The field of biological research in which biologists are attempting to create a living cell in the laboratory, essentially from scratch is known as __________. More modestly, this branch of biology also has a goal of developing novel life forms, beginning with existing organisms, that have a unique value in medicine, industry or in cleaning up the environment.

synthetic biology

What factor or factors discovered with electron microscopy distinguished prokaryotic from eukaryotic cells?

their size and the types of their internal structures or organelles

The genetic material of a prokaryotic cell is present in a _________, a poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm.

nucleoid

Despite being correct about the first two tenets of the Cell Theory, Schleiden and Schwann made an error about another central feature of cells. What was their error?

They both agreed that cells could arise from noncellular materials.

You are conducting an experiment by trying to reproduce the work performed in 1891 by Hans Driesch, a German embryologist. You are working with a fertilized sea urchin egg and allow it to complete the first cell division after fertilization. You then carefully separate the two cells of the embryo and allow their development to continue. Based on Driesch's experiment, which result below would you expect to happen?

Both cells develop into complete and normal embryos that are somewhat smaller.

Which of the following is not a model organism?

Homo sapiens

Which of the following statements about viruses is not true?

Viruses are obligatory intercellular parasites.

What characteristics distinguish prokaryotic and eukaryotic cells?

All of choices are correct.

Viruses like adenovirus, which causes respiratory infections in mammals, have a 20-sided polyhedral capsid.  What is this polyhedral shape called?

icosahedron

Studies on mice suggest that bacterial species predominating in obese individuals differ from those in the digestive tracts of lean individuals and that they play a role in weight gain in obese individuals.  Guess what these bacteria in obese individuals may be doing that increases weight gain in obese individuals?

The bacteria in obese individuals may release more calories from digested food than their counterparts in leaner individuals.

Which of the following are considered to be eukaryotes?

All of these choices are correct.

The first culture of human cells was begun by George and Martha Gey of Johns Hopkins University in 1951.  The cells were obtained from a malignant tumor and named ______ cells after the donor, _________.

HeLa, Henrietta Lacks

The process by which a relatively unspecialized cell becomes highly specialized is called _______.

Differentiation

The genetic material of a prokaryotic cell is present in a _________, a poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm.

nucleoid

Who is generally credited with the discovery of cells?

Hooke

What factor or factors discovered with electron microscopy distinguished prokaryotic from eukaryotic cells?

their size and the types of their internal structures or organelles

What characteristics distinguish prokaryotic and eukaryotic cells?

All of choices are correct.

Which of the following characteristics is(are) not a basic property of cells?

Cells carry out a variety of emotional reactions.

Cyanobacteria are obviously capable of photosynthesis, but many of them also convert nitrogen gas into reduced forms of nitrogen (such as ammonia) that can be used by cells in the synthesis of nitrogen-containing organic compounds, including amino acids and nucleotides. This process is called ______.

nitrogen fixation

Despite being correct about the first two tenets of the Cell Theory, Schleiden and Schwann made an error about another central feature of cells. What was their error?

They both agreed that cells could arise from noncellular materials.

Bacteria will often pass a piece of DNA from a donor bacterial cell to a recipient bacterial cell presumably through a structure called a pilus. What is this process called?

conjugation

The genetic material of a prokaryotic cell is present in a _________, a poorly demarcated region of the cell that lacks a boundary membrane to separate it from the surrounding cytoplasm.

nucleoid

Studies on mice suggest that bacterial species predominating in obese individuals differ from those in the digestive tracts of lean individuals and that they play a role in weight gain in obese individuals. Guess what these bacteria in obese individuals may be doing that increases weight gain in obese individuals?

The bacteria in obese individuals may release more calories from digested food than their counterparts in leaner individuals.

Which of the following are considered to be eukaryotes?

All of these choices are correct.

The process by which a relatively unspecialized cell becomes highly specialized is called _______.

differentiation

Which of the following is not typically a behavior exhibited by a cell with a proviral infection?

Immediate production of new viruses and subsequent lysis of the host cell.

The most stable atoms and thus those that are typically nonreactive are the atoms that have _______.

full outer shells

What kind of organism reaches equilibrium?

a dead organism

Doubling the concentration of enzyme will ______ the V_max
and _____ the K_M.

double, not alter

Under which circumstances would electrons be most likely to be shared equally?

when atoms of the same element are sharing them

The most electronegative atoms typically present in biological molecules are ____ and ____.

O, N

Enzymes work by ___________.

lowering the activation energy of a reaction and thus speeding up the reaction.

What is the effect of a competitive inhibitor on an enzyme-mediated reaction?

V_max stays the same, K_M increases

What kind of interaction is not involved in the binding of a substrate to a normally functioning enzyme?

a permanent covalent bond

Under which circumstances would electrons be most likely to be shared equally?

when atoms of the same element are sharing them

Metabolic pathways that make available raw materials from which other molecules can be synthesized and that provide chemical energy required for many cell activities are known as ______.

catabolism

Proteins are dynamic molecules that are capable of ________ motion that can have important functional relevance. The existence of this type of motion has suggested that enzymes are capable, even in the absence of substrate, of many of the same movements that can be detected during their catalytic cycle.

intrinsic and built-in

A release of hydrogen ions to a solution would most likely ____________.

lower pH

The low-molecular-weight building blocks of polymers are called _______.

monomers

What is the effect of a competitive inhibitor on an enzyme-mediated reaction?

V_max stays the same, K_M increases

Why are free ionic bonds of little importance and relatively unlikely to form in living organisms?

Cells are composed mostly of water, which interferes with ionic bonds between free ions.

Doubling the concentration of enzyme will ______ the V_max
and _____ the K_M.

double, not alter

Which of the following is a nucleotide?

adenine + ribose + phosphate

What kind of bond results from an unequal sharing of electrons?

polar covalent bond

Which of the following is not a model organism?

Homo sapiens

Despite being correct about the first two tenets of the Cell Theory, Schleiden and Schwann made an error about another central feature of cells. What was their error?

they both agreed that cells could arise from noncellular materials.

Which of the following is not typically a behavior exhibited by a cell with a proviral infection?

Immediate production of new viruses and subsequent lysis of the host cell.

The apical ends of intestinal cells face the intestinal channel and have long extensions that facilitate the absorption of nutrients. What is the name of these extensions and what cytoskeletal element forms their internal skeleton?

microvilli, actin filaments

The first compound light microscopes were constructed by the end of the sixteenth century. What is a compound microscope?

It has two lenses.

Which of the following statements about viruses is NOT true?

Viruses are obligatory intercellular parasites.

Studies on mice suggest that bacterial species predominating in obese individuals differ from those in the digestive tracts of lean individuals and that they play a role in weight gain in obese individuals. Guess what these bacteria in obese individuals may be doing that increases weight gain in obese individuals?

The bacteria in obese individuals may release more calories from digested food than their counterparts in leaner individuals.

Which of the following characteristics is(are) not a basic property of cells?

Cells carry out a variety of emotional reactions.

Cyanobacteria are obviously capable of photosynthesis, but many of them also convert nitrogen gas into reduced forms of nitrogen (such as ammonia) that can be used by cells in the synthesis of nitrogen-containing organic compounds, including amino acids and nucleotides. This process is called ______.

nitrogen fixation

In some cases, an infecting virus does not lead to the death of the host cell, but instead integrates its DNA into the DNA of the host cell's chromosomes. Integration of the viral DNA can have different effects like exhibiting normal behavior until exposure to a stimulus that activates the dormant viral DNA, production of viral progeny that bud off of the infected cell or a loss of control over growth and division leading to malignancy. Such an infection is referred to as a(n) ______ infection.

proviral

Where are hydrophobic interactions most likely to occur?

the core of a water-soluble protein

Proteins are dynamic molecules that are capable of ________ motion that can have important functional relevance. The existence of this type of motion has suggested that enzymes are capable, even in the absence of substrate, of many of the same movements that can be detected during their catalytic cycle.

intrinsic and built-in

The most electronegative atoms typically present in biological molecules are ____ and ____.

O, N

A reaction involving the gain of one or more electrons is a(n) _________ reaction.

reduction

Which of the following is a nucleotide?

adenine + ribose + phosphate

Which of the following is not a macromolecule formed by polymerization?

lipids

Under which circumstances would electrons be most likely to be shared equally?

when atoms of the same element are sharing them

What kind of noncovalent interaction is typified by interactions between two molecules that are so close together that they can experience weak attractive forces bonding them together?

van der Waals forces

Doubling the concentration of enzyme will ______ the V_max
and _____ the K_M.

double, not alter

How do amino acids like hydroxylysine and thyroxine, which are not among the 20 amino acids that are inserted into proteins, get into proteins?

They are the result of the alteration of R groups of the 20 amino acids after their incorporation into the polypeptide.

The low-molecular-weight building blocks of polymers are called _______.

monomers

Given the equation ΔG = ΔH - TΔS, which set of conditions would result in a reaction that is unambiguously nonspontaneous?

entropy decreases and the reaction is endothermic

The presently accepted model of enzyme action was proposed by Daniel Koshland in the 1960s and suggested that the enzyme was a flexible structure with an active site roughly complementary to the substrate that binds it. After its initial interaction with the substrate, the enzyme alters its shape and thus improves the fit of the substrate in the active site). What is the name of this model?

The Induced Fit model

Which property below is not a characteristic of enzymes?

They are required only in large amounts.

How do amino acids like hydroxylysine and thyroxine, which are not among the 20 amino acids that are inserted into proteins, get into proteins?

They are the result of the alteration of R groups of the 20 amino acids after their incorporation into the polypeptide.

What is the effect of a competitive inhibitor on an enzyme-mediated reaction?

Vmax stays the same, KM increases

The most stable atoms and thus those that are typically nonreactive are the atoms that have _______.

full outer shells

Which of the following is a nucleotide?

adenine + ribose + phosphate

Doubling the concentration of enzyme will ______ the Vmax

and _____ the KM.

double, not alter

Why are free ionic bonds of little importance and relatively unlikely to form in living organisms?

Cells are composed mostly of water, which interferes with ionic bonds between free ions.

What is caused by the inability of Na+ ion channels to open for several milliseconds after their inactivation?

a refractory period

Diffusion during which the substance to be transported binds selectively to a membrane-spanning protein, which helps the process along, is called ________.

facilitated diffusion

Where in a myelinated axon are nearly all of the ion channels concentrated?

nodes of Ranvier

Why did liposomes not work against diseases as hoped when they were first tried?

Immune system phagocytes removed them from the bloodstream before they could exert an effect.

A channel that opens in response to changes in ionic charge across a membrane is called a ________.

voltage-gated channel

What kind of membrane protein is found entirely outside the bilayer on either the extracellular or cytoplasmic surface? These proteins are covalently linked to a membrane lipid situated within the bilayer.

lipid-anchored protein

Which proteins move the farthest during SDS-polyacrylamide gel electrophoresis?

the smallest

Which of the following is not a function of membranes?

signal transition

Which of the following is not a potential biological role of the lipid asymmetry of the plasma membrane?

Phosphatidylserine on the surface of platelets serves as a signal for blood solubilization.

The ability, possessed by all organisms, to respond to external stimulation is known as _______.

irritability

Synaptic malfunction or dysfunction may cause which of the following diseases?

All of these are correct.

Where in a myelinated axon are nearly all of the ion channels concentrated?

nodes of Ranvier

Which of the following can be learned from a computer-based (computational) analysis of the amino acid sequence of a membrane protein, which can be readily deduced from the nucleotide sequence of its isolated gene?

both its structure and its orientation within the lipid bilayer

Impulse propagation by a myelinated axon is called ________ conduction.

saltatory

Which disease below is caused by the deterioration of the myelin sheath?

multiple sclerosis

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer?

both integral protein and transmembrane protein

Long-term potentiation is associated with NMDA receptors, one of several types of receptors that bind to the excitatory neurotransmitter _______. Its binding opens an internal cation channel within the receptor that allows _____ influx into the postsynaptic neuron, triggering a cascade of biochemical changes that lead to synaptic strengthening.

glutamate, Ca²⁺ ion

Which of the following is a function of membranes?

All of these are correct.

___________ is a process that strengthens certain synapses by repeated neuron stimulation over a short time period.

Long term potentiation

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer?

both integral protein and transmembrane protein

A transport system that moves one solute into the cell and another one out of the cell during a single cycle accompanied by the expenditure of energy through ATP hydrolysis could be called a(n) _______  .

active antiport

Why are the proteins being separated on an SDS polyacrylamide gel attracted equally to the positive electrode?

They carry a relatively uniform negative charge distribution.

Integral membrane proteins have been engineered to lack the portion that normally projects into the extracellular space. When the gene is inserted in cells, what happens to the mobility of this protein in the membrane?

They move at a much greater rate than the wild type protein.

What causes the refractory period in sodium channels after an action potential has been initiated? The sodium channel cannot be restimulated during this period.

The ion channel can only transform from the inactivated to the closed conformation after the inactivating peptide has swung out of the pore opening, and the sodium channels must close before they can be reopened in response to another stimulus.

What happens to phospholipid mobility when the cell is treated with agents that disrupt the underlying membrane skeleton?

Their mobility is increased because the fences that normally restrict their diffusion are removed.

The sodium-potassium pump makes the cell interior more ______ by pumping ____ sodium ions out of the cell for every ____ potassium ions pumped in.

negative, 3, 2

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer?

integral protein

What kind of membrane protein penetrates into the hydrophobic part of the lipid bilayer?

both integral protein and transmembrane protein

They are more gelated and highly ordered than the surrounding more fluid and disordered regions in artificial membranes that consist primarily of phosphoglycerides. They contain higher concentrations of sphingolipids and cholesterol and certain proteins become concentrated within them. What are they?

lipid rafts

A channel that opens in response to the binding of a specific molecule, which is usually not the solute that passes through the channel is called a ________.

ligand-gated channel

From what is the lipid-containing outer envelope surrounding the viral capsid of many animal viruses derived?

the plasma membrane

Glycolysis occurs in the _____, the Krebs (TCA) cycle occurs in the _____ of eukaryotes and the ______ of prokaryotes.

cytoplasm, mitochondria, cytoplasm

The energy stored in ATP is converted to mechanical energy that moves organelles around within the cell. This is an example of _______.

energy transduction

Proteins are often composed of two or more distinct modules that fold up independently of one another. They often represent parts of a protein that function in a semi-independent manner. These modules are called _______.

domains

In a living organism, where are ionic bonds most likely to be found?

deep in a protein's core where water is excluded

Which kind of bond results from an unequal sharing of electrons?

polar covalent bond

What property of membrane allows interactions to take place within the membrane, including the assembly of membrane protein clusters at particular sites and the formation of specialized structures?

membrane fluidity

What happens after a subthreshold depolarization?

no action potential

Why are integral membrane proteins difficult to study?

They are difficult to isolate in soluble form due to their hydrophobic transmembrane domains

______ trigger fusion of synaptic vesicles with the synaptic membranes of the presynaptic cell. This same stimulus also triggers ______.

Ca²⁺

ions, exocytosis

Why are viruses not considered to be organisms and not described as being alive?

Virions are unable to reproduce by themselves, Virions are not able to metabolize by themselves and Virions are not able to synthesize DNA by themselves

Which interaction is most important in enhancing the solubility of macromolecules in water?

H bonds

Entropy is associated with the _______ movement of particles of matter, which, because they are_______, cannot accomplish a directed work process.

random, random

What kind of enzyme adds phosphate groups to enzymes for the purpose of activating or deactivating them?

protein kinases

A molecule that is capable of releasing or donating a hydrogen ion (H⁺) is termed a(n) _______.

acid

Which site in a neuron receives incoming information from external sources?

Dendrites

You have fused a mouse cell and a human cell and then treated the cell with specific antibodies that are covalently linked to fluorescent dyes (antibodies to mouse proteins – green; antibodies to human proteins – red). What does the cell look like immediately after fusion?

The cell is half red and half green

A procedure in which the gene for an integral membrane protein is altered in such a way that the spatial relationships between some of the amino acids in the protein can be revealed is called ________.

site-directed mutagenesis

As an action potential is initiated, the membrane is ______. This is caused by the ____ of ____ ions.

depolarized, influx, Na+

Which part of a neuron conducts impulses away from the cell body toward the target cell(s)?

axon

How do Na+ ions enter a neuron when an action potential is initiated?

a voltage gated Na+ channel

How is a nerve impulse usually transmitted across a synapse from a presynaptic to a postsynaptic cell?

via a neurotransmitter

What word describes a molecule that contains both hydrophilic and hydrophobic portions?

amphipathic

How was the asymmetry of membrane lipids discovered?

Treatment of intact red blood cells with phospholipases.

Enzymes that move certain phospholipids between leaflets have also which of the following properties?

Play a role in establishing and maintaining membrane lipid asymmetry

The temperature at which a lipid bilayer shifts from a fluid state to a crystalline gel is called the ________.

transition temperature

When membrane lipids are extracted from cells and used to prepare artificial lipid bilayers, cholesterol and sphingolipids tend to self-assemble into _____ that are more gelated and highly ordered than surrounding regions consisting primarily of ________.

microdomains, phosphoglycerides

You modify the gene for an integral membrane protein so that the cytoplasmic portions of the protein are deleted. When the gene is inserted in cells, what happens to the mobility of this protein in the membrane?

They move much greater distances than the intact protein.

_____________ is a process that strengthens certain synapses by repeated neuron stimulation over a short time period.

Long term potentiation