2. The Cell Cycle
• Cells must divide to maintain maximum
efficiency.
• Mitosis is the process in which somatic
(body) cells divide to form a new cell.
• Mitosis consists of four phases.
• Interphase is the period in between each
mitotic cell division.
3. Reproduction
• Asexual Reproduction: A single cell or group of
cells each duplicates its genetic material and then
splits into two new genetically identical cells.
– The offspring are genetically identical
• Sexual Reproduction: Genetic material from each
of two parents combines, producing offspring that
differ genetically from either parent.
– Involves the union of sex cells (egg and sperm)
4. Parent
cell
DNA replicates
Cell division = One
cell makes two cells
Two daughter cells
are genetically
identical to each
other and to parent
cell = clones
5. The same DNA can appear in two forms
Chromatin = uncondensed DNA Chromosome = condensed DNA
6. 1 Chromosome
1 chromatid per chromosome
1 DNA double helix
DNA replication
1 Chromosome
2 chromatids per chromosome
2 DNA double helices
7.
8. Cell division in eukaryotic cells:
Cytokinesis = division of the cytoplasm
9. Interphase
• Interphase is made of 3 stages.
• The Gap 1 and 2 or G1 and G2 phase is when
cells grow and make RNA, proteins, and other
macromolecules.
• The S or Synthesis phase is when the cell is
making DNA.
10. DNA Replication
• During the S phase of the cell cycle, DNA
replicates.
• A short section of the DNA uncoils.
• New nucleotides bond to the open sections of
the DNA.
• The “new” and “old” sections of DNA
separate and now there are 2 DNA strands.
11. Interphase
• ATP is synthesized.
• Damaged parts are repaired.
• Wastes are excreted.
• Proteins are made.
• Organelles are formed.
• Chromosomes are copied.
• Specialized tasks are performed .
