Key Concepts in Genetics, Meiosis, DNA, Evolution, and Ecology

What is an allele and how do organisms inherit alleles?

An allele is a variant form of a gene, and organisms inherit alleles from their parents through the process of reproduction.

How do dominant and recessive alleles interact?

Dominant alleles mask the expression of recessive alleles in heterozygous individuals.

What is a Punnett square used for?

A Punnett square is used to predict the genetic outcomes of a mating between two individuals, applicable for both monohybrid and dihybrid crosses.

What is the difference between genotype and phenotype?

Genotype refers to the genetic makeup of an organism, while phenotype refers to the observable traits or characteristics.

What is the difference between homozygous and heterozygous?

Homozygous individuals have two identical alleles for a trait, while heterozygous individuals have two different alleles.

What are incomplete dominance and codominance?

Incomplete dominance is when the phenotype is a blend of both alleles, while codominance is when both alleles are fully expressed in the phenotype.

What are Mendel's three principles of inheritance?

Mendel's principles include the Law of Segregation, the Law of Independent Assortment, and the Law of Dominance.

What role did Mendel play in genetics?

Mendel is known as the father of genetics for his foundational work with pea plants, establishing key principles of heredity.

What are the genotypes for blood types in humans?

Blood types are determined by the ABO gene (A, B, AB, O) and the Rh factor (positive or negative), leading to multiple possible genotypes.

How do sex-linked traits work and why are they more common in males?

Sex-linked traits are associated with genes on sex chromosomes, and males are more affected because they have only one X chromosome.

What are examples of genetic disorders?

Genetic disorders can be dominant (e.g., Huntington's disease), recessive (e.g., cystic fibrosis), or caused by nondisjunction during meiosis (e.g., Down syndrome).

What is a pedigree and how is it used?

A pedigree is a diagram that shows the inheritance of a trait across generations, used to analyze genetic relationships.

What are the similarities and differences between mitosis and meiosis?

Both processes involve cell division, but meiosis results in four genetically diverse gametes, while mitosis produces two identical daughter cells.

What is the purpose of meiosis in genetics?

Meiosis produces gametes for sexual reproduction, ensuring genetic diversity through recombination and independent assortment.

What major events during meiosis contribute to genetic variation?

Crossing over and independent assortment during meiosis lead to genetic variation in gametes.

What are the major discoveries credited to Franklin, Watson & Crick, and Chargaff?

Franklin provided X-ray diffraction images of DNA, Watson & Crick proposed the double helix model, and Chargaff established base pairing rules.

What is the structure of DNA?

DNA is composed of nucleotides, which include a phosphate group, a sugar (deoxyribose), and nitrogenous bases (adenine, thymine, cytosine, guanine).

What is the Central Dogma of Biology?

The Central Dogma describes the flow of genetic information from DNA to RNA to protein.

What is transcription and its significance?

Transcription is the process of synthesizing RNA from a DNA template, crucial for gene expression.

What is translation and its significance?

Translation is the process of synthesizing proteins from mRNA, essential for cellular function.

What are the three types of RNA and their roles?

mRNA carries genetic information, tRNA transports amino acids, and rRNA is a component of ribosomes.

What are mutations and why can they be damaging?

Mutations are changes in the DNA sequence that can disrupt normal gene function, potentially leading to diseases or disorders.

What are the types of gene mutations?

Types include point mutations (substitutions), insertions, deletions, and frameshift mutations, each affecting protein function differently.

What is speciation and how does isolation contribute to it?

Speciation is the formation of new species, often occurring due to geographic, temporal, or behavioral isolation.

What are the types of natural selection?

Types include stabilizing selection (favoring average traits), disruptive selection (favoring extreme traits), and directional selection (favoring one extreme).

What is Hardy-Weinberg Equilibrium?

Hardy-Weinberg Equilibrium describes a population that is not evolving, allowing for predictions of allele frequencies.

What is a phylogenetic tree?

A phylogenetic tree (or cladogram) illustrates evolutionary relationships among species based on shared characteristics.

What are the ecological levels of organization?

The ecological levels include organism, population, community, ecosystem, biome, and biosphere.

What is the 10% rule in ecology?

The 10% rule states that only about 10% of energy is transferred from one trophic level to the next in an ecosystem.

What are the roles of producers, consumers, and decomposers?

Producers create energy through photosynthesis or chemosynthesis, consumers obtain energy by eating other organisms, and decomposers break down organic matter.

What factors limit productivity in ecosystems?

Limiting factors include energy and nutrient availability, which affect primary productivity and can lead to algal blooms.

What are the major environmental issues affecting biodiversity?

Major issues include climate change, habitat destruction, invasive species, pollution, and overharvesting.