Unit 4 Flashcards
What is mitosis?
Mitosis is a form of asexual reproduction where a single cell divides to produce two identical daughter cells. It is one of the stages in the cell cycle.
What is meiosis?
Meiosis is a type of cell division that occurs during sexual reproduction to produce gametes (sperm and eggs), reducing the chromosome number by half (from diploid to haploid) and increasing genetic diversity.
What is the difference between diploid (2n) and haploid (n)?
Diploid (2n) refers to a cell with two sets of chromosomes (one from each parent), while haploid (n) refers to a cell with one set of chromosomes (as in gametes).
What is a chromosome?
A chromosome is a structure made of DNA and proteins that carries genetic information. In preparation for mitosis, chromosomes duplicate into two sister chromatids connected by a centromere.
What is the purpose of mitosis in eukaryotic cells?
Mitosis allows for new growth, replacement of worn-out cells, and repair of damaged tissues.
What is the cell cycle?
The cell cycle consists of stages that prepare the cell for division. These include Interphase (G1, S, G2) and Mitosis (Prophase, Metaphase, Anaphase, Telophase).
What occurs during the G1 phase of Interphase?
During G1, the cell grows and performs its normal functions.
What happens during the S phase of Interphase?
In the S phase, DNA replication occurs, doubling the amount of genetic material in preparation for cell division.
What happens during the G2 phase of Interphase?
The cell continues to grow, and organelles and proteins required for cell division are synthesized.
Describe the four stages of mitosis.
Prophase: Chromosomes condense, and the nuclear envelope breaks down.
Metaphase: Chromosomes align at the metaphase plate.
Anaphase: Sister chromatids separate and move toward opposite poles.
Telophase: Chromosomes de-condense, and new nuclear envelopes form.
What is cytokinesis?
Cytokinesis is the division of the cytoplasm that occurs after mitosis, resulting in two distinct daughter cells. In animal cells, this occurs through a cleavage furrow; in plant cells, a cell plate forms.
What is meiosis, and how does it differ from mitosis?
Meiosis is the process of cell division that produces gametes with half the number of chromosomes. Unlike mitosis, which produces two identical cells, meiosis produces four genetically different haploid cells.
What happens during Prophase I of meiosis?
In Prophase I, chromosomes condense, homologous chromosomes pair up, and crossing-over (genetic recombination) occurs, where genetic material is exchanged between chromosomes.
What is the result of Metaphase I in meiosis?
Homologous chromosomes align at the metaphase plate, where random assortment occurs.
What happens during Anaphase I of meiosis?
Homologous chromosomes separate and are pulled to opposite poles of the cell.
What happens during Telophase I of meiosis?
Chromosomes reach the poles, and nuclear envelopes form, resulting in two haploid cells.
Describe the stages of Meiosis II.
Meiosis II is similar to mitosis, but it involves the separation of sister chromatids rather than homologous chromosomes. The stages are Prophase II, Metaphase II, Anaphase II, and Telophase II, resulting in four haploid cells.
How does meiosis contribute to genetic diversity?
Meiosis introduces genetic diversity through two main mechanisms: crossing-over (exchange of genetic material between homologous chromosomes) and independent assortment (random separation of chromosomes).
Who is considered the father of modern genetics?
Gregor Mendel, a 19th-century monk, is considered the father of modern genetics for his work on inheritance patterns in pea plants.
What is the significance of Mendel’s pea plant experiments?
Mendel’s experiments with pea plants led to the discovery of fundamental genetic principles, including the concepts of dominant and recessive traits and the inheritance of alleles.
What is a Punnett square, and how is it used in genetics?
A Punnett square is a diagram used to predict the genotype and phenotype probabilities of offspring from a genetic cross.
What is the difference between a monohybrid and dihybrid cross?
A monohybrid cross examines the inheritance of a single trait, while a dihybrid cross examines the inheritance of two traits simultaneously.
What is a dominant allele?
A dominant allele is one that expresses its trait in a heterozygous individual (with one copy of the allele).
What is a recessive allele?
A recessive allele is only expressed when an individual has two copies of the allele (homozygous recessive).
