A diploid human cell contains:
92 chromosomes
23 chromosomes
46 chromosomes
23 pairs of identical chromatids
A gamete is:
Haploid
A type of somatic cell
Diploid
Always produced by mitosis
A homologous pair of chromosomes:
Has the same genes at the same loci
Is formed only during mitosis
Carries identical alleles
Has different lengths and centromere positions
Crossing-over occurs during:
Metaphase I
Telophase I
Prophase I
Anaphase II
Independent assortment happens because homologous chromosomes:
Move to opposite poles during Telophase II
Replicate independently
Orient randomly at the equator during Metaphase I
Mutate randomly
Meiosis II resembles mitosis because:
Homologous pairs separate
Chromatids separate
DNA replication occurs
Crossing-over happens
A species has a diploid number of 24. Its haploid number is:
6
24
48
12
A cell showing chromatids being pulled to opposite poles is in:
Metaphase II
Telophase I
Anaphase I
Anaphase II
During Anaphase I, which of the following occurs?
Nuclear envelope reforms
Sister chromatids separate
Homologous chromosomes separate
Crossing-over occurs
Which stage directly produces four haploid cells?
Metaphase II
Telophase I
Prophase II
Telophase II
Which of the following best explains why meiosis leads to genetic variation?
Crossing-over and independent assortment generate new allele combinations
Homologous chromosomes pair randomly with non-homologous ones
DNA replication is error-free
Cytokinesis divides cytoplasm unevenly
In humans, how many possible combinations of chromosomes can result from independent assortment alone?
2^12
23^2
46^2
2^23
Which of the following happens in BOTH mitosis and meiosis?
Separation of sister chromatids
Formation of bivalents
Crossing-over
Separation of homologous chromosomes
A cell with 16 chromosomes undergoes meiosis. How many chromosomes will each gamete contain?
16
4
32
8
Crossing-over occurs between:
Any two random chromosomes
Non-sister chromatids of homologous chromosomes
Sister chromatids of the same chromosome
Centromeres only
Which event ensures that chromosome number is halved in meiosis?
Cytokinesis in Meiosis II
Separation of homologous chromosomes in Meiosis I
Crossing-over
DNA replication
During which phase do homologous chromosomes form bivalents?
Anaphase II
Prophase I
Metaphase II
Telophase I
The point where crossing-over occurs is called:
Centrosome
Centromere
Kinetochore
Chiasma
Which statement is TRUE about meiosis but NOT mitosis?
Chromosomes align at the equator
DNA replication occurs before division
Chromatids separate
Homologous chromosomes pair up
Independent assortment occurs because:
Chromosomes replicate randomly
DNA mutations occur during replication
Sister chromatids separate at different speeds
Homologous pairs line up randomly during Metaphase I
Which structure attaches chromosomes to the spindle?
Nucleolus
Ribosome
Vesicle
Centromere
A photomicrograph shows TWO new nuclei forming in ONE dividing cell. This stage is most likely:
Prophase II
Anaphase I
Telophase I
Metaphase II
A species has 50 chromosomes in diploid cells. How many different chromosome combinations can result from independent assortment?
2^50
2^25
25^2
50^2
Which of the following INCREASES genetic variation?
Chromosome condensation
Crossing-over
Nuclear envelope breakdown
Equal cytoplasm division
A cell in metaphase II will show:
Chromatids moving to opposite poles
Homologous pairs in the middle
Chromosomes in single file at the equator
Cytoplasm dividing
In which stage do centromeres split?
Prophase I
Anaphase II
Anaphase I
Telophase II
The formation of four genetically different gametes is the result of:
Meiosis I and meiosis II together
DNA replication
Nuclear envelope breakdown
Cytokinesis only
Sister chromatids become chromosomes during:
Metaphase I
Anaphase II
Prophase I
Telophase I
The random fusion of gametes contributes to variation because:
Any sperm can fertilise any egg
Only some sperm contain DNA
The zygote duplicates its chromosomes randomly
Gametes are always genetically identical
A student observes a cell with 4 groups of chromosomes and the cytoplasm beginning to divide. This stage is:
Telophase II
Prophase II
Telophase I
Anaphase I