BIO 101 HOLIDAY ASSIGNMENT
Answer All Questions
1. Normal human cell contains 23 pairs of chromosomes
2. Differentiate between synapsis and crossing over
- Synapses is the pairing of homologous chromosomes while crossing over is the exchange of
genetic materials between paired homologous chromosomes.
- Synapses allows matching chromosomes to line up accurately while crossing over swaps DNA
segments between chromosomes.
- Synapses prepares chromosomes for genetic exchange to occur while crossing over increases
genetic variation in offspring
3. Mention 5 differences between mitosis and meiosis.
In mitosis, diploid number of chromosomes are produced while in meiosis, haploid
number of chromosomes are produced
Mitosis occurs in body/ somatic cells while meiosis occurs only in reproductive cells.
Two daughter cells are formed in mitosis while in meiosis, four daughter cells are
formed.
In mitosis, daughter cells are identical to parent cells while in meiosis, variation exists
between daughter cells and parent cells.
Mitosis occurs in one stage while meiosis occurs in two stages.
4. Differentiate between Cleavage and chiasmata
A cleavage is a series of rapid cell divisions of a fertilized egg (zygote), while Chiasmata
are the X shaped structures where homologous chromosomes physically cross over and
exchange genetic materials during meiosis.
Cleavage occurs in the early embryonic stage while Chiasmata occurs in meiosis -
specifically in Prophase 1
In a cleavage, there is no exchange of genetic materials while in the chiasmata exchange
of genetic materials occur
5. Mention and explain the stages of mitosis.
Interphase
Prophase
Metaphase
Anaphase
Telophase
, Interphase: is the resting stage of the cell. Chromosomes are invisible.
Prophase: Chromosomes shorten (condense) and become visible. Spindle fibre begins to form.
Metaphase: Chromosomes align at the equator of the cell. Spindle fibres attach to the
centromeres attempting to pull individual chromatids away from each other.
Anaphase: Spindle fibres pull chromatids to opposite poles of the cell.
Telophase: Nuclear membranes reform around each set of chromosomes. Spindle fibres
disappear. Cytokinesis occurs.
6. What is a tetrad?
A tetrad is a structure made up of four chromatids formed when homologous chromosomes pair
during Prophase 1 of meiosis.
7. Differentiate between cytokinesis and karyokinesis?
Cytokinesis is the division of the cytoplasm while Karyokinesis is the division of the
nucleus.
Cytokinesis occurs after nuclear division while Karyokinesis occurs during mitosis and
meiosis
Cytokinesis produces two separate cells while Karyokinesis produces two daughter
nuclei.
8. State one significance of meiosis.
- It brings about genetic variation
9. What is binary fission and mention 2 organisms that reproduce through binary fission?
- Binary fission is a simple, asexual reproduction method where a single parent cell divides into
two genetically identical daughter cells, common in prokaryotes (bacteria, archaea) and some
single-celled eukaryotes.
10. Which stage of meiosis is responsible for the random separation of homologous
chromosomes?
- Stage 1 of meiosis
Answer All Questions
1. Normal human cell contains 23 pairs of chromosomes
2. Differentiate between synapsis and crossing over
- Synapses is the pairing of homologous chromosomes while crossing over is the exchange of
genetic materials between paired homologous chromosomes.
- Synapses allows matching chromosomes to line up accurately while crossing over swaps DNA
segments between chromosomes.
- Synapses prepares chromosomes for genetic exchange to occur while crossing over increases
genetic variation in offspring
3. Mention 5 differences between mitosis and meiosis.
In mitosis, diploid number of chromosomes are produced while in meiosis, haploid
number of chromosomes are produced
Mitosis occurs in body/ somatic cells while meiosis occurs only in reproductive cells.
Two daughter cells are formed in mitosis while in meiosis, four daughter cells are
formed.
In mitosis, daughter cells are identical to parent cells while in meiosis, variation exists
between daughter cells and parent cells.
Mitosis occurs in one stage while meiosis occurs in two stages.
4. Differentiate between Cleavage and chiasmata
A cleavage is a series of rapid cell divisions of a fertilized egg (zygote), while Chiasmata
are the X shaped structures where homologous chromosomes physically cross over and
exchange genetic materials during meiosis.
Cleavage occurs in the early embryonic stage while Chiasmata occurs in meiosis -
specifically in Prophase 1
In a cleavage, there is no exchange of genetic materials while in the chiasmata exchange
of genetic materials occur
5. Mention and explain the stages of mitosis.
Interphase
Prophase
Metaphase
Anaphase
Telophase
, Interphase: is the resting stage of the cell. Chromosomes are invisible.
Prophase: Chromosomes shorten (condense) and become visible. Spindle fibre begins to form.
Metaphase: Chromosomes align at the equator of the cell. Spindle fibres attach to the
centromeres attempting to pull individual chromatids away from each other.
Anaphase: Spindle fibres pull chromatids to opposite poles of the cell.
Telophase: Nuclear membranes reform around each set of chromosomes. Spindle fibres
disappear. Cytokinesis occurs.
6. What is a tetrad?
A tetrad is a structure made up of four chromatids formed when homologous chromosomes pair
during Prophase 1 of meiosis.
7. Differentiate between cytokinesis and karyokinesis?
Cytokinesis is the division of the cytoplasm while Karyokinesis is the division of the
nucleus.
Cytokinesis occurs after nuclear division while Karyokinesis occurs during mitosis and
meiosis
Cytokinesis produces two separate cells while Karyokinesis produces two daughter
nuclei.
8. State one significance of meiosis.
- It brings about genetic variation
9. What is binary fission and mention 2 organisms that reproduce through binary fission?
- Binary fission is a simple, asexual reproduction method where a single parent cell divides into
two genetically identical daughter cells, common in prokaryotes (bacteria, archaea) and some
single-celled eukaryotes.
10. Which stage of meiosis is responsible for the random separation of homologous
chromosomes?
- Stage 1 of meiosis
