Biology Final
Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. What is the most probable genotype of each parent?
(a) Gg × Gg; (b) genotypic = 1:2:1, phenotypic = 3:1
When Mendel crossed yellow-seeded and green-seeded pea plants, all the offspring were yellow-seeded. When he took these F1 yellow-seeded plants and crossed them to green-seeded plants, what genotypic ratio was expected?
1:1
Somatic cells of roundworms have four individual chromosomes per cell. How many chromosomes would you expect to find in an ovum from a roundworm?
2
emerging viruses arise by
All of the above the spread of existing viruses more widely within their host species. mutation of existing viruses. the spread of existing viruses to new host species.
Generally, only female cats have the tortoiseshell phenotype for fur color. Which of the following statements explains this phenomenon?
A male inherits only one allele of the X-linked gene controlling hair color.
why is sequencing an entire genome, such as C. elegans, a nematode, important for genetic research?
A sequence that is found to have a particular function in the nematode is likely to have a closely related function in vertebrates
During elongation, which site in the ribosome represents the location where a codon is being read?
A site
what is the difference between an epidemic and a pandemic?
An epidemic is restricted to a local region; a pandemic is global.
Codons are three-base sequences that specify the addition of a single amino acid. How do eukaryotic codons and prokaryotic codons compare?
Codons are a nearly universal language among all organisms.
the central rule of molecular biology states that ________
DNA is transcribed into RNA, which is translated into protein
Why does a new DNA strand elongate only in the 5' to 3' direction during DNA replication?
DNA polymerase can add nucleotides only to the free 3' end.
the final step in a Sanger DNA sequence reaction is to run the DNA fragments on a gel. What purpose does this serve?
It separates DNA fragments generated during the sequencing reaction based on one-nucleotide differences in their size.
what is the function of reverse transcriptase in retroviruses?
It uses viral RNA as a template for DNA synthesis.
if an animal cell suddenly lost the ability to produce GTP, what might happen to its signaling system?
It would not be able to activate G proteins on the cytoplasmic side of the plasma membrane.
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
Hydrangea plants of the same genotype are planted in a large flower garden. Some of the plants produce blue flowers and others pink flowers. This can be best explained by which of the following?
Environmental factors such as soil pH
DNA methylation and histone acetylation are examples of which of the following processes?
Epigenetic phenomena
In his transformation experiments, what phenomenon did Griffith observe?
Mixing a heat-killed pathogenic strain of bacteria with a living nonpathogenic strain can convert some of the living cells into the pathogenic form.
which electron carrier(s) function in the citric acid cycle?
NADH and FADH2
What is an adaptive advantage of recombination between linked genes?
New allele combinations are acted upon by natural selection.
if carbon-14 labeled uracil is added to the growth medium of cells, what macromolecules will be labeled?
RNA
In eukaryotes there are several different types of RNA polymerase. Which type is involved in transcription of mRNA for a globin protein?
RNA polymerase II
For a repressible operon to be transcribed, which of the following conditions must occur?
RNA polymerase must bind to the promoter, and the repressor must be inactive.
How does extracellular glucose inhibit transcription of the lac operon?
Reducing the levels of intracellular cAMP
how do transposons and retrotransposons differ in how they move around in a genome?
Retrotransposons move via an RNA transcript, whereas other transposons do not.
in large scale, genome-wide association studies in humans, what types of genetic markers do researchers look for?
SNPs where one allele is found more often in persons with a particular disorder than in healthy controls
The reason for differences in the sets of proteins expressed in a nerve and a pancreatic cell of the same individual is that nerve and pancreatic cells contain different ________.
Sets of regulatory proteins
How does natural selection apply to sexual reproduction as opposed to asexual reproduction?
Sexual reproduction results in many new gene combinations, some of which will lead to differential reproduction.
the receptors for steroid hormones are located inside the cell instead of the membrane surface like most other signal receptors. How do steroids gain access to their receptors?
Steroid hormones are lipid soluble, so they can readily diffuse through the lipid bilayer of the cell membrane.
What is meant by the description "antiparallel" regarding the two strands that make up the DNA double helix?
The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand.
what information is critical to the success of polymerase chain reaction (PCR) itself?
The DNA sequence of the ends of the DNA to be amplified must be known.
a mutation that knocks out the GTPase activity of a G protein would have what effect on a cell?
The G protein would always be active
When Thomas Hunt Morgan crossed his red-eyed F1 generation flies to each other, the F2 generation included both red- and white-eyed flies. Remarkably, all the white-eyed flies were male. What was the explanation for this result?
The gene involved is on the X chromosome.
According to the lac operon model proposed by Jacob and Monod, what is predicted to occur if the operator is removed from the operon?
The lac operon would be transcribed continuously.
the difference between vertical and horizontal transmission of plant viruses is that vertical transmission is __________.
Vertical transmission is transmission of a virus from a parent plant to its progeny,and horizontal transmission is one plant spreading the virus to another plant.
the first cloned cat, called Carbon Copy, was a calico, but she looked significantly different from her female parent. why was this the case with this clone?
X inactivation in the embryo is random and produces different patterns.
which domains of life are classified as prokaryotes?
bacteria and archaea
a principal problem with inserting an unmodified mammalian gene into a plasmid and then getting that gene expressed in bacteria is that _____.
bacteria cannot remove eukaryotic introns.
The bulldog ant has a diploid number of two chromosomes. Therefore, following meiosis, each daughter cell will have a single chromosome. In addition to mutations, how might genetic diversity be generated in this species?
crossing over and independent assortment
cells are ______
characteristic of prokaryotic and eukaryotic organisms
The anticodon of a particular tRNA molecule is _____.
complementary to the corresponding
water molecules can form hydrogen bonds with ______.
compounds that have polar covalent bonds
cilia and flagella bend because of __________.
a motor protein called dynein
in the formation of biofilms, such as those forming on unbrushed teeth, cell signaling serves which function?
aggregation of bacteria that can cause cavities
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
which kind of metabolic poison would most directly interfere with glycolysis?
an agent that closely mimics the structure of glucose but is not metabolized
in the form of gene therapy used successfully for severe combined immunodeficiency syndrome, SCID-XI, how is the genetic engineering of human cells achieved?
isolating the patient's bone marrow cells, infecting them with genetically engineered viruses, and injecting them back into the patient's bone marrow
why is carbon so important in biology?
it can form a variety of carbon skeletons and host functional groups
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
what are scaffolding proteins?
large molecules to which several relay proteins attach to facilitate cascade effects
why is sequencing of eukaryotic genomes more difficult than sequencing genomes of bacteria or archaea?
large size of eukaryotic genomes and the large amount of eukaryotic repetitive DNA
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
Translation requires _____.
mRNA, tRNA, and rRNA
Translation directly involves _____.
mRNA, tRNA, ribosomes, and GTP
Why are males more often affected by sex-linked traits than females?
males are hemizygous for the X chromosome.
humans can digest starch but not cellulose because _________.
humans have enzymes that can hydrolyze the alpha-glycosidic linkages of starch but not the beta-glycosidic linkages of cellulose
The fact that plants can be cloned from somatic cells demonstrates that ________.
differentiated cells retain all the genes of the zygote
cooking oil and gasoline are not amphipathic molecules because they ___________.
do not have a polar or charged region
a chemical reaction that has a positive △G is best described as _________.
endergonic
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
bioinformatics can be used to scan for short sequences that specify known mRNAs, called ________.
expressed sequence tags
one of the primary functions of RNA molecules is to _______.
function in the synthesis of proteins
the process by which the information in a gene direct the synthesis of a protein is called _____
gene expression
characters are transmitted from parents to offspring. _______ are the units of inheritance.
genes
in plant cells, the middle lamella __________.
glues adjacent cells together
which metabolic pathway is common to both fermentation and cellular respiration of a glucose molecule?
glycolysis
a controlled experiment ______.
includes at least two groups, one of which does not receive the experimental treatment
In comparing DNA replication with RNA transcription in the same eukaryotic cell, only DNA replication _____.
incorporates the entire template molecule in the product
melting of ice and thus reduced feeding opportunities for polar bears is occurring because of the _______.
increase in CO2 and other greenhouse gasses in the atmosphere
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
why might using retroviral vectors for gene therapy increase the patient's risk of developing cancer?
integrate recombinant DNA into the genome in ways that misregulate the expression of genes at or near the site of integration
diffusion of ions across membranes through specific ion channels is driven by ________.
ion electrochemical gradients
the label on a container of margarine lists "hydrogenated vegetable oil" as the major ingredient. hydrogenated vegetable oil ________
is solid at room temperature
the sodium-potassium pump is called an electrogenic pump because it ___
is used to drive the transport of glucose against a concentration gradient
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
a localized group of organisms that belong to the same species is called a _____.
population
you disrupt all hydrogen bonds in a protein. what level of structure will be preserved?
primary structure
a cell with a predominance of rough endoplasmic reticulum is most likely ________.
producing large quantities of proteins for secretion
one of the major categories of receptors in the plasma membrane functions by forming dimers, adding phosphate groups, and then activating relay proteins. which type does this?
receptor tyrosine kinases
when a molecule of NAD+ gains a hydrogen atom, the molecule becomes ________.
reduced
a current view of how the human and chimpanzee can share most of their nucleotide sequences yet exhibit significant phenotypic differences is that many of the most important sequence differences alter _______.
regulatory sequences
It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information. Which of the following characteristics of DNA is responsible for this?
sequence of bases
In eukaryotic cells, transcription cannot begin until _____
several transcription factors have bound to the promoter
when a neuron responds to a particular neurotransmitter by opening gated ion channels, the neurotransmitter is serving as which part of the signal pathway?
signal molecule
Meiosis II is similar to mitosis in that
sister chromatids of each chromosome separate.
what kinds of molecules pass through a cell membrane most easily?
small and hydrophobic
Crossing over of chromosomes normally takes place during which of the following processes?
meiosis I
Independent assortment of chromosomes is a result of which of the following processes?
meiosis I only
the voltage across a membrane is called the _________.
membrane potential
water has many exceptional and useful properties. which is the rarest property among compounds?
solid water is less dense than liquid water
why are hydrocarbons insoluble in water?
the majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages
the host range of a virus is determined by ______.
the proteins on its surface and that of the host.
There are sixty-one mRNA codons that specify an amino acid, but only forty-five tRNAs. This is best explained by the fact that _____.
the rules for base pairing between the third base of a codon and tRNA are flexible
what can proteomics reveal that genomics cannot?
the set of proteins present within a cell or tissue type
Imagine that there are 25 different species of protists living in a tide pool. Some of these species reproduce both sexually and asexually, and some of them can reproduce only asexually. The pool gradually becomes infested with disease-causing viruses and bacteria. Which species are more likely to thrive in the changing environment?
the sexually reproducing species
organic chemistry is currently defined as
the study of carbon compounds
In E. coli, what is the function of DNA polymerase III?
to add nucleotides to the 3' end of a growing DNA strand
in 1997, Dolly the sheep was cloned. which of the following processes was used?
transfer of an adult cell's nucleus into an enucleated sheep egg, followed by incubation in a surrogate
what is a primary function of integrins?
transmitting signals from the extracellular matrix to the cytoskeleton
cells require which of the following to form cilia or flagella?
tubulin
Albinism is a recessive trait. A man and woman who both have normal pigmentation have one child out of three who has albinism (without melanin pigmentation). What are the genotypes of this child's parents?
1/4
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
measurements show that the pH of a particular lake is 4.0. what is the hydroxide ion concentration of the lake?
10^-10 M
an ion with 6 protons, 7 neutrons, and a charge of 2+ has an atomic number of
18
in carbohydrates, the ratio of hydrogen to oxygen is _______.
2:1
Quaking aspen trees can send out underground stems for asexual reproduction. Sexual reproduction is not as common, but when it does happen, the haploid gametes have 19 chromosomes. How many chromosomes are in the cells of the underground stems?
38
Skin color in a certain species of fish is inherited by a single gene with four different alleles. How many different types of gametes would be possible in this organism?
4
how many electrons does one atom of carbon share to complete its valence shell?
4
How many unique gametes could be produced through independent assortment by an individual with the genotype AaBbCCDdEE?
8
When taken up by a cell, which of the following molecules binds to a repressor so that the repressor no longer binds to the operator?
A Inducer
why is it so important to be able to amplify DNA fragments when studying genes?
A gene may represent only a millionth of the cell's DNA
in recent times, it has been shown that adult cells can be induced to become pluripotent stem cells (iPS). to make this conversion, what has been done to the adult cells?
A retrovirus is used to introduce four specific regulatory genes.
How does termination of translation take place?
A stop codon is reached
Altering patterns of gene expression in prokaryotes would most likely serve an organism's survival by ________.
Allowing an organism to adjust to changes in environmental conditions
An obstetrician knows that one of her patients is a pregnant woman whose fetus is at risk for a serious disorder that is detectable biochemically in fetal cells. The obstetrician would most reasonably offer which of the following procedures to her patient?
Amniocentesis
Under what conditions does the trp repressor block transcription of the trp operon?
Binds to tryptophan
why might the cricket genome have eleven times as many base pairs as that of Drosophila melanogaster?
Crickets must have more noncoding DNA.
In DNA replication, the resulting daughter molecules contain one strand of the original parental DNA and one new strand. What is the explanation for this phenomenon?
DNA contains the template needed to copy itself but it has no catalytic activity in cells
what is the most favorable characteristic of retroviruses that makes them useful in gene therapy applications?
DNA copies of retroviral genomes become integrated into the genome of the infected cell.
In colorectal cancer, several genes must be mutated for a cell to develop into a cancer cell. Which of the following kinds of genes would you expect to be mutated?
Genes involved in control of the cell cycle
The somatic cells of a privet shrub each contain a total of 46 chromosomes. How do the chromosomes of this plant differ from the chromosomes of humans, who also have a total of 46?
Genes of privet chromosomes are significantly different than those in humans.
why do scientists consider HIV to be an emerging virus?
HIV suddenly became apparent and widespread in the 1980s.
How does the enzyme telomerase meet the challenge of replicating the ends of linear chromosomes?
It catalyzes the lengthening of telomeres, compensating for the shortening that occurs during replication.
What is the role of DNA ligase in the elongation of the lagging strand during DNA replication?
It joins Okazaki fragments together
Who performed classic experiments that supported the semiconservative model of DNA replication?
Meselson and Stahl
will treating a viral infection with antibiotics affect the course of the infection?
No; antibiotics work by inhibiting enzymes specific to bacteria. Antibiotics have no effect on eukaryotic or virally encoded enzymes.
After the first replication was observed in their experiments testing the nature of DNA replication, Meselson and Stahl could be confident of which of the following conclusions?
Replication is not conservative.
A human cell containing 22 autosomes and a Y chromosome is
Sperm cell
humans have 23 pairs of chromosomes, and chimps have 24 pairs of chromosomes. what is the most likely explanation for these differences in human and chimp genomes?
The common ancestor of humans and chimps had twenty-four pairs of chromosomes. After the two groups evolved, two human chromosomes fused end to end
Hutchinson-Gilford progeria is an exceedingly rare human genetic disorder in which there is very early senility and death, usually from coronary artery disease, at an average age of 13 years. Patients, who look very old even as children, do not live to reproduce. Which of the following statements represents the most likely assumption regarding this disorder?
The disorder may be due to mutation in a single protein-coding gene.
the first class of antiviral drugs developed to treat HIV infection, such as AZT, were known as reverse transcriptase inhibitors. How did these drugs carry out their functions?
The drug molecules bonded to the viral reverse transcriptase enzyme, thus preventing the virus from making a DNA copy of its RNA genome.
HIV is inactivated in the laboratory after a few minutes of sitting at room temperature, but the flu virus is still active after sitting for several hours. What are the practical consequences of these findings?
The flu virus can be transmitted more easily from person to person than HIV.
Map units on a linkage map cannot be relied upon to calculate physical distances on a chromosome for which of the following reasons?
The frequency of crossing over varies along the length of the chromosome.
In an experimental situation, a student researcher inserts an mRNA molecule into a eukaryotic cell after she has removed its 5' cap and poly-A tail. Which of the following would you expect her to find?
The molecule is digested by enzymes because it is not protected at the 5' end.
what does it mean to say that a signal is transduced?
The physical form of the signal changes as it passes from the cell membrane to the ultimate intracellular target.
a researcher lyses a cell that contains nucleic acid molecules and capsomeres of tobacco mosaic virus (TMV). the cell contents are left in a covered test tube overnight. the next day this mixture is sprayed on tobacco plants. what would you expect to happen to the plants that were sprayed with the mixture?
The plants would develop the typical symptoms of TMV infection.
What does a recombination frequency of 50% indicate?
The two genes are likely to be located on different chromosomes.
viruses use the host cell's machinery to make copies of themselves. however, some human viruses require a type of replication that humans do not normally have. for example, humans normally do not have the ability to convert RNA into DNA. how can these types of viruses infect humans, when human cells cannot perform a particular role that the virus requires?
The viral genome codes for specialized enzymes not found in the host cells.
why is it more difficult to identify eukaryotic genes than prokaryotic genes using genomic techniques?
There are introns in eukaryotic genes.
how have DNA microarrys made a huge impact on genomic studies?
They allow the expression of many or even all of the genes in a genome to be compared at once.
what role do phosphatases play in signal transduction pathways
They inactivate protein kinases to turn off signal transduction.
One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this type of chromosomal alteration called?
Translocation.
all the organisms on your campus make up _____.
a community
For a species with a haploid number of 23 chromosomes, how many different combinations of maternal and paternal chromosomes are possible for the gametes based on the independent assortment of chromosomes during meiosis?
about 8 million
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 humans, clear gender differentiation occurs not at fertilization, but after the second month of gestation. Which of the following statements describes the first event of this differentiation?
activation of SRY in male embryos and masculinization of the gonads
for a protein to be an integral membrane protein, it would have to be _______.
amphipathic, with at least one hydrophobic region
phosphorylation cascades involving a series of protein kinases are useful for cellular signal transduction because they ________.
amplify the original signal many times
A ribozyme is _____.
an RNA with catalytic activity
atoms have no electric charge because they have _______.
an equal number of protons and electrons
Mendel's observation of the segregation of alleles in gamete formation has its basis in which of the following phases of cell division?
anaphase 1
in comparison to eukaryotes, prokaryotes _______.
are smaller
the left to right order of elements in the periodic table is based on their _________
atomic number
Ribosomes can attach to prokaryotic messenger RNA _____.
before transcription is complete
in yeast signal transduction, a yeast cell releases a mating factor, which ____________
binds to receptors on the membranes of other types of yeast cells
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
amino acids are acids because they always possess _______ as the functional group?
carboxyl
which 2 functional groups are always found in amino acids?
carboxyl and amino groups
an animal cell lacking carbohydrates on the external surface of its plasma membrane would likely be impaired in which function?
cell-cell recognition
which organelle often takes up much of the volume of a plant cell?
central vacuole
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
a(n) ______ has charge but negligible mass, whereas a(n) ______ has mass but no charge.
electron; neutron
Van der Waals interactions may result when _______.
electrons are not asymmetrically distributed in a molecule
why has C. elegans proven to be a useful model for understanding apoptosis?
elegans undergoes a fixed and easy-to-visualize number of apoptotic events during its normal development.
Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S, have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a second gene, N, determines whether or not cacti have spines. Homozygous recessive nn cacti have no spines at all. The relationship between genes S and N is an example of which of the following inheritance patterns?
epistasis
why do hydrolysis reactions occur more readily in solution than dehydration reactions?
hydrolysis reactions are exergonic and increase entropy of the system
after finding a new medicinal plant, a pharmaceutical company decides to determine if the plant has genes similar to those of other known medicinal plants. what would annotation of the genome of this plant allow the company to determine?
identify genes and determine their functions
the kind and number of bonds an atom can form depends on ________
its electron configuration
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
where are the proteins of the electron transport chain located?
mitochondrial inner membrane
which organelle is the primary site of ATP synthesis in eukaryotic cells?
mitochondrion
All female mammals have one active X chromosome per cell instead of two. What causes this to happen?
modification of the XIST gene so that it is active only on one X chromosome, which then becomes inactive
you are asked to indicate the type and number of atoms in a molecule. which representation would work best?
molecular formula
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
in humans, the embryonic and fetal forms of hemoglobin have a higher affinity for oxygen than that of adults. Why is this the case?
nonidentical genes that produce different versions of globins during development.
bonds between two atoms that are equally electronegative are ________.
nonpolar covalent bonds
hydrophobic substances such as vegetable oil are ______.
nonpolar substances that repel water molecules
A woman is found to have 47 chromosomes, including three X chromosomes. Which of the following statements describes her expected phenotype?
normal female
Mendel continued some of his experiments into the F2 or F3 generation in order to ________.
observe whether or not a recessive trait would reappear
Why did all of the F1 offspring of Mendel's classic pea cross always look like one of the two parental varieties?
one allele was dominant
Radish flowers may be red, purple, or white. A cross between a red-flowered plant and a white-flowered plant yields all-purple offspring. The flower color trait in radishes is an example of which of the following inheritance patterns?
purple and long
a virus consisting of a single strand of RNA, which is reverse transcribed into complementary DNA, is referred to as a ______.
retrovirus
What molecules in the spliceosome catalyze the intron removal reactions?
ribozymes
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
a population of viruses with similar characteristics is called a _________.
strain/class
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
which branch of biology is concerned with the naming and classifying of organisms
taxonomy
A controlled experiment is one that
test experimental and control groups in parallel
In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer?
the 3' OH
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
in the term trace element, the adjective trace means that ______.
the element is required in very small amounts
What are telomeres?
the ends of linear chromosomes
what happens to glucose molecule when it loses a hydrogen atom as the result of an oxidation-reduction reaction?
the glucose molecule is oxidized
Which molecule or reaction supplies the energy for polymerization of nucleotides in the process of transcription?
the phosphate bonds in the nucleotide triphosphates that serve as substrates
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
why are yeast cells frequently used as hosts for cloning?
they are eukaryotic cells
when are atoms most stable?
when all of the electron orbitals in the valence shell are filled
can the mass of an element vary?
yes. adding or losing neutrons will change the atomic mass without forming a different element
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