Biology - Ch. 8
Cell division will accomplish which of the following functions in your body? Select all that apply.
-Growth and development -Cell replacement -Production of gametes
What is different concerning the DNA in bacterial cells as opposed to eukaryotic cells? (Select all that apply.)
-Whether the DNA is housed in a nucleus or not -Whether the DNA is linear or circular -The amount of DNA present
Homologous chromosomes
-are the same size -have the same genes at the same loci -can contain different versions of the same gene at the same loci
Humans have __ pairs of chromosomes. ___ pair(s) are autosomes and ____ pair(s) are sex chromosomes.
23...22...1
If a species of animal has six pair of chromosomes, how many DNA molecules would be present at the end of the S phase of Interphase?
24
A male organism of a species produces a sperm that is 4n, and the female produces an egg that is also 4n. If those two gametes fused, what would the resulting zygote be?
8n
How can you tell that the following image is a picture of a plant finishing cytokinesis?
A cell plate is forming.
Benign tumor
A lump of abnormal cells, that although growing out of control, remains at the original site
Cancer
A malignant tumor
Malignant tumor
Abnormally growing mass of cells that is actively spreading through the body
What is the difference between a benign tumor and a malignant tumor?
Benign tumors do not metastasize; malignant tumors do.
Haploid
Cell with a single set of chromosomes, n
Diploid
Cell with pairs of homologous chromosomes, 2n
Anaphase
Centromeres come apart and daughter chromosomes move toward opposite sides of the cell
Metaphase
Chromosomes aline at equator; mitotic spindle fully formed
Prophase
Discrete chromosomes appear; mitotic spindle begins to form; nuclear envelope begins to dissolve
Mitosis
Division of a cell's chromosomes; consists of PMAT
Cytokinesis
Division of the cytoplasm including organelles
True or false. Mitosis takes place during M phase of the cell cycle, which is longer than interphase.
False; interphase is the longest phase of the cell cycle
G1
First gap; normal cell functions occur
The function of meiosis is to make __________.
Four cells each with a haploid number of chromosomes
Fertilization
Fusion of an egg and sperm cell
Where are the three cell cycle checkpoints located in the cell cycle?
G1, G2, and Metaphase
The cell is performing normal functions
Interphase
After fertilization, the resulting zygote begins to divide by __________.
Mitosis
Accounts for only 10% of the cell cycle:
Mitosis/Mitotic phase
Carcinoma
Most common type of cancer, originates in tissues that line organs or epithelial tissues of the skin
Interphase
Normal cell functions; consists of G1, S, G2.
Telophase
Nuclear envelopes develop; chromatin fiber uncoils; end of mitosis
Crossing over occurs during _____.
Prophase I
During which stage of meiosis do synapsis and crossing over occur?
Prophase I
DNA replication occurs
S phase
G2
Second gap; cell completes preparations for cell division
Which of the following statements regarding mitosis and meiosis is true?
Sister chromatids separate during anaphase of mitosis and anaphase II of meiosis.
Metastasis
Spread of cancer cells from their site of origin to other sites in the body
S
Synthesis of DNA; chromosomes are duplicated
You and your lab partner are observing a cell under a microscope, but you do not know whether it is a eukaryote or a prokaryote. Which of the following observations regarding the chromosomes would you use to immediately conclude that the cell is a eukaryote?
The chromosomes are housed in a membrane-enclosed nucleus.
True or false: Binary fission is considered asexual reproduction.
True
Which of the following would result in a normal individual?
XYY
According to the graph, at what maternal age is the incidence of Down syndrome equal to five times the incidence at age 40?
about 46 or 47
Crossing over is important because it _____.
allows the exchange of genes between homologous chromosomes
The creation of genetically identical offspring by a single parent, without the participation of sperm and egg, is called
asexual reproduction.
Asexual and sexual reproduction differ in that sexual reproduction _____.
can produce great variation among the offspring
Karyotyping
can reveal alterations in chromosome number.
Which of the following occurs during interphase?
cell growth and duplication of the chromosomes
A cleavage furrow forms in animal cells during
cytokinesis
Division of the cytoplasm
cytokinesis
The process by which the cytoplasm of a eukaryotic cell divides to produce two cells is called
cytokinesis
As a patch of scraped skin heals, the cells fill in the injured area but do not grow beyond that. This is an example of
density-dependent inhibition.
Zygote
fertilized egg, has 2n set of chromosomes and begins division via mitosis.
Without crossing over,
genetic recombination could not occur.
During anaphase I, _____ and during anaphase II, _____ .
homologous chromosomes separate.... sister chromatids separate
Two chromosomes in a nucleus that carry genes controlling the same inherited characteristics are
homologous chromosomes.
Both mitosis and meiosis are preceded by
interphase.
During which phase of mitosis do the chromosomes line up on a plane equidistant from the two spindle poles?
metaphase
The chromosomes divide
mitosis
Gamete
name for egg and sperm cells, contain single set of chromosomes, n
Somatic cells
non-sex cells
Independent orientation of chromosomes at metaphase I results in an increase in the number of
possible combinations of characteristics.
Gonad cell
sex cells, produce gametes
Prior to mitosis, each chromosome of a eukaryotic cell consists of a pair of identical structures called
sister chromatids.
The genetic material is duplicated during
the S phase.
At the start of mitotic anaphase,
the centromeres of each chromosome come apart.
Mitosis and cytokinesis result in the formation of __________; meiosis and cytokinesis result in the formation of __________.
two diploid cells .... four haploid cells
When comparing the base sequence in sister chromosomes, they
will be identical.
Prokaryotic DNA differs from eukaryotic DNA because it
consists of a single circular chromosome.
Meiosis
division of nuclei, ending with four n cells
Mitosis
division of nuclei, ending with two 2n cells
Crossing over
exchange of corresponding segments of non-sister chromatids of homologous chromosomes
If these four cells resulted from cell division of a single cell with diploid chromosome number 2n = 4, what best describes what just occurred?
nondisjunction
In meiosis, a mistake where homologous chromosomes do not separate properly is called _____.
nondisjunction
Down syndrome results from
nondisjunction where the person has 3 copies of chromosome 21.
Karyotype
ordered display of an organisms chromosomes.
Synapsis
pairing of homologous chromosomes during prophase I
A cell that has a cell wall is undergoing cell division, and the following events are observed: the formation of a cell plate and the division of the cell into two daughter cells. What type of cell is being observed and what process(es) is it going through?
plant cell; telophase and cytokinesis of mitosis
Looking into your microscope, you spot an unusual cell. Instead of the typical rounded cell shape, the cell has a very narrow middle separating two bulging ends. It sort of looks like the number 8! You realize that this cell is
undergoing cytokinesis.