Cellular Reproduction Life Structure and Function

Atoms & Molecules make up the components of DNA

Nitrogen base pairing rules in DNA: adenine-thymine and cytosine-guanine

Chromosomes are structures in the nucleus that contain hereditary material. Chromosomes consist of large amounts (one molecule) of DNA wrapped around histone proteins, coiled up and condensed in the nucleus

Sister chromatids are identical copies of each other or known as a duplicated chromosome for cellular reproduction Sister chromatids are held together by a centromere

The centromere is the part of the chromosome that links sister chromatids together They serve as a checking point in mitosis to ensure the proper separation of the chromosomes

Homologous chromosomes pair up based on similar size, shape, and genetic information (traits) One chromosome comes from the maternal parent (mom) & the other chromosome is from the paternal parent (dad)

DNA is copied for two main reasons: 1)Cell division (growth, repair, & replacement of cells) 2) Making proteins (proteins regulate cell processes & make cell structures)

The cell cycle consists of 3 main stages Interphase (longest stage) Mitosis cytokinesis

Cell Cycle The cycle begins with one diploid cell and ends with two daughter cells (A diploid cell has paired chromosomes one from each parent)

Interphase During this stage of the cell cycle, chromatin, nuclear envelope and nucleolus are clearly visible (In animal cells the centrioles are also visible)

Mitosis (mitotic phase) There are four phases in mitosis…. Prophase Metaphase Anaphase Telophase

Prophase (1 st stage of mitosis) The chromosomes condense and become visible in the nucleus of the cell and the spindles begin to form in the cytoplasm

Metaphase (2 nd stage of mitosis) Spindle fibers connect to the centrioles that are at opposite poles from each other. The duplicated chromosomes are lined up in the middle along the metaphase plate