Biology Unit 1: Central Dogma

Unit 1: Central Dogma

• DNA is the blueprint of all life, a molecule of life that stores genetic information, which determines traits.
• DNA is a double helix structure made of sugar, phosphate, and nitrogenous bases (codons).
• Nitrogenous base pairing rules: A with T, and G with C.
• RNA plays a crucial role in the central dogma, being essential for making proteins.
• RNA is smaller and single-stranded, using uracil (U) instead of thymine (T).
• Three types of RNA:
  • mRNA (messenger RNA): carries instructions.
  • rRNA (ribosomal RNA): forms ribosomes.
  • tRNA (transfer RNA): carries amino acids.
• Transcription is the first step of the central dogma, where DNA is copied into mRNA.
• mRNA carries the message to the ribosome to build proteins.
• Ribosomes follow the instructions in mRNA to build protein.
• Gene expression: some genes are "turned on" to make proteins, others are "turned off".
• Translation is the second step, where mRNA is turned into protein.
• Translation occurs in the cytoplasm.
• tRNA with anticodons and amino acids bring amino acids to the mRNA codons.
• Ribosomes bind the amino acids from tRNA to the mRNA codons, building the protein.

Unit 2: Bioengineering

• DNA replication is essential for growth, repair, and reproduction.
• DNA replication ensures accurate passing down of genetic information.
• Enzymes like helicase and DNA polymerase play a crucial role in the replication process.
• Mutations are changes in DNA codon sequences, which can be neutral, harmful, or beneficial.
• Two types of mutations: Point(substitution) and Frameshift(insertion/deletion).
• Humans have 23 pairs of chromosomes.
• A karyotype is a picture of all the chromosomes.
• Cloning creates a genetically identical copy of an organism.
• Cloning involves transferring a nucleus from a donor cell into an egg cell.
• Selective breeding improves organism traits, but is slower.
• Genetic engineering is faster and more precise to modify genetic information.

Unit 3: Inheritance

• Asexual reproduction produces identical offspring, but limits adaptability.
• Sexual reproduction produces diverse offspring and increases survival in changing environments.
• Mendel's experiments with pea plants led to the foundation of modern genetics.
• Each individual has two versions of each gene (alleles).
• Dominant allele hides the recessive allele.
• Mendel's Law of Segregation states that allele pairs separate during gamete formation.
• Mendel's Law of Independent Assortment says that genes for different traits are inherited independently.
• Punnett squares predict offspring traits from crosses between parents.
• Genotype is the genetic makeup; phenotype is the observable traits.

Unit 4: Evolutionary Biology

• Fossils are remains of organisms preserved in sedimentary rock.
• Scientists use relative and absolute dating to estimate fossil ages.
• Fossil record and geologic time scale show the history of life on Earth.
• Individuals with traits beneficial in the environment are more likely to survive and reproduce.
• Species change over time to fit their environment.
• Adaptations may involve acquiring new traits, removing traits or improving traits.
• Comparative anatomy studies similarities in anatomy of organisms to understand relationships.
• Embryology and development studies the development within an organism to understand evolution.
• DNA comparisons show how related species are.
• Species distribution shows where species are located and how that changes.
• Phylogeny is the evolutionary history of a group of organisms.
• Cladograms are diagrams and phylogenetic trees show relationships among species.
• Clade is a group of organisms and their common ancestor.
• Cladistics compares traits to determine relationships in species.
• Homologous structures have same function and structure (common ancestry)
• Analogous structures have similar function, but different structures (similar environment)