Biology- Water, Biochemistry, Cells Flashcards
Just answer the questions.
What year was it announced that there was evidence of life on Mars? and who announced it?
1996, Dr. David McKay
What are the five things necessary for life?
growth, metabolism, movement, reproduction, and response to stimuli
what does it mean to be sterile?
unable to reproduce
what is a substance that dissolves in a liquid?
a solute
what is the liquid in which another substance is dissolved?
a solvent
what are chemical reactions?
changes in the chemical composition of substances
chemical reactions involve…
reactants and products
what types of atoms are in water?
hydrogen and oxygen
the smallest units into which a substance can be broken down, and they’re made of protons, neutrons, and electrons
atoms
which subatomic particles make up the nucleus?
protons and neutrons
consists of two or more atoms held together by chemical bonds
molecule
chemical bonds occur between…
two atoms in a molecule that share electrons
to pull electrons
electronegative
when shared electrons are closer to one atom than the other, that atom has what kind of charge?
partially negative
when shared electrons are farther from one atom than the other, that atom has what kind of charge?
partially positive
a molecule where different regions have different charges
polar
a type of weak chemical bond that forms between hydrogen and another type of atom and is based on the attraction of partial charges
a hydrogen bonding
the tendency of molecules to stick together
cohesion
why does salt dissolve in water?
the negative pole of water attracts the positively charged sodium and separates the sodium from the negatively charged chloride
a substance that gives H+ ions to a solution
acid
a substance that takes H+ ions
base
simple chemical substances composed of atoms that can’t be broken down
elements
the atomic number of an element is based on its number of…
protons
an atom’s mass number is based on…
the sum of protons and neutrons
