DNA The Genetic Material

What is DNA? DNA = deoxyribose nucleic acid DNA is the genetic material found in the nucleus that contains all the instructions for life. DNA is passed from parent cells to daughter cells after it is copied during the cell cycle

Discovery In 1953 James Watson and Francis Crick, figured out the structure of DNA. Rosalind Franklin also made very important contributions to the discovery of DNA!

DNA Structure DNA is shaped like a twisted ladder or a spiral staircase. Because of the shape it is often called a double helix

DNA Ladder The two sides of the ladder are made of sugar called deoxyribose The sugar molecules alternate with phosphate molecules Each rung (middle sections) are made of a pair of molecules called nitrogen bases.

Review How would you describe the shape of DNA? Twisted ladder Spiral staircase Double helix All of the above

Nitrogen Bases Adenine (A) Thymine(T) Guanine(G) Cytosine (C)

Base Pair Bonding Base pairs always bond with the same partner! A-T C-G

DNA The arrangement of nitrogen bases in the DNA forms a chemical code That is why DNA is known as a genetic code! Sections in the chromosome are called genes and they carry the “code” for different traits (hair color/eye color/etc.)

review DNA is known as: The brain of the cell The powerhouse The genetic code

DNA Replication Replication is the processes of making DNA copies What phase of the cell cycle does this happen?

DNA Replication A cell makes a copy of its DNA before mitosis occurs. (Interphase!) DNA replication makes sure that each daughter cell will have identical genetic information from the parent cell. Without DNA replication life would end as we know it!!!

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