Cell Division: Mitosis and Meiosis

Cell Division

• Mitosis: cell division resulting in two identical daughter cells with the same number of chromosomes as the parent cell
• Meiosis: cell division producing four non-identical daughter cells, each with half the chromosome number of the parent cell

Mitosis and Meiosis Comparison

• Mitosis: growth, repair, and asexual reproduction; produces two diploid (2n) daughter cells
• Meiosis: production of gametes (sperm and egg cells) for sexual reproduction; produces four haploid (n) daughter cells

Importance of DNA Replication

• Ensures each daughter cell has an identical set of chromosomes (mitosis) or the correct number of chromosomes (meiosis)

Human Chromosome Number

• 46 chromosomes (23 pairs)

Crossing-Over and Gene Shuffling

• Crossing-over: exchange of genetic material between homologous chromosomes during prophase I of meiosis
• Gene shuffling: random distribution of chromosomes during meiosis and crossing-over; contributes to genetic variation in offspring

DNA Structure and Function

• Double helix structure made of nucleotides (sugar, phosphate, and nitrogenous base)
• Functions as the blueprint for all genetic information

Relationship Between DNA, Chromosomes, and Genes

• DNA is organized into chromosomes
• Genes are segments of DNA that code for proteins

DNA and Proteins

• DNA contains instructions to make proteins, which are essential for cellular functions

Types of RNA and Functions

• mRNA: messenger RNA, carries genetic information from DNA to ribosomes
• tRNA: transfer RNA, brings amino acids to ribosomes during protein synthesis
• rRNA: ribosomal RNA, makes up the ribosomes

DNA, Proteins, and Mutations

• Mutations in DNA can lead to changes in protein structure and function, potentially causing genetic diseases

Replication, Transcription, and Translation

• Replication: process of copying DNA before cell division; ensures each new cell has a complete set of DNA
• Transcription: process of synthesizing RNA from DNA; produces mRNA for protein synthesis
• Translation: process of assembling proteins from mRNA; converts genetic information into functional proteins

Base Pairing Rules

• DNA: Adenine (A) pairs with Thymine (T), Cytosine (C) pairs with Guanine (G)
• RNA: Adenine (A) pairs with Uracil (U), Cytosine (C) pairs with Guanine (G)

Genetics

Mendel’s Experiments and Punnett Squares

• Mendel’s experiments: studied inheritance patterns in pea plants
• Punnett Squares: tool to predict the probability of offspring traits

Traits and Genotypes

• Dominant and recessive traits: dominant traits mask recessive traits
• Genotype and phenotype: genotype is the genetic makeup, phenotype is the physical expression of the genotype
• Homozygous and heterozygous genotypes: homozygous has two identical alleles, heterozygous has two different alleles

Modes of Inheritance

• Dominance, codominance, incomplete dominance, multiple alleles, polygenic traits, X-linked traits

Nondisjunction

• Failure of chromosomes to separate properly during meiosis; causes genetic disorders like Down, Klinefelter, and Turner syndromes

Sickle Cell Anemia and Malaria

• Relationship between genetic mutation (sickle cell) and resistance to malaria

Evolution

Graphs and Diagrams

• Interpret evolutionary trends and data

Artificial Selection

• Human-driven breeding to select for desired traits

Common Descent and Embryology

• Similar embryonic stages indicate common ancestry

Biomolecular Comparisons

• Comparing DNA/protein sequences to determine evolutionary relationships