Ch. 4, section 4
Line up of Genes
• 23 pairs or 46 chromosomes in the human
• Chromosomes are made of many genes joined
together like beads on a string.
Genes and DNA
DNA is made up of 4 nitrogen bases.
Gene- contains the info for one specific protein.
- Arranged in order ex. ATGACGTAG
Order of the Bases
• Nitrogen bases along a gene forms a genetic
code that specifies what type of protein will
• Proteins are long chains of individual amino
• A group 3 DNA bases codes for one specific
How cells make proteins
• Protein Synthesis: the cell uses information
from a gene on a chromosome to produce a
• Takes place on the ribosome in the cytoplasm
• Messenger RNA carries the genetic code from
the DNA inside the nucleus into the
cytoplasm. (ribonucleic acid)
• DNA has 2 stands
• RNA has 1 strand
• RNA contains a different sugar molecule.
• RNA contains uracil.
Types of RNA
• Messenger RNA- copies the coded message
from the DNA and then carries it to the
• Transfer RNA- carries amino acids to the
ribosome and adds them to growing proteins.