midterm Flashcards
cells are _______
characteristic of prokaryotic and eukaryotic organisms
in comparison to eukaryotes, prokaryotes _______.
are smaller
a localized group of organisms that belong to the same species is called a _____.
population
when your body temperature rises on a hot day, the neural and hormonal mechanisms activate sweating. evaporation of sweat leads to cooling of the body surface. this is an example of _______.
negative feedback regulation
characters are transmitted from parents to offspring. _______ are the units of inheritance.
genes
the process by which the information in a gene direct the synthesis of a protein is called _____.
gene expression
which branch of biology is concerned with the naming and classifying of organisms?
taxonomy
you are suffering from Streptococcus throat infection. you share the following with the bacteria that is responsible for your condition.
you both are made up of cells
How does a scientific theory differ from a scientific hypothesis?
theories are usually an explanation for a more general phenomenon; hypotheses typically address more specific issues
the best experimental design _______.
includes a large sample size and a control, and alters only one condition between the controls and the experimental condition
a controlled experiment ______.
includes at least two groups, one of which does not receive the experimental treatment
all the organisms on your campus make up _____.
a community
A controlled experiment is one that
test experimental and control groups in parallel
why is a scientific topic best discussed by people of varying points of view, from different subdisciplines, and representing diverse cultures?
robust and critical discussion between diverse groups improved scientific thinking
trace elements are those required by an organism in only minute quantities. which of the following in a trace element that is required by humans and other vertebrates, but not by other organisms such as bacteria or plants?
iodine
atoms have no electric charge because they have _______.
an equal number of protons and electrons
an ion with 6 protons, 7 neutrons, and a charge of 2+ has an atomic number of _____.
6
a(n) ______ has charge but negligible mass, whereas a(n) ______ has mass but no charge.
electron; neutron
the left to right order of elements in the periodic table is based on their _________
atomic number
a neutral atom has 2, 8, and 8 electrons in its 1st, 2nd, and 3rd energy levels. this information ________.
does not tell us about the atomic mass of the element
can the mass of an element vary?
yes. adding or losing neutrons will change the atomic mass without forming a different element
when are atoms most stable?
when all of the electron orbitals in the valence shell are filled
a salamander relies on hydrogen bonding to stick to various surfaces. therefore, a salamander would have the greatest difficulty clinging to a ________.
surface of hydrocarbons
bonds between two atoms that are equally electronegative are ________.
nonpolar covalent bonds
what is the difference between covalent bonds and ionic bonds?
covalent bonds involve the sharing of electrons between atoms; ionic bonds involve the electrical attraction between charged atoms
the atomic number of chlorine is 17. the atomic number of magnesium is 12. what is the formula for magnesium chloride?
MgCl2
Van der Waals interactions may result when _______.
electrons are not asymmetrically distributed in a molecule
you are asked to indicate the type and number of atoms in a molecule. which representation would work best?
molecular formula
in the term trace element, the adjective trace means that ______.
the element is required in very small amounts
the reactivity of an atom arises from _____.
the existence of unpaired electrons in the valence shell.
the partial negative charge in a molecule of water occurs because ________.
the electrons shared between the oxygen and hydrogen atoms spend more time around the oxygen atom nucleus than around the hydrogen atom nucleus
water molecules can form hydrogen bonds with ______.
compounds that have polar covalent bonds
water has many exceptional and useful properties. which is the rarest property among compounds?
solid water is less dense than liquid water
a dietary Calorie equals 1 kilocalorie. one kilocalorie equals ______.
1000 calories, or the amount of heat required to raise the temperature of 1 kg of water by 1 degree C
hydrophobic substances such as vegetable oil are ______.
nonpolar substances that repel water molecules
melting of ice and thus reduced feeding opportunities for polar bears is occurring because of the _______.
increase in CO2 and other greenhouse gases in the atmosphere
carbon dioxide in the atmosphere dissolves with the raindrops. the pH of raindrops is ________.
slightly acidic
which of the following is a hydrophobic material?
wax
measurements show that the pH of a particular lake is 4.0. what is the hydroxide ion concentration of the lake?
10^-10 M
the element present in all organic molecules is _______
carbon
the kind and number of bonds an atom can form depends on ________
its electron configuration
why is carbon so important in biology?
it can form a variety of carbon skeletons and host functional groups
how many electrons does one atom of carbon share to complete its valence shell?
4
why are hydrocarbons insoluble in water?
the majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages
which 2 functional groups are always found in amino acids?
carboxyl and amino groups
amino acids are acids because they always possess _______ as the functional group?
carboxyl
organic chemistry is currently defined as
the study of carbon compounds
The difference between an aldose sugar and a ketose sugar is _________.
the position of the carbonyl group
what does the term insoluble fiber refer to on food packages?
cellulose
a molecule with the chemical formula C6H12O6 is probably a _________.
monosaccharide
in carbohydrates, the ratio of hydrogen to oxygen is _______.
2:1
humans can digest starch but not cellulose because _________.
humans have enzymes that can hydrolyze the alpha-glyosidic linkages of starch but not the bets-glyosidic linkages of cellulose
cooking oil and gasoline are not amphipathic molecules because they ___________.
do not have a polar or charged region
the label on a container of margarine lists “hydrogenated vegetable oil” as the major ingredient. hydrogenated vegetable oil ________
is solid at room temperature
the central rule of molecular biology states that ________.
DNA is transcribed into RNA, which is translated into protein
one of the primary functions of RNA molecules is to _______.
function in the synthesis of proteins
if carbon-14 labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?
RNA
you disrupt all hydrogen bonds in a protein. what level of structure will be preserved?
primary structure
which domains of life are classified as prokaryotes?
bacteria and archaea
which structure is common to plant and animal cells?
mitochondrion
what is the function of the nuclear pore complex found in eukaryotes?
it regulated the movement of proteins and RNAs into and out of the nucleus
a cell with a predominance of rough endoplasmic reticulum is most likely ________.
producing large quantities of proteins for secretion
which organelle often takes up much of the volume of a plant cell?
central vacuole
which organelle is the primary site of ATP synthesis in eukaryotic cells?
mitochondrion
cyanide binds with at least one molecule involved in producing ATP. if a cell is exposed to cyanide, most of the bound cyanide is likely to be localized within the _______.
mitochondria
cilia and flagella bend because of __________.
a motor protein called dynein
cells require which of the following to form cilia or flagella?
tubulin
what is a primary function of integrins?
transmitting signals from the extracellular matrix to the cytoskeleton
in plant cells, the middle lamella __________.
glues adjacent cells together
the liver is involved in detoxification of many poisons and drugs. which of the following structures is primarily involved in this process and, therefore, abundant in liver cells?
smooth endoplasmic reticulum
for a protein to be an integral membrane protein, it would have to be _______.
amphipathic, with at least one hydrophobic region
a phospholipid bilayer with equal amounts of saturated and unsaturated fatty acids displays a specific permeability to glucose. what effect will increasing the proportion of unsaturated fatty acids in the bilayer have on the membrane’s permeability to glucose?
permeability to glucose will increase
the membranes of winter wheat are able to remain fluid when it is extremely cold by ____________.
increasing the proportion of unsaturated phospholipids in the membrane
an animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function?
cell-cell recognition
what kinds of molecules pass through a cell membrane most easily?
small and hydrophobic
when a plant cell, such as one from a tulip leaf, is submerged in a hypertonic solution, what is likely to occur?
plasmolysis will shrink the interior of the cell
the sodium-potassium pump is called an electrogenic pump because it _________.
is used to drive the transport of glucose against a concentration gradient
the voltage across a membrane is called the _________.
membrane potential
diffusion of ions across membranes through specific ion channels is driven by ________.
ion electrochemical gradients
a decrease in entropy is associated with which type of reaction?
dehydration
a chemical reaction that has a positive △G is best described as _________.
endergonic
why do hydrolysis reactions occur more readily in solution than dehydration reactions?
hydrolysis reactions are exergonic and increase entropy of the system
which of the following molecules is most similar in structure to ATP?
an RNA nucleotide
when chemical, transport, or mechanical work is done by an organism, what happens to the heat generated?
it is lost to the environment
how does a noncompetitive inhibitor decrease the rate of an enzyme-catalyzed reaction?
by binding to an allosteric site, thus changing the shape of the active site of the enzyme
in addition to activating or inhibiting enzymes through allosteric regulation, what other means does a cell use to control enzymatic activity?
localization of enzymes into specific organelles or membranes
what happens to glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction?
the glucose molecule is oxidized
when a molecule of NAD+ gains a hydrogen atom, the molecule becomes ________.
reduced
the oxygen consumed during cellular respiration is directly involved in which of the following processes or events?
accepting electrons at the end of the electron transport chain
in glycolysis, for each molecule of glucose oxidized to pyruvate, __________
two molecules of ATP are used, and four molecules of ATP are produced
which kind of metabolic poison would most directly interfere with glycolysis?
an agent that closely mimics the structure of glucose but is not metabolized
which electron carrier(s) function in the citric acid cycle?
NADH and FADH2
where are the proteins of the electron transport chain located?
mitochondrial inner membrane
in chemiosmosis, what is the most direct source of energy that is used to convert ADP and inorganic phosphate to ATP?
energy released from movement of protons through ATP synthase, down their electrochemical gradient
approximately how many molecules of ATP are produced from the complete oxidation of one molecule of glucose in aerobic cellular respiration?
30-32
why is glycolysis considered to be one of the first metabolic pathways to have evolved?
it does not involve organelles or specialized structures, does not require oxygen, and it present in most organisms
high levels of citric acid inhibit the enzyme phosphofructokinase, a key enzyme in glycolysis. citric acid binds to the enzyme at a different location from the active site. this is an example of ________.
allosteric regulation
the immediate energy source that drives ATP synthesis by ATP synthase during oxidative phosphorylation is the ______.
H+ concentration gradient across the membrane holding ATP synthase
which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
glycolysis
the final electron acceptor of the electron transport chain that functions in aerobic oxidative phosphorylation is _____.
oxygen
