Transcript DNAConnec[on (Remee v2)

DNA and
Genetics
The Structure of DNA
Chromosomes are
made of DNA. Each
chromosome
contains thousands
of genes. The
sequence of bases in
a gene forms a code
that tells the cell
what protein to
produce.
A Complex Molecule
• The shape of the molecule is like a twisted
zipper. It is called a double helix.
• The scientist that discovered DNA and its
shape realized that smaller molecules of DNA
bond together and form this double helix
shape.
The Genetic Code
• Genes and DNA: A gene is a section of DNA
molecule that contains the information to code
for one specific protein.
• Order of the Bases: The order of the nitrogen
bases along a gene forms a genetic code that
specifies what type of protein will be produced.
Adenine (A) Cytosine (C) Thymine (T) Guanine (G)
How Cells Make Proteins
Replication: the process of copying a DNA
molecule to make another DNA molecule which
produces identical strands of DNA.
• The Role of RNA: The genetic messenger, RNA,
must first carry the genetic code from the DNA
inside the nucleus into the cytoplasm. It is also
made of nucleotides.
• Types of RNA: Messenger RNA, Transfer RNA,
and ribosomal RNA. The process of making
protein from RNA is called translation.
Translating the Code
• To make proteins,
messenger RNA
copies information
from DNA in the
nucleus. Messenger
RNA and Transfer
RNA then use this
information to
produce proteins.
Mutations
• A mutation is any change in a gene or
chromosome. It can cause a cell to produce
an incorrect protein during translation. As a
result, the organism’s trait, or phenotype, may
be different from what it normally would have
been.
• The word comes from a Latin word that means
“change.”
Types of Mutations
During DNA Replication:
-A cell can end up with too many or too few
chromosomes
-A cell can also end up with extra segments of
chromosomes.
Effects of Mutations
• Good : can be a source of genetic variety.
» Antibiotic resistance in bacteria
• Harmful: if it reduces its chance for survival
and reproduction.
Odd fur coloring that makes it stand
out in its environment
Homework
• Read and add to notes pages 174-180.
• Test is on Friday, May 8.
• We will go over your notes in class tomorrow.
Study!!!