DNA

• Mitosis is a type of cell division in which one original parent cell splits into two identical daughter cells.
• Cell replication is the process by which cells replicate their genetic material and divide to form new cells.
• DNA stands for Deoxyribose Nucleic Acid.
• A Gene is a segment of a DNA chain that codes for an inheritable characteristic.
• Mutation is a change in the code sequence of a DNA molecule.
• Nucleotides are the basic components that make up a DNA molecule.
• Replication is the process by which the DNA molecule makes a copy of itself.
• Triplet code is a sequence of three nitrogen bases.
• The components of a nucleotide include a phosphate group, a nitrogen base, and a deoxyribose sugar molecule.
• The Watson-Crick model of DNA was discovered by James Watson and Francis Crick, who used x-ray data by Rosalind Franklin to discover the DNA molecule.
• The structure of the DNA double helix is likened to a spiral staircase in the notes, where the spiral steps represent nitrogen bases, and the spiral staircase consists of phosphate groups and deoxyribose sugar molecules.
• The steps of DNA replication involve the splitting of nitrogen bases, transportation of new nucleotides into place, linking them together to form a complementary strand based on the rule of base pairing, and the formation of two new double helices.
• DNA replication ensures the faithful transmission of genetic information by accurately copying the sequence of nitrogen bases, following the rule of base pairing.
• A DNA mutation is a change in the sequence of nitrogen bases, which serves as the code for carrying out normal cellular functions.
• DNA mutations can occur through deletion, where a nitrogen base is neglected during replication, leading to a change in the sequence, or substitution, where a nitrogen base is not copied properly, and a different base is substituted.
• The DNA molecule is located in the chromosomes of the nucleus.
• The sequence of nitrogen bases in DNA serves as a code for constructing protein molecules, and sets of three nitrogen bases form a triplet code, each coding for specific amino acids.
• Dominant alleles, represented by capital letters (e.g., C, T), only require one copy for an organism to exhibit the trait, while recessive alleles, represented by lowercase letters, require two copies for the trait to be expressed.
• Features of an organism are determined by inherited genes and interactions between the environment and genes.
• Environmental features that can influence an organism's survival include the availability of food and water, infectious diseases, and factors like latitude and sunlight.
• The main components of DNA are sugar, phosphate groups, and nitrogenous bases.
• These components contribute to the structure by forming nucleotides, which, when combined, create the double-stranded helix.
• Complementary base pairing in DNA is when Guanine pairs with Cytosine, and Adenine pairs with Thymine.
• DNA replication involves DNA helicase breaking hydrogen bonds between strands, unzipping the double helix, and DNA polymerase helping bind free nucleotides to exposed strands, producing an identical copy.
• During replication, DNA polymerase stitches newly joined nucleotides together, forming the sugar-phosphate backbone of the new DNA strand.
• Genetic variation is the difference in the DNA of individuals within the same species, reflecting differences in the genomes of similar organisms.
• Meiosis and independent assortment contribute to genetic variation by randomly arranging homologous chromosomes and segregating chromatids, resulting in the formation of daughter cells with a random set of chromosomes.
• Mutation refers to a change in the base sequence of an organism's DNA, contributing to genetic diversity by introducing different genes and traits.
• Crossing over during meiosis involves the swapping of sections between homologous chromosomes, producing new gene combinations and contributing to genetic variation.