final exam Flashcards
Separation of the sister chromatids is a characteristic of which stage of mitosis?
prometaphase
metaphase
anaphase
telophase
anaphase
What is a disadvantage of sexual reproduction over asexual forms of reproduction?
Half the population is capable of carrying offspring.
Identical offspring are not produced.
Adaptation to rapidly changing environments is more difficult.
Mutation rates are slower.
Half the population is capable of carrying offspring.
At which of the cell-cycle checkpoints do external forces have the greatest influence?
G1 checkpoint
G2 checkpoint
M checkpoint
G0 checkpoint
G1 checkpoint
FtsZ proteins direct the formation of a ________ that will eventually form the new cell walls of the daughter cells.
contractile ring
cell plate
cytoskeleton
septum
septum
Unpacking of chromosomes and the formation of a new nuclear envelope is a characteristic of which stage of mitosis?
prometaphase
metaphase
anaphase
telophase
telophase
What is the initial mechanism for repairing nucleotide errors in DNA?
DNA polymerase proofreading
mismatch repair
nucleotide excision repair
thymine dimers
DNA polymerase proofreading
During which phase of meiosis does the second round of genetic variation occur?
anaphase I
metaphase I
prophase II
Genetic variation only occurs during prophase I.
prophase II
What is a source of genetic variation in asexual reproduction?
crossing over of chromosomes
mutation of DNA
random assortment of chromosomes
There is no variation in asexual reproduction.
random assortment of chromosomes
What type of nucleic acid material is analyzed the most frequently in forensics cases?
cytoplasmic rRNA
mitochondrial DNA
nuclear chromosomal DNA
nuclear mRNA
nuclear chromosomal DNA
Which enzyme initiates the splitting of the double DNA strand during replication?
DNA gyrase
helicase
ligase
telomerase
helicase
During proofreading, which of the following enzymes reads the DNA?
DNA polymerase
helicase
topoisomerase
primase
DNA polymerase
Uracil is found where?
chromosomal DNA
helicase
mitochondrial DNA
mRNA
mRNA
The ends of the linear chromosomes are maintained by what?
DNA polymerase
helicase
primase
telomerase
telomerase
What structure is most important in forming the tetrads?
centromere
chiasmata
kinetochore
synaptonemal complex
synaptonemal complex
An organism’s traits are determined by the specific combination of inherited:
- cells
- genes
- proteins
- chromatids
genes
Which enzyme is most directly responsible for the main process of producing a new DNA strand?
DNA polymerase I
DNA polymerase II
DNA polymerase III
DNA polymerase I, DNA polymerase II, and DNA polymerase III
DNA polymerase III
The fusing of Golgi vesicles at the metaphase plate of dividing plant cells forms what structure?
cell plate
actin ring
cleavage furrow
mitotic spindle
cell plate
If the M checkpoint is not cleared, what stage of mitosis will be blocked?
prophase
prometaphase
metaphase
anaphase
anaphase
Which of the following is not involved during the formation of the replication fork?
helicase
ligase
origin of replication
single-strand binding proteins
ligase
The first level of DNA organization in a eukaryotic cell is maintained by which molecule?
cohesin
condensin
chromatin
histone
histone
What is the main prerequisite for clearance at the G2 checkpoint?
cell has reached a sufficient size
an adequate stockpile of nucleotides
accurate and complete DNA replication
proper attachment of mitotic spindle fibers to kinetochores
accurate and complete DNA replication
Which molecule is a Cdk inhibitor that is controlled by p53?
cyclin
anti-kinase
Rb
p21
p21
Nucleotide excision repair is often employed when UV exposure causes the formation of what?
phosphodiester bonds
purine conjugates
pyrimidine dimers
tetrad disassembly
pyrimidine dimers
Which of the following events does not occur during some stages of interphase?
DNA duplication
organelle duplication
increase in cell size
separation of sister chromatids
separation of sister chromatids
Identical copies of chromatin held together by cohesin at the centromere are called _____.
histones.
nucleosomes.
chromatin.
sister chromatids.
sister chromatids
If DNA of a particular species was analyzed and it was found that it contains 27% A, what would be the percentage of C?
23%
27%
30%
54%
23%
Many of the negative regulator proteins of the cell cycle were discovered in what type of cells?
gametes
cells in G0
cancer cells
stem cells
cancer cells
At metaphase I, homologous chromosomes are connected only at what structures?
chiasmata
kinetochores
microtubules
recombination nodules
chiasmata
Provide a name for a haploid cell produced by meiosis in a diploid-dominant organism.
gamete
gametophyte
spore
sporophyte
gamete
What happens when a dideoxynucleotide is added to a developing DNA strand?
The chain extends to the end of the DNA strand.
The DNA strand is duplicated.
The chain is not extended any further.
The last codon is repeated.
The chain is not extended any further.
Meselson and Stahl’s experiments proved that DNA replicates by which model?
conservative
converse
dispersive
semi-conservative
semi-conservative
If the sequence of the 5’ to 3’ strand is AATGCTAC, then the complementary sequence has the following sequence:
3’-AATGCTAC-5’
3’-CATCGTAA-5’
3’-TTACGATG-5’
3’-GTAGCATT-5’
3’-TTACGATG-5’
Separation of the sister chromatids is a characteristic of which stage of mitosis?
prometaphase
metaphase
anaphase
telophase
anaphase
The DNA double helix does not have which of the following?
antiparallel configuration
complementary base pairing
major and minor grooves
uracil
uracil
Chromosomes are duplicated during what portion of the cell cycle?
G1 phase
S phase
prophase
prometaphase
S phase
Which eukaryotic cell-cycle event is missing in binary fission?
cell growth
DNA duplication
mitosis
cytokinesis
mitosis
Which eukaryotic cell-cycle event is missing in binary fission?
cell growth
DNA duplication
karyokinesis
cytokinesis
karyokinesis
The individual chromosomes become visible with a light microscope during which stage of mitosis?
prophase
prometaphase
metaphase
anaphase
prophase
Which type of point mutation would result in the substitution of a stop codon for an amino acid?
frameshift
missense
nonsense
silent
nonsense
Which protein is a positive regulator that phosphorylates other proteins when activated?
p53
retinoblastoma protein (Rb)
cyclin
cyclin-dependent kinase (Cdk)
cyclin-dependent kinase (Cdk)
In eukaryotes, what is DNA wrapped around?
histones
polymerase
single-stranded binding proteins
sliding clamp
histones
Due to a mutation, the nucleotide sequence ATC-CAG-AGA becomes ATT-CAG-AGA on a gene. (Protein table is on next page) and mRNA is (AUU-CAG-AGA) after mutation.
What type of mutation would this be?
Silent mutation.
Missense mutation.
Nonesense mutation.
Frameshift mutation.
Silent mutation.
What part of meiosis is most similar to mitosis?
reduction division
interkinesis
meiosis I
meiosis II
meiosis II
Which enzyme is only found in prokaryotic organisms?
DNA gyrase
helicase
ligase
telomerase
DNA gyrase
Which type of point mutation would have no effect on gene expression?
frameshift
missense
nonsense
silent
silent
What is necessary for a cell to pass the G2 checkpoint?
cell has reached a sufficient size
an adequate stockpile of nucleotides
accurate and complete DNA replication
proper attachment of mitotic spindle fibers to kinetochores
accurate and complete DNA replication
A mutated gene that codes for an altered version of Cdk that is active in the absence of cyclin is a(n) _____.
kinase inhibitor.
tumor suppressor gene.
proto-oncogene.
oncogene.
oncogene
Which of the following does the enzyme primase synthesize?
DNA primer
Okazaki fragments
phosphodiester linkage
RNA primer
RNA primer
What is the name of the method developed by Fred Sanger to sequence DNA?
dideoxy chain termination method
double helix determination
polymerase chain reaction
polymer gel electrophoresis
dideoxy chain termination method
Which of the following statements is not true in relation to crossing over?
Chiasmata are formed.
Non-sister chromatids exchange genetic material.
Recombination nodules mediate cross over events.
Spindle microtubules guide the movement of chromosomal material.
Spindle microtubules guide the movement of chromosomal material.
Chromosomes are duplicated during what stage of the cell cycle?
G1 phase
S phase
prophase
prometaphase
S phase
What is a purine?
a double ring structure with a six-membered ring fused to a five-membered ring
a single six-membered ring
a six-membered ring
three phosphates covalently bonded by phosphodiester bonds
a double ring structure with a six-membered ring fused to a five-membered ring
In which direction does DNA replication take place?
5’ to 3’
3’ to 5’
5’
3’
5’ to 3’
At which stage of meiosis are sister chromatids separated from each other?
anaphase I
anaphase II
prophase I
prophase II
anaphase I
________ are changes to the nucleotides in a segment of DNA that codes for a protein.
Proto-oncogenes
Tumor suppressor genes
Gene mutations
Negative regulators
Gene mutations
A gene that codes for a positive cell cycle regulator is called a(n) ________.
kinase inhibitor
tumor suppressor gene
proto-oncogene
oncogene
proto-oncogene
Which portion of a chromosome contains Okazaki fragments?
helicase
lagging strand
leading strand
primer
lagging strand
You have developed a mutation that leads to skin cancer and you are pregnant. You are worried that your child will be born with the cancer mutation you have while carrying the baby. Should you be worried?
Yes, the cancer can spread to the baby.
No, the mutations causing the cancer are in somatic cells, not reproductive germ cells.
Yes, the mutations can be passed on to the child through the placenta.
No, UV light only affects adult, somatic cells.
No, UV light only affects adult, somatic cells.
How many and what type of daughter cells does meiosis produce?
four haploid
four diploid
two haploid
two diploid
four haploid
Attachment of the mitotic spindle fibers to the kinetochores is a characteristic of which stage of mitosis?
prophase
prometaphase
metaphase
anaphase
prometaphase
The mitotic spindles arise from which cell structure?
centromere
centrosome
kinetochore
cleavage furrow
centrosome
A gene that codes for a positive cell-cycle regulator is called a(n) _____.
kinase inhibitor.
tumor suppressor gene.
proto-oncogene.
oncogene.
proto-oncogene
Which negative regulatory molecule can trigger cell suicide (apoptosis) if vital cell cycle events do not occur?
p53
p21
retinoblastoma protein (Rb)
cyclin-dependent kinase (Cdk)
p53
