34 Questions
What process results in the halving of chromosomes and contributes to genetic variation in offspring?
Meiosis
During which stage of the human life cycle does the zygote produce somatic cells by mitosis?
Development into an adult
What is the main difference between gametes and somatic cells in humans?
Number of chromosomes
How do gametes differ from most other cells in the human body?
They are produced by meiosis
What is the significance of the alternation of meiosis and fertilization in sexual life cycles?
Maintains chromosome number
In which type of life cycle do plants and some algae exhibit both a diploid and haploid multicellular stage?
'Alternation of generations'
What holds the homologous chromosomes tightly together during synapsis in meiosis?
Synaptonemal complex
Which statement accurately describes the role of the synaptonemal complex in meiosis?
It holds homologous chromosomes together during prophase I.
Which phase of meiosis involves the breaking and joining of DNA segments between nonsister chromatids?
Prophase I
What is the main difference between the outcomes of mitosis and meiosis?
Mitosis produces genetically identical cells, while meiosis produces genetically diverse cells.
Which process is unique to meiosis I and contributes to genetic diversity?
Crossing over of homologous chromosomes
What occurs after interphase in meiosis that allows sister chromatids to be held together?
Proteins called cohesins
During which phase of meiosis does the synaptonemal complex, facilitating crossing over, form?
Early prophase I
In which phase of meiosis do cohesins get cleaved along the chromosome arms for the separation of homologs?
Anaphase I
What is the role of the synaptonemal complex in meiosis?
Promoting genetic diversity through crossing over
Which event occurs during anaphase I of meiosis?
Separation of homologs
In which phase of meiosis do sister chromatid cohesion allow sister chromatids to stay together?
Metaphase I
At which stage of mitosis are cohesins cleaved?
Metaphase
What is the role of gametes in the human life cycle?
Forming zygotes
What is the haploid number (n) for humans?
23
During which phase of meiosis does crossing over occur?
Prophase II
How do the sister chromatids align during metaphase II in meiosis?
Arranged at the metaphase plate
What characterizes cytokinesis in meiosis I?
Formation of a cleavage furrow
Which event distinguishes prophase II from prophase I of meiosis?
Formation of the spindle apparatus
What is the outcome of anaphase II in meiosis?
'X-shaped' regions separation
How many phases are involved in division during meiosis II?
4
What occurs in metaphase I of meiosis that differentiates it from metaphase in mitosis?
Homologous chromosomes pair up
Which phase involves the separation of homologous chromosomes in meiosis?
Anaphase I
Which mechanism does NOT contribute to genetic variation?
Protein denaturation errors
How many possible combinations of chromosomes can result from independent assortment and sexual reproduction in humans?
70 trillion diploid combinations
What is the original source of all genetic variation?
Mutation
Which process contributes to genetic variation by mixing maternal and paternal chromosomes?
Independent assortment
Random fertilization contributes to genetic variation by:
Allowing any sperm to fuse with any egg, each with a unique combination of chromosomes.
How does crossing over contribute to genetic variation?
By exchanging genetic material between homologous chromosomes.
Test your knowledge on human chromosomes and karyotypes with this quiz. Determine the number of chromosomes in human somatic cells and understand what a karyotype is. Choose the correct answers from the options provided.
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