chapter 8 and 11 bio
With the exception of gametes, a human cell contains _____ chromosomes.
46
Which of the following best describes cancer cells?
Controls governing cell division have been altered.
The cell cycle is a series of events that occur in which order?
G1, S, G2, mitosis, cytokinesis
The process of meiosis accomplishes which of the following choices?
It produces four haploid cells and allows exchange of genetic material between homologous chromosomes.
All your cells contain proto-oncogenes, which can change into cancer-causing genes. Why do cells possess such potential time bombs?
Proto-oncogenes are necessary for normal control of cell division.
Which events occur during prophase?
The nuclear envelope breaks down. Chromosomes condense and are attached to spindle fibers.
Replication of chromosomal DNA occurs __________.
before a cell divides
Most human cancers are __________.
caused by an accumulation of mutations
Most of an organism's DNA is carried by its _____.
chromosomes
Meiosis starts with _____ cells and produces _____ gametes.
diploid ... haploid
A cancer cell __________.
does not respond to the signals that control cell division
_____ is a carcinogen that promotes colon cancer.
fat
Cytokinesis _____.
finishes mitosis by dividing the cytoplasm and organelles of the original parent cell into two separate daughter cells
Meiosis and cytokinesis result in the formation of __________.
four haploid cells
The _____ separate in meiosis I; the _____ separate in meiosis II.
homologous chromosomes ... sister chromatids
Orientation of homologous pairs of chromosomes at metaphase I results in alternative arrangements that contribute to genetic variation in offspring. The orientation is called _____.
independent assortment
During _____, the cell carries out its normal functions and the chromosomes are thinly spread out throughout the nucleus.
interphase
Accidents can occur in meiosis wherein members of a chromosome pair fail to separate at anaphase. This is called _____.
nondisjunction
What name is given to a gene that causes cancer?
oncogene
Inheritance of certain genes increases the risk of getting certain cancers; thus, it can be said that ______.
predisposition to these cancers is inherited
Which of the following is the correct order for the four main stages of mitosis?
prophase, metaphase, anaphase, telophase
The genes that malfunction and cause a cell to become cancerous usually __________.
regulate cell division
The function(s) of meiosis is/are _____.
reproduction (production of gametes)
Looking through a light microscope at a dividing cell, you see two separate groups of chromosomes on opposite ends of the cell. New nuclear envelopes are taking shape around each group. The chromosomes then begin to disappear as they unwind. You are witnessing _____.
telophase
Crossing over is __________.
the exchange of corresponding portions of homologous chromosomes
Meiosis is typically accomplished in _____.
three steps. All of the chromosomes are duplicated in a diploid cell, and then there are two cell divisions to produce a total of four haploid gametes.
In sexually reproducing multicellular organisms, the main functions of mitosis are _____.
tissue repair/replacement of damaged cells, growth and development