Chapter 10 Flashcards
Compare and Contrast asexual and sexual reproduction
Asexual reproduction is a mode of reproduction where off spring are produced without the involvement of gametes or the fusion of genetic material from two parents. It results in genetically identical offspring, ensuring genetic uniformity.
How are genes inherited?
Genes are inherited through the transmission of DNA from parents to offspring. Offspring receive a combination of genes from both parents, influencing their traits and characteristics.
How does a life cycle look in eukaryotes?
The life cycle consists of alternating stages of haploid and diploid phases. It typically involves the processes of mitosis and meiosis, leading to the formation of gametes and the development of multicellular organisms
How are chromosomes displayed in a karyotype?
Chromosomes are arranged and displayed according to size, shape, and banding patterns. This visual representation helps identify chromosomal abnormalities and genetic disorders.
What are the different parts of a chromosome?
Chromosomes consist of two sister chromatids connected by a centromere. Each chromatid contains a double helix of DNA, and specific genes are located at particular positions along the chromosome.
Diploid vs. Haploid Cells
A diploid cell has two sets of chromosomes, one from each parent, while a haploid cell has only one set of chromosomes. Diploid cells are found in the most somatic cells, while haploid cells are involved in the formation of gametes.
How do chromosomes behave in the human life cycle?
Chromosomes behave different during the human life cycle, undergoing mitosis for somatic cell division and meiosis for the formation of gametes, ensuring the preservation of the diploid state in most cells.
Steps of meiosis
Meiosis involves two sequential divisions: Meiosis I and Meiosis II, each with specific phases: prophase, metaphase, anaphase, telophase. Meiosis I reduces the chromosome number and Meiosis II further divides the chromatids.
What is crossing over in Meiosis?
Crossing over occurs during meiosis I when homologous chromosomes exchange genetic material. This process contributes to genetic diversity by creating new combinations of alleles on chromosomes.
How do life cycles vary in different organisms?
Life cycles vary among organisms, including differences in the duration of haploid and diploid phases, the number of divisions during meiosis, and the contribution of sexual and asexual reproduction to offspring.
How does meiosis affect the number of chromosome sets in a cell?
Meiosis reduces the number of chromosomes sets in a cell from diploid to haploid, ensuring the correct chromosome number in gametes
Meiosis vs. Mitosis
Mitosis results in two identical daughter cells, maintaining the chromosome number, while meiosis produces four non-identical haploid cells, introducing genetic diversity.
How is genetic variation produced in sexual life cycles?
Genetic variation in sexual life cycles is produced through the independent assortment of chromosomes, crossing over, and fertilization, which combines unique genetic material from two parents.
How does crossing over affect chromosomes during meiosis?
Crossing over enhances genetic diversity during meiosis by shuffling genetic material between homologous chromosomes, leading to the formation of recombinant chromosomes.
What does independent assortment of chromosomes mean?
Independent assortment refers to the random distribution of homologous chromosomes during meiosis, contributing to genetic diversity by creating various combinations of alleles in gametes.
What is evolutionary significance of genetic variation within populations?
Genetic variation within populations is crucial for evolution. It provides the raw material for natural selection, allowing populations to adapt to change environments over time.
Gametes
Gametes are specialized reproductive cells (Sperm and egg in animals, pollen and ovule in plants) that fuse during fertilization to form a new organism. They are haploid cells containing half the usual chromosome number.
Chromosome number
Chromosome number represents the total count of chromosomes in a cells nucleus. In humans, for example, the chromosome number is typically 46, organized into 23 pairs.
Karyotype
A vital representation of individuals chromosomes arranged by size, shape, and banding patterns. It helps identify chromosomal abnormalities or genetic disorders.
Somatic Cells
Non-reproductive cells that make up body tissues and organs of an organism. They are diploid and undergo mitosis for growth, development, and repair.
Ploidy
Refers to the number of sets of chromosomes in a cell. Haploid cells have one set, while diploid cells have two sets
Homologs (Homologous)
Homologs are chromosomes that pair during meiosis and contain genes for the same traits at corresponding locations,. they may have different alleles, contributing to genetic diversity.
Haploid
refers to a cell that has one complete set of chromosomes. Gametes are typically haploid cells.
Diploid
Diploid refers to a cell that has two complete sets of chromosomes. Most somatic cells in animals are diploid
Fertilization
The process where male and female gametes fuse to form a zygote, which developed into a new organism with a complete set of chromosomes
Meiosis I and II
Two divisions of meiosis, a process that reduces the chromosome number and produces haploid cells.The phases include prophase, metaphase, anaphase and telophase, all occurring twice in meiosis.
Crossing over
Crossing over is a process during meiosis where homologous chromosomes exchange genetic material. It contributes to genetic diversity by creating new combinations off alleles.
Chiasma (ta)
the points where chromatids of homologous chromosomes exchange genetic material during crossing over in meiosis
Synapsis
Synapsis is the pairing of homologous chromosomes during the early stages of meiosis, ensuring proper exchange of genetic material
Recombination
Recombination is the creation of new combinations of genetic material through processes like crossing-over during meiosis
Independent assortment
The random distribution of homologous chromosomes during meiosis, leading to diverse combinations of alleles in the gametes
Recombinant chromosomes
Formed during crossing over in meiosis when genetic material is exchanged between homologous chromosomes, crating chromosomes with new combinations of genes.
