Science - Biology

• o   Genetics – a section of DNA which codes for the synthesis of proteins. It is the study of inheritance.
• DNA – stands for deoxyribonucleic acid. It is the genetic information inside the cells of the body that helps make people who they are.
• Nucleotide – the basic building block of nucleic acids (RNA and DNA)
• Chromosomes – a structure of tightly wound DNA
• o   Genes – the functional and physical unit of heredity passed from parent to offspring
• o   Centromeres – the point or region on a chromosome to which the spindle attaches during mitosis and meiosis
• o   Sister chromatids – the identical copies (chromatids) formed by the DNA replication of a chromosome, with both copies joined together by a common centromere
• Telomeres – a region of repetitive DNA sequences at the end of a chromosome
• o   mRNA – a type of RNA found in cells
• o   Transcription – the first stage of protein synthesis where the base sequence of the DNA is copied into the mRNA
• o   Translation – the second stage of protein synthesis where a sequence of mRNA is translated into a sequence of amino acids
• o   mRNA – Messenger RNA, a type of RNA found in cells
• o   Base Triplet – three DNA bases that code for amino acid
• o   Codons – three nucleotides (base triplet) on mRNA that code for an amino acid, the three nitrogenous bases are decoded in groups of three. [phosphate, pentose sugar, nitrogenous base]
• o   Uracil – one of the four nitrogenous bases found in ribonucleic acid. Replacing Thymine in DNA.
• o   Proteins – large molecules made up of amino acids and plays a significant role in the structure and function of living organisms
• o   Somatic cells – the body cells of an organism
• o   Gametes – sex cells that combine to produce new offspring
• o   Diploid – a cell containing two sets of chromosomes
• Haploid -  a cell containing only one set of chromosome
• o   Zygote – a fertilised egg produced by the fusion of male and female gametes
• o   Ova – eggs
• o   Embryo – a zygote eventually becomes an embryo
• o   Autosomes – Of the 23 pairs of chromosomes, pairs 1 to 22 are known as autosomes. Theses 44 chromosomes are found both in females, a non sex chromosome
• o   Sex chromosomes – in humans, the 23rd pair of chromosomes that determines the sex of a person
• o   Karyotype – An individuals complete set of chromosomes
• o   Homologous chromosomes – matching chromosomes
• o   Non – homologous chromosome – chromosomes that do not match, not containing similar information to another chromosome that if forms a pair with during meiosis
• o   Phenotype – The way an organism appears, characteristics you get from genotype
• o   Genotype – The combination of alleles for gene inherited from our parents, collection for alleles we have, e.g.Tt
• o   Homozygous – Having two identical alleles at a locus (locus is the location of a gene on chromosome, TT
• o   Heterozygous – Having two different alleles at a locus, Tt
• o   Punnett square – a specialised grid to show genetic crosses
• o   Dominant trait – a trait or characteristic is described as dominant, if you need only one allele for it to be expressed (WW or Ww)
• o   Recessive trait – the allele that needs to be inherited by both parents to be expressed (ww)
• o   Autosomal dominant – if two unaffected parents have an unaffected child, the trait must be dominant
• o   Autosomal recessive – if two unaffected parents have an affected child, the trait cannot be dominant
• o   X-Linked dominant - If a father is affected and all his daughters are affected, this suggests the trait is X - linked and dominant.
• o   X-Linked recessive – If an affected mother has all affected sons, the trait could be carried on the X chromosome and be recessive.
• o   Pedigree chart – a chart formed to study patterns of inheritance over generations