Objectives
Define the terms genetics, genome, chromosome, gene, genetic code, genotype and phenotype.
Genetics:is the study of how DNA is inherited and how small differences in DNA sequence leads to differences in individuals.
Genome: the complete set of instructions for any organism.
Chromosome:The organized structures that contain most of the DNA of an organism.
Genes: hold the DNA sequence to make all the amino acids of different proteins.
Genetic Code: messenger RNA codons in terms of what amino acids they specify.
Genotype: specific genetic makeup of an individual.
Phenotype:observable physical properties of an individual.
The function of a gene is..
-Dictates the amino acid sequence and chain length of a protein.
-dictates the primary structure of a protein
-carries genetic information
What happens to introns?
they are clipped out of the mRNA before translation
Define Anticodon
anticodon refers to the three nitrogen bases on a transfer RNA (tRNA) molecule which pair with a codon on the messenger RNA (mRNA).
What is a codon?
A group of three RNA nucleotides.
List the similarities and differences between DNA and RNA
Similarities: phosphate sugar backbone; A,C,G; Pentose sugars; nucleic acids; Gene expression
Differences:
DNA: Double helix (2 strands); Deoxyribose; found in nucleus in Eukaryotes; Stable; T
RNA: Single stranded; Ribose; Unstable; U; can act as hereditary material and an enzyme
The entire DNA double helix is copied during
DNA replication
The sequence of the mRNA transcribed from the DNA sequence
5' T A C C A A A C G A T G A C T 3'
will be
3' A U G G U U U G C U A C U G A 5'
What is RNA processing?
RNA processing is the removal of the introns.
TRUE OR FALSE
Introns are not present in prokaryotic chromosomes.
True
Describe and explain the processes of transcription and translation.
Transcription: Step 1 of the two step process of Gene expression. We are making an RNA copy of the DNA. RNA polymerase (enzyme) unwinds and pulls apart the two DNA strands. Uses one strand (sense strand) to make an RNA copy of the DNA.
Translation:We are translating DNA language (base coding) -> Protein language (amino acids). Translation takes place in the cytoplasm. Translates the genetic information (contained the specific order of the nucleotides in mRNA) into the specific order of the amino acids in a polypeptide “Language” called the genetic code. Made of BOTH protein and ribsomal RNAs (rRNAs). Made up of 2 parts: the small subunit and the large subunit
A polypeptide is synthesized during
translation
Use the codon dictionary on page 12 of Topic 10 to translate the following mRNA into a polypeptide.
5' A C A U G A U C U C C A C G 3'
The amino acid sequence of this polypeptide is:
methionine, isoleucine, serine, threonine
What are introns?
portion of genes that are not used to make a protein.
What is a polypeptide?
A polymer of amino acids, and the building blocks of proteins. Some proteins are a single polypeptide, and some proteins are two or more polypeptides complexed together (as in hemoglobin).
Define the term mutagen.
A chemical or substance that can induce a mutation.
tRNA carries amino acids during
If the DNA sequence A C G was changed to A C C, what kind of mutation would that be? (Don't forget to transcribe, then translate)
missense
Which type of Missense mutation is more severe?
Non-Conservative is more severe.
Look at chart on page 180 in book, Question 15 MUTATION EXAMPLES:
ACA,UGA, cysteine.
ACG,UGC,cysteine, silent.
ACC,UGG, tryptophan, missense.
ACT, UGA,"stop", nonsense.
Name different types of mutations.
Silent mutations:point mutation that does not change the resulting amino acid in the polypeptide.
Nonsense: point mutation that changes a codon from one that codes for an amino acid to one that stops codons.
Missense: point mutation that changes a codon that codes for one amino acid to a codon that codes for a different amino acid.
Frameshift mutations: when the insertion or deletion of DNA nucleotides that changes a gene's reading frame, that is it changes the wat the sequence is read.
Mutations can be caused spontaneously or by environmental factors.
mRNA is synthesized during
transcription
If the DNA sequence A C G was changed to A C T, what kind of mutation would that be? (Don't forget to transcribe, then translate)
nonsense
TRANSCRIPTION: Messenger ________ is synthesized using the ______ in a gene as the template.
TRANSLATION: A _______ is synthesized using the _______ sequence as a blueprint or code.
TRANSCRIPTION: Messenger _RNA_ is synthesized using the _DNA_ in a gene as the template.
TRANSLATION: A _polypeptide_ is synthesized using the _mRNA_ sequence as a blueprint or code.
Go to page 173 in your book Question 4 use that image to answer the question below.
The difference between the base thymine and the base uracil is that a -CH3 group (methyl group) in thymine is replaced with a hydrogen atom in uracil. Which of the following pictures (A or B in your book) is thymine and which is uracil?
A is thymine. B is uracil.
The difference between base thymine and the base uracil is that CH3 group(methyl group) in thymine is replaced with a hydrogen atom in uracil.