Meiosis & Genetic Diversity Flashcards
What is genetics?
The study of heredity and hereditary variation
Genetics involves understanding how traits are passed from one generation to the next.
Define heredity.
The transmission of traits from one generation to the next
This process involves the passing of genes from parents to offspring.
How are traits passed from parents to offspring?
Through genes
Genes are segments of DNA that code for basic units of heredity.
Differentiate between asexual and sexual reproduction.
Asexual: single individual, clones,no fusions of gametes; Sexual: two parents, offsprings are unique combinations of genes
Asexual reproduction involves one parent, while sexual reproduction involves genetic contributions from two parents.
What are homologous chromosomes?
A pair of chromosomes that carry the same genetic information
One homologous chromosome is inherited from each parent.
What is a karyotype?
A display of chromosome pairs ordered by size and length
Karyotypes visualize the number and structure of chromosomes in a cell.
What are somatic cells?
Diploid cells that have two complete sets of each chromosome
In humans, somatic cells have a diploid number of 2n = 46.
What are gametic cells?
Haploid cells that have one set of each chromosome
In humans, gametic cells (sperm and eggs) have n = 23.
What are autosomes?
Chromosomes that do not determine sex
Humans have 22 pairs of autosomes.
What are sex chromosomes?
X and Y chromosomes
Eggs carry X chromosomes, while sperm can carry either X or Y.
Define the term ‘life cycle.’
Sequence of stages in the reproductive history of an organism
This includes stages from conception to reproduction.
What occurs during fertilization?
A sperm cell fuses with an egg cell to form a zygote
This process combines haploid gametes to create a diploid zygote.
What is meiosis?
A process that creates haploid gamete cells in sexually reproducing organisms
Meiosis results in daughter cells with half the number of chromosomes as the parent.
How many rounds of division occur in meiosis?
Two rounds of division: Meiosis I and Meiosis II
Each round involves different processes and outcomes.
What is the result of mitosis?
Two diploid daughter cells that are genetically identical
Mitosis occurs in somatic cells.
What are the three key events in meiosis that are unique?
Prophase I: synapsis and crossing over; Metaphase I: (Independent orientation)tetrads line up at the metaphase plate; Anaphase I: homologous pairs separate
These events contribute to genetic variation.
What happens during Telophase 1 and Cytokinesis 1?
Nuclei and cytoplasm divides, there is now a haploid set of chromosomes in each daughter cell.
What happens during crossing over?
DNA is exchanged between homologous chromosomes
This process occurs at the chiasmata during Prophase I.
What is independent assortment?
Chromosomes are randomly oriented along the metaphase plate during Metaphase I
This leads to a variety of genetic combinations in gametes.
True or False: Meiosis produces genetically identical daughter cells.
False
Meiosis results in genetically unique daughter cells.
What is the end result of Telophase II and cytokinesis in meiosis?
Four haploid cells that are genetically unique
Each daughter cell results from the two rounds of meiotic division.
How does meiosis lead to genetic variation?
Through crossing over, independent assortment, and random fertilization
These mechanisms ensure diverse genetic combinations in offspring.
Fill in the blank: Meiosis followed by _______ ensures genetic diversity.
fertilization
This combination plays a critical role in natural selection.
