Evolution textbook knowledge

• Chromosome: Long molecule made from DNA found in the nucleus of cells.
• Homozygous refers to having two of the same alleles present in an organism.
• Gene: Sequence of DNA that codes for a protein.
• A dominant allele causes polydactyly.
• A dominant allele is always expressed, even if only one copy is present.
• Genotype: Combination of alleles an individual has.
• Alleles are different forms of the same gene.
• Normal human body cells contain 23 pairs of chromosomes.
• The structure of DNA is two complementary strands forming a double helix.
• Sex determination: Determining the sex of the offspring based on the sex chromosomes.
• A recessive allele causes cystic fibrosis.
• A recessive allele needs to be present twice to be expressed.
• Phenotype: Physical expression of the genotype.
• A genome is the entire genetic material of an organism.
• The genetic material in cells is called DNA.
• Heterozygous: When an individual carries two different alleles for a trait.
• Mitosis is the type of cell division involved in asexual reproduction.
• Genetic crosses: Considering the offspring that might result from two known parents.
• In flowering plants, the male gamete is pollen and the female gamete is ovule.
• Meiosis is the type of cell division involved in sexual reproduction.
• A Punnett square can be used to determine the probability of offspring being male or female.
• Meiosis is a cell division that produces four daughter cells (gametes), each with a single set of chromosomes.
• The probability is always 50% in humans as there are two XX outcomes and two XY outcomes.
• Heterozygous refers to having two different alleles present in an organism.
• Recessive: Allele that needs two copies present to be expressed.
• A gene is a small section of DNA that codes for a particular amino acid sequence, to make a specific protein.
• Dominant: Allele that only needs one copy present to be expressed.
• Normal human body cells have 23 pairs (46) chromosomes.
• Homozygous: When an individual carries two copies of the same allele for a trait.
• Studying the human genome is important for searching for genes linked to certain diseases, understanding and treating inherited disorders, and tracing past human migration.
• Allele: Different forms of the same gene.
• Sexual reproduction is the joining (fusion) of male and female gametes.
• In humans, the male sex chromosome is Y and the female sex chromosome is X.
• Gamete: Specialised sex cell formed by meiosis.
• Punnett squares: Used to predict the outcome of a genetic cross.
• In human females, the sex chromosomes are the same (XX, homozygous), and in males they are different (XY, heterozygous).
• Allele is a term in genetics.
• Chromosome is a term in genetics.
• Clone is a term in genetics.
• DNA is a term in genetics.