unit 1 Flashcards
Biology =
The scientific study of life
Science =
field of study that attempts to comprehend the nature of the universe
key functions of life:
*Order
*Sensitivity to stimuli
*Reproduction
*Adaptation
*growth and development
*Regulation/homeostasis
*energy processing
*evolution
The cell theory:
If it isnt made of at least one cell, it isnt considered living
Three components of cell theory:
1) Living things are made up of one or more cells
2) Cells are the simplest structural unit of life
3) All cells come from pre-existing cells
Bacteria =
single celled organisms.
very small and simple cells
viruses =
Molecules of DNA or RNA that are wrapped in a protein coat
Prions =
Misshaped protein that cause other proteins to become misshapen
Yeast =
Single celled fungi
Organization of life from smallest to largest:
Atoms—molecules—cells—tissues—organs—organ systems—organisms
what are atoms made of?
Protons, neutrons, and electrons
an atoms nucleus is made of what?
protons and neutrons
atomic number -
the number of protons in an atom
what is the number at the bottom of an atomic symbol?
average atomic mass
what is atomic mass?
the number of protons and neutrons
what defines the element number?
the number of protons
when and atom gains or loses electrons, what happens?
it becomes electrically charged
it becomes an ion
what determines an atoms reactivity?
the outter electrons
what is the outter layer of electrons called?
valent electrons
what are electrolytes?
ions in body fluids that must be kept in balance. they conduct electrical charges
when is an atom most stable?
what is the name for the rule?
when the outter shell of electrons is full
(the octet rule)
what is a molecule?
atoms held together by bonds
what is a compound?
a molecule made up of 2 or more different elements
what are the 3 types of chemical bonds?
ionic, covelent, and hydrogen bonds
a bond where electrons are donated is a…
ionic bond
ionic bond =
ions are formed when electrons are donated and opposits attract
a bond where electrons are shared is called…
a covalent bond
a bond where electrons are shared equally…
non-polar covalent bonds
a covelent bond where electrons are unequally shared is called a…
polar covalent bond
what do polar covalent bonds result in?
molecules with partial charges
a bond where an already bonded H is attracted to a negatively charged neighbor is a…
hydrogen bond
things to note about hydrogen bonds
*only occurs between a hydrogen atom and a negatively charged atom that is not hydrogen.
*easily made and broken
what is dihydrogen monoxide?
water/ H2O
humans are mostly made of what 4 elements?
carbon, oxygen, hydrogen, and nitrogen
(property of water) what is adhesion?
water is attracted to other water molecules and creates surface tension
(water sticks together)
(property of water) what is adhesion?
the tendancy of water molecules to stick to other objects
properties of water - temperature
water resists temperature changes.
it takes alot of heat to cause water to increase in temperature and/or change state
is solid water more or less dense than liquid water?
less dense which is why it floats
what is the universal solvent of life?
water
hydrophilic =
polar or charged molecules that dissolve in water
hydrophobic =
non-polar molecules that do not dissolve in water
the acidic side of the ph scale is…
6-0
the basic side of the ph scale is…
8-12
what is neutral on the ph scale?
7
more hydrogen ions are found in a solution that is
acidic
more hydroxide ions are found in a solution that is…
more basic
what is a buffer?
molecule or solution that resists change
what can a ph buffer do?
it can absorb H+ and/or OH- or release H+
what is homeostasis
to maintain a nearly constant internal environment
EX. PH, temperature, and salinity
what are 4 major organic molecules?
*carbohydrates
*proteins
*nucleic acids
*lipids
how many covalent bonds can carbon form?
up to 4
chains of carbons and hydrogens are called what?
hydrocarbons
what are functional groups?
atoms that form the chemically reactive part of an organic molecule
