Microtubules are tiny, hollow, bead-like tubular structures that help cells maintain their shape. Along with microfilaments and intermediate filaments, they form the cytoskeleton of the cell, as well as participate in a variety of motor functions for the cell.
Complete question:
Prophase of meiosis I has some important differences from prophase of mitosis. These differences include: ___________BLANK pair, and _________BLANK occurs.
A: chromatids; condensation
B.,chromosomes; separation
C. homologous chromosomes; crossing over
D. homologous chromatids; separation
Answer:
C. homologous chromosomes; crossing over
Explanation:
Prophase I of meiosis and prophase of mitosis are quite distinct with respect to the events occurring in the cells. Prophase-I of meiosis is a relatively long stage. The Zygotene stage of prophase-I includes the pairing of homologous chromosomes. This pairing is mediated by synaptonemal complex and the process is called synapsis. The paired chromosomes undergo the process of crossing over during the pachytene stage of prophase-I. In crossing over, the non-sister chromatids of the bivalents exchange some genetic material between them. The events of synapsis and crossing over do not occur during prophase of mitosis.
Degeneracy
Degeneracy simply means that most of the amino acids produced during protein synthesis from DNA is coded by more than one codon. A codon is a sequence of 3 <span>nucleotides that codes for a specific amino acid.
Because more than 1 codon can produce the same amino acid, the chances of having the synthesis of proteins affected by mutations (i.e. point mutations) is decreased. For example, if the codon with the nucleotide series GAA, which codes for the amino acid glutamate, becomes the codon GAG, the codon will still produce glutamate because the code is degenerate. </span>
Answer:
Enzymes allow many chemical reactions to occur within the homeostasis constraints of a living system. Enzymes function as organic catalysts. A catalyst is a chemical involved in, but not changed by, a chemical reaction. Many enzymes function by lowering the activation energy of reactions.
Explanation:
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