BIOL 207 Molecular Genetics And Heredity | 755 Questions
And Answers | Latest Study Updates
Typical definition of Genetics ANS The study of genes, heredity, and genetic variation
What is a gene? ANS •Basic unit of heredity
•Sequence of DNA that codes for a product (RNA or protein) and it's regulatory regions
•Located on chromosomes
What is an allele? ANS One of two or more versions of a gene
What is a genome? ANS •The complete set of genetic material in a cell (including mitochondrial,
chloroplast, plasmid DNA)
•Includes genes as well as non-coding DNA regions
Genes vs Traits/phenotypes ANS •Genes are inherited
•Traits/phenotype are not directly inherited
•Traits/phenotype
•Observable characteristic
•Manifest as a result of the genes an individual carries, and the environment that influences the expression of
the genes
•Heritable trait - when a particular trait can be passed genetically
Central dogma ANS DNA -> RNA -> Protein
Since all organisms are thought to have evolved from a common ancestor this implies? ANS the coding
system for genetic information is the same in all living organisms
ATCG
Model Genetic Organisms ANS Organisms with characteristics that make them useful for genetic analysis
-six have been the most intensively studied genetically
,Six most intensively studied organisms ANS Fruit fly, E. coli (bacterium), Nematode, Arabidopsis thaliana,
house mouse, bakers yeast
Common characteristics of model organisms ANS 1. Short generation time
2. Production of numerous progeny
3. The ability to carry out controlled genetic crosses
4. The ability to be reared in a laboratory environment
5. The availability of numerous genetic variants
6. An accumulated body of knowledge about their genetic systems
How have model organisms advanced our knowledge of human genetics? ANS Helped identified that
certain alleles/genes are responsibly for certain phenotypes.
Example of early genetics ANS domestication of plants and animals
Pangenesis ANS -each part of the body contains genetic information for that particular part
-specific particles called gemmules carry info from parts of the body to the reproductive organs (via blood)
then passed to the embryo at the moment of conception
Inheritance of Acquired Characteristics / Lamarckian Inheritance ANS -traits acquired in a person's
lifetime become incorporated onto the person's hereditary info and are passed onto offspring
ex. those who develop musical abilities may pass it done to there children
Preformationism ANS -inside egg or sperm is a tiny version of an adult (homunculus)
-this little man simple enlarges in the course of development
-offspring is genetically solely of the mother or of the father
Blending inheritance ANS -each traits of offspring are a blend or mixture of parental traits
-suggested genetic material blends like colored traits
What led to the proposal of the Weismann : Germ-plasm theory ANS -tested the idea of acquired
inheritance of acquired traits by cutting of the tails of mice for 22 generations
,-this did not alter their tail length thus no evidence to support inheritance of acquired characteristics
Weismann : Germ-plasm theory ANS cells in reproductive organs carry a complete set of genetic info that
is passed to the egg and sperm
Schleiden and Schwann ANS The Unified Cell Theory
-Q: What are living things made of?
-all life composed of cells and the cell is the fundamental unit of structure and function in living organisms
Abiognesis ANS -cells arise spontaneously
-disproved: cells arise only from pre-existing cells
Darwin ANS -put forth the theory of evolution through natural selection
-recognized the weakness in his theory: lack of understanding of heredity
Key Ideas of Darwin ANS -variation of traits within populations
-traits are inherited
-offspring with traits that increase their probability of survival survive to reproduce
Gregor Mendel ANS -principles of heredity
-discovered basic principles of heredity
-conclusions not widely known in the scientific community until 35 yrs after their publication
-laid the foundation for our modern understanding of heredity
-generally recognized today as the father of genetics
-
3 Laws of Heredity ANS 1. The law of independent segregation: Each individual carries two copies of an
inherited trait (e.g., alleles), which segregate equally in the following generation.
2. The law of independent assortment: Different inherited traits sort independently of one another (e.g., pea
plant height and flower colour)
3. The law of dominance: For a trait, one allele is dominant and appears in a 3:1 ratio. Identification of
dominant and recessive genes.
, Walther Flemming: chromosomes ANS -Examined salamander embryos
-First to publish on the movement of chromosomes during cell division in 1879
-Published description of mitosis
-"Solved" the separation of chromosomes from mother to daughter cells
-His observations that chromosomes double is significant to the later-discovered theory of inheritance
Theodor Boveri & Walter Sutton ANS •Sperm and eggs contribute the same number of chromosomes
•Behaviour of chromosomes during cell division (highly organized, appear the same in daughter cells, and
doubles before cell division) can explain Mendel's laws of inheritance
•The Boveri-Sutton Chromosome Theory: Heritable units are located on chromosomes
•A heavily debated and controversial theory at the time
Thomas Hunt Morgan ANS -Bred millions of Drosophila in his lab, hoping to study emergence of new
traits and speciation
-Discovered the first mutant fruit fly in 1910 with white eyes
-Sex-linked trait (red dominant, white recessive)
-Sex chromosomes in Drosophila are different sizes (observable)
-Linked the heritable information for eye colour to X sex chromosome
What did the studies of Thomas Hunt Morgan confirm? ANS 1.Mendel's laws of inheritance
2.Boveri-Sutton Chromosomal Theory that the heritable information is present on chromosomes.
transmission genetics ANS Field of genetics that encompasses the basic principles of heredity and how
traits are passed from one generation to the next.
Molecular genetics ANS Study of the chemical nature of genetic information and how it is encoded,
replicated, and expressed
Population genetics ANS Study of the genetic composition of populations and how that composition
changes geographically and with the passage of time.
And Answers | Latest Study Updates
Typical definition of Genetics ANS The study of genes, heredity, and genetic variation
What is a gene? ANS •Basic unit of heredity
•Sequence of DNA that codes for a product (RNA or protein) and it's regulatory regions
•Located on chromosomes
What is an allele? ANS One of two or more versions of a gene
What is a genome? ANS •The complete set of genetic material in a cell (including mitochondrial,
chloroplast, plasmid DNA)
•Includes genes as well as non-coding DNA regions
Genes vs Traits/phenotypes ANS •Genes are inherited
•Traits/phenotype are not directly inherited
•Traits/phenotype
•Observable characteristic
•Manifest as a result of the genes an individual carries, and the environment that influences the expression of
the genes
•Heritable trait - when a particular trait can be passed genetically
Central dogma ANS DNA -> RNA -> Protein
Since all organisms are thought to have evolved from a common ancestor this implies? ANS the coding
system for genetic information is the same in all living organisms
ATCG
Model Genetic Organisms ANS Organisms with characteristics that make them useful for genetic analysis
-six have been the most intensively studied genetically
,Six most intensively studied organisms ANS Fruit fly, E. coli (bacterium), Nematode, Arabidopsis thaliana,
house mouse, bakers yeast
Common characteristics of model organisms ANS 1. Short generation time
2. Production of numerous progeny
3. The ability to carry out controlled genetic crosses
4. The ability to be reared in a laboratory environment
5. The availability of numerous genetic variants
6. An accumulated body of knowledge about their genetic systems
How have model organisms advanced our knowledge of human genetics? ANS Helped identified that
certain alleles/genes are responsibly for certain phenotypes.
Example of early genetics ANS domestication of plants and animals
Pangenesis ANS -each part of the body contains genetic information for that particular part
-specific particles called gemmules carry info from parts of the body to the reproductive organs (via blood)
then passed to the embryo at the moment of conception
Inheritance of Acquired Characteristics / Lamarckian Inheritance ANS -traits acquired in a person's
lifetime become incorporated onto the person's hereditary info and are passed onto offspring
ex. those who develop musical abilities may pass it done to there children
Preformationism ANS -inside egg or sperm is a tiny version of an adult (homunculus)
-this little man simple enlarges in the course of development
-offspring is genetically solely of the mother or of the father
Blending inheritance ANS -each traits of offspring are a blend or mixture of parental traits
-suggested genetic material blends like colored traits
What led to the proposal of the Weismann : Germ-plasm theory ANS -tested the idea of acquired
inheritance of acquired traits by cutting of the tails of mice for 22 generations
,-this did not alter their tail length thus no evidence to support inheritance of acquired characteristics
Weismann : Germ-plasm theory ANS cells in reproductive organs carry a complete set of genetic info that
is passed to the egg and sperm
Schleiden and Schwann ANS The Unified Cell Theory
-Q: What are living things made of?
-all life composed of cells and the cell is the fundamental unit of structure and function in living organisms
Abiognesis ANS -cells arise spontaneously
-disproved: cells arise only from pre-existing cells
Darwin ANS -put forth the theory of evolution through natural selection
-recognized the weakness in his theory: lack of understanding of heredity
Key Ideas of Darwin ANS -variation of traits within populations
-traits are inherited
-offspring with traits that increase their probability of survival survive to reproduce
Gregor Mendel ANS -principles of heredity
-discovered basic principles of heredity
-conclusions not widely known in the scientific community until 35 yrs after their publication
-laid the foundation for our modern understanding of heredity
-generally recognized today as the father of genetics
-
3 Laws of Heredity ANS 1. The law of independent segregation: Each individual carries two copies of an
inherited trait (e.g., alleles), which segregate equally in the following generation.
2. The law of independent assortment: Different inherited traits sort independently of one another (e.g., pea
plant height and flower colour)
3. The law of dominance: For a trait, one allele is dominant and appears in a 3:1 ratio. Identification of
dominant and recessive genes.
, Walther Flemming: chromosomes ANS -Examined salamander embryos
-First to publish on the movement of chromosomes during cell division in 1879
-Published description of mitosis
-"Solved" the separation of chromosomes from mother to daughter cells
-His observations that chromosomes double is significant to the later-discovered theory of inheritance
Theodor Boveri & Walter Sutton ANS •Sperm and eggs contribute the same number of chromosomes
•Behaviour of chromosomes during cell division (highly organized, appear the same in daughter cells, and
doubles before cell division) can explain Mendel's laws of inheritance
•The Boveri-Sutton Chromosome Theory: Heritable units are located on chromosomes
•A heavily debated and controversial theory at the time
Thomas Hunt Morgan ANS -Bred millions of Drosophila in his lab, hoping to study emergence of new
traits and speciation
-Discovered the first mutant fruit fly in 1910 with white eyes
-Sex-linked trait (red dominant, white recessive)
-Sex chromosomes in Drosophila are different sizes (observable)
-Linked the heritable information for eye colour to X sex chromosome
What did the studies of Thomas Hunt Morgan confirm? ANS 1.Mendel's laws of inheritance
2.Boveri-Sutton Chromosomal Theory that the heritable information is present on chromosomes.
transmission genetics ANS Field of genetics that encompasses the basic principles of heredity and how
traits are passed from one generation to the next.
Molecular genetics ANS Study of the chemical nature of genetic information and how it is encoded,
replicated, and expressed
Population genetics ANS Study of the genetic composition of populations and how that composition
changes geographically and with the passage of time.
