Table of Contents
- 1 Why is the homologous chromosome The main character in the production of gametes?
- 2 Are homologous chromosomes genetically identical?
- 3 Why do homologous chromosomes separate during meiosis?
- 4 How are homologous chromosomes different?
- 5 When does an organism have only one pair of chromosomes?
- 6 Can a gamete have two alleles of any gene?
Why is the homologous chromosome The main character in the production of gametes?
The pairing up of homologous chromosomes during meiosis is important to promote genetic variation. Because of the genetic recombination that occurs between homologous pairs at meiosis, the resulting haploid gametes contain chromosomes that are genetically different from each other.
Are homologous chromosomes genetically identical?
Since homologous chromosomes are not identical and do not originate from the same organism, they are different from sister chromatids. Sister chromatids result after DNA replication has occurred, and thus are identical, side-by-side duplicates of each other.
What happens to homologous chromosomes during meiosis?
When recombination occurs during meiosis, the cell’s homologous chromosomes line up extremely close to one another. Then, the DNA strand within each chromosome breaks in the exact same location, leaving two free ends. Each end then crosses over into the other chromosome and forms a connection called a chiasma.
What are homologous chromosomes quizlet?
Homologous chromosomes are chromosome pairs, one from each parent, that are similar in length, gene position and centromere location. Homologous chromosomes are similar but not identical. Each carries the same genes in the same order, but the alleles for each trait may not be the same.
Why do homologous chromosomes separate during meiosis?
During meiosis, the pairs of homologous chromosome are divided in half to form haploid cells, and this separation, or assortment, of homologous chromosomes is random. This means that all of the maternal chromosomes will not be separated into one cell, while the all paternal chromosomes are separated into another.
How are homologous chromosomes different?
The two chromosomes in a homologous pair are very similar to one another and have the same size and shape. Aside from small regions of similarity needed during meiosis, or sex cell production, the X and Y chromosomes are different and carry different genes. The 44 non-sex chromosomes in humans are called autosomes.
Are there homologous chromosomes in gametes?
Homologous chromosomes have the same genes, though they may have different alleles. So, though homologous chromosomes are very similar, they are not identical. The homologous chromosomes are separated when gametes are formed. Therefore, gametes have only 23 chromosomes, not 23 pairs.
Why do gametes have more than one sex chromosome?
Many organisms have sex chromosomes that are only present in one copy in the diploid organism [choice (c)]. Gametes have only one member of each pair of homologous chromosomes, but because most organisms have more than one pair of homologous chromosomes, most gametes have more than one chromosome [choice (d)].
When does an organism have only one pair of chromosomes?
Each organism has a diploid complex of chromosomes, when it has only one pair, it indicates that it has homologous pairing of the chromosome.
Can a gamete have two alleles of any gene?
Many alleles can exist for any gene [choice (a)], and a diploid individual can have either two different or two identical alleles of any given gene [choice (b)]. Every gamete only has a single allele of any gene [choice (c)].
How are haploid cells used to reproduce in animals?
19-6 To reproduce sexually, an organism must create haploid *germ* cells, or *gametes*, from diploid cells via a specialized cell division called *meiosis*. During mating, the father’s haploid cells, called *sperm* in animals, fuse with the mother’s haploid cells, called *eggs*.