DNA Flashcards
What is DNA?
DNA, or deoxyribonucleic acid, is the genetic material essential for life, serving as the instruction manual for building and maintaining living organisms.
DNA is a polymer made of nucleotide bases: adenine (A), thymine (T), cytosine (C), and guanine (G)
What is the structure of DNA?
The structure of DNA is a double helix, resembling a twisted ladder, where the rungs are formed by base pairs (A-T and G-C) held together by weak hydrogen bonds.
DNA is organized into chromosomes within the nucleus of cells.
What are genes?
Genes are specific sequences of nucleotides that code for proteins, which are necessary for cellular functions.
The human genome consists of approximately 3 billion base pairs.
How many chromosomes are in human cells?
Humans have 46 chromosomes organized in 23 pairs.
Each chromosome contains numerous genes.
What is the analogy used to explain DNA structure?
The analogy compares bases to letters, DNA to words, genes to recipes, chromosomes to cookbooks, and the genome to the entire cuisine.
This analogy helps to understand the organization and function of genetic material.
What is the cell cycle?
The cell cycle consists of six key stages: Interphase, Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.
Interphase is the preparatory phase where the cell grows and duplicates its DNA.
What happens during mitosis?
Mitosis is the process of cell division that results in two genetically identical daughter cells.
It is crucial for growth and tissue repair.
What are the stages of mitosis?
The stages of mitosis are:
* Prophase
* Metaphase
* Anaphase
* Telophase
* Cytokinesis
What is meiosis?
Meiosis is a specialized form of cell division that produces gametes with half the number of chromosomes (haploid).
It consists of two rounds of division: Meiosis I and Meiosis II.
What is genetic variation?
Genetic variation arises during reproduction, where offspring inherit half of their DNA from each parent, leading to unique combinations of traits.
This variation is crucial for evolution and adaptation.
What is the difference between sexual and asexual reproduction?
Sexual reproduction involves two parents contributing genetic material, while asexual reproduction involves a single parent producing genetically identical offspring.
Asexual reproduction is common in organisms like plants.
What are dominant and recessive alleles?
Dominant alleles are expressed over recessive alleles, requiring two recessive alleles for expression.
Example: Brown eyes are dominant; blue eyes are recessive.
What is the difference between genotype and phenotype?
Genotype refers to the genetic makeup of an individual, while phenotype refers to the observable characteristics resulting from the genotype.
An individual can have the same phenotype but different genotypes.
What is cystic fibrosis?
Cystic fibrosis is caused by a recessive allele, requiring two copies of the faulty allele for the disorder to manifest.
This illustrates how genetic inheritance can lead to various health conditions.
What is the role of the 23rd chromosome pair in humans?
The 23rd chromosome pair determines biological sex (XX for female, XY for male).
This pair is crucial for sex determination during fertilization.
What is selective breeding?
Selective breeding is the intentional mating of organisms to produce offspring with desirable traits.
This process can lead to new varieties in plants and animals.
What are the risks of selective breeding?
Risks include reduced genetic variation, vulnerability to diseases, unintended consequences, and physical problems in selectively bred animals.
Example: Hip dysplasia in large dog breeds.
What is genetic variation and its importance?
Genetic variation refers to the differences in DNA sequences among individuals within a species, which is crucial for evolution and adaptation.
It allows populations to adapt to changing environments.
What is biodiversity?
Biodiversity refers to the variety of different species within a given ecosystem, essential for ecosystem resilience and adaptability.
The measurement of biodiversity can inform conservation efforts.
What is a karyotype?
A visual representation of an organism’s chromosomes, used to identify genetic disorders.
Karyotyping helps diagnose chromosomal abnormalities and genetic diseases.
Who established the principles of inheritance?
Gregor Mendel through his experiments with pea plants.
Mendel’s work laid the foundation for the field of genetics.
What was pivotal in understanding genetics?
The discovery of DNA’s structure by Watson, Crick, Franklin, and Maurice.
This discovery revealed how genetic information is stored and transmitted.
What was the aim of the Human Genome Project?
To map all human DNA, leading to advancements in personalized medicine and disease prevention.
The project has significant implications for understanding genetic diseases.
What is asexual reproduction?
A reproduction method involving a single organism producing offspring without gametes.
Examples include hydra and strawberries.
