Inheritance

• Genome refers to the entire DNA of an organism.
• Gene is a section of a molecule of DNA that codes for a specific protein.
• Chromosomes are located in the nucleus of a cell where genes are located.
• DNA is two strands coiled to form a double helix with base pairs A-T (adenine and thymine) and C-G (cytosine and guanine).
• Genes exist in alternate forms which are called alleles which create differences in inherited characteristics.
• Dominant allele will always be expressed if present in the gene.
• Recessive gene will only be expressed if both alleles in the gene are recessive.
• Homozygous refers to both alleles in the gene are the same.
• Heterozygous refers to the alleles are different and can only be dominant and recessive.
• Phenotype is an observable trait in an organism.
• Genotype is the genetic makeup of an organism.
• Codominance is when both alleles in the gene of the organism are expressed separately to yield different characteristics in an organism.
• Phenotypic features are a result of polygenic inheritance rather than single genes (multi gene inheritance).
• The sex of a person is controlled by one pair chromosome: XX in a female, XY in a male.
• Mitosis happens during cloning, growing, repair, asexual reproduction.
• Random fertilization increases genetic diversity when a male gamete and a female gamete finally meet, each is the result of an immense number of genetic possibilities created during independent assortment and crossing over.
• In humans the diploid number of chromosomes is 46, haploid number of chromosomes is 26.
• Variation in an organism can be environmental, genetic or a combination of both.
• Mutation is a rare random change that can be inherited.
• The incidence of mutations can be increased by exposure to ionising radiation (for example, gamma rays, x-rays, and ultraviolet rays) and some chemical mutagens (for example, chemicals in tobacco).
• Natural selection is a mechanism of evolution.
• Organisms that are more adapted to their environment are more likely to survive and pass on the genes that aided their success.
• This process causes species to change and diverge over time.
• Resistance to antibiotics can increase in bacterial populations and appreciate how such an increase can led to infections being difficult to control.