DNA/Genetics Test Review

What is DNA? DNA is our genetic blueprint. DNA is a double helix –It looks like a twisted ladder It is made up of nucleotides (Deoxyribose, nitrogen base, phosphates) What is the Base Pairing Rule? The four nitrogen bases are: Adenine (A), Thymine (T), Cytosine (C), Guanine (G) A – T; G – C

What is replication? Replication is when DNA makes a copy of itself. A DNA molecule unzips and and each side of the DNA molecule gets copied.

What is RNA? The three types are: mRNA, rRNA, tRNA RNA is made up of nucleotides (like DNA) which includes a phosphate group, nitrogen group, but has the sugar Ribose Also, RNA has the base Uracil (U) instead of Thymine (T); G – C, but A - U

What is transcription? Transcription is first step in decoding DNA. RNA makes a copy of DNA, and transports this copy to the ribosome. What is translation? The RNA brings the copy to the ribosome. The ribosome reads each codon; each codon codes for an amino acid. Three bases make up a codon

Genetics What is mitosis? Prophase, Metaphase, Anaphase, Telophase Each daughter cell produced has 2 sets of chromosomes (46 total in humans) – Diploid (2N) What is meiosis? Prophase I, Metaphase I, Anaphase I, Telophase I; Prophase II, Metaphase II, Anaphase II, Telophase II 4 daughter cells are produced which have one set of chrmosomes (23 total in humans) – Haploid (N) In crossing over, chromosomes will exchange genetic information.

What are the differences between Diploid and Haploid? Diploid = 2 sets of chromosomes (2N) Haploid = 1 set of chromosomes (N) What are genes? Genes are the characteristics contained in the DNA Each gene is made up of 2 alleles- one from each parent. An allele is a version of a trait. Genotype = the genetic make up of an organism ( the two allele combination ex. TT, Tt, tt) Phenotype = the physical trait expressed (Tall or short)

What is a mutation? Mutation is a change in the genetic code Mutations are the ultimate source of all variety on the planet Types: gene mutation and chromosomal mutation Gene mutation – point mutations, and frameshift mutations Chromosomal – Deletion, inversion, duplication, translocation.

Punnett Squares Ex) TT x tt ; Tt x Tt What are the difference patterns of inheritance? Law of Dominance – in a heterozygous genotype, the dominant allele is expressed (shows) Co-dominance – neither allele is dominant nor recessive Incomplete Dominance – neither allele is dominant and both traits blend into one. Multiple Alleles – there are more than two alleles for gene Polygenic Trait – Traits that are controlled by more than one gene

What is transformation? Transformation: When you add more DNA to a cell’s DNA Recombinant DNA: DNA from two species put together Bacterial DNA is shaped like a circle and called a plasmid Restriction Enzymes: Cut DNA The plasmid is removed and cut using Restriction Enzymes A new piece of insulin DNA is added to the plasmid (recombinant DNA) and the plasmid is put back into the bacteria