DNA Structure, Function and Cell Specialization

• DNA, or deoxyribonucleic acid, carries the genetic information in all living things.
• DNA belongs to the nucleic acids class of molecules, which are polymers of nucleotide units.
• Each nucleotide consists of three components: a phosphate molecule, a five-carbon sugar molecule (deoxyribose in DNA), and a nitrogenous base.
• The nitrogenous base can be cytosine (C), guanine (G), adenine (A), or thymine (T).
• DNA acts as a code that determines the shape and functions of every living thing as it grows.
• DNA provides instructions for building an organism, detailing what to include, the order of assembly, and how parts should function together.
• The DNA blueprint remains in every living cell, providing information on how the cell must then function.
• DNA ensures that only the proteins required for the particular cell type are produced.
• Each adult organism cell type has a unique protein collection which causes observable physical characteristics.
• Muscle and bone tissue cells are specialized due to the specific proteins produced in each cell type.
• Even though all cells contain the same genetic information, the genes used/expressed by the cell may differ.
• While much of the DNA code is known, vast amounts within plants, insects, animals, and humans remain undeciphered.
• Scientists debate the purpose of the extra DNA, considering it "junk" with no real purpose or a high-level operating system for the genome.
• A worldwide project revealed 80% of human genome DNA code is "functional," with nearly every bit being read by one cell or another.
• Some scientists argue that reading the DNA code doesn't necessarily equate to it being useful.
• Scientists can't verify the function of "junk" DNA by removing it from people, but a new pond plant discovery may offer insights.
• The bladderwort plant has almost no "junk" DNA, suggesting every piece has a purpose that is able to be worked out.
• Extra DNA in complex organisms may have aided the evolution of their advanced traits.

DNA and Protein Production

• DNA carries genetic information and codes for assembling amino acids into necessary proteins.
• DNA, or deoxyribonucleic acid, contains information in all living organisms.
• DNA is stored in the nucleus in animal, plant, and fungal cells, coiled up in thread-like structures called chromosomes.
• A skin cell's nucleus contains approximately two meters of DNA; therefore a chromosome is a very large molecule compacted into a small space.
• DNA provides cells with instructions to make proteins, playing a big part in determining specialized cells and whole organisms characteristics.
• Eye color, muscle mass, height, and the ability to learn new skills are a result of specific protein activity.
• The building blocks of DNA are called nucleotides.
• The four DNA bases (adenine, thymine, cytosine, and guanine) are the part of a nucleotide that differentiates it.
• The four DNA bases are abbreviated as A, T, C, and G.
• Nucleotides link to form twisted strands of nucleotides creating a double helix.
• Strands are held together by weak bonds between base pairs.
• Complementary shapes allow certain base pairs to form bonds (interchain hydrogen bonds.
• H-bonds pair bases to complementary bases: A/T and G/C.
• Base A bonds with base T, and base G bonds with base C, forming complementary pairs.
• The nitrogenous bases specifically link across the two strands such that cytosine (C) on one strand only base pairs with guanine (G) on the other and adenine (A) on only one strand of base pairs with thymine (T) on the other.
• A single DNA molecule strand is called a chromosome, containing many genes.
• Genes are DNA sections that code for certain proteins.
• Genes are the functional units of genetic information in cells, consisting of a nucleotide sequence coding for a specific protein.
• Humans have 20,000 to 25,000 protein-coding genes on 46 chromosomes (23 pairs).
• These genes, with the in-between bits of DNA, compose the human genome.
• Every three-base sequence on a DNA molecule is a codon, containing codes for specific amino acids that code for different proteins, making up a gene.
• The sequence of bases in each gene provides instructions for building proteins.
• Proteins make the most tissue in organisms' bodies and help control the chemical reactions in organisms.
• When cells read the bases that make up a gene, they interpret them in three-base groups called codons.
• Codons "code" for amino acids, the building blocks of proteins.
• Genes comprise base sequences, bases group into codons, codons code for amino acids, and amino acids produce proteins.
• DNA in chromosomes carries a permanent copy of available genetic information for cells.
• Specific DNA nucleotide sequences, or genes, are located along the chromosomes.
• Genes carry instructions for making proteins coding for proteins to make an organism function
• Bacterial cells (prokaryotes) lack a nucleus; their DNA is in the cytoplasm.
• The sequence of bases in a DNA molecule determines the order of amino acids in a protein molecule.
• Groups of three bases called triplets represent different amino acids, which create the basis of the genetic code.

Messenger RNA

• Animal, plant, and fungal cells store instructions for making proteins and place protein-making structures in different locations.
• DNA stores in the nucleus, while proteins are assembled from free amino acids in cytoplasm via ribosomes.
• Messenger RNA (mRNA) forms in the nucleus and carries a specific gene's DNA base sequence copy in the cytoplasm.
• Ribosomes connect to mRNA, using its instructions to assemble amino acids in proper order to make a particular protein.
• mRNA is a temporary information molecule delivering genetic information from DNA in the nucleus to the part of the cytoplasm that makes proteins.
• Like DNA, RNA (or ribonucleic acid) is a nucleic acid type forming nucleotide polymers.
• Unlike DNA, RNA nucleotides contain the sugar ribose (not deoxyribose) and uracil (rather than thymine) as one of its nitrogenous basses; it is also shorter and single-stranded.
• Messenger ribonucleic acid, or mRNA, is a short-lived molecule used to deliver a small portion of genetic information from chromosomal DNA to where cells manufacture proteins.
• Comparatively, DNA carries the instructions for making all needed proteins of the cell, is much larger and has a long lifespan.
• Transcription to mRNA, then translation to tRNa, amino acids then chain together for protein synthesis.
• Organisms consist of proteins made of amino acids.
• Amino acids for protein synthesis encode in the organism's DNA, where transcription and translation start to, theoretically, calculate strands of DNA and amino acid chains for what an organism is coded.

Mutations

• DNA impacts how bodies are built/function, and small informational changes, or mutations, can greatly affect this.
• Often, mutations occur through imperfect DNA copying. Occasionally, misspellings form in the body, but often are inherited.
• Mutations can detrimentally alter vital protein construction, but many have no noticeable effects.
• BRCA2, a well-studied gene, has a mutation that elevates a woman's chance of breast cancer five to tenfold.
• A new mutation of the same gene increases the risk of lung cancer in smokers and is dangerous differently.
• Two small gene tweaks can carry two different/dangerous outcomes.

Point Mutations

• Point mutations involve changing a single base.
• Substitution: one base is replaced with another.
• Insertion: a new base adds to the existing base sequence.
• Deletion: one base removes from the sequence.

Explore the structure and function of DNA, including its role in protein production and cell specialization. Investigate the composition of nucleotide polymers and differences between cell types.