bio quizzes
Why do neurons and some other specialized cells divide infrequently?
They have entered into G0.
Cytokinesis:
refers to the division of a cell's cytoplasm.
Which of the following does not occur during mitosis?
replication of the DNA
Evolution through natural selection will occur most rapidly for populations of plants that
reproduce sexually and live in an unstable environment
If your hypothesis is "Hair that is shaved grows back coarser and darker," what is your null hypothesis?
There is no difference in the coarseness or color of hair that is shaved relative to hair that is not shaved.
Which statement is true regarding human sex chromosomes?
Which statement is true regarding human sex chromosomes?
Which of the following descriptions best fits the class of molecules known as nucleotides?
a nitrogenous base, a phosphate group, and a sugar
Through a microscope, you can see a cell plate beginning to develop across the middle of a cell and nuclei forming on either side of the cell plate. This cell is most likely
a plant cell in the process of cytokinesis.
"Complex carbohydrate" is another term for:
a polysaccharide.
Which property of water allows a paper towel to pick up a puddle of water?
adhesion of water molecules to other kinds of molecules
Metaphase is characterized by ________.
alignment of chromosomes on the equator of the cell
Atoms have no electric charge because they have ________.
an equal number of protons and electrons
Dietary proteins:
are considered "complete" only if they contain all of the essential amino acids required by humans.
Bacteria divide by a type of ______________________ called ____________________.
asexual reproduction; binary fission
All matter on earth, both living and non-living, is made up of:
atoms
The human chromosomes that do not determine whether an individual is male or female are
autosomes
The process by which a sperm cell combines with an egg cell is
fertilization
In eukaryotic cells, the sequences of mRNA that are removed from an mRNA molecule before being translated are
introns
The kind and number of bonds an atom can form depends on ________.
its electron configuration
The proteins involved in attaching the chromosomes to the mitotic spindle are
kinetochores
The best definition of "male" for all living organsims is the sex with:
motile gametes.
Which of these is not a required characteristic of life?evolution movement energy use structural organization
movement
Pure water and aqueous solutions that are neither acidic nor basic are said to be:
neutral
An abnormal number of chromosomes can occur due to one particular erroneous meiotic event called:
nondisjunction (chromosomes don't separate).
All lipids are:
nonpolar and insoluble in water.
Amino acids are to proteins as ____________________ are to DNA.
nucleotides
Thinking scientifically relies on:
objective observation and experimentation.
A group of prokaryotic genes that are controlled together is a(n)
operon
To be considered living, an organism must minimally consist of
one or more cells
The DNA you inherited from your parents provides the instructions to make:
porteins
A cell divides by mitosis. The result is:
two identical daughter cells.
A carbonated soft drink that has a pH of 3 is ________ times more acidic than water.
10,000
In a diploid cell with 5 chromosome pairs (2n = 10), how many sister chromatids will be found in a nucleus at prophase of mitosis?
20
If a DNA molecule consists of 20% adenine, what percent is cytosine?
30%
Cytosine makes up 42% of the nucleotides in a sample of DNA from an organism. Approximately what percentage of the nucleotides in this sample will be thymine?
8%
A particular triplet of bases in the coding strand of DNA is AAA. The anticodon on the tRNA that binds this mRNA codon is _____.
AAA
Which of the following statements about mutations is true?
Any mutation that doesn't kill an organism or decrease its fitness can be beneficial.
If the base sequence of one strand in a DNA molecule is GACACATAGCAC, then the base sequence of the other strand must be:
CTGTGTATCGTG.
Which of these is not a feature of cancer cells?
Cancer cells divide very slowly.
Cells from advanced malignant tumors often have very abnormal chromosomes and an abnormal number of chromosomes. What might explain the association between malignant tumors and chromosomal abnormalities?
Cell cycle checkpoints are not in place to stop cells with chromosome abnormalities.
Considering the organization of living systems, which of the following groups is in the correct order, from smallest to largest?
Cell, tissue, organ, organism, population
Evaporation from the leaves of a tree will pull water up through the roots as an unbroken column throughout the entire height of the tree. This feat is possible because of which characteristic of water?
Cohesion
The central dogma of molecular biology states that
DNA is transcribed into RNA, which is translated into protein.
Which of the following best summarizes the relationship between dehydration reactions and hydrolysis?
Dehydration reactions assemble polymers; hydrolysis reactions break polymers apart.
Which statement best explains the observation that more autism cases exist now than in the past? Autism is caused by a new mutation and has just shown up in the last few years. The vaccine for measles, mumps, and rubella has been established as a significant cause of autism. Autism has been selected for in recent generations by natural selection. Doctors are more aware of the condition and have better techniques for diagnosing and reporting it.
Doctors are more aware of the condition and have better techniques for diagnosing and reporting it.
Cell A has half as much DNA as cells B, C, and D in a mitotically active tissue. Cell A is most likely in
Gap 1
By 1796 it had been observed that milkmaids who had been exposed to cowpox did not succumb to the deadly plague of smallpox that was ravishing both Europe and Britain. From this observation, Edward Jenner was able to construct the world's first successful vaccine. Which of the following statements best fits Jenner's hypothesis that led him to his creation of the vaccine?
If exposure to cowpox gives immunity to smallpox in milkmaids, then exposure to cowpox should give immunity to smallpox in other individuals as well.
Which of the following statements best describes the significance of the TATA box in the promoters of eukaryotes?
It is the recognition site for the binding of a specific transcription factor.
Which statement about the disadvantages of sexual reproduction is false?
It leads to offspring that are genetically different from one another and from their parents.
Since its discovery in 1953, the double-helix structure of DNA is now one of the most recognizable molecules in biology. What was so groundbreaking about the "double" part of the double-helix molecule?
It suggested how genetic information could be copied and inherited.
What can happen if an enzyme is altered, even slightly?
Its active site may change, causing the enzyme to stop functioning.
The genetic code is redundant. What is meant by this statement?
More than one codon can specify the addition of the same amino acid. The genetic code is universal (the same for all organisms).
Which statement about the similarities and differences between chemotherapy and radiation therapy as cancer treatments is false?
Radiation therapy has a significantly higher success rate than chemotherapy.
In the Hershey and Chase experiment that helped confirm that DNA, not protein, was the hereditary material, what was the key finding?
Radioactively labeled phosphorus was present inside the infected bacteria.
Why is it common for people to have dramatic weight loss when they first start on a low-calorie diet?
The body breaks down glycogen with water molecules bound to it; much of the weight loss is water loss.
If a cell were unable to produce histone proteins, which of the following results would be a likely effect on the cell?
The cell's DNA could not be packed into its nucleus.
Why are hydrocarbons insoluble in water?
The majority of their bonds are nonpolar covalent carbon-to-hydrogen linkages.
Which feature of large biological molecules explains their great diversity?
The many ways that monomers of each class of biological molecule can be combined into polymers
The cities of Portland, Oregon, and Minneapolis, Minnesota, are at about the same latitude, but Minneapolis has much hotter summers and much colder winters than Portland. Why?
The ocean near Portland moderates the temperature.
The ingredient label on a container of shortening indicates "partially hydrogenated vegetable oil." This means that during processing, the number of carbon-carbon double bonds in the oil was reduced. What is the result of decreasing the number of double bonds?
The oil is now more likely to be solid at room temperature.
A beaker contains 100 milliliters (mL) of NaOH solution at pH = 13. A technician carefully pours into the beaker 10 mL of HCl at pH = 1. Which of the following statements correctly describes the result of this mixing?
The pH of the beaker's contents will decrease.
Which of the following statements is true about buffer solutions?
They maintain a relatively constant pH when either acids or bases are added to them.
What type of evidence most increases our confidence in experimental results?
Three different scientists do three different studies, all with the same result.
DNA is packaged to protect and manage the genetic information of the cell. What is the correct comparison between the packaging units of DNA?
While chromatin is the collective term for the substance of DNA and associated proteins, chromosomes are the distinct units thatare compact and visible during cell division.
Which of the following human sex chromosome genotypes is not possible?
YY
Can the atomic mass of an element vary?
Yes. Adding or losing neutrons will change the atomic mass without forming a different element.
The partial negative charge at one end of a water molecule is attracted to the partial positive charge of another water molecule. What is this attraction called?
a hydrogen bond
Eukaryotic cells can divide by:
both mitosis and meiosis.
About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living matter?
carbon, hydrogen, nitrogen, oxygen
In terms of structural materials, _______ is to plants as _______ is to lobsters and crabs.
cellulose; chitin
What is the name of the microtubule-organizing center found in animal cells as an identifiable structure present during all phases of the cell cycle?
centrosome
Which lipid is an important component of most cell membranes?
cholesterol
In a "silent" mutation the
codon that mutates does not cause a change in the amino acid specified.
Which of the following may occur in meiosis but not in mitosis?
crossing over
A cell with two full sets of chromosomes would be termed a __________cell.
diploid
A(n) ________ has charge but negligible mass, whereas a(n) ________ has mass but no charge.
electron; neutron
The step of translation in which amino acids are added one at a time to the growing polypeptide
elongation
Most genetic diseases result from mutations that cause a gene to produce a non-functioning ______________, which in turn blocks the functioning of a metabolic pathway.
enzyme
What is the primary role of carbohydrates in living organisms?
fuel for cellular mechanisms
The purpose of the experimentation phase of the scientific method is to:
gather evidence to support or reject a hypothesis.
Sister chromatids are
genetically identical and attached to each other at the centromere
Which of the following correctly describes the molecular structure of a triglyceride?
glycerol head and three fatty acid tails
A scientist, who wants to study the effects of nitrogen on wheat plants, sets up an experiment with 4 groups of wheat plants: group A gets 20 pounds per acre, group B gets 40 pounds per acre, group C gets 60 pounds per acre, and group D gets 0 pounds per acre. Which of the following is the control group?
group D
An experiment was designed to determine the effect of temperature on the growth rate of phasmids—insects more commonly known as "walking sticks." Five walking sticks were grown in four different incubators, set at variable temperatures for two weeks. Which component of the experiment is the dependent variable?
growth of walking sticks
If you mate a donkey (2n = 62) with a horse (2n = 64) you get a mule. Mules are sterile and cannot produce gametes by meiosis because they
have an odd number of chromosomes
One important difference between covalent and ionic bonds is that:
in covalent bonds, two atoms share electrons, whereas in ionic bonds, one atom gives one or more electrons to the other atom.
The best experimental design ________.
includes a large sample size and a control, and alters only one condition between the controls and the experimental condition
The step of translation in which an mRNA, a small ribosomal subunit, and tRNA carrying methionine, are aligned together is
initiation
Identify the molecule that is not a carbohydrate.
lactase
An important difference between mRNA and DNA is:
mRNA can move throughout the cell, whereas DNA stays in the nucleus.
The starting point of a gene on the DNA where the RNA polymerase binds is called the
promoter
The mitotic spindle plays a critical role in which of the following processes?
separation of sister chromatids
Sexual reproduction is important to the survival of a species in a changing environment because
sexual reproduction produces genetically variable individuals in the population.
Which of the following does not influence the rate at which an enzyme catalyzes a reaction?
size of a catalyst
An experiment was designed to determine the effect of temperature on the growth rate of phasmids—insects more commonly known as "walking sticks." Five walking sticks were grown in four different incubators, set at variable temperatures for two weeks. Which component of the experiment is the independent variable?
temperature of incubators
The step of translation in which release factors bind to a stop codon is
termination
The complexity and variety of organic molecules is due to _____.
the chemical versatility of carbon atoms
Recombination, or crossing over, means the same as:
the process by which pieces of homologous chromosomes are exchanged.
In the lac operon, the protein that binds to the operator to prevent transcription is
the repressor
A relationship that has been established based on a large amount of observational and experimental data is a(n):
theory
People who are lactose intolerant cannot extract energy from milk because ________.
they are missing an enzyme
The first energy shell of an atom has one orbital. Therefore, it can contain a maximum of electron(s).
two
Which property of water allows a water strider to walk on water?
water's high surface tension
When are atoms most stable?
when all of the electron orbitals in the valence shell are filled
