The science of hereditary and study of genes and how they carry information is termed
The genetic information in the cell is called
The genetic makeup of an organism is termed
The physical traits that appear in an individual as a result of its genetic make up is called
Phenotype. eg. brown eyes
The segments of DNA that code for functional products are
Genes, which contain the information for inherited characteristics: motphology, metabolism, behavior, pathology.
a long linear polymer found in the nucleus of a cell and formed from nucleotides and shaped like a double helix. DNA is made up of two antiparallel strands joined by hydrogen bonds. Each strand has alternating sugar and phosphate groups and a nitrogenous base is attached to each sugar. In eukaryotic cells DNA is wound around clusters of histones (chromosomal proteins). Three basic parts:
1. Base: Adenine always pairs with thymine, and cytosine always pair with guanine.
2. Sugar: Deoxyribose
The process in which one parental double stranded DNA molecule is converted to two identical daughter molecule is called
enzyme responsible for adding complementary base pairs and proofreads the new double stranded DNA.
Why is the process of replication referred to as Semiconservative?
Because each new double-stranded DNA molecule contains one original (conserved) strand and one new strand.
RNA & PROTEIN SYNTHESIS
DNA --------→mRNA ----------→Protein
The process of synthesizing messenger RNA (mRNA) from a DNA template is called
Transcription. It takes place in the ribosomes, the cellular machinery for protein synthesis. Involves RNA polymerase binding to a promoter. In transcription Uracil substitutes thymine. For example, the template portion of DNA has sequence ATGCAT, the newly synthesized mRNA will have the complementary base UACGUA.
The use of a mRNA template in protein synthesis is called
Translation, because it involves decodin the language of nucleic acids and converting that information in language of proteins. The language of mRNA is in the form of codons like AUG,GGC OR AAA.
Process of Translation
1. Initiation: The mRNA leaves the DNA and goes to the ribosome.
2. Then the tRNA pairs up with the mRNA. This sets up the initiator cudon AUG
3. Elongation: The messages are in a sequence of three bases. (called codons)
4. Each triplet codes for a specific amino acid
5. The 1st bonded mRNA/tRNA is called an "anticodon".
6. Termination: The ribosome moves along the mRNA bringing each codon for the specific protein.
7. Peptide bonds form between the 2 amino acids.
8. This continues until all of the amino acids of the protein are in order and the stop codon (UGA) is reached.
9. The protein then folds into the shape needed for its job.
a process of removing a desirable gene from one organism an transplanting it into another organism.
worked with two strains of Strep. pnumoniae. One heat killed virulent with capsules and one live virulent with no capsules.
the transfer of genetic material in the form of DNA fragments from one cell to another as naked DNA solution.
Mechanisms of transformation
Fragments of DNA from lysed cells are taken up by other bacteria and recombine with their own DNA.
The direct transfer of DNA by cell to cell contact is termed
Conjugation, which must generally be of opposite mating type. Donors carrying F cells attach to recipient F cels by means of sex pili and transfers genetic material. It can transfer plasmid or parts of its own chromosome.
The transfer of genetic information from one bacteria to another by means of a bacteriophage is called
Plasmids and transposons
are genetic elements that provide additional mechanisms for genetic change.
Small self replication circles of DNA found in many bacteria. The F plasmid (fertility) is a conjugative plasmid that carries genes for sex pili and for transfer of the plasmid to another cell.
encode enzymes for catabolism of unusual compounds. Possible use in Bioremediation.
Toxic proteins that kill another bacteria
Resistance Factor (R Factor)
a plasmid that provide multiple genes for antibiotic resistance.
(jumping genes) short strands of DNA capable of moving from one location to another within a cell's genetic material. ------ contain the information for its own transposition. ------- contain insertion sequences that code for an enzyme (transposase) for cutting and resealing DNA. Complex ------- carry other genes in addition to transposase genes.
change in a DNA sequence that affects genetic information. ------ in gametes can passed on offspring.
random change in the DNA due to errors in replication or natural background radiation that occur without known cause
Result from exposure to known mutagens, physical (primarily radiation) or chemical agents that interact with DNA in a disruptive manner. Result from human intervention or other identifiable causes (ultraviolet light, radiation, chemical agents, ect.)
Categories of Mutations
1. Base substitution: A single base at one point in a DNA sequence is replaced witha different base.
2. Same sense mutation: Mutation that does not change the amino acid sequence. (Redundancy in the same base)
3. Mis-sense mutation: point mutations that codes for different amino acid, result in altered proteins that are still functional but can be harmful. e.g. Sickle cell anemia.
4. Non-sense Mutation: A mutation, which inserts a stop codon in the middle of mRNA.
5. Frameshift Mutation: a mutation, such as the insertion or deletion of a nucleotide in a coding sequence, that results in the misreading of the code during translation because of a change in the reading frame.
ability of an organism to control which genes are transcribed in response to the environment
Produced constantly (present at all times). Not subject to repression.
Subject to repression., usually are on all the time and turned off by certain conditions.
these are only produced in the presence of an inducer. , their synthesis is induced by a chemical signal. Is turn on when needed.
Selective expression of genes
model for switching genes off and on.
A gene that codes for a protein that can block the expression of another gene.
region of DNA that indicates to an enzyme where to bind to make RNA
controls the activity of the structured genes (switches on/off to control transcription)
gene encoding the amino acid sequence of a protein. Non-regulatory gene.
one that is usually on; binding of a repressor to the operator shuts off transcription. The gene product act as a Corepressor. The Corepressor activates the repressor changing their shape. eg. Allolactose binds to protein and changes its shape
a small molecule that cooperates with a repressor protein to switch an operon off.