Final Version
DNA Cheat Sheet
11.1
DNA controls you by giving the necessary instructions your body needs to produce the proteins you need.
DNA stands for Deoxyribo-Nucleic Acid.
DNA is a double helix.
Nucleotides are made of:
A simple sugar (ribose)
A phosphate group
A nitrogen base
Nitrogen base – carbon ring structure that contains one or more atoms of nitrogen
4 possible base types: Adenine, Guanine, Cytosine, and Thymine
Pairing: Good Cats : Annihilate Tacos! GC, AT
Purines: Good Angels are pure (G and A)
Pyrimidines: Thebes the Cat's pyramid (T and C)
Nucleotides bond by connecting phosphate and deoxyribose molecules.
Important people in DNA discovery:
Watson
Crick
Franklin
Chargaff
The sequence of nucleotides is the genetic code of an organism.
DNA replication is the process of copying DNA.
Steps
1. DNA is seperated with DNA Polymerase (an enzyme)
2. Nucleotides in the nucleoplasm bond with the separated DNA strands.
3. Another enzyme joins the nucleotides and already constructed strand together.
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11.2
DNA codes for all the proteins your body makes.
RNA makes the protines
Differences between RNA and DNA
RNA is single stranded.
The sugar in RNA is ribose (DNA has deoxyribose)
RNA has uracil instead of thymine.
Three types of RNA
messenger RNA (mRNA)
contains information for making proteins
is made via transcription (process like DNA replications, but instead RNA is formed and breaks off into a single strand instead of a double)
transfer RNA (tRNA)
has anti-codons
chains together amino acids with peptide bonds
ribosomeal RNA (rRNA)
RNA on the ribosome for translation
Codon – 3 nitrogen bases that get made into an amino acid
All organisms have the same genetic code for amino acids.
The process of converting RNA to proteins is called translation.
Step 1: tRNA's anti-codon temporarily bonds with a corresponding mRNA codon.
Step 2:
REMEMBER: Things must be transcripted before they can be translated.
11.3
Changes in DNA sequences are called mutations
Mutated organisms are called mutants
Mutation can occur
as a result of changes in the DNA of sex cells
from environmental sources (radiation, mutagens)
Cancer can result from mutations
Point mutations are mutations where a single base pair is changed in DNA.
Frameshift mutations are mutations in which a single base is added or deleted from DNA.
Chromosomal mutations are changes in chromosomes, such as nondisjunction.
These changes occur frequently in plants.
Few chromosomal mutations are passed on to the future generations.
Most CM organisms are either sterile (cannot reproduce) or die at birth.
4 chromosomal mutations:
deletion: part of chromosome is left out
insertion: part of a sister chromatid attaches itself to the other sister chromatid
inversion: parts in the chromosome are exchanged
translocation: parts of a chromosome are attached to a completely different chromosome
Any agent that causes a change in DNA is called a mutagen.
Radiation, chemicals, and sometimes high temperatures are all mutations.
Radiation can delete bases.
Chemical mutagens usually result in a substitution mutations.
DNA can repair itself with special enzymes.
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