Unit 7 Bio Test Flashcards Preview

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Flashcards in Unit 7 Bio Test Deck (45)

What is a karyotype?

a display of every pair of homologous chromosomes within a cell, organized according to size and shape


Which of the following does NOT occur during interphase?
A) chromatin condensing into chromosomes
B) cell growth
C) DNA synthesis
D) replication of DNA and organelles

A) chromatin condensing into chromosomes


Put these essential steps in meiosis in order to logically illustrate it's sequence
1) formation of four new nuclei, each with half the chromosomes present in the parental nucleus
2) alignment of tetrads at the metaphase plate
3) separation of sister chromatids
4) separation of homologues; no uncoupling of the centromere
5) synapsis; chromosomes moving to the middle of the cell in pairs



What step in meiosis is also in mitosis?

separation of sister chromatids


Which of the following occurs in meiosis but not in mitosis?
A) production of daughter cells
B) synapsis of chromosomes
C) alignment of chromosomes at equator
D) chromosome replication
E) condensation of chromatin

B) synapsis of chromosomes


In animals, meiosis results in gametes, and fertilization results in ___________.



In which stage of meiosis do the centromeres of sister chromatids disjoin and the chromatids themselves separate?

anaphase 2


In which stage of meiosis do the tetrads of chromosomes align at the equator of the spindle; alignment determines independent assortment?

metaphase 1


In which stage of meiosis does synapsis of homologous pairs occur; crossing over may occur?

prophase 1


Cells grown in a petri dish tend to divide until they form a thin layer covering the bottom of the dish. If cells are removed from the middle layer of the dish, the cells bordering the open space will begin dividing until they have filled the empty space. What does this experiment show?

the controls on cell growth and division can be turned on and off


The daughter cells of binary fission are ____________.

genetically identical


Asexual reproduction results in identical offspring unless what occurs?

crossing over


Which of the following is true concerning cancer cells?
A) they do not exhibit density-dependent inhibition when growing in culture
B) when they stop dividing, they do so at random points in cell cycle
C) they are not subject to cell cycle controls
D) B and C only
E) A, B, and C

E) A, B, and C


An advantage of sexual reproduction over asexual reproduction is that sexual reproduction ________________.

provides genetic diversity


If there are 20 chromatids in a cell, how many centromeres are there?



After telophase 1 of meiosis, the chromosomal makeup of each daughter cell is ______________.

haploid, and the chromosomes are each composed of two chromatids


Nondisjunction can occur in meiosis 1 and/or meiosis 2. What haploid cell would result if nondisjunction occurred during anaphase of meiosis 1?

two cells with n+1 chromosomes, and two cells with n-1 chromosomes


A human cell containing 22 autosomal and a Y chromosome is ___________.

a sperm


Why do chromosomes coil during mitosis?

to allow the chromosomes to move without becoming entangled and breaking


Vinblastin is a drug that interferes with the assembly of microtubules. It is widely used for chemotherapy in treating cancer patients whose cells are actively dividing to form tumors. How do you think Vinblastin slows tumor growth?

the drug blocks the spindle fibers from forming therefore mitosis can not occur


What does NOT happen during mitosis?

production of diploid cells


If there are 12 chromosomes in an animal cell in the G1 stage, what is the haploid number of chromosomes for this organism?



Cancer cells divide uncontrollably and often send chemical signals causing blood vessels to grow towards them and provide nutrients. This process is called _______________.



What is the difference between a benign and a malignant tumor?

benign tumors don't metastasize; malignant tumors do


How do the daughter cells at the end of mitosis and cytokinesis compare with their parent cell when it was in G1 of the cell cycle?

the daughter cells have the same amount of chromosomes and the same amount of DNA


In eukaryotic cells, the timing of the cell cycle is regulated by proteins called _________.



Oncogenes are mutated genes that ____________.

were originally proto-oncogenes and do not listen to cell signals and continue cell division; like a gas pedal in a car stuck down


Chromosomes form tetrads during ___________.

prophase 1 of meiosis


The somatic cells derived from a single-celled zygote divide by which process?



If a p53 is mutated, the cell will _________.

continue to divide


If cells in the process of dividing are subjected to colchicine, a drug that interferes with the functioning of the spindle apparatus, at which stage will mitosis be arrested?



What is the role of the spindle fibers during mitosis?

they help separate sister chromatids


How can a gene be mutated with no resulting change in the protein that is produced from that gene?

A codon has changed, but it codes for the same amino acid as the original codon


Which is true of a species with the chromosome number of 2n=16?
A) the species is diploid with 32 chromosomes per cell
B) each cell has 8 homologous pairs
C) the species has 16 sets of chromosomes per cell
D) during the S phase of the cell cycle there will be 32 separate chromosomes

B) each cell has 8 homologous pairs


Starting with a fertilized egg(zygote), a series of five cell divisions would produce an early embryo with how many cells?



Besides the ability of some cancer cells to overproliferate (divide too much), what else could logically result in a tumor?

lack of appropriate cell death


The human X and Y chromosomes ____________.

include genes that determine an individual's sex


What kind of mutation occurs when one base is changed to another at a single location on the DNA?

substitution (point)


Cell reproduction in prokaryotic cells differ from eukaryotic cells in that ______________.

each prokaryotic cell has a circular chromosome but the chromosomes of eukaryotic cells are linearly condensed into chromosomes


A cell containing 92 chromatids at metaphase of mitosis would, at its completion, produce two nuclei each with how many chromosomes?



A "mini gene" allele has the following sequence:

What would be the consequence if the first nucleotide of the sequence was deleted?

all of the codons after that point will be changed


The fusion of vesicles from the Golgi across the middle of a cell and nuclei are re-forming at opposite ends of the cell. What kind of cell is this?

a plant cell undergoing cytokinesis


Independent assortment of the chromosomes is a result of ___________.

the random and independent way in which each pair of homologous chromosomes lines up at the metaphase plate during meiosis 1


Chiasmata are what we see under the microscope hat let us know that what occurred?

crossing over


During normal mitosis cell division, a parent cell that has four chromosomes will produce two daughter cells, each containing _________.

four chromosomes