Biology 1308 CH 8
If a cell begins meiosis with a 2n (diploid) number of 16, how many chromosomes are there in the cell at anaphase I? 64 128 8 16 32
16
If a cell begins meiosis with a 2n (diploid) number of 16, how many chromosomes are there in each cell at metaphase II? 32 16 128 8 64
8
Which of the following allows sexual reproduction to occur generation after generation? Mitosis Cytokinesis Crossing over Meiosis Independent assortment
Meiosis
During which phase of the cell cycle does DNA replication occur? S Cytokinesis M G1 G2
S
In humans, meiosis produces cells that are __________. haploid, called somatic cells diploid and identical haploid, called gametes haploid and identical
haploid, called gametes
Why are no two gametes exactly alike genetically? Because each gamete has a different combination of parental chromosomes that is the result of both crossing over and independent assortment Because each gamete has chromosomes produced through crossing over Because each gamete has a different combination of parental chromosomes Because each gamete undergoes a slightly different version of mitosis during its formation Because cell membranes are unique for each gamete
Because each gamete has a different combination of parental chromosomes that is the result of both crossing over and independent assortment
If a cell has 30 chromosomes before mitosis, how many does each daughter cell have afterward? ANSWER 30 25 10 20 15
30
A human somatic (body) cell has __________ chromosomes. 48 16 23 46 26
46
A human skin cell, in prophase of mitosis, contains 46 chromosomes. How many chromatids does it contain in total? 46 23 or 46, depending on when during prophase you look at the cell 23 92
92
How does meiosis generate genetic diversity? During metaphase I, chromosomes align randomly, and during prophase II, chromosomes exchange material. Homologous chromosomes cross over during prophase I. During metaphase I, chromosomes align randomly. Homologous chromosomes cross over during prophase I, and during metaphase I, chromosomes align randomly. During prophase II, chromosomes exchange material.
Homologous chromosomes cross over during prophase I, and during metaphase I, chromosomes align randomly.
Which of the following is true about prophase I? It occurs only during mitosis. It involves pairing up of homologous chromosomes. It can occur only during wound healing. It involves division of the cytoplasm. Condensed chromosomes begin to uncoil to form chromatin.
It involves pairing up of homologous chromosomes.
Which of the following is true about meiosis II? It results in the production of two haploid cells. It results in cells that have two complete sets of chromosomes. It requires homologous chromosomes to pair up. It results in the production of four haploid cells. It is a process by which genetic material is exchanged between homologous chromosomes.
It results in the production of four haploid cells.
Which of the following terms describes a failure of chromosomes to sort properly during meiosis? Translocation Nondisjunction Inversion Deletion
Nondisjunction
Which of the following is the last stage of mitosis? Anaphase Metaphase Prophase Telophase Cytokinesis
Telophase
While working in a medical clinic, you are asked to assist in the care of a 16-year old female patient who has not yet begun menstruating. You also notice that she is small in stature and has a wider than average neck. You suspect that she might have __________. hemophilia Turner syndrome red-green colorblindness Huntington's disease sickle-cell anemia
Turner syndrome
During meiosis, homologous chromosomes separate at __________. metaphase I anaphase I metaphase II prophase I anaphase II
anaphase I
Homologous chromosomes __________. are inherited from the father only are inherited from the mother only carry the same genes carry the same alleles carry the same DNA sequence
carry the same genes
Crossing over between homologous chromosomes normally occurs __________. during prophase I during anaphase II during mitosis during fertilization
during prophase I
A karyotype __________. is a picture of chromosomes arranged in ordered pairs of a normal human cell shows 48 chromosomes of a normal woman will have both an X and a Y chromosome displays chromosomes from multiple species
is a picture of chromosomes arranged in ordered pairs
The number of chromosomes found in a somatic eukaryotic cell __________. will be larger if the organism is an animal rather than a plant can vary from cell to cell can vary if the organism is young or old is constant during its entire life will decrease during mitosis
is constant during its entire life
Diploid cells become haploid during __________. meiosis I mitosis meiosis II and mitosis meiosis II meiosis I and mitosis
meiosis I
Plant cells divide by __________. mitosis followed by cytokinesis by cell plate formation Cytokinesis by cell plate formation only cytokinesis without mitosis mitosis without cytokinesis
mitosis followed by cytokinesis by cell plate formation
The sex of a human fetus is determined by the __________. time of conception sex chromosome found in the sperm age of the mother sex chromosome found in the egg age of the father
sex chromosome found in the sperm
In meiosis II, __________. crossing over occurs sister chromatids are separated into different daughter cells haploid cells fuse to make a diploid cell homologous chromosomes are separated into different daughter cells
sister chromatids are separated into different daughter cells
