Genetics

Watson and Crick

(1953) Were the first to publish the structure of DNA

DNA Polymerase

-only extends nucleic acid chain -cannot start from scratch so, RNA primase synthesizes RNA primers

DNA Replication

-the copying of double stranded DNA -necessary for cell reproduction prior to cell division

direction of replication

5'>3'

Describe Purine

A 6 membered ring attached to a 5 member ring

Nucleotide

A building block of DNA, consisting of a five-carbon sugar covalently bonded to a nitrogenous base and a phosphate group.

Trait of a Sex Linked Disorder

A higher enrichment of expression in one gender

deoxyribonucleic acid

A nucleic acid molecule, usually a double stranded helix, in which each polynucleotide strand consists of nucleotide monomers with a deoxyribose sugar and the nitrogenous bases A T C G; capable of being replicated and determining the inherited structure of cell's proteins.

Codon

A three-nucleotide sequence of DNA or mRNA that specifies a particular amino acid or termination signal; the basic unit of the genetic code.

Chargaff Rule

A=T => C=G

Homozygote

AA or aa

Heterozygote

Aa =

Helicase

An enzyme that unwinds the double helix of DNA and separates the DNA strands in preparation for DNA replication.

Hershey & Chase

Blender Experiment Radio-actively labeled sulfur in proteins and radio-actively labeled phosphorus in a second experiment the virus and allowed to infect bacteria. Showing it was the DNA that entered the bacteria and not the protein

Trait of a Dominant Disorder

Cannot skip a generation

DNA Structure

Deoxyribonucleic acid

Haploinsuffucuency

Dominant Mutation- one copy dominant genes leads to mutation

DNA Polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule

Mendel's first law

Equal segregation 1:3:1, and 1:2:1 Ratios are diagnostic of single-gene inheritance and based on equal segregation.

Phenotype vs Genotype

Genotype is the complement of genes Phenotype is the determined by genotype and it the expression of thoses genes

Meiosis

Making a Diploid parent cell into four Haploid daughter cells

Mitosis

Making a Diploid parent cell into two diploid daughter cells

Sex Linked Genes

Male=XY => Female=XX

X-linked repressive disorders

More prevalent in males as the only have set of X chromosomes

Autosomal chromosomes

None are sex linked chromosomes

Elements of DNA

Phosphate, Sugar Back-bone, Nitrogenous base (A,T,G and C)

Transcription

Process by which the DNA molecule in the nucleus makes a copy of itself using mRNA, then leaves nucleus of cell to go to protein synthesis [ribosomes] in cytoplasm.

Null Alleles

Proteins that have no activity

Watson and Crick

Published the first structure of DNA, 1953

rRNA

Ribosomal RNA. A nucleic acid found in all living cells. Transfers information from mRNA to the protein-forming Ribosomes system of the cell.

RNA Primer

Sequence of RNA nucleotides bound to a region of single-stranded DNA to initiate DNA replication.

Replication Origin

Specific sequence of DNA where DNA synthesis begins.

Elongation

Taq polymerase adds NTPs

Zygote

Two Haploid gametes combine to produce one Zygote

Topoisomerase

Uncoils overly coiled DNA Labeld as #3

Fredrich Griffith

Used "S" and "R" strains of bacteria to show the DNA held the genetic information as well as that bacteria can take up genetic materials

Franklin and Wilkins

Used x-ray crystalography to show two helical strands

Allele

Version of a gene, usually with fundamental implications

Gregor Mendal

Worked on Pea Plants showed gene Factor

Polymerase

add the base pairs on to the ssDNA

Denaturing

at 95 degrees

Sliding Clamp

binds polymerase to the ssDNA

DNA is a stranded

double helix

Proteins Involved in DNA replication

helicase, SSB, primase, DNA polymerase, RNase H, Ligase

Annealing

primers anneal at specific sites

DNA Replication

the process of making identical copies of DNA before cell division

Describe Thomas Morgan's work

(1913)Worked on Fruit Flies and was able to show that the genetic information was stored on chromosomes and knew that chromosomes are made up of DNA and Protein. He did not show if the information was stored on the DNA or the proteins

Describe Alfred Hershey and Martha Chase's work

(1952) "Blender Experiment" Viruses (bacterial phages) were radioactively labeled with one group having Proteins with radioactive sulfur and another group with radioactive phosphorus in the DNA. The viruses were allowed to infect bacteria and then then the phages were knocked off the bacteria. The infected bacteria were then tested for radio active P or S and it showed that it was the DNA that was passed to the bacteria as genetic material as there was no S detected but there was P detected.

Basic make-up of DNA

1. Phosphate 2. Sugar Back-bone 3. Nitrogenous base (Adenine, Thymine, Guanine, Cytosine)

Requirements of hereditary Material

1. Stable =>Storage of Information 2. Accurate but Variable => Able to pass on Information 3. Mutations => Variability

Describe Oswald Avery, Colin Macleod and Maclyn McCarthy's work

(1944) They took a pathogenic "S" strain bacteria and individually inactivated each component of the bacteria separately. The RNA, DNA, Carbohydrates, Lipids, or Proteins and then infected mice. Only the bacteria with the inactive DNA allowed the mice to survive. This showed more specifically that the DNA was the only material able to pass on the pathogenic properties

Semi Conservative

Each half of an original DNA molecule serves as a templete for a new strand, and the two new DNA molecules each have one old and one new strand.

phenylketonuria

Enzyme deficit. A deficiency where the phenylalanine is not able to be converted to Tyrosine

Thomas Morgan

Fruit Flies showed genes are on chromosomes made of DNA and Protein

Traits of a Recessive disorder

Often skip a generation

Haplosufficientcy

Only one gene copy is active but it is enough to produce sufficient enzymes. Aa Heterozygotic

Chargaff's rule

The concentration of Adenine=Thymine and Guanine=Cytosine. [A]=[T], [G]=[C]

Translation

The process whereby genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in the cytoplasm.

Oswald Avery

Showed it was the DNA that indeed what held the genetic information by deactivating all other materials individually

SSBP

Single Strand Binding Proteins keep the replication bubble open

Okazaki fragments

Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.

Describe how Rosalind Franklin and Maurice Wilkins work helped show the structure of DNA

Through X-ray crystallography it was able to be seen that the structure was double stranded, helical and the that the distance between the strands were consistent and anti-parallel

Describe Gregor Mendals work

Worked on Pea plants and showed there is a "genetic factor" or "gene" involved in heritability. Did not show where information was stored

Describe pyrimidines

a 6 membered ring

Replication Fork

a Y-shaped point that results when the two strands of a DNA double helix separate so that the DNA molecule can be replicated

DNA ligase

enzyme which connects the individual okazaki fragments on the lagging strand by forming covalent bonds

the leading strand

the strand of DNA that is continuously synthesized during replication

Describe Fredrick Griffith's work

(1928) He took rough edged "R" strain (non-pathogenic) and smooth edged, "S" strain (pathogenic) and tested them on mice. The "S" strain was then boiled and destroyed the proteins but allowed for the DNA to reform. The "S" strain DNA was then injected into "R" strain bacterium and allowed to infect mice. The mice lived using the pure "R" strain but died using the "S" strain DNA. This showed that bacteria can take up genetic material and reproduce from it and that DNA must be the cause of the pathogenic properties.

Three requirements of Hereditary Material

1. Stable - Able to store information 2. Accurate - Replicable and able to be passed on 3. Variability - Some mutations are allowed to prevent cloning

DNA REPLICATION

Before the lagging-strand DNA exits the replication factory, its RNA primers must be removed and the Okazaki fragments must be joined together to create a continuous DNA strand. The first step is the removal of the RNA primer. RNAse H, which recognizes RNA-DNA hybrid helices, degrades the RNA by hydrolyzing its phosphodiester bonds. Next, the sequence gap created by RNAse H is then filled in by DNA polymerase which extends the 3' end of the neighboring Okazaki fragment. Finally, the Okazaki fragments are joined together by DNA ligase that hooks together the 3' end of one fragment to the 5' phosphate group of the neighboring fragment in an ATP- or NAD+-dependent reaction. REPLICATION IN ACTION We are now ready to review the steps of DNA replication. The process begins when the helicase enzyme unwinds the double helix to expose two single DNA strands and create two replication forks. DNA replication takes place simultaneously at each fork. The mechanism of replication is identical at each fork. Remember that the proteins involved in replication are clustered together and anchored in the cell. Thus, the replication proteins do not travel down the length of the DNA. Instead, the DNA helix is fed through a stationary replication factory like film is fed through a projector. Single-strand binding proteins, or SSBs, coat the single DNA strands to prevent them from snapping back together. SSBs are easily displaced by DNA polymerase. The primase enzyme uses the original DNA sequence as a template to synthesize a short RNA primer. Primers are necessary because DNA polymerase can only extend a nucleotide chain, not start one. DNA polymerase begins to synthesize a new DNA strand by extending an RNA primer in the 5' to 3' direction. Each parental DNA strand is copied by one DNA polymerase. Remember, both template strands move through the replication factory in the same direction, and DNA polymerase can only synthesize DNA from the 5' end to the 3' end. Due to these two factors, one of the DNA strands must be made discontinuously in short pieces which are later joined together. As replication proceeds, RNAse H recognizes RNA primers bound to the DNA template and removes the primers by hydrolyzing the RNA. DNA polymerase can then fill in the gap left by RNase H. The DNA replication process is completed when the ligase enzyme joins the short DNA pieces together into one continuous strand.

ribonucleic acid

Consist of nucleotide monomers with a ribose sugar and the nitrogenous bases adenine (A), cytosine (C), guanine (G), and uracil (U); usually single-stranded; functions in protein synthesis and as the genome of some viruses.

Leaky Mutations

Has some activity but lower than normal.

mRNA

Messenger RNA molecule that carries copies of instructions for the assembly of amino acids into proteins from DNA to the rest of the cell

Double Helix

The form of native DNA, referring to its two adjacent polynucleotide strands wound into a spiral shape.

"F1" Daughter plants

The mixed second generation of the "P" plants

"P" Parental Mendal model

The original homozygotic parent plants

the lagging strand

The strand that is synthesized in fragments using individual sections called Okazaki fragments

tRNA

Transfer RNA. An RNA molecule that functions as a translator between nucleic acid and protein languages by carrying specific amino acids to the ribosome, where they recognize the appropriate codons in the mRNA.

Primase

synthesizes RNA primers for start of elongation