Inheritance, Variation and Evolution

• What is the main difference between sexual and asexual reproduction?

  Sexual reproduction involves two parents and gamete fusion, while asexual reproduction involves one parent without gamete fusion.
• What are the advantages of asexual reproduction?

  • Only one parent needed
  • Faster than sexual reproduction
  • More time and energy efficient
  • Can produce many identical offspring in favorable conditions
• What types of gametes are involved in sexual reproduction in animals?

  Sperm and egg cells
• What is the significance of genetic variation in sexual reproduction?

  It leads to variety in the offspring, which can provide a survival advantage.
• What is the process of gamete formation in sexual reproduction?

  • Involves meiosis
  • Produces gametes with half the number of chromosomes
  • Results in genetically different gametes
• What is the reproductive method of malarial parasites in humans and mosquitoes?

  Malarial parasites reproduce asexually in humans and sexually in mosquitoes.
• How do fungi reproduce in different conditions?

  Fungi reproduce asexually by spores but also sexually in poor conditions to increase variation.
• What is the advantage of asexual reproduction in plants?

  Asexual reproduction is advantageous when plants are overcrowded or need to colonize areas quickly.
• What is the main purpose of meiosis?

  Meiosis produces gametes with half the number of chromosomes.
• What are the steps involved in meiosis?

  1. Genetic information duplicates
  2. Chromosomes arrange into pairs
  3. The cell divides twice
  4. Four offspring cells are formed, each with half the chromosomes
• What happens after fertilization in humans?

  Two gametes fuse, restoring the chromosome number, and the zygote divides by mitosis to form an embryo.
• What is DNA and its structure?

  DNA is a polymer made of two strands forming a double helix, containing genetic material.
• What is a gene?

  A gene is a small section of DNA on a chromosome that codes for a specific protein.
• What is the human genome?

  The human genome is the entire genetic material of a human organism.
• What are the limitations of understanding the human genome?

  • Search for genes linked to diseases
  • Understanding treatment of inherited disorders
  • Tracing human migration patterns
• What are the four bases of DNA?

  A, T, C, G
• What is the role of complementary base pairing in DNA?

  It ensures that A pairs with T and C pairs with G, maintaining the structure of the DNA helix.
• What is protein synthesis?

  1. DNA unwinds and opens
  2. mRNA is made from one strand of DNA
  3. mRNA leaves the nucleus and joins a ribosome
  4. tRNA brings amino acids to the ribosome
  5. Amino acids are joined to form a polypeptide chain
  6. The polypeptide folds to form a protein
• What are examples of proteins and their functions?

  Enzymes speed up reactions, hormones carry messages, and structural proteins provide strength.
• What is a mutation?

  A mutation is a change in the genetic code of a gene.
• What are the types of mutations?

  • Spontaneous mutations: mistakes during DNA replication
  • Induced mutations: caused by radiation or chemicals
• What are the advantages and disadvantages of mutations?

  Advantages include potential survival benefits, while disadvantages can lead to cancer or altered gene expression.
• What is the definition of a gamete?

  A gamete is a sex cell, such as a sperm or egg cell.
• What is the difference between dominant and recessive alleles?

  Dominant alleles are expressed even if only one is present, while recessive alleles are expressed only if two are present.
• What is the difference between homozygous and heterozygous genotypes?

  Homozygous has the same alleles, while heterozygous has different alleles for a particular gene.
• What is monogenic inheritance?

  Monogenic inheritance is the inheritance of a single gene.
• What are examples of inherited disorders?

  • Polydactyly: extra fingers or toes, caused by a dominant allele
  • Cystic Fibrosis: thick mucus production, caused by a recessive gene
• What are the advantages and disadvantages of embryo screening?

  Advantages:

  • Prevents suffering from genetic disorders
  • Ensures healthy embryos in IVF
  • Saves long-term treatment costs

  
  

  Disadvantages:

  • Selective parenting
  • Expensive process
  • Ethical concerns regarding 'bad' genes
• How many pairs of chromosomes do ordinary human body cells contain?

  23 pairs
• What determines the sex of a human?

  The last pair of chromosomes determines sex, with females having XX and males having XY.
• What are Mendel's three key conclusions about inheritance?

  1. Law of Dominance: Dominant alleles are expressed in the phenotype.
  2. Law of Segregation: Allele pairs segregate during gamete production.
  3. Law of Independent Assortment: Alleles for different genes assort independently.
• What challenges did Mendel face in his work?

  Mendel faced financial difficulties, public rejection of his findings, and personal health issues.