More about DNA and genes Flashcards
Chromosomes are located…
in the nucleus of a cell
Chromosomes contain..
stretches of DNA called genes
Genes contain…
coded information that controls the heredity of particular traits (eye & hair color etc)
The coded information is made up of the…
sequences of the nitrogenous bases of DNA
What are the bases of DNA…
adenine, guanine, thymine, cytosine,
Each piece of the code is called ______ and is composed of ________.
codon, three of the bases
Each codon matches to a specific…
amino acid
There are ____ different amino acids.
20
A chain of amino acids forms a _______.
protein
What are the workhorses of the cell?
proteins
One gene matches to…..
one protein
What are responsible for the expression of genetic traits?
proteins
The sum of all the proteins directed by the genes of an individual are responsible for…
the inherited differences between one person and another
What is a genome?
a complete set of DNA for an individual that contains all genes
Mutations in the genome occurs by what two mechanisms:
errors during DNA replication or via a mutagen
What is a mutagen?
a substance that induces mutations
What is the enzyme called that speeds up DNA replication?
DNA polymerase
What are the two mechanisms cells use to reduce errors?
DNA polymerase proofreads and will attempt to correct, also mismatch pair scans over the DNA
If a mutation is able to pass through the cracks of the two mechanisms…
The DNA sequence from then on is altered
Certain forms of cancer arise because of…
failure in mismatch pair
During the life of a cell what mechanisms inspect the DNA for damage?
excision repair
Excision repair mechanism will…
cut the defective strand of DNA, remove those bases that are near, and allow DNA polymerase to regenerate a new correct piece of DNA
What can be a result of the excision repair mechanism not functioning properly?
certain skin diseases
Mutations will only pass on to future generations if they are present in…
the DNA germ cells
What are germ cells?
reproductive cells that give rise to gametes (sperm and ovum)
What are phenotypes?
the physical expressions of genetic traints
What is a genotype??
an organisms underlying genetic makeup of code
