UNIT 1- BIOLOGY EXPLORING LIFE & THE CHEMICAL BASIS
OF LIFE ASSESSMENT TEST
All organisms composed of - ANSWER-Matter
Matter-anything that has mass and occupies space
Element - ANSWER-A pure substance made of only one kind of atom
Living organisms - ANSWER-Made of 95% O, C, H, N
trace elements - ANSWER-Present in small amounts and required for
growth and function
protons and neutrons located - ANSWER-in the nucleus of an atom
Electrons - ANSWER-Negatively charged particles
Orbit the nucleus at various distances and are constantly in motion
Chemical elements distinguished by others by - ANSWER-Number of
protons in each of its atoms
atomic mass - ANSWER-sum of protons and neutrons
Atomic weight - ANSWER-Average of the mass numbers of all isotopes
Isotopes - ANSWER-Atoms of the same element that have different
numbers of neutrons
Many found in nature are unstable and will break up into elements with
lower atomic numbers
,UNIT 1- BIOLOGY EXPLORING LIFE & THE CHEMICAL BASIS
OF LIFE ASSESSMENT TEST
Can be hazardous to life
Also can be used for medicinal purposes
Radioisotopes - ANSWER-unstable isotopes that emit radiation and decay
into other isotopes
Atoms chemical behavior - ANSWER-Depends on the number of electrons
in its outermost shell
Unfilled shells(vacancies) - ANSWER-Make atoms non stable or reactive
Chemical reactions occur - ANSWER-When one of more substances are
changed into other substances by the making or breaking of chemical
bonds
Brownian motion - ANSWER-the random motion or vibration of atoms and
molecules resulting from their collision with other atoms and molecules
Atoms interact to form - ANSWER-molecules
Starting material in reaction - ANSWER-Reactant
end materials in a chemical reaction - ANSWER-products
most substances are - ANSWER-Composed of electrically neutral groups
of atoms that are tightly bound together
, UNIT 1- BIOLOGY EXPLORING LIFE & THE CHEMICAL BASIS
OF LIFE ASSESSMENT TEST
Covalent bonds - ANSWER-Bonds created by sharing valence electrons
with other atoms.
Covalent bond is said to be what if the electrons are shared equally -
ANSWER-Nonpolar
Covalent bonds are polar - ANSWER-When electrons spend more time
near the nucleus with the more protons, unequal sharing
Ionic bonds - ANSWER-Formed by electrical attraction between atoms
bearing opposite charges
atom loses electrons - ANSWER-cation
Atom gains electrons - ANSWER-anion
Water - ANSWER-Essential molecule of life
Required for chemical reactions
Cells Made up of 70-95% water
Water electronegativity - ANSWER-Oxygen is more electronegative then
hydrogen so the electrons spend more time around the oxygen molecule
making water polar
-Makes oxygen slightly negative
-hydrogen slightly positive
OF LIFE ASSESSMENT TEST
All organisms composed of - ANSWER-Matter
Matter-anything that has mass and occupies space
Element - ANSWER-A pure substance made of only one kind of atom
Living organisms - ANSWER-Made of 95% O, C, H, N
trace elements - ANSWER-Present in small amounts and required for
growth and function
protons and neutrons located - ANSWER-in the nucleus of an atom
Electrons - ANSWER-Negatively charged particles
Orbit the nucleus at various distances and are constantly in motion
Chemical elements distinguished by others by - ANSWER-Number of
protons in each of its atoms
atomic mass - ANSWER-sum of protons and neutrons
Atomic weight - ANSWER-Average of the mass numbers of all isotopes
Isotopes - ANSWER-Atoms of the same element that have different
numbers of neutrons
Many found in nature are unstable and will break up into elements with
lower atomic numbers
,UNIT 1- BIOLOGY EXPLORING LIFE & THE CHEMICAL BASIS
OF LIFE ASSESSMENT TEST
Can be hazardous to life
Also can be used for medicinal purposes
Radioisotopes - ANSWER-unstable isotopes that emit radiation and decay
into other isotopes
Atoms chemical behavior - ANSWER-Depends on the number of electrons
in its outermost shell
Unfilled shells(vacancies) - ANSWER-Make atoms non stable or reactive
Chemical reactions occur - ANSWER-When one of more substances are
changed into other substances by the making or breaking of chemical
bonds
Brownian motion - ANSWER-the random motion or vibration of atoms and
molecules resulting from their collision with other atoms and molecules
Atoms interact to form - ANSWER-molecules
Starting material in reaction - ANSWER-Reactant
end materials in a chemical reaction - ANSWER-products
most substances are - ANSWER-Composed of electrically neutral groups
of atoms that are tightly bound together
, UNIT 1- BIOLOGY EXPLORING LIFE & THE CHEMICAL BASIS
OF LIFE ASSESSMENT TEST
Covalent bonds - ANSWER-Bonds created by sharing valence electrons
with other atoms.
Covalent bond is said to be what if the electrons are shared equally -
ANSWER-Nonpolar
Covalent bonds are polar - ANSWER-When electrons spend more time
near the nucleus with the more protons, unequal sharing
Ionic bonds - ANSWER-Formed by electrical attraction between atoms
bearing opposite charges
atom loses electrons - ANSWER-cation
Atom gains electrons - ANSWER-anion
Water - ANSWER-Essential molecule of life
Required for chemical reactions
Cells Made up of 70-95% water
Water electronegativity - ANSWER-Oxygen is more electronegative then
hydrogen so the electrons spend more time around the oxygen molecule
making water polar
-Makes oxygen slightly negative
-hydrogen slightly positive
