All cells arise from other cells Flashcards
What is the process of cell division called?
Mitosis - it occurs for growth or repair
What are the 5 main stages in mitosis?
1) Interphase
2) Prophase
3) metaphase
4) anaphase
5) telophase
What happens during interphase? Step 1 of mitosis
In interphase the cell makes a copy of its chromosomes involving replication of DNA. Cell grows and undergoes it’s normal physiological functions.
What happens during prophase? Step 2 of mitosis
In prophase chromosomes coil, becoming shorter and fatter. We can now see them with and optical microscope. Nuclear envelope disappears. Protein fibres form a spindle in the cell. Each chromosome consists of two chromatids, each containing an identical DNA molecule from DNA replication.
What happens during metaphase? Step 3 of mitosis
In metaphase one or more spindle divers attach to the centromere of each chromosome. The chromosomes line up in the middle of the spindle
What happens during anaphase? Step 4 of mitosis
In anaphase the centromere holding each pair of sister chromatids together divides. Spindle diners shorten and pull one of each pair of sister chromatids to opposite poles of the spindle. We can now refer to the chromatids as chromosomes
What happens during telophase? Step 5 of mitosis
In telophase the two sets of separated chromosomes collect at opposite ends of the cell. A new nuclear envelope forms around each set of chromosomes. Chromosomes become long and thin. We can no longer see them clearly with an optical microscope. Cytoplasm divides to form two new cells [cytokinesis]
What is cytokinesis?
Cytokinesis is the cytoplasmic division of a cell at the end of mitosis or meiosis, bringing about the separation into two daughter cells.
What holds chromatids together so they are a chromosome?
The centromere is the thing in the center of a chromosome that holds it together
