Post on 11-May-2015
DNA Science
Biology I Factoids
Factoid 154
• Section 10
• DNA controls the production of every protein in a cell. Proteins control all of the process in a cell.
Factoid 153
• DNA is made up of nucleotides. Nucleotides are made up of a sugar (either ribose for RNA or deoxiribose for DNA), a phosphate group, and a nitrogen base.
Factoid 154
• There are 5 nitrogen bases:
• Adenine and Guanine are purines.
• Cytosine, Thymine, and Uracil are Pyrimidines.
• Uracil is only found in RNA not DNA.
Factoid 155
• In 1953 two scientists named James Watson and Francis Crick were the first people to determine the structure of DNA
Factoid 156
– DNA is like a twisted ladder (called a double helix) whereby the sugar and phosphate units make up the sides of the ladder and the nitrogen bases make up the steps of the ladder.
Factoid 157
• The sequence of the nucleotides in DNA determines the information that is passed on by the genes.
Factoid 158
• DNA replication (during the S phase of the cell cycle) makes a copy of the DNA. The DNA ladder splits and nucleotides join to form an extra copy of DNA.
Factoid 159
• Since DNA will contain one old strand and one new strand of DNA, the process is called semi-conservative.
Factoid 160
• There are 3 ways DNA and RNA are different:– RNA has a ribose sugar unit instead of the
deoxiribose sugar unit.– DNA is double stranded and RNA is single
stranded.– In RNA A pairs with U and not T. There is no
Thymine in RNA.
Factoid 161
• There are 3 types of RNA– Messenger RNA (mRNA) carries instruction
from the DNA to the ribosomes.
Factoid 162
– Transfer RNA (tRNA) bring amino acids to the ribosomes.
Factoid 163
– Ribosomal RNA (rRNA) bind with the ribosomes to help make proteins.
Factoid 165
• Protein synthesis (the making of proteins) has two parts: Transcription and translation.
Factoid 165
• To transcribe DNA means to make a copy of it. When DNA is transcribed, a copy of the nucleotide sequence is copied by RNA.
Factoid 166
• Transcription makes mRNA in the nucleus. The mRNA then leaves the nucleus.
Factoid 167
• Nucleotides are “read” in groups of 3 (called a codon). Every 3 nucleotides code for 1 amino acid.
Factoid 168
• During translation, the mRNA is bound to an rRNA and a ribosome. The ribosome makes the new protein.
Factoid 169
• The tRNA brings an amino acid to the ribosome to build the protein.
Factoid 170
• Chargaff’s Rules
• A always bonds with T and visa versa
• C always bonds with G and visa versa
• In RNA, A always bonds with U and visa versa.
Factoid 171
• The process of protein synthesis can be summarized:
DNA mRNA ribosomes protein
Factoid 172
• The study of DNA molecules and making changes in DNA is called molecular genetics.
Factoid 173
• A subfield of molecular genetics is called genetic engineering which involves changing an organism’s DNA
Factoid 174
• The first step in examining an organisms DNA is DNA extraction or removing the DNA from the cell.
Factoid 175
• DNA is very large. It must be cut into smaller pieces using restriction enzymes.
Factoid 176
• Restriction enzymes cut DNA in very specific sequences. They will only work on a specific nucleotide sequence.
Factoid 177
– Once cut into pieces (called fragments) the DNA is separated using gel electrophoresis.
Factoid 178
• DNA travels from the negative side of the DNA gel to the positive side of the gel. The smaller fragments travel farther and make a banding pattern on the gel.
Factoid 179
• Patterns on a DNA gel can be used to prove or disprove paternity, guilt or innocence of a crime, determining evolutionary history, etc
Factoid 180
• Taking short pieces of DNA from one organism and joining it to the DNA of another organism is called recombinant DNA.
Factoid 181
• Transgenic organisms are organisms that contain genes from a different organism.
Factoid 182
• Cloning refers to taking genetic information out of a donor cell and placing it into an egg, then implanting the egg in a female for birth.
Factoid 183
• Mutations are mistakes in DNA that can be beneficial, harmful, or have no effect at all.
Factoid 184
• There are two types of mutations gene mutations (or point mutations) or chromosome mutations.
Factoid 185
• There are three types of gene mutations• Insertion – A nucleotide is added and changes the
codons.• Substitution – A different nucleotide is inserted
instead of the intended one.• Deletion – A nucleotide is left out.
Factoid 186
• There are 4 types of chromosome mutations
• Deletion – A piece of chromosome is removed.• Duplication – Part of a chromosome is copied• Inversion – Pieces of chromosomes switch places.• Translocation – Pieces of one chromosome
change places with pieces from another chromosome.
Factoid 187
• Karyotype – A picture of chromosomes used to see if there are abnormal numbers of chromosomes