Inheritance

• What is the fundamental process in sexual reproduction for eukaryotes?

  The production of haploid gametes and zygote formation
• What is haploid gamete production and how does it occur?

  • Produced through meiosis
  • Occurs in reproductive organs
  • Males: sperm in testes
  • Females: egg cells (ova) in ovaries
• What is the result of meiosis in terms of chromosome number?

  Meiosis reduces the chromosome number by half, resulting in haploid gametes.
• How many sets of chromosomes does each parent contribute to the offspring?

  One set of chromosomes
• What ensures genetic variability in offspring during meiosis?

  The random assortment of chromosomes and crossing over
• What is formed when haploid gametes fuse?

  A diploid zygote
• What happens during the fertilization of an egg cell by a sperm cell?

  The nuclei of the sperm and egg cells fuse, combining genetic material from both parents.
• What is the chromosome set of a zygote?

  A full set of chromosomes (diploid)
• Why is haploid gamete production and diploid zygote formation important in eukaryotic sexual life cycles?

  • Maintains species' chromosome number
  • Introduces genetic diversity
  • Combines traits from two parents
• What type of cells have two copies of each autosomal gene?

  Diploid cells
• What are autosomal genes?

  Genes located on non-sex chromosomes
• How do two copies of each gene affect traits in an organism?

  They allow for various combinations of alleles, affecting trait expression.
• What are the key concepts in genetic crosses in flowering plants?

  • P generation: Parental generation
  • F1 generation: Offspring of P generation
  • F2 generation: Offspring of F1 generation
  • Punnett grid: Diagram for predicting genotypes
• What does pollen contain in flowering plants?

  Male gametes
• Where are female gametes housed in flowering plants?

  In the ovary of the flower
• What occurs during pollination in flowering plants?

  Pollen is transferred to the stigma, growing down to fertilize the ovules.
• What are the types of pollination in flowering plants?

  • Cross-pollination: Pollen from one plant fertilizes another
  • Self-pollination: Pollen fertilizes ovules of the same or another flower on the same plant
• Why can plants like peas undergo self-pollination?

  They produce both male and female gametes on the same plant.
• What are the steps to perform a controlled genetic cross?

  1. Select parent plants with desired traits
  2. Remove anthers from female parent (emasculation)
  3. Collect pollen from male parent
  4. Apply pollen to stigma of female parent
  5. Allow fertilization and collect seeds
  6. Grow seeds to produce F1 generation
  7. Self-pollinate or cross F1 plants for F2 generation
• What is the importance of genetic crosses in plant breeding?

  • Develop new crop varieties with improved traits
  • Create ornamental plants with novel characteristics
  • Study inheritance patterns and gene interactions
• What is a genotype?

  The genetic makeup of an organism
• What are alleles?

  Alternative forms of a gene
• How many alleles does an individual typically inherit for each gene?

  Two alleles, one from each parent
• What is the difference between homozygous and heterozygous genotypes?

  • Homozygous: Two identical alleles (e.g., AA or aa)
  • Heterozygous: Two different alleles (e.g., Aa)
• Why is understanding genotypes and alleles critical in inheritance?

  They determine traits expressed and predict trait probabilities in offspring.
• What is an allele in relation to a gene?

  A specific version of a gene
• What is a gene?

  A segment of DNA that codes for a specific protein
• What is the phenotype?

  • Observable characteristics or traits of an organism
  • Result from the interaction between genotype and environmental influences
• What factors can influence phenotype?

  Genotype, environment, and their interaction
• What are examples of traits influenced by genotype only?

  • Blood type in humans
  • Eye color
  • Genetic disorders like cystic fibrosis
• What are examples of traits influenced by environment only?

  • Scars from injuries
  • Tanned skin from sun exposure
  • Certain learned behavioral traits
• What are examples of traits influenced by genotype-environment interaction?

  • Height
  • Intelligence
  • Skin color
• Why is understanding the interplay between genotype and environment important?

  • Explains variation in traits among individuals with similar genetics
  • Helps in modifying expression of genetic predispositions
• What are dominant and recessive alleles?

  • Dominant alleles: Expressed in phenotype with one copy
  • Recessive alleles: Expressed only with two copies
• What happens if an organism has at least one dominant allele?

  The dominant trait will be expressed in the phenotype.
• When is the recessive trait expressed in an organism?

  When there are two copies of the recessive allele present.
• Why do homozygous dominant and heterozygous genotypes produce the same phenotype?

  • Dominant alleles code for functional proteins
  • One copy is sufficient for dominant phenotype
  • Dominant allele masks recessive allele in heterozygotes
• What is an example of dominant and recessive alleles in humans?

  • B = Brown eye color allele (dominant)
  • b = Blue eye color allele (recessive)
  • Genotypes: BB (brown), Bb (brown), bb (blue)
• Why can recessive traits "skip" generations?

  Because they can be masked by dominant alleles in heterozygotes.
• Why do certain traits appear more frequently in populations than others?

  Due to the presence of dominant alleles in the population.