Bio Lab Exam 2
interphase
A cell preparing to undergo meiosis duplicates its chromosomes during
before it is about to divide
A cell replicates its entire chromosomal DNA only __________.
24
A certain species of animal has six pairs of chromosomes. How many DNA molecules are present in the nuclei of these animals during G2 phase?
16
A diploid organism whose somatic (nonsex) cells each contain 32 chromosomes produce gametes containing ________ chromosomes.
mitosis
After fertilization, the resulting zygote begins to divide by __________.
Trisomy for the other autosomal chromosomes is often lethal, and the affected embryos are miscarried.
Although in humans there are 22 pairs of autosomal chromosomes, only three different chromosomal trisomies are commonly seen in newborns. Of the remaining 19 autosomes, many trisomies have not been seen in newborns. Why not?
hypotonic
An animal cell placed in a(n) _______ solution will gain water, swell, and possibly burst.
somatic cell
An example of a cell that is 2n is a __________.
cancer
An individual with a malignant tumor is said to have ____________
telophase I
At the end of _____ and cytokinesis, haploid cells contain chromosomes that each consist of two sister chromatids
It ensures that each daughter cell receives one copy of the chromosomes.
During binary fission, each copy of the duplicating chromosome moves to opposite ends of the cell. What does this achieve?
They organize the microtubules
During cell division, what role do centrosomes play?
nondisjunction
During meiosis, homologous chromosomes sometimes "stick together" and do not separate properly. This phenomenon is known as _____.
1
How many generations does it take to develop a new plant species by polyploidy?
22
How many pairs of autosomes do humans have?
The DNA molecule would have irregular widths along its length
How would the shape of a DNA molecule change if adenine paired with guanine and cytosine paired with thymine?
malignant tumor
abnormally growing mass of cells that is actively spreading through the body
crossing over
the exchange of homologous portions of nonsister chromatids
anaphase II
During _____ sister chromatids separate.
carcinoma
-always originates in tissues that line organs. -most common kind of cancer
her egg cells
A female that is planning to become pregnant is concerned about her exposure to environmental mutagens which may have caused DNA mutations. In order for these mutations to become heritable, they must affect the:
92
A human bone marrow cell in the prophase stage of mitosis contains 46 chromosomes. Therefore, there are a total of __________ sister chromatids in this cell.
facilitated diffusion
A molecule moves down its concentration gradient using a transport protein in the plasma membrane. This is an example of
mutagen
A physical or chemical agent that changes the nucleotide sequence of DNA is called a(n)
hypertonic
A plant cell placed in a(n) _________ solution will lose water and plasmolyze.
isotonic
A plant cell surrounded by a(n) ______ solution will be flaccid (limp).
binary fission
Bacteria divide by:
prophase
Chromosomes become visible during ________.
telophase
Cytokinesis often, but not always, accompanies ________.
small
DNA replication occurs at an unbelievably fast rate. Once replication is complete, we can expect to find a _____ number of mistakes.
the s phase of interphase
DNA replication occurs in _____.
passive transport
Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of
nondisjunction of chromosome 21 during meiosis
Down syndrome can be the result of _____.
Each parental strand serves as a template for the synthesis of a complementary strand
During DNA replication, _____. - replication begins at one end of the chromosome and continues all the way to the other end - one daughter molecule ends up with two newly synthesized DNA strands - each parental strand serves as a template for the synthesis of a complementary strand - four identical DNA molecules are produced
prophase II
During _____ a spindle forms in a haploid cell.
metaphase II
During _____ chromosomes align single file along the equator of a haploid cell.
prophase I
During meiosis, segments of nonsister chromatids can trade places. This recombination of maternal and paternal genetic material is a key feature of meiosis. During what phase of meiosis does recombination occur?
Homologous chromosomes stick together in pairs
During prophase I of meiosis, - there are two daughter cells, each with 23 chromosomes. - the homologous chromosomes separate and move towards opposite poles. - there are four haploid daughter cells. - homologous chromosomes stick together in pairs. - chromosome pairs are positioned in the middle of the cell.
two chromosomes and four chromatids
During prophase a homologous pair of chromosomes consists of _____.
interphase
Eukaryotic cells spend most of their cell cycle in which phase?
Each person has a unique set of carbohydrate chains attached to his or her plasma membranes.
Frequently, transplanted organs are rejected by the recipient's body. How is this reaction related to plasma membranes?
meiosis
Gametes are produced by__________.
Bacteria can't survive in a hypertonic solution because they lose water.
Green olives may be preserved in brine, which is a 20-30% salt solution. How does this method prevent contamination by microorganisms?
anaphase I
Homologous chromosomes migrate to opposite poles during _____.
all of the above
How do mutations affect an organism? - they may cause the development of a disease-causing allele - they may cause the development of a more beneficial allele - they, in some cases, may have no noticeable affect - all of the above
Chromatids
Identical copies of each other if they are part of the sane chromosome
an inversion
If a fragment of a chromosome breaks off and then reattaches to the original chromosome at the same place but in the reverse direction, the resulting chromosomal abnormality is called _____.
the relative inelasticity and strength of the plant cell wall
If placed in tap water, an animal cell will undergo lysis, whereas a plant cell will not. What accounts for this difference?
(b) the replica strands are complementary to the templates
In DNA replication, (a) the original strands remain together. (b) the replica strands are complementary to the templates. (c) each replica strand has the same base sequence as its template. (d) DNA copies itself. both (b) and (d).
Thymine...cytosine
In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand.
5
In a cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing _____ chromosomes
1'....5'
In a nucleotide, the nitrogenous base is attached to the sugar's _____ carbon and the phosphate group is attached to the sugar's _____ carbon.
Each DNA helix would have one radioactive strand and one non-radioactive strand
In an experiment, a scientist fed radioactive nucleotides to a cell that was previously non-radioactive. After the cell duplicated its DNA, which statement would be true? - The old DNA helices would be non-radioactive; the new ones would be radioactive. - In each strand, half the nucleotides would be radioactive and half non-radioactive. - Each DNA helix would have one radioactive strand and one non-radioactive strand.
sister chromatids are separated
In meiosis II, _____. - chromosome number is reduced from diploid to haploid - chromosomes cross over to exchange genetic information - homologous chromosomes pair to ensure their even distribution to daughter cells - sister chromatids are separated
large cells containing many nuclei
In some organisms such as certain fungi and algae, cells undergo mitosis repeatedly without subsequently undergoing cytokinesis. What would be the consequence of this?
two... haploid
Meiosis I produces _____ cells, each of which is _____.
crossing over
Meiosis differs from mitosis in that _____ only occurs in meiosis.
four haploid cells
Meiosis starts with a single diploid cell and produces
two diploid cells : four haploid cells
Mitosis and cytokinesis result in the formation of __________; meiosis and cytokinesis result in the formation of __________.
proteins
Most of the functions of a cell membrane, including transport and enzymatic function, are performed by
23
Normal human gametes carry _____ chromosomes.
5' to 3'
Nucleic acids are assembled in the _____ direction.
interphase
Nucleoli are present during _______.
the difference in water concentration across a selectively permeable membrane
Osmosis is often viewed incorrectly as a process driven directly by differences in solute concentration across a selectively permeable membrane. What really drives osmosis?
A normal watermelon has 22 chromosomes but seedless watermelons have 33 chromosomes.
Polyploidy is involved in which of the following examples? - Some plants alternate between haploid and diploid phases. - XYY males - XO females - A normal watermelon has 22 chromosomes but seedless watermelons have 33 chromosomes.
centromere
Sister chromatids are joined together at a _________
prometaphase
Spindle fibers attach to kinetochores during _____.
prophase I
Synapsis occurs during _____.
telophase
The chromosomes arrive at the poles and nuclear envelopes form during which phase of mitosis?
fertilization
The diploid phase of the human life cycle begins with _____.
5' to 3'
The direction of synthesis of an RNA transcript is _____.
reciprocal translocation
The exchange of parts between nonhomologous chromosomes is called _____. - transformation - reciprocal translocation - inversion - crossing over
DNA replication
The first step of bacterial replication is ______.
diverse proteins embedded in a phospholipid bilayer
The fluid mosaic model describes the plasma membrane as consisting of
hypotonic
The ideal osmotic environment for a plant cell is a(n) __________ environment.
isotonic
The ideal osmotic environment for an animal cell is a(n) _______ environment
so that the nonpolar parts of two lipids point toward each other
The lipids in a cell membrane are arranged _____.
endocytosis
The plasma membrane forms a pocket that pinches inward, forming a vesicle that contains material from outside the cell. This describes the process of
Oxygen and carbon dioxide
The plasma membrane is selectively permeable. Which of the following can pass freely through the membrane with no assistance?
Anaphase
The sister chromatids separate and begin moving toward opposite poles of the cell during which phase of mitosis?
ribosomes in the cell cytoplasm
The site of translation
active transport
The sodium-potassium pump uses energy from ATP to move sodium ions out of the cell, and potassium ions into the cell. This is an example of
hypertonic
There is a net diffusion of water out of an animal cell when it is placed in a(n) ____________ solution.
Only one copy of the X chromosome is functional, regardless of the total number of X chromosomes.
Trisomy for most autosomes is fatal, yet trisomy or even tetrasomy (four copies) of the X chromosome is not. What is the explanation for this difference?
False
True or false. Mitosis takes place during M phase of the cell cycle, which is longer than interphase.
causes mutations in DNA
UV radiation is damaging because it________.
through facilitated diffusion or diffusion
Water crosses the plasma membrane - using a process that requires energy from the cell. - through active transport. - through facilitated diffusion or diffusion. - through cotransport. - against its concentration gradient.
formation of a cell plate
What feature of plant cell division that distinguishes it from animal cell division?
All of the above are difference between prokaryotic and eukaryotic DNA
What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells? - the amount of DNA present - whether the DNA is housed in a nucleus or not - whether the DNA is linear or circular - all of the above are differences between prokaryotic and eukaryotic DNA
The chromosomes must be duplicated
What must happen before a cell can begin mitosis?
osmosis
What name is given to the process by which water crosses a selectively permeable membrane?
form spontaneously in aqueous environments
When considering the formation of membranes, they __________.
its cells each have one set of chromosomes
When we say that an organism is haploid, we mean that _____.
Nucleotide pairing affects the action of DNA polymerase
Which fact is most important in explaining why wrong base pairs are rarely incorporated into the double helix? - Strands of the helix won't separate if base pairs are wrong. - A-T and G-C are the only base pairs that can join with hydrogen bonds. - Nucleotide pairing affects the action of DNA polymerase. - Sugars cannot link with wrongly paired bases. - Wrong base pairs are low in energy.
A check that chromosome replication has been successfully completed
Which of the following checkpoints does not occur late in G1? - A check that chromosome replication has been successfully completed - A check that the cell is large enough for division - A check that nutrients are sufficient - A check that growth factors are present
mRNA attaches to the small subunit of a ribosome
Which of the following does not occur during RNA processing? - A modified guanine nucleotide is added to the beginning of the RNA strand as a cap. - Adenine nucleotides are added to the end of the RNA strand, forming a tail. - mRNA attaches to the small subunit of a ribosome. - Segments of the RNA strand that do not actually code for the protein are removed. - Segments of RNA that do code for the protein are reconnected.
A molecule of RNA is formed based on the sequence of nucleotides in DNA
Which of the following events occurs during transcription? - The message in mRNA is translated into a protein. - mRNA binds to a ribosome in the cytoplasm. - A molecule of RNA is formed based on the sequence of nucleotides in DNA. - Those segments of the RNA strand that do not actually code for the protein are removed. - A cap is added to the RNA molecule.
XO
Which of the following indicates Turner syndrome?
mRNA moves from the nucleus to the cytoplasm following RNA processing
Which of the following is a correct statement about mRNA? - mRNA moves from the nucleus to the cytoplasm following RNA processing. - Segments of mRNA that code for protein are removed before translation. - mRNA includes a cap that consists of extra adenine nucleotides. - mRNA binds directly to amino acids during translation. - mRNA is transcribed from DNA in the cytoplasm.
Its strands have a sugar-phosphate backbone.
Which of the following is true about double-stranded DNA? - The two strands are identical. - It is shaped like a triple helix. - Its strands have a sugar-phosphate backbone - Adenine and uracil are present in equal amounts.
Two daughter nuclei, one at each pole of the cell, are generated
Which of the following occurs during mitosis? - Organelles replicate. - Chromosomes replicate. - Two daughter nuclei, one at each pole of the cell, are generated. - Two genetically different daughter cells result.
DNA is synthesized in the S phase of interphase
Which of the following statements correctly describes the timing of DNA synthesis? - DNA is synthesized only during mitosis. - DNA is synthesized in G2 of interphase immediately preceding mitosis. - DNA is synthesized continuously throughout the cell cycle - DNA is synthesized in the S phase of interphase.
The strands run in opposite directions.
Which of the following statements is true about double-stranded DNA? - The two strands are said to be identical. - It contains ionic bonds. - Adenine and uracil are present in equal amounts. - The strands run in opposite directions.
The cell cycle control system operates independently of the growth factors
Which of the following statements regarding the cell cycle control system is false? - The cell cycle control system receives messages from outside the cell that influence cell division. - The cell cycle control system operates independently of the growth factors. - The cell cycle control system includes three key checkpoints to complete a cell cycle. - The cell cycle control system triggers and controls major events in the cell cycle.
Mitosis allows organisms to generate genetic diversity
Which of the following statements regarding the function of mitosis is false? - Mitosis allows organisms to grow. - Mitosis allows organisms to generate genetic diversity. - Mitosis allows organisms to reproduce asexually. - Mitosis allows organisms to repair tissues.
Na+
Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer? - a small, nonpolar molecule such as butane(C4H10) - Na+ - O2 - CO2
flowering plants
Which of the following types of organisms commonly demonstrates polyploidy? - reptiles - flowering plants - fish - mammals
a G paired with a T
Which of the following would indicate a base pairing mutation in DNA? - an A paired with a T - a C paired with a G - a G paired with a T - all of the above are improper base pairs
DNA is double-stranded, whereas RNA is single-stranded.
Which of these is a difference between a DNA and an RNA molecule? - DNA contains nitrogenous bases, whereas RNA contains phosphate groups. - DNA is double-stranded, whereas RNA is single-stranded. - DNA is a polymer composed of nucleotides, whereas RNA is a polymer composed of nucleic acids. - DNA contains five-carbon sugars, whereas RNA contains six-carbon sugars. - DNA contains uracil, whereas RNA contains thymine.
Thymine
Which of these nitrogenous bases is found in DNA but not in RNA? - cytosine - thymine - guanine - uracil - adenine
DNA
Which one of the following does not play a role in translation? - Amino Acids - DNA - tRNA - Anticodon - ribosomes
None of the above
Why do cells make nucleic acids from monomers? - Each nucleotide has three phosphates. - Free nucleotides cannot base-pair with the template. - They don't. Cells make nucleic acids from free nucleotides. - Extra phosphates cause stronger base pairing. - None of the above.
a similar but not identical combination of genes
With the exception of identical twins, siblings who have the same two biological parents are likely to look similar, but not identical, to each other because they have
The sequences are identical
Within one chromosome, what is the relationship between the sequence of bases in DNA of one sister chromatid compared to the other?
Asexual
_______ reproduction is a means of creating new individuals solely by mitosis, the form of cell division that creates genetically identical daughter cells.
Sexual
________ reproduction, generates genetically unique offspring. To accomplish this, an organism must produce gametes through the process of meiosis. The cells produced this way will be haploid, meaning that they can contain a single set of chromosomes. Such cells are produced only in the gonads.
46
a human somatic cell contains ______ chromosomes
benign tumor
lump of abnormal cell, that although growing out of control, remains at its original site
are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes
many organisms, including humans, chromosomes are found in homologous pairs. Homologous chromosomes _____. - are identical in the arrangement of their genes, but some versions of the genes may differ between the chromosomes - have roughly similar arrangements of their genes, but some versions of the genes may differ between the chromosomes - are similar in size and shape, but this deceptive similarity has nothing to do with placement of gene arrangement or type - are identical both in the arrangement of their genes and in every version of every gene
active transport
molecules move across the plasma membrane against their concentration gradient.
In the telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _____.
prophase
metastasis
spread of cancer cells from their site of origin to other sites in the body