Bio ch 2
which of the following describes facilitated diffusion
it requires the assistance of proteins it requires a concentration gradient
what are lipids
lipids are hydrophobic molecules composed primarily of hydrogen and carbone
arrange the following states of water in order from MOST dense to LEAST dense
liquid solid gas
the cells of all living things are composed of ____; very large molecules that contain thousands and in some cases even billions of atoms
macromolecules
a dalton is a unit of
mass
which of the following are methods of passive transport
osmosis transport of water by aquaporins
electrons in the same energy level
always have the same potential energy
by applying chemical stains to cells, we can improve which of the following between different cellular components
contrast
which of the following are mechanisms of bulk transport
exocytosis endocytosis
a ____ _____ consists of a long chain hydrocarbon with a carboxyl group attached to one end
fatty acid
the extracellular matrix is made primarily of which of the following
glycoproteins
which of the following is a stack of flattened thylakoid tubules
granum
in which of the following covalent bonds are electrons considered to be equally shared between atoms
h-h c-c c-h
which of the following are structural formulas
h-h o=o
water tend to repel or exclude _____ molecules
nonpolar
the surface of the nucleus is bounded by 2 phospholipid bilayer membranes called
nuclear envelope
unique among macromolecules, _______ acids are able to serve as templates to produce precise copies of themselves
nucleic
a ribosome consist of a large and small subunit and each contains RNA molecules, which are made in
nucleolus
ionic bonds involve
an attraction between atoms with opposite electrical charges a transfer of electrons from one atom to another
large molecules and particles that cannot cross the hydrophobic barrrier created by the plasma membrane enter or leave the cell by ______
bulk transport
the 2 main categories of _____ ______are endocytosis and exocytosis
bulk transport
how is information stored in a molecule of DNA
by varying the sequence of the 4 types of nucleotides that make up each strand
in order to survive grow and reproduce a cell must
exchange materials and information with its environment
what type of bond can form between 2 identical atoms?
nonpolar
the surface of the nucleus is bounded by 2 phospholipid bilayer membranes, called the ________
nuclear envelope
In order to obtain a stable outer shell of electrons, carbon forms four strong bonds of
covalent
which structure is involved with eukaryote cell division
microtuble organizing center
the function of these fibers of the cytoskeleton include moving materials within the cell and organizing the cytoplasm
microtubles
the structure of ____ is usually discussed in terms of hierarchy of 4 levels
proteins
atoms of the same element always have the same number of ___ and this number is unique for that element
protons
proteins are made up of one or more unbranched chains of
amino acids
when two amino acids are linked together, a peptide bond is formed between the _____ group of one and the ____ group of the other.
amino and carboxyl
which functional group is found in glycerol but not in a fatty acid
hydroxol
if two solutions have unequal concentrations of solutes, the solution with the higher solute concentration is called _______ and the solution with the lower solute concentration is called
hypertonic hypotonic
which type of RNA carries information from DNA
messenger
which of the following best describes the relationship between temperature and enzyme activity
each enzyme has an optimum temperature where it functions best
the volume of space around the nucleus where and electron is most likely to be found is known as
electron orbital
the affinity of an atom for an electron is also known as which of the following
electronegativity
In living organisms, chemical energy is stored in high-energy ____ which can be transferred from one atom to another during redox reactions
electrons
the chemical behavior of an atom depends o the number and configuration of its
electrons
which of the following best describes a contemporary model of electron movement within atoms?
electrons move in orbitals where the probability of finding them is high
a ____ is a substance that cannot be broken down into simpler substances by ordinary chemical means
element
phagocytosis is one of the mechanisms of which of the following
endocytosis
when electrons move closer to the nucleus
energy is released
the letters k, l, m and so on are used to designate different
energy levels in an atom
In living organisms, almost all chemical reactions are catalyzed by protein catalysts called
enzymes
the limitation of resolution for the human eye is how many micrometers.
100
An atom has 11 protons, 12 neutrons and 10 electrons. This atom has an atomic number of ______, and atomic mass of ______, and an overall charge of _____.
11; 23; +1
how many subunits make up a ribosome
2
how are disaccharides formed
2 monosaccharides are linked together through dehydration synthesis
proteins are polymers made up of how many different amino acids
20
if an atom has an atomic number of 6, how many covalent bonds must it form in order to have a stable outer shell of electrons?
4
in a double covalent bond, ____ electrons are shared
4
the diameter of most cells is less than
50 micrometers
an electrically neutral atom has an atomic number of 6 and an atomic mass of 14. this atom has ______ protons, ______ neutrons and _____ electrons.
6, 20; 8
which type of interaction involves the formation of a covalent bond between 2 different amino acid side chains
Disulfide bridge
which of the following statements about a molecule of hydrogen are true
It has no net charge the shared electrons are attracted equally by both nuclei after they bond together, each hydrogen atom has a stable outer shell of electrons it is composed of 2 hydrogen atoms that share one pair of electrons
Water consists of one oxygen atom joined on two hydrogen atoms by which of the following?
Two single polar covalent bonds
a polypeptide is a long, unbranched chain of
amino acids
each kind of protein has a unique sequence of ______ _______
amino acids
Which of the following describes the structure of a phospholipid
a polar head and 2 long nonpolar tails
triglycerides and phospholipids are different because only phospholipids have
a polar head and 2 nonpolar tails a phosphate group attached to one carbon atom in the backbone
in phospholipids, a phosphate is attached to the third carbon of glycerol, what is typically attached to the phosphate
a polar or charged organic molecule
compared to carbon, the electronegativity of hydrogen is
about the same
the carboxyl group is ______ while the amino group is ______
acidic basic
during the contraction of muscle, which fiber is used
actin
identify the fibers which are used in cell division in animals
actin microtubles
which of the following are main points of cell theory
all organisms are composed of one or more cells cells are the smallest living things cells arise only by division of a preexisting cell
how can amino acid side chains affect the structure and function of a protein
amino acid side chains play a role in protein folding amino acid side chains are invloved in catalysis at the active site of enzymes
a chlorine atom that has gained and electron and has an overall negative charge is an example of
anion
atoms with a net negative charge are known as _____, wherease atoms with a net positive charge are known as
anions, cations
a solution where water is the solvent is called a _____ solution
aqueous
of the 2 types of prokaryotes, ______ are abundant throughout the soil, water and the human digestive tract. While ______ are also common, they are typically found in more extreme environments such as hot springs and deep sea thermal vents.
bacteria archaea
which of the following bonds are best described as polar
c-o c-n
which of the following bonds are polar
c-o c-n o-h
which of the following molecules are polar
c2h5oh and h2o
the ability of water to rise inside a tube of narrow diameter against the pull of gravity is called
capillary action
_____atoms form the framework of biological molecules
carbon
which of the following is not a function of intermediate filaments
cell division
identify the functions of actin filaments
certain cell movement pinching of the cell during division cell strength
a chemcal reaction invloves the breaking and formation of
chemical bonds
which of the following are polysaccharides
chitin cellulose glycogen starch
which of the following are correct concerning Eukaryotic DNA structure
chromatin is present the dna is organized in linear chromosomes
_____ are composed of microtubles, but are typically shorter that flagella and tend to cover all or part of the surface of a cell.
cilia
Nitrogenous bases that pair with each other in a DNA molecules are referred to as
complementary
which of the following describe monosaccharides
composed of carbon, hydrogen and oxygen simplest sugars monomers that can be joined together to form more complex carbohydrates
which of the following is true of transmembrane domains
composed of hydrophobic amino acids typically contain configurations of alpha helices
a ___ bond is formed when 2 atoms share one or more pairs of valence electrons.
covalent
what is the term for the region of the cell contained within the plasma membrane
cytoplasm
which of the following are features that ALL cells have in common
cytoplasm ribosomes plasma membrane nucleus
the eukaryotic cell structure involved in supporting the shape of the cell and anchoring organelles to fixed locations
cytoskelton
polymers are formed via chemical reactions termed ____reactions and are broken down by chemical reactions called ____ reactions
dehydration hydrolysis
Carbon-12, carbon-13 and carbon-14 are
different isotopes of the same element
most cell are relatively small for reasons related to the ____ of substances into and out of the cells
diffusion
most cells are relatively small for reasons related to the _____ of substances into and out of the cells
diffusion
net movement of a substance from a region where it has a higher concentration to a region where it has a lower concentration is called
diffusion
the two basic types of secondary structure are ____ helix and ____ sheet.
alpha beta
a hydrogen bond can form between the partially negative _____ atom of one water molecule and the partially positive _____ atom of another water molecule
oxygen hydrogen
the covalent bond that joins 2 amino acids is called a ____ bond.
peptide
archaea cell walls lack
peptidoglycan
most bacterial cells are encased by a strong cell wall composed of ______which is carbohydrate matrix cross linked by polypeptide
peptidoglycan
complex lipids called ______ form the core of all biological membranes
phospholipids
which of the following is not a component of archaea cell walls
phospholipids
which of the following structures are UNIQUE to prokaryote cells
pili nucleoid
what structure surrounds all cells
plasma membrane
a long, unbranched chain of amino acids is called
polypeptide
if two atoms are joined by a polar covalent bond, the atom with the lower electronegativity will have a partial ______ charge.
positive
which of the following contain their genetic material in a nucleoid region
prokaryotes
which of the following are lipids
prostaglandins fats steriods
Ribosomes are responsible for _____ synthesis in the cell
protein
among subatomic particles, each _____ has a charge of +1. each _______ has a charge of -1 and each___ has no charge.
proton electron neutron
Atomic number refers to the number of ______in a atom
protons
which subatomic particles determine the atomic mass of an atom
protons and neutrons
which two particles are the primary determinants of an elements atomic mass?
protons and neutrons
____ isotopes are unstable and tend ot break apart into elements with lower atomic numbers while releasing a significant amount of energy
radioactive
_____ isotopes are often used to label or "tag" specific molecules and then follow their progress either in a chemical reaction or in living cells and tissues.
radioactive
by determining the _____ of the different isotopes of carbon in a sample, scientists are able to accurately determine the age of the sample
ratio
during a chemical reaction, the substances we start out with are called _______ and the substances we end up with are called
reactants and products
an atom participating in a chemical reaction gains one or more electrons. The process of gaining electrons in a reaction is called
reduction
typically, fats found in animals (usually solid) are _____, while fats found in plants (usually liquid) are ____
saturated unsaturated
A hydrogen ion, formed during the disassociation of water, has a charge of which of the following.
+1
which of the following are functions of proteins
they play a key role in moving materials within a cell they catalyze chemical reactions they help the body recognize and destroy foreign microbes and cancer cells they transport oxygen in the blood of vertabrates
during proper base pairing in DNA, adenine pairs with _____ and cytosine pairs with ______
thymine guanine
the purpose of microscopes can best be described as
to allow for visualization of cells and cellular components
the role of the nucleolus is
to produce ribosomal subunits
which type of RNA carries amino acids
transfer
the diffusion of these molecules across a selectivley permeable membrane is called osmosis
water
the most abundant molecule in the cytoplasm is the ____ molecule
water
the surface tension of water is due to which reason
water molecules attract each other
how are ions formed
when atoms lose or gain one or more electrons
the _____ are cellular organelles, which use chemical energy stored within the covalent bonds of organic molecules to produce ATP
mitochondria
which of the following amounts of a substance has a weight in grams equal to the combined atomic masses of all atoms that make up on basic unit of the substance?
mole
one ___ of sucrose contains 6.02 x 10 23 _____ of sucrose
mole and molecules
the simplest carbohydrates are
monosaccharides
a fatty acid with one carbon to carbon double bond is _____ while a fatty acid with two or more carbon to carbon double bonds is _____
monounsaturated polyunsaturated
electrons that are farther from the nucleus always have which of the following
more potential energy
which of the following are acurate statements concerning bacterial flagella
movement is powered by a proton gradient they propel cells forward
which of the following involves active transport
movement of a substance against its own concentration gradient
water carries two partial _____ charges on the oxygen atom and two partial ______ charges, one on each hydrogen atom
negative positive
Isotopes differ in the number of _____ they contain
neutrons
a ____ covalent bond involves and equal sharing of one or more pairs of electrons
non polar
almost all the mass of an atom is located in
nucleus
how do channel and carrier proteins differ
only carrier proteins actually bind to the substance being transprorted only carrier proteins can be used for active transport
match the bases that pair in DNA molecules.
A adenine-thymine B guadine-cytosine
the production of proteins is achieved by
ribosomes
Match each subatomic particle with its electrical charge.
+1, proton 0, nuetron -1, electron
A hydroxide ion has a charge of which of the following?
-1
A group of atoms held together by one or more covalent
...
which of the following describes passive transport
...
a single water molecule can spontaneously break apart (ionize) to form
1 positive hydrogen ion and one negative hydroxide ion
transport that requires a cell to expend some of its own energy, typically from _____,is called _____transport
ATP active
identify the fibers that are used in the cell division of animals
Actin microtubles
how are starch and cellulose SIMILAR
Both are polysaccharides Both are found in plants
what are the 3 major structural components of an amino acid?
Carboxyl group r group amino group
regarding the chemical nature of nitrogenous bases in DNA, which of the following are CORRECTLY matched
Cytosine-pyrimidine Adenine-purine
This molecule stores the genetic code within a given cell
DNA
which of the following molecules have the ability to serve as templates to produce precise copies of themselves
DNA
in living organisms, molecules of _______ are used to store and transmit the genetic information from one generation to the next, while molecules of _______ use the genetic information to actually assemble proteins
DNA RNA
identify the two major classed of nucleic acids
DNA and RNA
describe the structure of DNA
DNA is a double stranded molecule that forms a double helix when the 2 strands wind around one another.
This type of subatomic particle can be found at various distances from the nucleous
Electron
Which of the following are subatomic particles?
Electrons, Neutrons, and Protons
In living systems, which of the following catalyze almost every chemical reaction necessary for life
Enzymes
typically, as the temperature increases, what happens to the rate of a chemical reaction?
It also increases
the 4 main groups of biological micromolecules are
Nucleic acids lipids proteins carbohydrates
Water molecules are attracted to polar molecules, because polar molecules have regions that carry a ________ electrical charge.
Partial
what are the 3 basic components of a nucleotide
Pentose sugar phosphate group nitrogenous base
carbon-oxygen and carbon-nitrogen bonds are described as
Polar covalent formed by an unequal sharing of electrons
how is the crystal structure of salt formed
Positively charged sodium ions are attracted to negatively charged chloride ions
The 3 main types of subatomic particles are
Protons neutrons electrons
All electrically nuetral atoms contain one or more of the following
Protons and electrons
which of the following statements about lipid structure is true?
Steriods are composed of interlocking carbon rings while fats are composed of glycerol and fatty acids. Fats are more similiar in structure to phospholipids than they are to steriods Phospholipids have distinct polar and nonpolar regions Although they may have small polar regions, lipids are mostly nonpolar
triglycerides and phospholipids are similiar because they both have
a backbone derived fri glycerol
which of the following accurately describes the chemical structure of a typical amino acid found in a protein?
a central carbon atom is bound to an amino group, carboxyl group, a side chain and hydrogen atom
when a carbohydrate is formed by linking 2 monosaccarides by a condensation reaction, we get water plus
a disaccharide
which of the following could be the result of a deficiency in chaperons proteins
a disease caused by improper folding of proteins
a defining feature of biological membranes is the presence of
a lipid bilayer
which of the following may occur during a chemical reaction?
existing chemical bonds are broken atoms are transferred from one molecule to another new types of molecules are formed new chemical bonds are formed
which of the following is not one of the 4 main components of all plasma membranes
extracellular matrix
which structure forms a protective layer rich in glycoproteins on the surface of cells
extracellular matrix
which of the following involve passive transport
facilitated diffusion diffusion
Most bacteria are able to cause disease
false
electrons are found in the atom's nucleus
false
the inner or the outer surface of the plasma membrane contain the same type of phospholipids, in similiar proportions
false
during photosynthesis, chloroplasts capture light energy and synthesize which of the following organic material
glucose
which regions of the phospholipid molecule are hydrophilic
glycerol backbone polar or charged molecule attached to the phosphate group phosphate group
which of the following molecules is likely to have the highest specific heat and the highest heat of vaporization
h2o
____ atoms usually have no neutrons
hydrogen
the lightest atom is
hydrogen
which of the following characteristics do lipids share in common
hydrophobic nonpolar
a protein is initially driven into its tertiary structure by ______ _____ of nonpolar groups from water.
hydrophobic exclusion
a catalyst is any substance that ____ the rate of a reaction without being altered itself.
increases
in living systems, ionic compounds generally exist as which of the following
individual ions
if an atom gains or loses electrons, it is known as
ion
unlike _____ bonds, which produce a crystal lattice, ____ bonds are formed between 2 individual atoms, giving rise to true, discrete molecules
ionic covalent
atoms in which the number of electrons does not equal the number of protons are called
ions
in cell membranes,the interior of the lipid layer repels _____
ions hydrophilic molecules polar molecules
organic molecules with the same molecular formula may exist in different forms called
isomers
if 2 solutions have the same concentration of solutes, they are
isotonic
what does it mean when we say water is adhesive
it is attracted to other polar molecules and ions
which of the following statements about receptor-mediated endocytosis is true
its a type of bulk transportation it is used to transport ldls into the cell
which of the following determined the function of a protein molecule.
its shape
Double bonds between carbon atoms cause _____ in the hydrocarbon chains of fatty acids
kinks
when writing out structural formulas, covalent bonds are represented by solid ______ between atomic symbols
lines
Anything that has mass and occupies space is defined as
matter
Regular and repeated patterns of coiling or folding within a polypeptide chain that are due to hydrogen bonding between polar groups within the polypeptide backbone make up which level of the proteins structure
secondary
which of the following statements about orbitals is true
several different orbitals may occupy the same energy level Each orbital contains a maximum of 2 electrons They have a variety of 3d shapes that indicate where an electron is most likely to be found
which of the following about channel proteins is not true
some channel proteins use energy from ATP to facilitate net movement of a substance up its concentration gradient
suppose the concentration of oxygen is higher outside of the cell than inside. which of the following is true
some oxygen molecules will move into the cell the net movement of oxygen will be into the cell some oxygen molecules will move out of the cell
substances that can not easily cross the lipid bilayer can still diffuse across the plasma membrane with the help of
specific channel or carrier proteins
the amount of heat 1g of a substance must absorb or lose to change its temperature by 1 c is called
specific heat
match each plolysaccharide with its function
starch-the main storage polysaccharide in plants cellulose-the main structural polysaccharide in plants chitin-a structural polysaccharide in arthropods and fungi glycogen-the main storage polysaccharide in animals
individual polypeptides within a protein are referred to as
subunits
because of the many hydrogen bonds that form between its molecules, water has a very high _______ ______. this allows small insects to walk on water
surface tension
the ____ of a substance is a measure of how rapidly its individual molecules are moving
temperature
a proteins _____ structure refers to the final 3 D shape of the polypeptide chains that make up the protein
tertiary
Which of the following statements about proteins are true?
the ability of a protein to function depends on its 3 d shape Denatured proteins are usually biologically inactive The shape of a protein is affected by environmental conditions such as temperature, ph and ionic concentration
what is the definition of the heat vaporization of water
the amount of energy needed to change 1g of water from a liquid to a gas
the symbol (H+) means
the molar concentration of hydrogen ions
which regions of a phospholipid bilayer face water and which face the interior of the membrane away from the water
the polar regions face toward the water and the non polar regions face away from the water
what factors contribute to whether a fat is a solid or a liquid at room temperature
the presence of double bonded carbons in fatty acid hydrocarbon chains the degree of packing of fatty acid chains
where are the sugar-phosphate backbones and the nitrogenous bases located in the DNA double helix
the sugar phosphate backbones run along the outside of the double helix while the nitrogenous bases pair the middle
water rises inside a glass tube with narrow diameter for which reason
there are electrical charges on the surface of the glass
water is cohesive. Which describes the water molecules
they are attracted to each other
which of the following is a characteristic that ALL lipids share
they are largely insoluble in water
which of the following characteristics of lipids have in common
they are mostly nonpolar they are hydrophobic
what is the strength of individual hydrogen bonds that form between water molecules
they are very weak
choose all statements that describe phospholipids
they consist of glycerol joined to 2 fatty acids and a phosphate group they spontaneously form micelles or bilayers in water they have a polar head and two nonpolar tails
which describes steroids
they contain 4 interlocking rings they are lipids they are hydrophobic
how can cells allow large polar molecules to enter the cell
they enter through carrier proteins they can enter through channel proteins they can enter through endocytosis
characteristics of phospholipids include
they form the core of biological membranes
why are fats and oils more efficient for storing energy that carbohydrates or proteins
they have a higher ratio of energy storing C-H bonds
which describes most plant fats
they have one or more double bonds between the carbon atoms in the hydrocarbon chains they are liquid at room temperature they are unsaturated
which describes most animal fats
they have only single bonds in their hydrocarbon chains they are saturated they are solid at room temperature
which of the following statements about nonpolar molecules are true
they have the same number of protons and electrons the distribution of electrical charge is uniform they are electrically neutral
which describes steroids ?
they include certain hormones such as estrogen and testosterone they include cholesterol, an important component of animal cell membranes
