Genetics
By Jenna Parr
Structure of DNA and RNA
DNA:
- Double-stranded
- Nitrogen Bases are A, T, G, and C
- Deoxyribose sugar
- Cannot leave the nucleus
- Single-stranded
- Nitrogen bases are A, U, G, and C
- Ribose sugar
- Can leave the nucleus
Traits/Heredity
- Heredity is the passing of DNA from generation to generation. Ex: the 1st picture
- Traits are characteristics you inherit from your parents. Ex: the 2nd picture
Dominant/Recessive
- Dominant is the allele that masks/hides the other. Ex: "A" would be dominant in the allele, Aa.
- Recessive is the allele that is masked/hidden. Ex: "a" would be recessive in the allele, Aa.
Homozygous/Heterozygous
- Homozygous is when the alleles are the same. Ex: AA, aa
- Heterozygous is when the alleles are different. Ex: Aa
Punnett Squares
- A monohybrid punnett square is used to determine the genotypes and phenotypes an organism will have.
- A phenotype is the organism's physical appearance. Ex: brown hair
- A genotype is the organism's allele combination. Ex: AA, Aa, aa
Complimentary DNA and RNA Strands
Complimentary strands of DNA and mRNA match up like puzzle pieces. Ex:
- DNA: ATGCTCATG
- mRNA: UACGAGUAC
When DNA replicates, it has a complimentary strand. Ex:
- First strand: ATGCGCTAG
- Second strand: TACGCGATC
X-Linked Disorders
An X-Linked disorder is a disorder caused by a mutation on the X chromosome. Ex: Hemophilia A and B, Hunter's Disease, and Color Blindness
DNA Replication
- The DNA opens or "unzips" at the hydrogen bonds and copies in both directions.
- Base pairs are bonded until entire chain is copied.
- Since the DNA is copied in both directions, 2 copies of DNA are made.
Protein Synthesis
Step 1. Transcription:
- Transcription takes place in the nucleus - mRNA gets the code from DNA for a specific protein.
- mRNA carries the code into the cytoplasm and meets up with rRNA at the ribosome.
- Once mRNA and rRNA join up in the cytoplasm, they take the code and translate it into instructions for making proteins for the cell.
- Next, tRNAs bring the specific anit-codon to mRNA/rRNA and add the amino acids together to make the particular protein.
Genetic Engineering
Genetic engineering is a way to genetically alter an organism by inserting new DNA or other materials. Ex: genetic engineering to produce insulin
Steps to genetic engineering to produce insulin:
- Researchers found part of a human chromosome that has a gene for making insulin.
- They carefully cut out the gene using a restriction enzyme.
- Gene is put into bacterial DNA.
- The plasmid with the insulin producing gene is placed into a new bacterium.
- The bacterium grew and multiplied producing a large number of bacteria with the insulin producing gene.
DNA Fingerprinting
- Used to determine evolutionary relationships, paternity relationships, crime scene matches, and disease identification and therapy.
- You can find DNA in blood, saliva, hair, fingernails, and toothbrushes.
- Gel Electrophoresis is a method for separation and analysis of macromolecules and their fragments, based on their size and charge.
Mitosis (2n-2n)
Mitosis is when 1 diploid cell makes 2 exact diploid cells. It is a type of asexual reproduction and produces somatic cells. The steps are:
- Prophase - Chromosomes condense and prepare
- Metaphase - Meet in the middle
- Anaphase - Pull away
- Telophase - The end and cytokinesis
(A comparison is below)
Meiosis (2n-n)
Meiosis is when 1 diploid cell makes 4 haploid sex cells. It is a type of sexual reproduction. The steps are:
- Prophase 1 - Chromosomes condense and prepare
- Metaphase 1 - Meet in the middle
- Anaphase 1 - Pull away
- Telophase 1 - The end and cytokinesis
- Prophase 2 - Chromosomes condense and prepare
- Metaphase 2 - Meet in the middle
- Anaphase 2 - Pull away
- Telophase 2 - The end and cytokinesis
Crossing Over occurs in Prophase 1. It gives us genetic variation.
(A comparison is above)
Gametes
Gametes are sex cells. Ex: egg and sperm
Haploid and Diploid
- Diploid = 2n = Full Set of Chromosomes Ex: somatic cells
- Haploid = 1n = Half the number of chromosomes Ex: sex cells
Gregor Mendel
- He is considered the Father of Genetics.
- He was the first to scientifically prove parents pass some of their DNA/genes/traits to their offspring.
Mutations
- A mutation is a permanent change in DNA.
(Examples below)
Substitution Mutation
A mutation that exchanges one base for another.
Duplication Mutation
A portion of the genetic code is duplicated.
Deletion Mutation
A mutation in which a section of DNA is lost, or deleted.