Meiosis & genetics Flashcards
What occurs during Prophase I of meiosis?
Homologous chromosomes pair up and form a tetrad.
Define tetrad in the context of Prophase I.
1-2 homologous chromosomes (4 sister chromatids).
What special process occurs in Prophase I?
Crossing Over.
What is synapsis?
Pairing of homologous chromosomes.
What happens during Crossing Over?
Homologous chromosomes break apart and exchange genes.
Why is crossing over an important process?
It allows for genetic variation and new combinations of genes.
Fill in the blank: Crossing over allows you to get some genes from _______ and some from _______.
[Mom], [Dad].
What are sex cells also called?
Gametes
Sex cells include egg and sperm cells.
Where are egg cells made?
In the ovaries of a woman
Ovaries are the female reproductive organs.
Where are sperm cells made?
In the testes of a man
Testes are the male reproductive organs.
What type of cells are body cells?
Diploid cells
Diploid cells have two of each type of chromosome.
How many chromosomes do diploid cells have in a human?
46 chromosomes
This is the total number of chromosomes in human diploid cells.
What type of cells are sex cells?
Haploid cells
Haploid cells have one of each type of chromosome.
How many chromosomes do haploid cells have in a human?
23 chromosomes
This is the total number of chromosomes in human haploid cells.
Fill in the blank: Haploid is ______ the diploid number.
Half
This indicates the relationship between haploid and diploid cell counts.
Fill in the blank: Diploid is ______ the haploid number.
Double
This indicates the relationship between diploid and haploid cell counts.
What does ‘n’ represent in relation to chromosomes?
Number of chromosomes
‘n’ is used to denote the haploid number of chromosomes.
Why do gametes have 1⁄2 the number of chromosomes?
Because when the sperm and egg combine they need to make a regular cell, so to do that they both have to be half
The zygote is a fertilized egg cell.
What is formed when an egg cell and sperm cell combine?
A zygote (a fertilized egg cell).
This process is known as sexual reproduction.
What are diploid cells?
Diploid cells have homologous chromosomes.
Diploid means that the cell contains two complete sets of chromosomes.
What are homologous chromosomes?
Pairs of chromosomes (1 from Mom, 1 from Dad) that have similar genes.
Homologous chromosomes are crucial for genetic diversity.
What is a karyotype?
Number and appearance of chromosomes
Shows 23 pairs of homologous chromosomes
What are the stages of Meiosis I?
- Prophase I
- Metaphase I
- Anaphase I
- Telophase I
What are the stages of Meiosis II?
- Prophase II
- Metaphase II
- Anaphase II
- Telophase II
How many full cycles of cell division occur during meiosis?
2 full cycles of cell division
What is the result of meiosis from 1 diploid cell?
4 haploid cells (gametes)
What occurs during interphase before meiosis begins?
Chromosomes duplicate (double) and become visible
Fill in the blank: Meiosis is a type of _______.
[cell division]
What is meiosis?
A type of cell division where 1 body cell divides to make 4 sex cells (egg or sperm)
Meiosis is distinct from mitosis.
How many stages are there in mitosis?
4 stages (PMAT)
PMAT stands for Prophase, Metaphase, Anaphase, and Telophase.
What does mitosis produce?
2 new identical cells
Mitosis is involved in cell growth and regeneration.
What is the primary function of mitosis?
Used for cell growth (tissues, organs, organ system) and regeneration
Regeneration replenishes cells that have died.
How many stages does meiosis take place in?
2 stages: Meiosis I and Meiosis II
Each stage consists of its own phases.
How many full cycles of cell division occur in meiosis?
2 full cycles of cell division
Each cycle corresponds to one of the two stages of meiosis.
True or False: Meiosis is the same as mitosis.
False
Meiosis and mitosis serve different functions in cell division.
