Mastering Biology #1 Flashcards
A cell has the following molecules and structures: enzymes, DNA, ribosomes, plasma membrane, and mitochondria. It could be a cell from
nearly any eukaryotic organism. a bacterium. any multicellular organism, like a plant or an animal. an animal, but not a plant. any kind of organism.
Nearly any EUKARYOTIC organism
Which of the following clues would tell you if a cell is prokaryotic or eukaryotic?
the presence or absence of ribosomes
the presence or absence of a rigid cell wall
whether or not the cell carries out cellular metabolism
whether or not the cell contains DNA
whether or not the cell is partitioned by internal membranes
Whether or not the cell is partitioned by internal membranes
Part complete
Hydrolytic enzymes must be segregated and packaged to prevent general destruction of cellular components. Which of the following organelles contains these hydrolytic enzymes in animal cells?
Lysosomes
Part complete
Which structure is the site of the synthesis of proteins that may be exported from the cell?
rough ER free cytoplasmic ribosomes lysosomes plasmodesmata Golgi vesicles
Rough ER
What happens when two atoms form a chemical bond?
View Available Hint(s)
All electrons in atoms participate in chemical bonds.
A chemical bond forms when two atoms transfer or share protons to achieve a stable nucleus.
Two atoms fuse together to form a chemical bond.
A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells.
A chemical bond forms when two atoms transfer or share outer electrons to complete their outer shells
Nitrogen (N) is much more electronegative than hydrogen (H). Which of the following statements is correct about the atoms in ammonia (NH3)?
The nitrogen atom has a strong positive charge; each hydrogen atom has a strong positive charge.
There are covalent bonds between the hydrogen atoms and polar bonds between each hydrogen atom and the nitrogen atom.
Each hydrogen atom has a partial positive charge; the nitrogen atom has a partial negative charge.
Each hydrogen atom has a slight negative charge; the nitrogen atom has a strong positive charge.
The nitrogen atom has a slight positive charge; each hydrogen atom has a slight negative charge.
Since nitrogen is more electronegative, it will have a partial negative charge, while Hydrogen, the less electronegative atom, will get a positive charge
Van der Waals interactions result when
electrons are not symmetrically distributed in a molecule.
two polar covalent bonds react.
molecules held by ionic bonds react with water.
hybrid orbitals overlap.
a hydrogen atom loses an electron.
Occur when electrons are not symmetrically distributed in a molecule
If a salamander relied on hydrogen bonds to cling to surfaces, what type of surface would cause the most problems for this animal?
a surface made with carbon and hydrogen atoms covalently bonded together
a surface coated with a thin film of water
a surface made with carbon, hydrogen, nitrogen, and oxygen atoms covalently bonded together
a surface made with silicon and oxygen atoms covalently bonded together
a surface made with carbon, hydrogen, and oxygen atoms covalently bonded together
A surface made of carbon and hydrogen, since it would be the most nonpolar, opp of H bonds
Part complete
Which statement about weak bonds is correct?
View Available Hint(s)
Weak bonds are transient and easily reversible.
Weak bonds are less important to living things than strong covalent bonds.
Weak chemical bonds form only between atoms of similar electronegativity.
Weak bonds are the most important type of a bond to living things
Weak bonds are transient and reversible
The partial negative charge in a molecule of water occurs because
one of the hydrogen atoms donates an electron to the oxygen atom.
the oxygen atom forms hybrid orbitals that distribute electrons unequally around the oxygen nucleus.
the oxygen atom has two pairs of electrons in its valence shell that are not neutralized by hydrogen atoms.
the oxygen atom acquires an additional electron.
the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus.
The electrons share between the O and H atoms spend more time around O bc it’s more electronegative
Water molecules have a polarity, which allows them to be electrically attracted to other water molecules and other polar molecules by weak chemical bonds known as _____.
View Available Hint(s)
ionic bonds polar covalent bonds Van der Waals interactions hydrogen bonds nonpolar covalent bonds
Hydrogen bonds
Part complete
Liquid water’s high specific heat is mainly a consequence of the
absorption and release of heat when hydrogen bonds break and form.
fact that water is a poor heat conductor.
higher density of liquid water than solid water (ice).
high specific heat of oxygen and hydrogen atoms.
small size of the water molecules.
Absorption and release of heat when hydrogen bonds break and form
Many mammals control their body temperature by sweating. Which property of water is most directly responsible for the ability of sweat to lower body temperature?
water’s high surface tension
water’s change in density when it condenses
water’s ability to dissolve molecules in the air
the release of heat by the formation of hydrogen bonds
the absorption of heat by the breaking of hydrogen bonds
The absorption of heat by the breaking of hydrogen bonds
Part complete
An acid is a substance that _____.
View Available Hint(s)
is a versatile solvent
forms covalent bonds with other substances
reduces the hydrogen ion concentration of a solution
increases the hydrogen ion concentration of an aqueous solution
contains hydrogen
INCREASES the H+ conc in solution
What functional group is commonly used in cells to transfer energy from one organic molecule to another?
View Available Hint(s)
carboxyl amino phosphate sulfhydryl hydroxyl
Phosphate
