Answer:
1. They must be removed before sister chromatids or homologous chromosomes can separate
Explanation:
During the S-phase of the cell cycle, not only does DNA have to be replicated, but also newly synthesized DNA molecules have to be connected with each other. This replicated DNA (sister chromatids) remain physically connected with each other from S phase until metaphase. This physical connection is called Sister chromatids cohesion.
Sister chromatid cohesion depends on COHESIN, a tripartite protein complex that forms a ring structure to hold sister chromatids together during mitosis and meiosis. Cohesin regulates the separation of sister chromatids during cell division, either mitosis or meiosis. This sister chromatid cohesion is essential for the biorientation of chromosomes on the mitotic or meiotic metaphase spindle, and is thus an essential prerequisite for chromosome segregation. Without the cohesion, sister chromatids would not be segregated symmetrically between the forming daughter cells, resulting in aneuploidy.
Cohesion is established during S-phase of DNA replication, and the cohesins hold the sister chromatid together after DNA replication until anaphase when the removal of cohesin leads to separation of sister chromatids (meiosis II and mitosis) and homologous chromosomes (meiosis I).
Answer:
chromosome
Explanation:
A chromosome consists of entire set of genes with in an organism’s total population.
DNA with is a chromosome is arranged in a discrete short and wide units. A chromosome consists of millions of DNA base pairs which consists of large number of genes. The chromosome structure comprises of double helix DNA wrapped around proteins. DNA with in chromosome provide basis for chromosome synthesis.
Carbon moves from plants and animals to soils. When plants and animals die, their bodies, wood and leaves decays bringing the carbon into the ground.
Answer:
Explanation:
An archegonium (pl: archegonia), from the ancient Greek ἀρχή ("beginning") and γόνος ("offspring"), is a multicellular structure or organ of the gametophyte phase of certain plants, producing and containing the ovum or female gamete. The corresponding male organ is called the antheridium.
Answer:
Ovoviviparous
Explanation:
Embryos develop inside the mother's body using an egg yolk for nourishment is a mode of reproduction called ovoviviparity.
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