Molecular Basis of Genetics Quiz

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Questions and Answers

What is the definition of a gene?

A type of RNA molecule involved in protein synthesis.

A discrete section of DNA that codes for a product. (correct)

A complete set of chromosomes in an organism.

A mutation that alters an organism's phenotype.

Which of the following describes a haploid organism?

An organism with multiple copies of each chromosome.

An organism with one set of chromosomes. (correct)

An organism with chromosomes that are genetically identical.

An organism with two sets of chromosomes.

What is the primary outcome of meiosis?

Increase in chromosome number in a cell.

Production of four genetically unique haploid cells. (correct)

Replication of DNA without cell division.

Formation of genetically identical diploid cells.

What term is used to refer to the position of a specific gene on a chromosome?

Locus Signup and view all the answers

Which statement about mutations is correct?

They can be beneficial, neutral, or harmful to the organism. Signup and view all the answers

In a heterozygous individual, how many different forms of a gene are present at a locus?

Two Signup and view all the answers

What does the term 'dominant' refer to in genetics?

A form of a gene that is always expressed when present. Signup and view all the answers

What is genetic recombination?

The creation of new genetic combinations through crossing over. Signup and view all the answers

What effect does a population bottleneck have on genetic diversity?

Significantly reduces genetic diversity Signup and view all the answers

Which of the following practices is an example of gene flow?

Migration of individuals between different populations Signup and view all the answers

What does the Hardy-Weinberg Law state about a population in equilibrium?

Allele frequencies remain constant in the absence of certain factors Signup and view all the answers

What is a consequence of non-random mating in a population?

Change in allele frequencies Signup and view all the answers

What is an important factor that must be absent for the Hardy-Weinberg Law to hold?

Natural selection Signup and view all the answers

How does natural selection influence a population's genetic traits?

By favoring certain traits for survival and reproduction Signup and view all the answers

Which example is NOT typically considered evidence for natural selection?

Random mating in a population Signup and view all the answers

What characterizes random mating in a population?

Matings occur randomly with respect to genotype frequencies Signup and view all the answers

Study Notes

Molecular Basis of Genetics

Genome: Complete genetic makeup of an organism
Chromosome: A single DNA molecule bound to histone proteins
DNA: Double-helix structure composed of a 5-carbon sugar, phosphate, and a nitrogenous base
Central Dogma: The flow of genetic information: DNA to RNA to Protein/Polypeptide
Gene: Segment of DNA coding for RNA or a protein
Locus: Specific position of a gene on a chromosome
Mutation: Alteration in the nucleotide sequence of DNA or RNA (substitution, duplication, insertion, deletion, or inversion)
Allele: Different forms of the same gene
Karyotype: Number and appearance of chromosomes in a eukaryotic cell's nucleus
Haploid: One set of genes (and chromosomes)
Diploid: Two sets of genes (and chromosomes)
Polyploid: More than two sets of genes/chromosomes

Terminology and Concepts of Genetics

Meiosis: Cell division producing four haploid cells from a diploid cell
Genetic recombination: Creation of genetically unique individuals from the same genes through independent assortment and crossing over of homologous chromosomes
Dominant: Always expressed gene when present
Recessive: Gene expressed only if homozygous
Genotype: Hereditary information that influences an organism's structure and function
- Homozygous: Two copies of the same allele for a gene at a specific locus
- Monomorphic: When the common allele's frequency within a population is > 95%
Heterozygous: More than one form of a gene at a locus
- Polymorphic: The common allele's frequency in a population is < 95%
Adaptive Evolution: Evolution that increases an organism's fitness and adaptation to its environment
- Natural Selection: The driving force of adaptive evolution
Non-adaptive Evolution: Evolution that does not increase an organism's fitness or adaptation to its environment
- Genetic drift: Changes in allele frequencies due to random chance
Population bottleneck: Significant reduction in genetic diversity leading to potential extinction due to environmental events
Gene flow: Migration of genes into a population from other populations through dispersal and interbreeding
Non-random mating: Mating influenced by sexual selection, social structure, etc.
Random mating: Mating occurs without regard to genotype; often referred to as "panmixia" or a panmictic population
Allele frequency: Measurement of the relative abundance of alleles in a population
Hardy-Weinberg Law: A model in population genetics that describes constant allele and genotype frequencies across generations in a large, randomly mating population with no mutation, migration, or selection
- Assumptions of the Hardy-Weinberg Law:
  - Infinite population size
  - No mutations
  - No migration
  - No natural selection
  - Random mating

Forces of Evolution, especially Natural Selection

Evolution: Change in the frequency of genetic traits within a population across generations
Natural selection: Differential survival and reproduction of individuals based on their traits, influencing the frequency of those traits in a population
- Survival of the fittest: A simplified phrase for natural selection, more accurately represented as "survival and reproduction of the fittest"
Prerequisites of Natural Selection:
- Variation in traits among individuals
- Traits are heritable
- Differential survival and reproduction based on traits
- Limited resources
Evidence of Natural Selection:
- Artificial selection
- Antibiotic resistance in bacteria
- Camouflage in animals
- Resistance to pesticides in insects

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Description

Test your understanding of essential genetic concepts such as chromosomes, DNA structure, and the central dogma of molecular biology. This quiz covers key terminology related to genes, mutations, and types of cells in genetics. Challenge yourself and deepen your knowledge of genetic principles!