Asexual Reproduction and Meiosis: Contrasting Reproductive Strategies

This page continues the discussion on reproductive strategies by outlining the advantages and disadvantages of asexual reproduction.

Advantages of asexual reproduction:

• Only one parent is needed
• The process is rapid

Disadvantages of asexual reproduction:

• No genetic variation
• Offspring are susceptible to new diseases
• Less chance of adapting to environmental changes

The page then introduces meiosis, the process by which gametes (sex cells) are produced. Meiosis results in cells with half the genetic material of normal cells (haploid cells).

Definition: Meiosis is a type of cell division that produces gametes with half the number of chromosomes as the parent cell.

The steps of meiosis are outlined, including DNA replication, chromosome alignment, and cell division.

Highlight: Understanding meiosis is crucial for grasping how genetic variation is generated in sexual reproduction, a key concept in Inheritance, variation and evolution GCSE Biology AQA.

Genotypes and Phenotypes: From Genes to Observable Traits

This page delves deeper into genetic concepts, explaining the differences between homozygous and heterozygous genotypes. It also introduces the relationship between genotype (the collection of alleles an organism has) and phenotype (the observable characteristics resulting from the genotype).

Definition: Homozygous refers to having two of the same allele, while heterozygous means having two different alleles.

The page then describes the structure of nucleotides, the monomers that make up the DNA polymer. Each nucleotide consists of a phosphate group, a sugar, and a nitrogenous base.

Vocabulary: The four DNA bases are Adenine, Thymine, Cytosine, and Guanine.

The concept of complementary base pairing is introduced, which is crucial for DNA replication and protein synthesis.

Highlight: Understanding the relationship between genotype and phenotype is essential for predicting inheritance patterns in GCSE Biology inheritance, variation and evolution exam questions.

Gregor Mendel: The Father of Genetics

This page introduces Gregor Mendel, often referred to as the founding father of genetics. It describes his groundbreaking experiments on pea plants, which laid the foundation for our understanding of inheritance.

Highlight: Gregor Mendel's experiments involved crossbreeding pea plants and observing the inheritance patterns of various traits.

Key findings from Mendel's law of inheritance include:

• The concept of hereditary units (now known as genes)
• The distinction between dominant and recessive traits

Vocabulary: A recessive trait is only expressed if an organism inherits the allele from both parents.

Highlight: Mendel's work was initially criticized because DNA had not yet been discovered, highlighting the importance of his contributions to the field of genetics.

This information is crucial for answering questions about what did Gregor Mendel discover and why did Gregor Mendel use peas in his experiments in AQA GCSE Biology Inheritance, variation and evolution exam questions.