DNA & Meiosis Flashcards
What is the structure of DNA?
DNA is a double helix.
What are chromatids?
Chromatids are duplicated chromosomes.
What is the centromere?
The centromere is where the spindle fibers attach to align the chromosome and pull apart the sister chromatids.
What are the phases of the cell cycle?
The phases include Interphase, Prophase, Metaphase, Anaphase, and Telophase.
What is a nucleotide?
A nucleotide is a single subunit (piece) of DNA.
What are the components of a nucleotide?
A nucleotide consists of deoxyribose sugar, a phosphate group, and nitrogenous bases (adenine, thymine, cytosine, guanine).
What is a karyotype?
A karyotype is the organization of condensed chromosomes/chromatids from a cell, arranged from longest to shortest.
What are autosomes?
Autosomes are chromosomes that contain genes for 22 pairs in a normal human.
What is the definition of a Diploid cell?
Contains the full complement of homologous chromosome pairs
In humans, a diploid cell has 46 chromosomes (23 homologous pairs)
How many chromosomes are present in diploid cells of humans?
46 chromosomes
This includes 23 homologous pairs
What are homologous chromosomes?
Chromosomes that have the same structure and gene sequence
They are paired together in diploid cells
One homologous chromosome is inherited from the mother, and the other from the father
What is the role of adult stem cells in relation to diploid cells?
They produce new stem cells through mitosis
Specialized cells do not go through mitosis
What is the outcome of mitosis?
Production of identical diploid cells
Each daughter cell has the same number of chromosomes as the parent cell
What is the definition of haploid cells?
Contain half the complement of chromosomes to produce an individual
In humans, haploid cells have 23 chromosomes
What type of cells are produced from haploid cells?
Gametes (reproductive cells)
Examples include sperm and eggs
How many chromosomes do haploid cells contain in humans?
23 chromosomes
None of these chromosomes are homologous
What is the primary function of meiosis?
To produce haploid cells from diploid cells
This process is essential for sexual reproduction
What are sister chromatids?
Identical copies of a chromosome
They are formed during DNA replication before cell division
True or False: Mitosis occurs in the production of new stem cells.
True
Mitosis is responsible for producing identical daughter cells
How many pairs of sex chromosomes do humans have?
1 pair
This pair consists of two chromosomes.
What are the sex chromosomes for biological females?
XX
This combination typically results in female biological characteristics.
What are the sex chromosomes for biological males?
XY
This combination generally leads to male biological characteristics.
What is meiosis?
A type of cell division that leads to the formation of gametes
What is a centromere?
The region of a chromosome where the two sister chromatids are joined
What occurs during Prophase I of meiosis?
Homologous chromosomes come together to allow for crossing over of genetic material
SYNAPSIS
What is a tetrad?
A pair of homologous chromosomes, each consisting of two sister chromatids
What is the role of the kinetochore?
Where spindle fibers attach to the chromosome
What is spermatogenesis?
The process of sperm meiosis
What is a spermatogonium?
A diploid (2n) cell that undergoes meiosis to form sperm
What is oogenesis?
The process of egg meiosis
What happens during the formation of polar bodies?
They are small, useless cells produced during oogenesis, while one functional mature egg is formed
Fill in the blank: In meiosis, a mature sperm cell is _______.
haploid (n)
Fill in the blank: The functional mature egg produced during oogenesis is _______.
haploid (n)
