CYTO

• The central dogma of molecular biology states that DNA is transcribed into RNA, which is then translated into protein

  
• DNA replication produces identical molecules during the S phase of the cell cycle, happening once during mitosis and meiosis
• Transcription involves copying the DNA sequence of a gene to make an RNA molecule, specifically mRNA
• In transcription, one strand of the DNA that makes up a gene acts as a template for the synthesis of a complementary RNA strand via an enzyme called RNA polymerase
• After transcription, the product is mRNA, ready to direct protein synthesis in the process called translation
• Translation involves decoding the mRNA sequence to specify the amino acid sequence of a polypeptide through initiation, elongation, and termination steps
• During translation, the nucleotide sequence of mRNA is translated into the amino acid sequence of a polypeptide, with codons representing groups of three nucleotides
• There are 61 codons specifying amino acids, with one start codon indicating where to begin translation and three stop codons signaling the end of a polypeptide
• The genetic code relates codons to amino acids, with the flow of information from DNA to RNA to protein known as the central dogma of molecular biology
• Genetics is the study of inherited traits and their variation, with genes being the units of heredity found on nucleic acids, specifically DNA
• DNA is a long ladder-like molecule that forms a double helix, storing and transferring genetic information present in all organisms, typically found in the nucleus of eukaryotic cells
• RNA, important in protein synthesis, is found in all living organisms, both inside and outside the nucleus, with mRNA carrying instructions for protein synthesis to the sites of protein synthesis
• The cytoskeleton of a cell, made up of microtubules, microfilaments, and intermediate filaments, gives the cell its shape and allows movement
• Mitosis is a type of cell division where one somatic cell gives rise to two new ones, while meiosis is involved in the production of gametes
• Alleles, products of mutations, are the source of all genetic variation, with mutations defined as any heritable change in the DNA sequence
• Phenotype refers to observable traits or features of an organism, while genotype is the set of alleles for a given trait carried by an organism
• Genome is the complete set of genetic instructions characteristic of an organism, including protein-encoding genes and other DNA sequences
• Chromosomes are structures resulting from DNA coiling in association with proteins, with genes encoding for the production of proteins and having different variants called alleles
• Population genetics studies genetic composition changes in biological populations, providing information on past migrations, evolutionary relationships, and adaptation to the environment
• Cytogenetics is the branch of genetics studying the structure of DNA within the cell nucleus, focusing on the number and morphology of chromosomes
• Molecular genetics studies the molecular structure of DNA, its cellular activities, and its influence on determining the overall makeup of an organism, relying heavily on genetic engineering techniques like recombinant DNA technology
• The cytoskeleton of a cell is a network of proteins that gives the cell its shape and allows it to move, made up of microtubules, microfilaments, and intermediate filaments
• Microtubules, the thickest filaments in the cytoskeleton, are made up of tubulin and are responsible for the cell's shape and moving things within the cell
• Microfilaments, the thinnest filaments in the cytoskeleton, are made up of actin and are responsible for the cell's ability to move
• Intermediate filaments, made up of various proteins, are responsible for holding the cell together
• Anaphase is the stage of mitosis where sister chromatids of each chromosome separate and move to opposite poles of the cell

  
• A chromosome structure includes the centromere, kinetochore, and telomeres, and shows the process of DNA replication

  
• The chromosome theory of inheritance states that heredity depends on genes in chromosomes, which are contributed by gametes, and that traits are controlled by genes on chromosomes
• In mitosis, chromosomes are copied and distributed to daughter cells, each receiving a diploid set of chromosomes
• In meiosis, cells receive one chromosome from each pair, resulting in a haploid number of chromosomes
• The chromosomal theory of inheritance states that inherited traits are controlled by genes on chromosomes transmitted through gametes, maintaining genetic continuity from generation to generation
• DNA is a long, ladder-like macromolecule that twists to form a double helix, with a sugar and phosphate backbone
• DNA's name comes from its structure composed of sugar and phosphate, with deoxyribo referring to the sugar and nucleic acid to the bases and phosphate
• DNA has a double helix structure with two antiparallel strands, with each strand made up of nucleotides containing A, G, C, T base pairs
• RNA is similar to DNA but contains a different sugar, is generally single-stranded, and can form a complementary structure with DNA or RNA
• Gene expression starts with transcription in the nucleus, followed by translation in the cytoplasm where mRNA binds to ribosomes to synthesize proteins
• Proteins, the end product of gene expression, perform diverse biological functions and are made from a combination of 20 different amino acids
• Microtubules, the thickest filaments in the cytoskeleton, are made of tubulin and are responsible for the cell's shape and moving things within the cell
• Microfilaments, the thinnest filaments in the cytoskeleton, are made of actin and are responsible for the cell's ability to move
• Intermediate filaments, made of various proteins, are responsible for holding the cell together