Lecture--Chapter 1 Flashcards
Genes are:
unit of heredity
Traits are:
characteristics
Genomes are:
all the DNA contained within the chromosomes
Approximately how many genes code for proteins that perform most life functions?
20 000 - 25 000
Approximately how many DNA base pairs per set of chromosomes?
3 billion
The four major groups of cellular macromolecules are:
- lipids
- carbohydrates
- proteins
- nucleic acids
What are lipids?
Molecules that form fats, phospholipids, waxes, steroids; function in energy metabolism and components of membranes.
What are carbohydrates?
Molecules composed of hydrocarbon-rings, which form monosaccharides and polysaccharides; function in energy metabolism and storage polymer formation.
What is an example of a monosaccharide?
glucose
What is an example of a polysaccharide?
starch
What are proteins?
polymers of amino acids (polypeptides); function in cell structures, immune defense, as enzymes; proteome
What is a proteome?
All of the proteins that an organism can make.
What are nucleic acids?
DNA or RNA; polymers of nucleotides; hereditary information, direct protein synthesis.
Each nucleotide of DNA contains one:
nitrogenous base
What are the nitrogenous bases?
- adenine
- thymine
- cytosine
- guanine
What is a nucleotide?
a molecule containing a sugar, a phosphate, and a nitrogenous base
What is a triplet code?
genetic information stored in the linear sequence of bases
Start codon:
ATG (codes for methionine)
What are the three different traits?
- morphological traits
- physiological traits
- behavioural traits
morphological traits:
affect the appearance, form, and/or structure of an organism
physiological traits:
affect how an organism functions
behavioural traits:
affect the ways an organism responds to the environment
Traits are affected by:
the gene allele that is expressed
Traits are expressed:
at different levels of biological organisation
Traits are governed:
both by genes and by the environment
What is a morph?
A contrasting form within a single species (2 or more phenotypes of the same species that occupy the same habitat at the same time, within a population with random mating).
Genetic variation is a result of different types of changes at the DNA molecular level:
- gene mutations
- chromosomal mutations
- aneuploidy
What are gene mutations?
any change in the local DNA sequence as simple as a single nucleotide change; create new alleles
What are chromosomal mutations?
any change in the structure of the chromosome; deletions, inversion, translocations, or duplications
What is aneuploidy?
chromosomes lost or gained
Define biological evolution:
The genetic makeup of a population can change over many generations.
Define natural selection:
The gradual, non-random process by which biological traits become either more or less common in a population as a function of differential reproduction of their bearers; beneficial alleles have a higher probability of being passed onto subsequent generations.
Random DNA mutations lead to:
- neutral alleles
- beneficial alleles
- deleterious alleles
Neutral alleles:
no advantage or disadvantage to the individual
Beneficial alleles:
are advantageous to individuals since they make them better able to compete for resources and reproduce
Deleterious alleles:
make individuals less able to compete for resources and reproduce
What are the 2 different experimental approaches that genetics research uses?
- hypothesis testing
2. discovery-based science
What are the three fields of genetics research?
- transmission genetics
- molecular genetics
- population genetics
Transmission genetics:
examines how traits are passed from one generation to the next
Molecular genetics:
deals with the molecular features of DNA and how these underlie gene expression
Population genetics:
deals with the genetic composition of populations and how it changes over time and space
What does transmission genetics entail?
- looks at patterns of inheritance (Mendelian and non-Mendelian)
- the basic experimental approach in transmission genetics is the genetic cross
What is the genetic cross?
the mating of 2 individuals and analysis of the traits of their offspring over several generations
What does molecular genetics entail?
- goal is to describe the molecular features of gene structure and function, scaling from DNA molecules to whole genomes
- molecular technologies allow the introduction of genes into animals and plants–treatment for genetic diseases; agriculture modification of animals and plants in various ways
What does population genetics entail?
- connects the work of Mendel on inheritance to that of Darwin
- genetic technologies allow the introduction of genes into animals and plants–agriculture modification of plants and animals; gene therapy for treatment of genetic diseases
