Biology Genetics & Biological Diversity Flashcards

What is the role of DNA in genetic inheritance?

Answer: It stores and transmits genetic information

Deoxyribonucleic acid (DNA) is the fundamental molecule of heredity. Its primary role is to store the genetic instructions necessary for an organism's development, functioning, growth, and reproduction, and to accurately transmit this information from one generation to the next.

Which of the following best defines a gene?

Answer: A sequence of DNA coding for a trait

A gene is a specific segment of DNA that contains the instructions for building a particular protein or functional RNA molecule. These sequences are the fundamental units of heredity, determining an organism's traits and characteristics.

How does meiosis contribute to genetic diversity?

Answer: By reducing chromosome number and introducing variation

Meiosis is a specialized cell division process that produces gametes (sperm and egg cells) with half the number of chromosomes of the parent cell. During meiosis, processes like crossing over and independent assortment shuffle genetic material, creating unique combinations of alleles and significantly increasing genetic diversity in offspring.

What is a phenotype?

Answer: The observable traits of an organism

A phenotype refers to the observable physical or biochemical characteristics of an organism, such as eye color, height, or disease susceptibility. These traits are the result of the interaction between an organism's genetic makeup (genotype) and its environment.

Which process results in the formation of gametes?

Answer: Meiosis

Meiosis is the specific type of cell division that produces gametes (sex cells like sperm and eggs). This process reduces the chromosome number by half and introduces genetic variation, which is essential for sexual reproduction.

What does homozygous mean in terms of alleles?

Answer: Two identical alleles

In genetics, an organism is described as homozygous for a particular gene when it possesses two identical alleles for that gene. This means both copies of the gene, one inherited from each parent, are exactly the same.

What is genetic drift?

Answer: Random changes in allele frequencies

Genetic drift is a mechanism of evolution characterized by random, chance fluctuations in the frequencies of alleles within a population, especially pronounced in small populations. Unlike natural selection, it does not involve differential fitness based on traits but is purely due to random events.

What is the significance of a Punnett square?

Answer: To predict genetic cross outcomes

A Punnett square is a visual tool used in genetics to predict the probable outcomes of a genetic cross between two individuals. It systematically shows all possible combinations of alleles that offspring could inherit, allowing for the determination of expected genotypic and phenotypic ratios.

Which term refers to an organism’s complete set of DNA?

Answer: Genome

The genome refers to an organism's complete set of DNA, including all of its genes and non-coding sequences. It contains all the hereditary information required to build, maintain, and reproduce that organism.