molecules are cohesive? Back: They cling together due to hydrogen bonding.

Front: What does it mean that water molecules are adhesive? Back: Water's positive and negative poles allow it to adhere to polar surfaces.

Front: Why is water an excellent transport system? Back: Because it is cohesive and adhesive.

Front: What is surface tension? Back: The stronger the force between molecules in a liquid, the greater the surface tension.

Front: How does high surface tension benefit some insects? Back: It allows them to walk on the surface of a pond or lake.

Front: Is frozen water (ice) more or less dense than liquid water? Back: Less dense.

Front: At what temperature is liquid water densest? Back: 4°C.

Front: Why does water expand when it freezes? Back: A crystal lattice forms with hydrogen bonds farther apart.

Front: Why does ice float on liquid water? Back: Because it is less dense.

Front: What are acidic solutions characterized by? Back: High H+ concentrations.

Front: What are acids? Back: Substances that release hydrogen ions when dissociated in water.

Front: What does the pH scale indicate? Back: The acidity or alkalinity of a solution.

Front: What is the range of the pH scale? Back: 0-14.

Front: What pH values are acidic, alkaline, and neutral? Back: Below 7 is acidic, over 7 is alkaline, and 7 is neutral.

Front: What is the pH of stomach acid? Back: 1 (1x10^-1M).

Front: What is the pH range of human blood? Back: 7.2-7.4.

Front: What is a buffer? Back: A chemical or combination of chemicals that keep pH within normal limits.

Front: What elements do organic molecules always include? Back: Carbon (C) and Hydrogen (H).

Front: What are organic molecules with only hydrogen and carbon called? Back: Hydrocarbons.

Front: Who made a model of the structure of DNA in 1953? Back: James Watson and Francis Crick.

Front: What is DNA a chain of? Back: Nucleotides.

Front: What are the three subunits of each nucleotide in DNA? Back: Phosphoric acid (phosphate), a pentose sugar (deoxyribose), and a nitrogen-containing base.

Front: Who came up with the structure of DNA? Back: Rosalind Franklin.

Front: What is the sugar in DNA? Back: Deoxyribose.

Front: What are the bases in DNA? Back: Adenine, guanine, thymine, cytosine.

Front: How many strands does DNA have? Back: Double stranded.

Front: Does DNA have a helix structure? Back: Yes.

Front: What is the sugar in RNA? Back: Ribose.

Front: What are the bases in RNA? Back: Adenine, guanine, uracil, cytosine.

Front: How many strands does RNA have? Back: Single stranded.

Front: Does RNA have a helix structure? Back: No.

Front: What are the four possible bases in DNA? Back: Two purines (Adenine (A), Guanine (G)) and two pyrimidines (Thymine (T), Cytosine (C)).

Front: What is DNA replication? Back: The process of copying one DNA double helix into identical double helices.

Front: What is the key enzyme in DNA replication? Back: DNA polymerases.

Front: How does semi-conservative replication work? Back: It uses each original strand as a template to produce a new complementary strand.

Front: What does each daughter DNA molecule consist of after replication? Back: One new chain of nucleotides and one from the parent DNA molecule.

Front: What happens before DNA replication begins? Back: The two strands of the parent molecule are hydrogen-bonded together.

Front: What enzyme unwinds and "unzips" the double-stranded DNA? Back: DNA helicase.

Front: How do new complementary DNA nucleotides fit into place during replication? Back: By complementary base pairing along separated strands.

Front: What enzyme positions and joins the new DNA nucleotides? Back: DNA polymerase.

Front: What enzyme seals any breaks in the sugar-phosphate backbone during DNA replication? Back: DNA ligase.

Front: What is the result of DNA replication? Back: Two double helix molecules that are identical to each other and to the original DNA molecule.