Genetics Quiz: Traits and Inheritance

Single Trait Cross (Monohybrid Cross)

• A genetic cross focusing on a single trait.
• Offspring exhibit one of two possible phenotypes.
• Key concepts: genotype, phenotype, dominant/recessive alleles, Punnett square.

Two Trait Cross (Dihybrid Cross)

• Involves inheritance of two traits.
• Offspring can exhibit various combinations of traits.
• Key concepts: dihybrid, independent assortment, Punnett square.

Codominance

• Two alleles are fully expressed in the offspring.
• Phenotype is a blend or combination of parental traits.
• Examples: blood type (A and B alleles), some plant colors.

Incomplete Dominance

• Offspring phenotype is intermediate between parental phenotypes.
• Neither allele is completely dominant.
• Examples: snapdragon flower colors (red x white = pink), some human skin tones.

Multiple Alleles

• More than two alleles for a single trait exist.
• Can result in more than two possible phenotypes.
• Examples: blood type (A, B, AB, O alleles), rabbit coat color.

Sex-Linked Traits

• Traits determined by genes on sex chromosomes (usually the X chromosome).
• Often more prominent in males.
• Examples: color blindness, hemophilia, Duchenne muscular dystrophy.

Blood Typing

• Determining blood type by identifying antigens on red blood cells.
• Blood types: A, B, AB, O.
• Rh factor: presence (+) or absence (-) of a protein on red blood cells.

Cell Cycle

• Series of events in cell growth and division.
• Two main phases: interphase and mitosis.
• Cytokinesis: physical division of cytoplasm.

Meiosis

• Specialized cell division creating gametes (sperm/egg).
• Reduces chromosome number to half.
• Key concepts: homologous chromosomes, crossing over, haploid/diploid.

DNA

• Deoxyribonucleic acid, carrying genetic instructions.
• Nucleotides are building blocks (sugar, phosphate, nitrogenous base).
• Double helix structure with base pairing (A-T, C-G).

Discovery of the Transforming Principle

• Avery-MacLeod-McCarty experiment demonstrated DNA as the genetic material.
• DNA transfers traits between organisms.

History of DNA Structure

• Watson and Crick proposed the double helix model.
• X-ray crystallography helped determine DNA structure.
• Chargaff's rules identified base pairing patterns.

DNA Replication

• Process of copying DNA molecules.
• Semiconservative replication: original strands serve as templates.
• Replication fork: site of replication.
• DNA polymerase: enzyme synthesizing new strands.

Mutations

• Changes in DNA sequence.
• Various effects, ranging from no change to severe disorders.
• Types: point mutations, frameshift mutations.
• Mutagens cause mutations.

Protein Synthesis

• Process of producing proteins.
• Transcription: creating mRNA from DNA.
• Translation: using mRNA to synthesize proteins.
• Genetic code: specifies amino acid sequences.

Test your knowledge on genetic crosses including single trait (monohybrid) and two trait (dihybrid) crosses. Explore concepts such as codominance, incomplete dominance, and multiple alleles with various examples. This quiz will enhance your understanding of phenotypes and genotypes in genetics.