Mitosis And Meiosis Flashcards
Describe the structure of a chromosome.
A chromosome is formed of two chromatids held together at the centre by a centromere.
What are telomeres?
They are repeat sequences at each chromosome/chromatid.
Describe homologous chromosomes/alleles.
They are chromosomes which have the same genes, however genes on homologous chromosomes may contain different alleles. Alleles are variants of the same gene.
What is mitosis?
Cell division that occurs in somatic cells, producing two identical daughter cells with the same chromosome content as the parental cell.
What occurs during prophase?
Nuclear envelope dissolves, nucleolus disappears, chromosomes condense and spindle fibres disappear.
What occurs during metaphase?
Spindle fibres attach to chromosomes, chromosomes align at centre.
What occurs during anaphase?
Centromeres divide and sister chromatids move to opposite poles
What occurs during telophase?
Nuclear envelope reforms, chromosomes decondense and spindle fibres.
What occurs during cytokinesis?
Cytoplasm divides and two daughter cells with identical genetic information are produced.
What occurs in meiosis I?
The nuclear membrane dissolves and chromosomes condense.
What occurs during prophase I?
Homologous chromosomes pair up, chiasmata (crossing over) occurs and recombinant chromosomes are found.
What occurs during metaphase I?
Spindle forms and chromosomes line up at the centre of the cell.
What occurs during anaphase I?
The chromosomes migrate to either side of the cell.
What occurs during telophase I?
Nuclear membrane reforms, chromosome decondenses and cytokinesis occurs.
What occurs in meiosis II?
The same steps that take place in meiosis I, but without DNA replication.
