BLS Flashcards
What is reproduction?
Reproduction is the process by which organisms produce or replicate themselves sexually or asexually.
What does the cell cycle allow organisms to do?
The cell cycle allows multi-cellular and single-celled organisms to grow and reproduce.
How do multicellular organisms use cell division?
All multicellular organisms use cell division for growth and the maintenance and repair of cells and tissues.
How do single-celled organisms use cell division?
Single-celled organisms use cell division as their method of reproduction.
What are somatic cells?
Any normal body cells of an organism that are not involved in reproduction.
What do somatic cells contain?
One copy of chromosomes from each parent. Total of two
What are the two major phases of the cell cycle?
The cell cycle has two major phases: interphase and the mitotic phase.
What occurs during interphase?
During interphase, the cell grows and DNA is replicated.
What occurs during the mitotic phase?
During the mitotic phase, the replicated DNA and cytoplasmic contents are separated and the cell divides.
What is meiosis?
Meiosis is the nuclear division of diploid cells into haploid cells, which is a necessary step in sexual reproduction.
What is the purpose of meiosis in sexual reproduction?
To produce cells with half the number of chromosomes as the original cell.
What are gametes?
Gametes are haploid cells used in sexual reproduction, formed during meiosis.
What is the difference between diploid and haploid cells?
Diploid cells have two sets of chromosomes, while haploid cells have a single set of unpaired chromosomes.
What happens during meiosis I?
In meiosis I, homologous chromosomes exchange DNA and the diploid cell is divided into two haploid cells.
What occurs during prophase I?
During prophase I, homologous chromosomes condense, pair up to form a tetrad, and exchange genetic material by crossing over.
What is crossing over?
Crossing over is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes.
What occurs during metaphase I?
During metaphase I, the tetrads line themselves up at the metaphase plate and homologous pairs orient themselves randomly.
What happens during anaphase I?
In anaphase I, centromeres break down and homologous chromosomes separate.
What is the result of telophase I and cytokinesis?
Two haploid cells are the end result of the first meiotic division.
What occurs during meiosis II?
During meiosis II, the sister chromatids within the two daughter cells separate, forming four new haploid gametes.
What is interkinesis?
Interkinesis is a brief interphase that some species enter before meiosis II, lacking an S phase.
What happens during telophase II and cytokinesis?
The chromosomes arrive at opposite poles, decondense, and the two cells divide into four unique haploid cells.
What happens to chromatids during meiosis?
Chromatids are pulled apart by the kinetochore microtubules and move toward opposite poles. Non-kinetochore microtubules elongate the cell.
What occurs during Telophase II and Cytokinesis?
The chromosomes arrive at opposite poles and begin to decondense. Nuclear envelopes form around the chromosomes. Cytokinesis separates the two cells into four unique haploid cells.
