Chapter 9 Flashcards
What is genetics and what does it study?
Genetics is the study of the inheritance, or heredity, of living things
1) the transmission of biological properties from parent to offspring
2) the expression and variation of traits
3) the structure and function of genetic material
4) the change of genetic material
What is an organisms genome?
The sum total of the genetic material of an organism
What are chromosomes?
Discrete cellular structures composed of neatly packaged DNA molecule
How is a gene described in both classical and molecular/biochemical terms?
Classical- the fundamental unit of hereditary responsible for a given trait in an organism (part of DNA that gives you a physical trait)
Molecular/ biochemical- site on the chromosome that provides info for a certain cell function
Genes fall into what 3 basic categories?
1) structural genes
2) RNA genes
3) regulatory genes
What is the difference between genotype and phenotype?
Genotype- genetic makeup of a gene or genome
Phenotype- physical expression of a gene
What are the basic units of DNA?
Nucleotides
How are nucleotides (what type of bond) to one another within each strand?
Covalent phosphate bonds
How are the two opposite strands of DNA connected (what type of bond)?
Hydrogen bonds
What are the 3 major types of RNA?
1) Messenger RNA (mRNA)
2) Transfer RNA (tRNA)
3) Ribosomal RNA (rRNA)
What is transcription?
Conversion of DNA to RNA (specifically mRNA)
What type of RNA is created during transcription?
mRNA
What is translation?
The conversion of mRNA to protein
What is the function of RNA polymerase?
To convert DNA to RNA
What are triplets and codons?
Triplets- segments of 3 DNA nucleotides that encode for a single amino acid
Codons- when triplets are converted when DNA is converted to RNA during transcription
What do triplets and codons code for?
Triplets code for single amino acids
When triplets codes of a DNA molecule are transcribed and translated it dictates the type and order of amino acids in the primary protein structure
What is mutation?
Any permanent change in nucleotide sequence of an organism’s genome, a viral genome, extrachromosomal genetic elements
What are the 2 types of chemical mutagens discussed?
Acridine dyes and nucleotide analogs
What are the common sources of physical mutagens?
X-rays, gamma rays, and UV light rays
What are the 3 types of point mutation?
1) additive- the insertion of an extra nucleotide
2) deletion- the removal of a nucleotide
3) substitution- a change from one nucleotide to another
What is a missense mutation?
Any mutation in a nucleotide sequence that leads to placement of a different amino acid in the primary protein sequence
What is a silent mutation?
Involves the alteration of a nucleotide base but doesn’t lead to a change in the amino acid sequence
What is a nonsense mutation?
Changes a normal codon into a step codon and stole the production of the protein wherever it occurs in the sequence, often leading to incomplete and non-functional proteins
Frameshift mutation
Occurs when a base pair is inserted or deleted/ shifts the “reading frame” and changes every amino acid that occurs after the shift
