From the beginning of the cell division to the end is called the
A cell's genetic information is called its ____________ which is made upof DNA
DNA molecules are packages into
The bodies cells (all except the reproductive cells) are called
Somatic cells have ____________ chromosomes
Reproductive cells, or ___________ -spermand eggs- have half as many chromosomes as somatic cells
Somatic cells are also called
Gametes are also called ____________ because they have half the amount of chromosomes
The sign for diploid is ______. The sign for haploid is _____
Eukaryotic chromosomes are made of ____________, a complex of DNA and associated protein molecules.
Each duplicated chromosomes has two _______________.
The sister chromatids are attached by
sister chromatid cohesion
Two chromatids are attached at their "waist" called the
the division of the nucleus
The division of the cytoplasm immediately following mitosis is called
Gametes are produced by
Meiosis only occures in
the testes or ovaries
The mitotic (M) phase includes _____________ and ____________
During _________ the cell grows and copies its chromosomes
Interphase can be divided into 3 phases
S phase (synthesis)
During the subphases of interphase the cell grows by producing
proteins and cytoplasmic organelles
Chromosomes are duplicated in the
Mitosis is broken down into 5 stages
The mitotic spindle is made up of
microtubules and associated proteins
A sub-cellular region containing material that functions throughout the cell cycle to organize the cell's microtubules is called the
A pair of _______________ is located at the center of the centrasome
The centrosome relicates during which phase of the cell cycle
Short microtubles extend form the centrosomes of a dividing cell are called
Sister chromatids of a replicated chromosome have a _______________, a structure of proteins associated with specific sections of chromosomal DNA
At metaphase, the centromeres of all the duplicated chromosomes are on a plane midway between the spindle's two poles called the
During _____________ the nucleoli dissapear and each duplicated chromosome appears as two identical sister chromatid
During ________________ the nuclear envelope fragments, the microtubules extend from each centrasome and the chromosomes have become even more condensed
During __________________ the centrasomes are at opposite poles of the cell, the chromosomes convene on the metaphase plate.
________________ is the longest stage of mitosis
The shortest phase of mitosis is
During ___________________ the sister chromatids part suddenlyand begin to move away from the metaphase plate and towards the centrosomes
During ____________ two daughter nuclei form in the cell, Mitosis is now complete
In animal cells, cytokinesis involves the formation of the ____________ which pinches the cell in two
The function of the cell cycle is to produce daughter cells that
are geneticaly identical to the parent cell
all of the above
The complex of DNA and protein that makes up a eukaryotic chromosome is properly called
The region of a chromosome holding the two double strands of relicated DNA together is called
If an intestinal cell in a grasshopper contains 24 chromosomes, a grasshopper sperm cell would contain ____________ chromosomes
The centromere is a region in which ___________
sister chromatids are attached to one another in prophase
how many maternal chromosomes are present in a somatic human cell not engaged in cell division?
A cell entering the cell cycle with 32 chromosomes will produce two daughter cells, each with ___________
Cytokinesis refers to ___________
division of the cytoplasm
identical copies of each otherif they are part of the same chromosome
If a cell contains 60 chromatids at the start of mitosis, how many chromosomes will be found in each daughtercell at the completion of the cell cycle?
A biochemist measured the amount of DNAin cells growing in the laboratory and found that the quantity of DNA in the cells daoubles between _____ phase and _____ phase
G1 and G2
During interphase, the genetic material of a typical eukaryotic cell is _____
dispersed in the nucleus as long strands of chomatin
DNA relication occures in ____________
Chromatids form during
the S phase
If a somatic human cell is just about to divide, it has ____________ chromatids
Which one of the following does not occure during mitosis
replication of chromosomes
During what phase in the cell cycle, would you find the most DNA per cell?
In telophase of mitosis, the mitotic spindle breaks down and the chromatin uncoils. This is essentially the opposite of what happens in _________
Which phase of mitosis is essentially the opposite of prometaphase in terms of the nuclear envelope?
At which point in the cell cycle do centrosomes begin to move apart to two poles of the cell in a dividing human skin cell?
The phase of mitosis during which the chromosomes move toward separate poles of the cell is
One event occuring during prophase is ___________
the beginning of the formation of a spindle apparatus
The nuclear envelope disappears during
Sister chromatids separate during
In animal cell mitosis, the cleavage furrow forms during
At which stage of mitosis are chromosomes lined up in one plave in preparation for their seperation to opposite poles of the cell?
You would know a dividing cell is a plant cell if yousaw that
It had formed a cell plate
_____________ does not occur in dividing bacteria
During binary fission in a bacterium ________
the origins of replication move apart
Binary fission in bacteria cells involves __________
distribution of a copy of the single parental chromosome to each daughter cell
When a cell in s phase is fused with a cell in G1, _________
DNA synthesis begins immediately in the original G1 nucleus
Tissue culture experiments with PDGF demonstrate that without this substance ______________
fibroblasts fail to divide
You would be unlikely to see which of the following human cells dividing?
Observations of cancer cells in culture support the hypothesis that cancer cells ______________
do not exhibit density-dependant inhibition
What is the difference between a benign tumor and a malignant tumor?
Cells of benign tumors do not metastasize; those of malignant tumors do
Monomers for the synthesis of DNA are called
In DNA, thetwo purines are ______________, and the two pyridimines are ________________
Adenine and guanine, cytosine and thymine
Which bases are always together which each other and how many hydrogen bonds do they form
adenosine and thymine form 2 hydrogen bonds, guanine and cytosine form 3 hydrogen binds
The two sugar-phosphate strands of a DNA molecule are joined to each other through
hydrogen bonds between nucleotide bases
The informationin DNA is contained in
the sequence of nucleotides along the length of the two strands of the DNA molecule
Which of the following attributes of DNA is most crucial to its accurate duplication?
its specific base pairing and hydrogen bonding
During the replicaiton of DNA,_____________-
both strands of molecules act as templates
The DNA structures of prokaryotes and eukaryotes are different in several ways, but one way in which they are the same is that
they both have a sugar-phsophate backbone
At each end of a DNA replicaiton bubble is
a replication fork
The role of DNA polymerases in DNA replicaiton is to
attach free nucleotides to the new strand
The rate of elongation in prokaryotes is ____________ the rate in eukaryotes
much faster than
The two strands of a DNA double helix are antiparallel. This means that _________
one strand runs in the 5' to 3' direction, the othe rruns in the 3' to 5' direction
DNA polymerase adds nucleoties to __________ of the leading strands, and to the ________ of the lagging strands (Okazaki fragments)
3' end, 3' end
What enzyme joins Okazaki fragments?
After the formation of a replication bubble, what is the correct sequence of enzymes used for the synthesis of the lagging DNA strand
helicases, primase, DNA polymerase, ligase
What is the componant required for DNA replication?
The removal of the RNA primer and addition of DNA nucleotides to the 3' end of Okazaki fragments in its place is carried out by
DNA polymerase I
The unwinding of DNA at the replication fork causes twisting and strain in the DNA ahead of the fork, which is relieved by an enzyme called
Once the DNA at the replication fork is unwound by helicases, what prevents the two strands from coming back to reform a double helix?
Single-strand binding proteins bind the unwound DNA and prevent the double helix from reforming
____________ seperate the two strands of the double helix, the DNA polymerases then construct two new strands using each of the original strands as templates
The overall error rate in the completed DNA molecules is approximately
1 to 10,000,000,000 nucleotides
The incorporation of an incorrect base into the DNA during replication can be repaired by
the mismatch repair system
The set of enzymes involved in nucleotide excision repair are
nulease, DNA polymerase and ligase
Unlike prokaryotic replicaiton, replicaiton of eukaryotic chromosomes
cannot be completed by DNA polymerase
____________ get shorter with continued cell division.
_____________ is an enzyme that lengthens telomeres.
How many genes are present in the human genome?
tens of thousands
What is a locus
the precise location of a gene on a chromosome
Sexual and asexual reproduction are alike in that ______
they can both occur in multicellular organisms
Unless the chromosomes were stained to show band patterns, a karyotype would be least likely tp show
part of a chromosome turned around
A karyotype is
a photograph of all of an individual's chromosomes
a diploid zygote
A life cycle in which the only multicellular form is haploid os most typical of
_______________ is where a cell contains half the parental chromosome number.
In sexually reproducing species, the chromsome number remains stable over time because _______ and ___________ always alternate.
meiosis and fertilization
The egg of a rabbit contains 22 chromosomes. How many chromosomes are in the somatic cells of the rabbit?
In a diploid cell containing 10 chromosomes, meiosis results in the formation of daughter cells containing _____________ chromosomes
How many pairs of autosomes do humans have?
Sister chromatids are _____________________ formed during DNA synthesis
identical copies of each other
When we say that an organism is haploid, we mean that
its cells have a single set of chromosomes
Nearly all life cycles have both haploid and diploid phases. Usually, the transition from haploid to diploid takes place at
fertilization, when gametes fuse
At the end of telophase I of meiosis and the first cytokinesis, there are ___________
two haploid cells
What is the result when a diploid cell undergoes meiosis?
four haploid cells
Synapsis occurs during
Sister chromatids separate and move to opposite poles duirng
the division of one cell into two
What is the function of meiosis?
To make cells with a haploid number of chromosomes
Crossing over occurs during
Regions of chromosomes where nonsister chromatids cross over are called
The synaptonemal complex _________
physically connects homolgous chromosomes during prophase I
An organism has a haploid chromosome number n=4. How many tetrads will form during meiosis?
What event occurs only during prophase I of the first meiotic division
Synapsis of homologous pairs occurs
In a male mammal, every cell that undergoes meiosis gices rise to _______ sperm
What occurs in meiosis but not mitosis?
homologous chromosomes seperate
Ignoring crossover, how many kinds of gametes can be produced by an organism with a diploid numebr of 8?
In humans, the haploid number of chromosomes is 23. Independent assortment has the possibility of producing ________ different types of gametes
The major contribution of sex to evolution is that ____________
It provides a method to increase genetic variation.
Genetic information of eukaryotic cells is transferred from the nucleus to the cytoplasm in the form of ______
Each amino acid in a protein is coded for by _____ bases in the DNA
When RNA is being made, the RNA base ______ always pairs with the base ____ in DNA
Generally speaking, how many genetic codes are there?
What mRNA codon would be made from the DNA triplet CGT
The number of bases "read" together on the mRNA to designate each amino acid is ________; this unit is called a _______
The codons AAA, CCC, and UUU specify the amino acid lysine, proline, glycine, and phenylalanin. Which DNA sequence would specify the peptide pro-gly-lys-phe if present in the semplate strand?
The codons AAA, CCC, GGG, and UUU specify the amino acid lysine, proline, glycine and phenylalanin. What peptide sequence would 5'-CCCAAATTTGGG-3', if present in the ciding strand of the DNA?
How many nucleotides are needed to code for a protein with 450 amino acids?
at least 1,350
In many cases, more than one codon codes for the same amino acid. Because of this, we say that the code is __________
Bacteria can transcribe and translate human genes to produce funtional human proteins because ____________
the genetic code is universal
At one point as a cell carried out its day-to-day activities, the nucleotides GAT were paired with the nucleotides CUA. This paring occurred __
What catalyzes the linkage between ribonucleotides to form RNA during gene expression?
In eukaryiotic cells, a terminator in mRNA synthesis is __________
a specific nucleotide sequence in DNA that signals the RNA polymerase to stop
In a eukaryotic cell. transcription takes place in _________
During the transcription of a given portion of a DNA molecule __________
mRNA is synthesized on only one of the chains
In eukaryotes, what is the mechanisms of gene regulation that operate after transcription, but before translation of mRNA into protein?
Usually, in eukaryotic gene exons are ______________, but the RNA ________ from introns does not leave the nucleus.
Introns are cut out of the primary transcript, and the resulting exons are spliced together describes _____________
The structures called snRNPs are part of
Nuclei of eukaryotic cells contain spliceosomes that are made up of _______
snRNA and protein
A cell biologist found that two different proteins with largely different structures were translated from two different mRNAs. These mRNAs, however, were transcribed from the same template within the cell nucleus. Which mechanism could best account for this?
Exons from the same gene could be spliced in different ways to make different mRNA's
The funtions of tRNA during protein synthesis is to___________
deliver amino acids to their proper site during protein synthesis
The bonds that hold tRNA molecules in the correct three-dimentional shape are
During translation in a eukaryotic cell polypeptides are synthesized at _______, according to instructions carried by _____
The P site of a ribosome does what?
It holds the tRNA carrying the growing polypeptide chain
The first amino acid inserted into a new polypeptide chain in eukaryotic cells is always ___________
During translation, amino acid chain elongation occurs until __________
the ribosome encounters a "stop" codon
Polysomes may be defined as ____________
groups of ribosomes
What is the proper order of events in the expression of a eukaryotic gene?
modification of protein
What is a key difference in gene expression between eukaryotic and prokaryotic cells?
In prokaryotic cells, the mRNA transcript is immediately available as mRNA without processing.
A genetecist found that a particular mutation had no effect on the polypeptide encoded by the gene. This mutation probably involved ________
a silent or neutral mutation
What type of mutation is least likely to affect the function of the protein corresponding to the gene in which the mutation occurs?
A base-pair substitution mutation in a germ cell line is likey to have no effect on phenotype if the substitution ______
occurs in an intron
A virus infects a cell and randomly inserts many short segments of DNA containing a stop codom throughout the organism's chromosomes. This will probably cause
manufactured proteins to be short and defective
A point mutation in which a single base pair is inserted or deleted from DNA is called a
Ultraviolet radiation is damaging to cells because it ___________--
causes mutations in the DNA
Transcription factors are found in ___________
archaea and eukaryotes
These unwinds the parental double helix at the replication forks
This binds to and stabalizzes single-strand DNA until it can be usedd as a template
Single-strand binding protein
_______________ relieves strain ahead of replication forks by breaking, swiveling and rejoining DNA strands
_____________- synthesizes and RNA primer at 5' end of leading strand and each of Okazaki fragment of lagging strand
__________________ uses parental DNA as a template, synthesizes new DNA strand by covalently adding nucleotides to the 3' end of a pre-existing DNA strand or RNA primer
DNA pol III
_________________ removes RNA nucleotides of primer from 5' end and replaces them with DNA nucleotides
DNA pol I
_____________ joins 3' end of DNA that replaces primer to rest of leading strand and joins Okazaki fragments of lagging strand