Reproductive cells in most species are different from the cells that make up the rest of the organism. What are the “body” cells called and how are they different from the reproductive cells?
- Body cells are called gametes and they have half the number of chromosomes found in reproductive cells.
- Body cells are called somatic cells and have the same number of chromosomes as reproductive cells.
- Body cells are called somatic cells and have double the number of chromosomes found in reproductive cells.
- Body cells are called gametes and have double the number of chromosomes found in reproductive cells.
Spores are structures produced by some plants and all fungi. Which is true about them?
- Spores are haploid reproductive cells that can produce haploid organisms through mitosis.
- Spores are haploid precursors to gametes that give rise to gametes when environmental conditions are favorable.
- Spores are haploid reproductive cells that can produce diploid cells without fertilization.
- Spores are haploid cells formed only during asexual reproduction and so are not formed by meiosis.
In prophase I, the homologous chromosomes are paired up and linked together. What binds the chromosomes together and maintains their alignment?
- cohesin proteins
- the centromere
- synaptonemal complex
One of the ways that sexual reproduction enhances the diversity of offspring from the same parents is through a process called crossing over. What entities does this occur between during prophase I?
- sister chromatids
- non-homologous chromosomes
- non-sister chromatids of homologous chromosomes
There are three sources of genetic variation in sexual reproduction. Which is not considered random?
- All are random.
- Crossing over
- Egg and sperm fertilization
- Tetrad alignment on the meiotic spindle.
Which one of the three types of life cycles of sexually reproducing organisms does not have a multicellular haploid stage?
- alternation of generations
- They all have a multicellular haploid stage in their life cycles.
How are spores produced in alternation of generation life cycles?
- by gametophytes
- by germ cells
- through mitosis
- through meiosis
What is one thing that is true of haploid-dominant life cycles but not of alternation of generation life cycles?
- (+) and (−) mating types
- a free-living haploid stage