Genetics

• What is sexual reproduction?

  It involves the joining of male and female gametes, each containing genetic information from the parents.
• What are the gametes in animals and flowering plants?

  Sperm and egg cells in animals; pollen and egg cells in flowering plants.
• How are gametes formed?


  Gametes are formed by meiosis, resulting in non-identical cells.
• How many chromosomes does a normal human cell have?

  A normal cell has 46 chromosomes, or 23 pairs.
• What happens to the chromosomes during fertilization?

  Each gamete, which has 23 chromosomes, fuses during fertilization to produce a cell with 46 chromosomes.
• What is the significance of genetic variation in offspring?

  Genetic variation increases the likelihood that some individuals will survive if the environment changes.
• What is asexual reproduction?


  Asexual reproduction involves one parent and does not involve gametes joining.
• How are identical cells formed in asexual reproduction?

  Identical cells are formed through the process of mitosis.
• What are some examples of organisms that reproduce asexually?

  Bacteria, some plants, and some animals.
• What are the advantages of sexual and asexual reproduction?

  Advantages of sexual reproduction:

  • Produces variation in offspring.
  • Increases survival advantage in changing environments.
  • Decreases the chance of extinction.

  
  

  Advantages of asexual reproduction:

  • Only one parent is needed.
  • Allows for selective breeding.
  • Uses less energy and is faster as no mate is needed.
• What is the role of meiosis in reproduction?

  Meiosis produces haploid gametes (sperm and egg cells) with one copy of each chromosome.
• How many cells are produced at the end of meiosis?

  Meiosis produces four non-identical cells from one cell.
• What happens to the chromosomes during meiosis?

  The cell makes copies of its chromosomes, divides into two cells with half the chromosomes, and then divides again to produce four cells with 23 chromosomes each.
• Why are gametes genetically different from each other?

  Gametes are genetically different because the chromosomes are shuffled during meiosis.
• What is the normal number of chromosomes in a fertilized cell?

  The normal number of chromosomes in a fertilized cell is 46.
• What is DNA and where is it found?

  DNA is a chemical that contains genetic material and is found in the nucleus.
• What does DNA stand for?

  DNA stands for deoxyribonucleic acid.
• What are the components of a nucleotide?


  A nucleotide is made up of one sugar molecule, one phosphate molecule, and one of the four types of organic bases.
• What are the four types of organic bases in DNA?

  The four types of organic bases are A, C, G, and T.
• What is complementary base pairing?

  Complementary base pairing is when A bases connect to T bases, and C bases connect to G bases.
• What is a gene?


  A gene is a short section of DNA that codes for many amino acids to make a specific protein.
• How many types of amino acids are there?

  There are 20 types of amino acids.
• What does the term genome refer to?


  The genome describes all the genetic information (DNA) of a single organism.
• How has studying the human genome improved our understanding of diseases?

  It has improved our understanding of genes linked to diseases, treatment of inherited disorders, and tracing human migration patterns.
• What are the steps to extract DNA from fruit?

  1. Mix 50ml cold water, half a teaspoon of salt, and 10ml washing up liquid; heat at 50°C for 5-10 minutes.

  2. Peel and chop kiwi, then pulverize.

  3. Add the solution to the kiwi.

  4. Filter using kitchen paper and a sieve; pour into a test tube.

  5. Add 10ml pineapple juice and let rest.

  6. Add 2 teaspoons of cold ethanol and wait 10 minutes.
• What should be observed after adding ethanol in the DNA extraction process?

  A white mass should precipitate at the top of the tube, which is the DNA from the kiwi.
• Why is pineapple juice added during DNA extraction?

  Pineapple juice contains bromelain, which breaks down proteins attached to the DNA, making it clearer.
• What is the purpose of adding ethanol in the DNA extraction process?

  Ethanol causes the DNA to precipitate out of the solution, making it visible.
• What is protein synthesis?

  Protein synthesis is the process of producing a protein from DNA.
• What does each group of three bases in DNA code for?

  Each group of three bases codes for an amino acid.
• How do amino acids relate to proteins?

  Amino acids are joined together and folded to make a protein, with the order determining the type of protein.
• What are non-coding parts of DNA responsible for?

  Non-coding parts of DNA can control whether genes are expressed, i.e., whether a gene is used to form a protein.
• What happens to DNA when it is too big to move out of the nucleus?

  mRNA is created as a template of the original DNA to move out of the nucleus.
• What is the role of RNA polymerase in protein synthesis?

  RNA polymerase binds to non-coding DNA and allows mRNA nucleotides to match to their complementary bases on the DNA strand.
• What happens to mRNA after it is formed?

  mRNA moves out of the nucleus to the cytoplasm and onto ribosomes.
• How are amino acids brought to the ribosomes?

  Amino acids are brought to the ribosomes by carrier molecules called tRNAs (transport RNAs).
• What happens when the amino acids connect at the ribosomes?

  They form a polypeptide linked by peptide bonds, which then folds to form a unique 3D structure, the final protein.
• What are genetic variants?

  Genetic variants are small changes in the order of bases that make up a strand of DNA.
• What is the difference between genotype and phenotype?

  Genotype refers to the genes present in the DNA, while phenotype refers to the visible effects of those genes.
• How does a genetic variant in coding DNA affect proteins?

  A genetic variant in coding DNA alters the sequence of bases, changing the sequence of amino acids and thus the final structure of the protein.