Meiosis
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Transcript of Meiosis
7th Grade Science
Cell Division and Meiosis
Chromosomes>Genes>DNA• The nucleus of a cell
contains long chains of information called DNA(Deoxyribonucleic Acid).
• The DNA of a cell is like a set of instructions that “build” an organism.
Chromosomes>Genes>DNA• The instructions for the
cell are organized in parts called chromosomes.
• The number of chromosomes varies within the five kingdoms.
• Humans = 46• Fruit Fly = 8
Chromosomes>Genes>DNA• Chromosomes are broken
up into genes.• Which genes an organism
has determines which traits it has.
• One (or more) genes “codes” for each trait we have. (ex. Hair, eye color, shape of features)
Chromosomes>Genes>DNAGenes: Certain parts of each chromosome that code for how to build structures in your body.
Asexual Reproduction• Some living things
undergo asexual reproduction, that is where ONE individual is needed to produce offspring.
• Go to p152 in the Life Science Textbook
Sexual Reproduction• Male sperm unite
with female eggs in sexual reproduction.
• A variety of living things undergo sexual reproduction including many types of plants and animals.
Sexual Reproduction• Males have sperm,
which contain HALF of the genetic information.
• Females have eggs, which contain HALF of the genetic information.
• 1/2 + 1/2 = ?
Cell Division• Cells can divide in
two ways.• Mitosis: A cell
divides to create two identical copies. This happens in growth of human cells and in asexual reproduction.
Cell Division• Another type of cell
division is meiosis. • In meiosis, cells are
produced that have HALF of the genetic information.
• This occurs in the creation of sperm and egg.
Chromosomes>Genes>DNA