Quiz 1 (Modules 1 and 2, Slides 1-4) Flashcards
Define the term genome
a complete set of genetic instructions for any organism
List the three major divisions of genetics and explain what each includes
Transmission genetics (classical genetics)
Molecular genetics
Population genetics
Transmission genetics (classical)
Study of genetics of individual organisms
Basic principles of heredity and how traits are passed from one generation to the next
(Focuses on the individual organism)
Molecular genetics
Studies of the chemical nature of a gene of individual organisms
How genetic information is encoded, replicated, and expressed
Focus on the molecular genetics of the gene
- its structure, organization, and function
Population genetics
Study of the group of genes found in a population
Studies the genetic composition of populations
How genetic composition changes geographically and with the passage of time (includes evolution)
Focus is on the group of genes found in a population
Describe common features of most model genetic organisms and explain model organisms why are useful for scientists
Common characteristics of model organisms:
Short generation time
Production of numerous progeny
The ability to carry out controlled genetic crosses
The ability to be reared in a laboratory environment
The availability of numerous genetic variants
An accumulated body of knowledge about their genetic systems
Give a definition of a gene
unit of information that determines genetic characteristics.
The exact definition depends on the context
Explain the relationship of genes and alleles
Different versions of the same gene are called alleles
Alleles differ in their DNA sequence
Different alleles result in rabbits with fur that is brown, white, black, or chinchilla.
Explain the difference between phenotype and genotype.
Genotype: specific alleles (version of a given gene) that an individual has
- determined by the sequence in that individual’s DNA
Phenotype: the observable traits of an individual
- The phenotype of an individual is determined by their genotype
- Proteins are the links between genotype and phenotype
State the “Central Dogma” of biology
gene expression is often referred to as the Central Dogma of Biology
The order of the steps of gene expression in eukaryotic cells (like you did in the Central Dogma activity)
DNA, RNA, Protein
Explain the relationship between genes and chromosomes
- Genes are located on chromosomes
- Genes are stretches of DNA located on chromosomes
Each chromosome contains a large number of genes - Every gene is located at a specific place on a specific chromosomes
Explain what homologous chromosomes are
The two chromosomes in a pair
Explain the basic characteristics of the genetic code
the set of rules that determine which codons code for WHICH amino acids
the triplet nature of the genetic code
Set of 3 nucleotides that encodes a single amino acid
the meaning of the term codon
a triplet RNA code
that the code is degenerate, and what that means
(it is redundant): each amino acid encoded by more than one codon
that the code is unambiguous, and what that means
each codon codes for one amino acid
that AUG is the start codon
- AUG marks the start of protein (when correct sequences are upstream) AND
- AUG codes for also codes for one of the amino acids (Met) So: all polypeptide chains start with Met
- But: AUG also codes Met when it is inside coding region of a gene
that there are stop codons and understand why they work
There are 3 Termination (stop) codons:
UAA
UAG
UGA
The termination codons do not code for any amino acids
If given a sequence of RNA and a genetic code, be able to say the amino acid sequence encoded by that stretch of RNA
Use the genetic code in order to decipher it
Define, and explain the different effects of, somatic mutations and germ-line mutations
Germ-line mutations: From an individual to subsequent generations
- Mutation occurs during meiosis; results in change in genome of sperm or egg cell
Somatic mutations: From a cell to its descendants
- Mutation occurs during mitosis; results in change to somatic (body) cells
base substitutions
Mutation on which only a single nucleotide is changed
- Base substitutions are also referred to as a point mutation
Base substitutions can cause (a) missense: One amino acid is changed
(b) nonsense: Protein is shortened (premature termination of translation)
(c) silent mutations: Does not change amino acid sequence
insertions
mutation in which one or more nucleotides are added to a sequence
deletions
mutation in which one or more nucleotides are deleted from a sequence
expanding nucleotide repeats
A type of mutation in which a set of tandemly repeated sequences replicates inaccurately to increase the number of repeats.
For point mutations: missense
Changes a sense codon into a different sense codon, resulting in the incorporation of a different amino acid in the protein
nonsense
Changes a sense codon into a nonsense (stop) codon, causing premature termination of translation
silent
Changes a sense codon into a synonymous codon, leaving the amino acid sequence of the protein unchanged
neutral
Changes the amino acid sequence of a protein without altering its ability to function