1. Chapter 3 section 4
The DNA Connection

2. A. The Genetic Code
Main function of genes is to control the
the production of proteins in cells
2. proteins help to determine the size, shape,
and many other traits of the organism
3. Chromosomes are composed mostly of DNA

5. 4. made up of four different nitrogen bases
-adenine (A)
-thymine(T)
-guanine(G)
-cytosine(C)

6. -the order of the nitrogen bases along a gene
forms a genetic code that specifies what type
of protein will be produced
5. group of three bases codes for attachment
of amino acids which are the building blocks
of proteins

7. B. How Cells Make Proteins:
1. protein synthesis:
-takes place in the ribosomes in the
cytoplasm of the cell

10. 2. The Role of RNA
-A messenger must first carry the genetic
code from the DNA inside the nucleus into
the cytoplasm.
-genetic messenger is called RNA

11. 3. different from DNA
-looks like one side of the
DNA ladder
-contains different sugar
molecule
-contains the same nitrogen
bases except thymine
-has uracil (U) instead

13. 4. several types of RNA involved in protein
synthesis:
-messenger RNA:
-copies the coded message from the
DNA in the nucleus and carries the
message into the cytoplasm

14. -transfer RNA
-carries amino acids and adds them
to the growing protein