exam 3 flashcards
If a cell contained a mutation in the gene that encodes FtsZ, which process would affected?
Septation
Crossing over between homologous chromosomes takes place during
Prophase I
As the two strands of DNA are unraveled, which enzyme relieves the strain on the two strands?
DNA gyrase
In bacterial cell division, the cell divides into two nearly equal halves. This process is referred to as:
binary fission
This protein or protein complex functions in the cell to stop cell division if the cell has experienced extensive DNA damage:
p53
Nucleotides have a phosphate group attached at the ____ carbon atom of the sugar.
5’
If a cell has 32 chromosomes prior to S and undergoes mitosis followed by cytokinesis, each new daughter cell will have how many chromosomes?
32
A duplicate copy of all of the hereditary information contained in the nucleus of eukaryotic cells is made during what stage of the cell cycle?
S phase
In what portion of the cell cycle do the chromosomes appear invisible under a light microscope because they are not yet condensed?
Interphase
What stage of mitosis is essentially the reverse of prophase?
Telophase
During DNA replication, DNA polymerase III or DNA polymerase delta synthesizes lagging strand in segments, called
Okazaki fragments
Which enzyme adds new nucleotides to the end of a growing strand?
Polymerase
Based on their experiment with bacteriophages (and blenders), Hershey and Chase concluded that
____ functions as the _______ __________.
DNA functions as the genetic material
A codon is composed of how many bases?
3
Watson and Crick developed a model of DNA in which the two strands twist into the shape of a ______ ______.
double helix
In animals, the cells that will eventually undergo meiosis to produce gametes are set aside early in development. These are called
germ-line cells
_______ cells contain one set of chromosomes
Haploid
This stage of mitosis is characterized by the disassembly of spindle apparatus, the reestablishment of the nuclear membrane, and the decompensation of the chromosomes:
Telophase
_______ is process of nuclear division that reduces the number of chromosomes per cell from 2 sets to 1 set.
Meiosis
During this stage of mitosis, the nuclear envelope begins to break down and the spindle begins to form.
Prophase
A scientist wants to study histones. Histones are
a) proteins that double-stranded DNA molecules wrap around in eukaryotes.
b) proteins that double-stranded DNA molecules wrap around in prokaryotes and eukaryotes
c) proteins that regulate checkpoints in the mitotic cell cycle
d) proteins that serve as the spindle fiber to pull sister chromatids apart during anaphase
e) proteins that required for the activity of Cdk enzymes
A
You are studying meiosis in an organism where 2n=24. How many chromosomes will each nucleus have after meiosis II is complete?
12
Which cells never divide by meiosis? (3)
a) Haploid cells
b) Diploid cells
c) Somatic cells
d) Germ-line cells
e) Zygotes
haploid cells, somatic cells, zygotes
Interphase is made up of what stages of the cell cycle?
a) G1 + G2 + S
b) S + cytokinesis
c) prophase + metaphase + anaphase + telophase
d) cytokinesis + mitosis
e) G0 + G1 + G2
a) G1 + G2 + S
The sequence of nucleotides in a DNA molecule is called the _____ code.
genetic
According to Chargaff’s rules about proportions of nitrogenous bases,
A=T and G=C
During translation, amino acids are carried to the ribosome by
tRNA
DNA primase
a) creates a short RNA primer that is complementary to an RNA template
b) creates a short DNA primer that is complementary to an RNA template
c) creates a short DNA primer that is complementary to a DNA template
d) creates a short DNA template that is complimentary to an RNA primer
e) creates a short RNA primer that is complementary to a DNA template
e) creates a short RNA primer that is complementary to a DNA template
Which structures indicate where crossing over has occurred?
Chiasmata
Which events occurs first during meiosis?
Sypnapsis of homologous chromosomes
Animal cells typically achieve cytokinesis by
forming a cleavage furrow that pinches the cell into two
At what checkpoint(s) does the cell arrest in response to DNA damage?
G1/S and G2/M
Plant cells typically achieve cytokinesis by:
forming a _____ _____ across the ________ of the cell
forming a cell plate across the middle of the cell
If a chromosome contains a mutation such that it cannot bind to the kinetochore complex, what would be the consequence?
That the chromosome would not be able to bind to the…
mitotic spindle
If there were no suppression of DNA replication between meiotic divisions and cytokinesis proceeded normally, what is the most likely outcome of meiosis?
__ diploid cells
4 diploid cells
The chemical bond connecting one nucleotide with the next long one strand of a DNA molecule is a called a
phosphodiester bond
The point of constriction on chromosomes that contains certain repeated DNA sequences that bind specific proteins is called:
The centromere
Following S phase, a human cell would have how many pairs of sister chromatids and how many individual DNA molecules?
46 pairs of sister chromatids and 92 individual DNA molecules
The stage of mitosis characterized by the physical separation of sister chromatids is called:
Anaphase
The Central Dogma of biology can be stated as
DNA –> RNA –> Proteins
During transcription of mRNA in eukaryotes, some sequences are cut out of the primary transcript and the remaining sequences are joined together. This processing of mRNA is called _______.
splicing
True or False?
The newly synthesized DNA is packaged into one nucleus, and the original DNA is packaged into another nucleus
false
If a short sequence of DNA in 5’ AATTGCCGT 3’, its complement of DNA is
3’ TTACGGCA 5’
Eukaryotic chromosome complexes are composed 60% protein and 40% DNA. This complex is referred to as:
Chromatin
The cell produced by the fusion of an egg and a sperm is the
zygote
A somatic cell from a garden pea plant normally contains 14 chromosomes. How many sister chromatids would that cell contain during G1 of the cell cycle?
0
How does organization of the bacterial genome differ from the organization of the eukaryotic genome?
a) Most bacterial chromosomes are circular and the eukaryotic chromosomes contained in the nucleus are not
b) Bacterial chromosomes are made up of RNA and eukaryotic chromosomes are made up of DNA
c) The eukaryotic genome is found in chromosome
d) Eukaryotic chromosomes have to be tightly packed to fit into the nucleus, and bacterial chromosomes do not require tight packing to fit into the cell
a) Most bacterial chromosomes are circular and the eukaryotic chromosomes contained in the nucleus are not
This stage of the cell cycle is characterized by growth and it contains a checkpoint to verify that all of the DNA has been replicated prior to mitosis
G2
During protein synthesis in eukaryotes, which molecule passes from the nucleus to the cytoplasm and specifies the sequence of amino acids in the new polypeptide?
mRNA
During ________, RNA polymerase synthesizes molecule of RNA using DNA as a template.
transcription
Fitting the very long DNA strands from a chromosome into the limited space of the nucleus is achieved by coiling the DNA around beads of histones with repeating subunits. These DNA-wrapped histones are called:
Nucleosomes
A somatic cell form a corn plant normally contains 20 chromosomes. How many sister chromatids would that cell contain during G2 of the cell cycle?
40
During replication, which enzyme unwinds the DNA double helix?
DNA helicase
The portion of the cell cycle when the cell is growing and does not contain a replicated genome is referred to as:
G1
The stage of cell cycle during which the cytoplasm divides to form two cells is called:
Cytokinesis
Information obtained by Franklin from X-ray crystallography on DNA suggested that it is shaped like a
helix
These structures are held together by cohesin:
Sister chromatids
During what stages of the cell cycle are sister chromatids bound together by cohesin? (4)
S, G2, prophase, metaphase
The two copies of each type of chromosome found in normal somatic (body) cells in an organism, throughout the cell cycle, are called:
homologous chromosomes
_______ is the genetic material for all cellular organism and some viruses
DNA
Before cell division of somatic cells, each chromosomes must be replicated. After replication, the resulting two parts of each chromosome are held together by cohesion at the centromere. These two parts are referred to as:
Sister chromatids
The method of DNA replication, where each original strand is used as a template to build a strand, is called the
semiconservative method
Crick, Brenner, and their colleagues proposed that the genetic code consists of a series of blocks of information, called _______, each corresponding to one amino acid in an encoded protein.
codons
If there are 32 sister chromatids in a normal somatic cell, how many chromosomes are there?
16
When polypeptide is being assembled, the bond that forms between a newly added amino acid and the previous amino acid in the chain is a _________ bond.
peptide
The zygote has _____ copy(ies) of each chromosome
two
Sister chromatids move to opposite poles of the cell during ________________________.
-anaphase II of meiosis
-anaphase of mitosis
Most eukaryotic genes contain noncoding sequences called _________ that are interspersed with the coding sequences representing expressed genes.
introns
Which molecule combines with proteins to form both the large and small ribosomal subunits?
rRNA
If there are 32 sister chromatids in a normal somatic cell, what is the haploid number for that cell?
8
In life cycles that alternate between haploid and diploid stages, fertilization doubles the number of chromosomes per cell while ________ reduces it in half.
meiosis
Telomeres protect the ends of _________ _____________ from nucleuses and are specific _______ ___________ sequences of DNA
linear chromosomes; specific short repeated
Compared to asexual reproduction, the main advantage of sexual reproduction is that it
increases the ________ ________ of offspring
increases the genetic diversity of the offspring
The pairing of chromosomes along their lengths, which is essential for crossing over, is referred to as
synapsis
In eukaryotes, pre-mRNA processing may involve all of the following except
- removal of exons from the pre-mRNA
- addition of a 5’ cap
- addition of a 3’ poly-A tail
- pre-mRNA splicing by the spliceosome
removal of exons from the pre-mRNA
Homologous chromosomes pair along their length during prophase I of meiosis. While two homologues are paired, genetic exchange may occur between them in a process called __________ _______.
crossing over
DNA consists of two antiparallel strands of nucleotides held together by
hydrogen bonds
What is the sequence of events in a typical eukaryotic cell cycle?
G1 to S G2 to mitosis to cytokinesis
