Biology: Chapter 9 - Sexual Reproduction and Meiosis
_____________ allows the reassortment of parental combinations of alleles.
Crossing over
Chromosomes that look alike and carry the same sequence of genes for the same traits are
homologous chromosomes.
A diploid germ cell will produce cells that have reduced the chromosome number by half, generating four haploid nuclei in
meiosis
The gene shuffling that occurs during _________ allows two parents to produce genetically diverse offspring.
meiosis
Centromeres divide in
mitosis and meiosis II.
Meiotic cell division replicates a cell's DNA ____________ and then divides ______________.
once, twice
Crossing over occurs during ___________ of meiosis.
prophase I
In meiosis, homologous chromosomes align next to one another during
prophase I
In which stage of meiosis does recombination, or crossing over, occur?
Prophase I
Drag a label to identify what stage of meiosis each image represents.
Prophase I and Telophase II
During meiosis II, what are pulled apart during anaphase II?
Sister chromatids
In humans, which parent determines the sex of the child?
the father
Use the animation and your knowledge of crossing over to select the true statement.
No answer is correct.
Consider the image below, which shows a cell nucleus with one pair of homologous chromosomes. Then, click on all of the true statements.
-Chromatid A will separate from chromatid B during anaphase II. -Chromatid D will line up next to chromatid A during metaphase II. -Chromosome AB will separate from chromosome CD during anaphase II. -Chromatid C will separate from chromatid D during anaphase I.
Drag a label to identify what stage of meiosis each image represents.
-Metaphase II -Anaphase I -Anaphase II -Telophase I -Metaphase I
Which of the following statements is/are true about meiosis? Select all that apply.
-The daughter cells of meiosis have half as many chromosomes as the parent cell. -Meiosis produces gametes. -Meiosis produces four haploid cells. -Meiosis produces nonidentical cells.
Use the drop-down menus to answer the following questions about chromosomes. For all questions, assume that individuals of this species typically have 24 chromosomes in diploid cells. 1. Individuals have _____ chromosomes in haploid cells. 2. When two haploid gametes combine, a zygote with _____ chromosomes forms. 3. Suppose an error in meiosis produced diploid gametes. After fertilization, each offspring would have _____ chromosomes in its diploid cells.
1. 12 2. 24 3. 48
Arrange the following events in the proper order in which they occur during meiosis I. 1 = Separation of homologous chromosomes 2 = Coming together of homologous chromosomes 3 = Crossing-over 4 = Random alignment of homologous chromosomes at cell equator
2, 3, 4, 1
A cell in your heart or lungs or bones is not doing sexual reproduction. Think wound healing. These cells are said to be ___.
2n, diploid
In meiosis, a cell divides into:
4 cells, each contains half the original number of DNA
Sperm and eggs are:
Haploid, n
During meiosis I, what are pulled apart during anaphase I?
Homologous chromosomes
The importance of crossing over is to:
Increase variability
Which process must occur in order for sexual reproduction to occur?
Meiosis
In which stage does crossing over occur?
Meiosis I
Autosomes are the chromosomes that code for body traits such as arms and legs, and do NOT take part in sex determination.
true
Down syndrome results when a kid receives an extra copy of the 21st chromosome.
true
Each person receives a copy of each chromosome from each parent.
true
In people, the male sex chromosome is the Y.
true
Somatic cells are the cells that make up muscles, skin, and are referred to as "body cells" and are not used to create sperm and eggs.
true
In which of these birth control methods are the uterine tubes cut, so that oocytes never reach uterus?
tubal ligation
Diploid means having
two complete sets of chromosomes.
If crossing over occurrs only between two genes on homologous chromosomes, what combinations are produced in the gametes?
two gametes with parental combinations of alleles, and two recombinant gametes