Meiosis Flashcards
A type of cell division where the sex cells divides and reduces to produce 4 gamete cells.
Meiosis
- Meiosis is SEXUAL reproduction
- Includes TWO divisions
It is the reproductive cell of an animal or plant.
Gametes
- Female; Egg cell / Oogenesis
- Male; Sperm cell / Spermatogenesis
What is a cell containing two copies of each chromosome?
Diploid
(2n)
What is a cell containing a single set of chromosome?
Haploid
(n)
What type of cell contains half the number of chromosomes?
Gamete
- Female; Egg cell / Oogenesis
- Male; Sperm cell / Spermatogenesis
Where does meiosis occur?
Gonads
- Testes
- Ovaries
How many phases does meiosis have?
8
- 4 phases in Meiosis I
- 4 phases in Meiosis II
When does the homologous chromosomes seperate?
Meiosis I
Produces two haploid cells, each containing one chromosome from the homologous pair
When does the sister chromatids seperate?
Meiosis II
What is the group of four sister chromatids in paired homologous chromosomes?
Tetrad
What is the pairing of homologous chromosomes called?
Synapsis
It is the recombination of alleles or genetic material in homologous chromosomes.
Crossing-over
- Happens during Prophase I (Pachytene)
What is the different versions of the same gene on each chromosome called?
Allele
What is the pair of chromosomes similar in shape and size called?
Homologous Chromosome
- Maternal and Paternal
How many pairs of homologous chromosomes does a human have?
23 Pairs
- 22 pairs Autosomes (body)
- 1 pair Sex chromosomes
It is the the point of contact between two non-sister chromatids.
Chiasmata
What may occur between
non-sister chromatids at sites called chiasmata?
Crossing-over
- Causes Genetic Recombination
What is the longest and most complex phase in meiosis?
Prophase I
What stage does the chromosome starts to condense.
Leptotene
Prophase I (1st Stage)
What is the fertilized egg cell that results from the union of a female gamete with a male gamete?
Zygote
It is the phase where the cell duplicates its DNA.
Interphase
Can be found both in Mitosis and Meiosis
It is the phase where the sister chromatids can be clearly seen.
Prophase I
First Phase of Meiosis I
It is the phase where the Nucleus & Nucleolus disappear.
Prophase I
First Phase of Meiosis I
It is the phase where the spindle fiber forms.
Prophase I
First Phase of Meiosis I
It is the phase where Tetrads form & Crossing over Occurs
Prophase I
First Phase of Meiosis I
It is the phase where Chromosomes coil & Synapsis occurs.
Prophase I
First Phase of Meiosis I
Which phase is the shortest in Meiosis?
Metaphase I
Second Phase of Meiosis I
At which stage does the chromosomes begin to pair of?
Zygotene
Priphase I (2nd Stage)
At which stage does crossing over happen?
Pachytene
Prophase I (3rd Stage)
At which stage does the chromosome begin to uncoil?
Diplotene
Prophase I (4th Stage)
It is the stage where the homologous chromosomes continue to separate.
Diakinesis
Prophase I (5th Stage)
How many substages does Prophase I have?
5
- Leptotene
- Zygotene
- pachytene
- Diplotene
- Diakinesis
In which phase does the homologous chromosomes (or tetrads) align on the equitorial plate (or equator)?
Metaphase I
It is the central plane of the spindle in dividing cell, to which chromosomes migrate during the metaphase of Mitosis or Meiosis.
Equitorial Plate
It is when Independent assortment occurs where the chromosomes separate randomly causing Genetic Recombination.
Metaphase I
In which stage does the Homologous Chromosomes separate and move towards the opposite poles.
Anaphase I
Sister Chromatids remain attached at their centronomes
It is when each pole now has a haploid set of chromosomes.
Telophase I
Which meiosis is a process of reduction of chromosome?
Meiosis I
Which division separates the chromosomes into two chromatids?
Meiosis II
This stage has no interphase and no DNA replication.
Meosis II
Which stage in Meiosis is very similar to Mitosis?
Meiosis II
It is the phase in meiosis where the Nucleus & nucleolus disappear, chromosomes condense, and spindle forms.
Prophase II
It is the phase in Meiosis where chromosomes (not homologous) line up at equator.
Metaphase II
It is the phase in Meiosis where Nuclei & Nucleoli reforms and the spindle fiber disappears.
Produces 4 Haploids
Telophase II
It is the fusion of sperm and egg cell to form a zygote.
Fertilization
- Egg (n = 23) ; Zygote (n = 46)
- Sperm (n = 23)
