Bio Unit 2 Flashcards
Learn the Nature and Properties of Matter
What is an atom?
the basic unit of chemical elements made up of subatomic particles
What are the subatomic particles?
protons, neutrons, electrons
What is the charge of a proton? Were is it located in the atom?
positive
in the nucleus
What is the charge of a neutron? Were is it located in the atom?
neutral
in the nucleus
What is the charge of a electron? Were is it located in the atom?
negative
in shells around the nucleus
What is an element?
a pure substance consisting of only one type of atom
How can you identify the atomic mass of an element?
last number on the block of an element
number of protons + number of neutrons
How can you identify the number of neutrons in an element?
atomic mass - atomic number
How can you identify the number of protons in an element?
atomic number
How can you identify the atomic number of an element?
first number on the block of an element
number of protons
How can you identify the number of electrons in an element?
atomic number (assuming the element is neutral)
How can you tell if an element is an ion (based on the element card)? How can you identify the number of electrons in an ion?
If the element has a (+) or (-) or a number and a (+) or (-) listed after the element symbol, that means that the element is charged.
(+) means that the element is positively charged and has lost the same number of electrons as the number before the plus sign (no number = 1 electron lost)
(-) means that the element is negatively charged and has gained the same number of electrons as the number before the plus sign (no number = 1 electron gained)
What are isotopes?
versions of an element with different numbers of neutrons but the same chemical properties
What is a radioactive isotope? What do they allow for?
when the nuclei in an elements are unstable and break down at a constant rate over time
carbon dating, detecting cancer, and killing bacteria
What are chemical compounds? How are they different from pure elements?
a substance formed by the chemical combination of two or more elements in definite proportions (e.g. H2O = 1 oxygen atom, 2 hydrogen atoms)
their physical and chemical properties are different
What are hydrogen bonds?
a weak bond between two molecules formed when the partial negativity of the oxygen in one molecule attracts to the partial positivity of hydrogen in another
What are covalent bonds?
a bond formed when two atoms’ shells overlap, and electrons can freely flow between the two
What is electronegativity?
the tendency of an atom to attract more electrons in a covalent bond, making that atom partially negative
What is an ion?
An atom with a positive or negative electrical charge
What are ionic bonds? What do they cause?
a bond formed when one or more electrons are transferred from one atom to another
atoms becoming charged
What is a cation? What made it a cation?
a positively charged ion
lost electrons to another atom
What is an anion? What made it an anion?
a negatively charged ion
gained electrons from another atom
What are the properties of water?
polarity, cohesion, adhesion, high specific heat, less dense as a solid
What is polarity? How does it affect bonds?
the uneven distribution of charges among atoms connected by a chemical bond
when charges are uneven, the negative parts attract the positive parts of other atoms (and vice versa), forming hydrogen bonds
What is cohesion?
an attraction between molecules of the same substance
What is adhesion?
attraction between molecules of different substances
What is surface tension?
a measure of how hard it is to break the surface of a liquid as a result of the attraction between the molecules
What is capillary action?
the use of cohesion and adhesion to transport water against gravity (like in plants)
What is heat capacity?
amount of energy needed to raise one unit substance’s temperature by one degree
How do you change a substance’s temperature (what needs to occur)?
by making its molecules move faster
What does it mean that water has high specific heat? How is this useful?
it resists temperature changes and takes a lot of energy for temperature to increase or decrease
no drastic temperature changes in aquatic environments or bodies, helping to keep life alive
How are ice’s properties different from water’s? How is this useful?
ice is less dense, so it floats on top of water
this allows animals to continue living below water even if the top is frozen
What does polarity have to do with solubility?
water’s polarity makes it a solvent, so it can dissolve other substances called solutes
What is a low pH score? What does it mean?
0-6
acidic
higher concentration of hydrogen ions
What is a medium pH score? What does it mean?
7
neutral
What is a high pH score? What does it mean?
8-14
basic
low concentration of hydrogen ions
What do buffers do?
maintain homeostasis by raising or lowering pH levels
What are the four macromolecules?
carbohydrates, lipids, nucleic acids, and proteins
What are the monomers of carbs? Examples of polymers? Elements that make them up? Major functions?
glucose (the monosaccharide)
starch, cellulose, chitin (polysaccharides)
1 carbon, 2 hydrogen, 1 oxygen (CHO)
provide short-term energy and form structures (such as cell walls or exoskeletons)
What are the monomers of lipids? Examples of polymers? Elements that make them up? Major functions?
glycerol and fatty acids
fats, oils, and waxes
carbon, hydrogen, oxygen (CHO)
store energy and provide structural support in membranes (also aren’t generally soluble in water)
What are the monomers of nucleic acids? Examples of polymers? Elements that make them up? Major functions?
nucleotide (5-carbon sugar, nitrogenous base, phosphate group)
DNA and RNA
carbon, hydrogen, oxygen, nitrogen, phosphorous (CHONP)
carry genetic information
What are the monomers of proteins? Examples of polymers? Elements that make them up? Major functions?
amino acids (carboxyl group with a double bonded oxygen, amino group, placeholder for another substance)
enzymes and other proteins
carbon, hydrogen, oxygen, nitrogen
plays a role in metabolism, help speed up chemical reactions, and regulate cell processes
Define chemical reaction
the changing of one set of chemicals into another
What happens in chemical reactions? How do enzymes affect them?
the bonds in the reactants break and form new bonds, creating the products
enzymes speed up reaction speed by lowering activation energy and providing a place where reactants can be brought together
What are the two types of chemical reactions? How are they graphed?
- endothermic reactions are non-spontaneous and absorb energy/heat
- exothermic reactions are spontaneous and release energy/heat
in an endothermic graph, the reactants have less energy than the products and the energy peaks when the activation energy occurs
in an exothermic graph, the reactants have more energy than the products and the energy peaks when the activation energy occurs
How do you graph the enzyme-substrate complex?
- enzyme (round) has a substrate shaped hole at the top; substrate is above it but not connected
- substrate connects to the enzyme, filling the hole and attaching to the active/binding site
- enzyme remains, but instead of the substrate, two separate products are released, no longer connecting to the enzyme
What graph shows how enzymes affect reactions?
take the normal graph of how chemical reactions work, then decrease the curve that represents the activation energy, showing that enzymes decrease the activation energy needed to cause a reaction
What happens when enzymes are put in extreme environments/environments outside the optimum environment?
the enzyme’s structure may change, causing it to be less effective because it won’t perfectly fit the substrate, or it may be fully denatured, meaning that the active/bonding site breaks and the enzyme no longer works
