Exam 1 Flashcards
Biology
scientific study of organisms, living and fossil
Cell
the basic unit of life
Organism
living individuals that consist of more than 1 cell
5 characteristics of living things
- homeostasis
- uses energy
- is organized
- reproduces, grows, and develops
- evolves
Example of homeostasis
maintaining body temperature
levels of organization
atom, molecule, organelle, cells, tissue, organ, organ system, organism
prokaryotes
- bacteria and archaea
- first organisms
- single celled organisms only
- doesn’t have nucleus or organelles
eukaryotes
- formed billions of years after eukaryotes
- can be single or multicellular
- has a nucleus and organelles
most inclusive taxonomic group
domain
least inclusive taxonomic group
species
3 domains
bacteria, archaea, and eukarya
4 kingdoms in domain eukarya
Protista, Fungi, Plantae, and Animalia.
First domain to emerge first
Protista
How old is Earth?
4.6 billion years old
When did the first life form appeared?
4 billion years ago
Photosynthetic organisms?
2.5 billion years ago
First land plants and animals
500 million years ago
What changed in atmosphere to allow organisms to move onto land?
Photosynthesis increased oxygen production, which allowed aerobic capable organisms to flourish due to being able to make energy, and also led to O3 (ozone layer) production, which protected the animals from harmful UV radiation
Unifying principle of biology?
Evolution
Evolution
results in change in the genetic makeup of populations over time
artificial selection
selective breeding of plants and animals to get desirable traits
Natural selection and adaptations
the process through which populations of living organisms adapt and change
Scientific method
- make observations
- ask questions
- form a hypothesis
- make a prediction
- design and conduct an experiment
IV
what’s manipulated in the experiment
DV
What your measuring in the experiment
Standardized variables
variables that don’t change in an experiment
Control group
a group in the experiment which a variable is not being tested
Atom
smallest chemical unit of a type of pure substance
Molecule
group of joined atoms
Element
pure substance having only one kind of atom
Compound
molecule made up of 2+ elements bonded together in a fixed ratio
3 particles of an atom
protons, electrons, and neutrons
Ion
+ or - charged atoms
Location of the 3 particles
Protons and neutrons are located in the nucleus
Electrons are located outside the nucleus on orbital rings
Mass of protons and neutrons
1 Dalton = 1.7 x 10^-14 g.
Mass of an electron
9.1 x 10^-28 g.
Atomic number
number of protons in the atoms
Atomic weight
total weight of an atom
Molecular weight
sum of atomic weights of all atoms in a molecule
Mass number
number of protons and neutrons in the nucleus
Isotope
forms of the same element with different numbers of neutrons
Orbital
where an electron is 90% of the time and can hold up to 2 electrons
Electron shell
energy level
Valence shell
Outermost shell, reactive ones have unpaired electrons
Ionic bond
M - M or M - NM bond, formed between two or more atoms by the transfer of one or more electrons between atoms
Covalent bond
NM - NM, NM - Metalloid, a bond in which atoms share one or more electrons
Polar bond
a molecule in which one end of the molecule is slightly positive, while the other end is slightly negative, and atoms with different electronegativities share electrons unequally in a covalent bond
Nonpolar bond
a type of chemical bond where two atoms share a pair of electrons with each other
Hydrogen bond
attraction between the positive end of one molecule and the negative end of another
van der Waals
attractions between nonpolar molecules close together
Redox reactions
electron transferred between 2 molecules
When something is oxidized - loses electrons, e- donor or reducing agent
When something is reduced - gains electrons, e- acceptor or oxidizing agent
Characteristics of water
Single molecule - polar bond
Double molecule - polar bond
Cohesion - an attraction between molecules or atoms of the same substance
Adhesion - an attraction between molecules of different chemical substances
Is water denser as a liquid or a solid
water is denser as a liquid due to the solid structure forming a crystalline structure with hydrogen bonds that push them further apart, creating more space between them and resulting in a lower density compared to liquid water where the molecules are more tightly packed together
