Genetics
the science that studies how characteristics (or traits) get passed from one parent to offspring (called inheritance)
what year(s) did scientists determine that DNA was the molecule that stored genetic information
the 1920's
DNA stands for
Deoxyribonucleic acid
DNA is composed of...
a string of nucleotides
DNA strings are made of 3 parts…
5-carbon sugar called deoxyribose, A phosphate group, A nitrogen base (4 choices; Adenine, Guanine, Cytosine, and Thymine)
Edwin Chargaff
determined that A=T & G=C, base pairing system
Rosalind Franklin
used an X-ray to show that 2 DNA strands were twisted
Francis Crick & James Watson
Used Franklin’s picture to create the first model of DNA
Adenine pairs with…
thymine
Guanine pairs with…
cytosine
The shape of DNA
double helix
double helix
-composed of alternating deoxyribose sugar and phosphate groups
-commonly called the “sugar-phosphate backbone”
-looks like a twisted ladder
-The rungs of the ladder are made of nitrogen bases
-WEAK SO THAT THEY CAN BREAK AND COME BACK TOGETHER
gene
a segment of DNA that codes for the protein, thereby causing a genetic characteristic of a trait, ike Hair color, eye color, or height
cells are constantly...
growing and dividing, which must be accomplished without breaking the DNA strands
In order to protect the DNA….
it is tightly coiled around proteins called histones and condensed into chromosomes
DNA can....
tell many things about a person and genetic differences between people are very important so diseases are not as deadly
DNA replication
when a cell divides, DNA must be copied, requires the strands to be unwound first
replication fork
-After the DNA is unwound from the histones, an enzyme called helicase “unzips” the two strands of DNA
-This location is known as the replication fork.
DNA polymerase
brings nucleotides to match one of the DNA strands (known as the parent strand)
Stem cell(s)
a cell that has not been assigned a part yet
DNA replication is a semi-conservative process because....?
only half of each parent strand remains in the new DNA molecule
SUMMARY OF DNA REPLICATION:
To make it easy to move DNA without damage, it is wrapped around histones and condensed into chromosomes. To copy the DNA (called DNA replication), enzymes separate the two strands and use one side as the blueprint to make a complementary strand.
SUMMARY OF DNA:
DNA is the molecule that stores genetic information for cells. It is shaped like a double helix with bases on the inside. These match in pairs with A bonding with T and C bonding with G
histone
a group of basic proteins that help protect DNA
chromosome
-a structure of nucleic acids and protein
-found in the nucleus of most living cells
-carries genetic information in the form of genes
complementary DNA strands
two strands of DNA with corresponding bases/chains (google definition: (either of the two chains that make up a double helix of DNA, with corresponding positions on the two chains being composed of a pair of complementary bases)