introduction Flashcards
(20 cards)
What is the literal definition of a gene?
A theoretical unit of heredity of living organisms
The term ‘gene’ has a specific definition that relates to heredity.
What does genetics study?
Transmission and variation of inherited characteristics, particularly chromosomes and DNA
Genetics involves both the study of genes and their hereditary implications.
How can we define ‘genetics’ more precisely?
The branch of biology that deals with the transmission and variation of DNA
This definition reflects advancements in molecular biology.
What is a problem with over-precise definitions of genetics?
They may exclude organisms whose heredity does not occur by DNA
Not all genetic systems are based on DNA, which complicates strict definitions.
What is a phenotype?
Any observable characteristic of an organism, such as morphological, developmental, biochemical, or physiological properties, or behavior
Phenotypes can be influenced by both genetics and the environment.
What are the main factors that can influence an organism’s phenotype?
- Inheritance from parents
- Effects of the environment
- Interplay of genetics, development, upbringing, and chance
Phenotypic traits often arise from multiple factors, making attribution complex.
What does Mendelian genetics refer to?
The connection between discontinuous phenotypic variation and specific genotypic variation
Mendelian genetics is a powerful tool but is rare in real populations.
What is a characteristic of phenotypic variation in populations?
Usually highly continuous and difficult to connect to specific genotypic variation
Continuous variation complicates the study of traits in populations.
What is the importance of twin studies in genetics?
They help determine the heritability of traits by comparing identical and non-identical twins
Twin studies can separate genetic and environmental influences.
What is the typical genetic structure of eukaryotic organisms?
Diploid, having two sets of chromosomes
Eukaryotes inherit genetic material from two parents, leading to Mendelian inheritance patterns.
What is unique about bacterial genetics?
Bacteria are exclusively haploid and exchange genetic material through conjugation
This leads to non-Mendelian patterns of inheritance.
What does the term ‘horizontal gene transfer’ refer to?
The transfer of genetic material between organisms through non-sexual means
This process is common in bacteria and contributes to genetic diversity.
What constitutes an organism’s genome?
The total heritable genetic material it possesses
The genome is usually composed of DNA, but not always.
Why is DNA packaged in chromosomes?
To ensure the stability of the genome and act as particles of heredity
Chromosome theory of inheritance emphasizes their role in heredity.
What is the central function of a genome?
An instruction manual for cellular and organismal function
The genome also provides a mechanism for stable inheritance.
What are housekeeping genes?
Genes that encode proteins always needed for basic cellular functions
These genes are essential for maintaining basic life processes.
What is differential gene expression?
The process by which cells only express the subset of genes needed for their function
This regulation is crucial for cellular efficiency and function.
What is reverse genetics?
Starts with unknown genes, identifies the protein produced, and studies its function
This method allows researchers to determine the role of specific genes.
What does forward genetics begin with?
A biological question about phenotypic variation
Forward genetics aims to link phenotypic traits to specific genetic causes.
