Topic 3 - Genetics

• What are the advantages of Asexual reproduction?

  - The rapid production of offspring.

  - Only 1 parent is needed for reproduction.
• What is the disadvantage of Asexual reproduction?


  No variation in the population.
• What is the advantage of sexual reproduction?


  Genetic diversity and adaptation.
• What are the disadvantages of sexual reproduction?


  - It requires a lot of time and energy.

  - It requires 2 parents.
• What is Meiosis?


  The Cell division process that produces gametes (sex cells) with half the number of chromosomes as the parent cell. It only happens in the reproductive organs.
• How many daughter cells are produced in Meiosis?


  4.
• How does Meiosis introduce genetic variation when forming 4 non-identical cells?


  Meiosis introduces genetic variation through independent assortment and crossing over, resulting in non-identical gametes and diverse offspring.
• What is the DNA structure?


  A polymer with two strands coiled into a double helix.
• What is complementary base pairing?


  The pairing of nucleotide bases in DNA, where adenine (A) pairs with thymine (T) and cytosine (C) pairs with guanine (G).
• How are the DNA strands held together?


  Strands are held together by weak hydrogen bonds.
• What is a nucleotide?


  A nucleotide is the basic building block of DNA and RNA, consisting of a sugar molecule, a phosphate group, and a base.
• what is a genome?


  The complete set of genetic material in an organism.
• What is a gene?


  A gene is a segment of DNA that contains the instructions for building a specific protein or performing a specific function in an organism.
• Where is DNA stored?


  nucleus in which they are coiled up to form a chromosome.
• What is the method for DNA extraction?


  1. Mash fruit into a beaker with detergent and salt.
  2. The detergent breaks cell membranes, releasing DNA; salt causes DNA to stick.
  3. Filter to remove debris.
  4. Gently add ice-cold ethanol to precipitate DNA.
  5. DNA appears as a stringy white solid.
  6. Precipitate can be extracted with a glass rod if needed.
• what is a codon?


  A sequence of three nucleotides that codes for a specific amino acid or serves as a start or stop signal for proteinsynthesis.
• DNA controls the production of protein in a specific order and time.
• Triplets of bases, called codons, code for specific amino acids, and the sequence of these codons guides the order of amino acids in the protein.
• The sequence of amino acids influences the folding of the protein into a specific three-dimensional shape.
• Non-coding DNA changes affect traits by influencing protein levels through RNA polymerase binding.
• what is a mutation?


  A mutation is a change in the DNA sequence of a gene or chromosome, which can result in a change in the organism's traits or phenotype.
• A genetic variant can arise from Mutations. This can result in a change in the amino acid sequence of a protein. This would change the final shape of the protein - affecting its purpose.
• What is protein synthesis?


  Protein synthesis is the process by which cells build proteins using the instructions encoded in DNA.
• What are the stages of protein synthesis?


  Transcription and translation.
• What is transcription?


  Transcription is the process of copying a single gene from DNA to mRNA as the DNA is too large to leave the nucleus.
• What is translation?


  Conversion of mRNA sequence into amino acid sequence to form a polypeptide.
• How does the RNA polymerase make mRNA during transcription?


  1. RNA polymerase binds to non-coding DNA located in front of a gene.
  2. RNA polymerase produces a complementary mRNA strand from the coding DNA of the gene.
  3. The mRNA moves to the ribosome, to begin with translation.
• What are the complementary base pairs for mRNA?


  A-U (adenine-uracil) and G-C (guanine-cytosine).
• How is a protein assembled during translation?


  During translation, the ribosome reads the mRNA code in groups of three letters, each specifying an amino acid. It links these amino acids together, following the mRNA instructions. When it reaches the "stop" signal, the ribosome finishes and the linked amino acids form a protein.
• Mendel is the founder of modern genetics. He discovered that genes are inherited in discrete units. He concluded that characterisitcs of a plant is determined by hereditary units. People did not understand his concepts at the time as they had no idea about genes and hereditary concepts.
• What are alleles?


  Alleles are alternative forms of a gene that occupy the same position on a chromosome and determine specific traits. Individuals inherit one allele from each parent.
• The allele that is dominant determines the certain characteristic of an organism.
• For an organism to display a recessive characteristic, it must contain two copies of the recessive allele.
• What is a chromosome?


  • A thread-like structure in the cell nucleus composed of DNA and proteins, carrying genetic information.
• What is a gene?


  1. A segment of DNA that codes for a specific trait or protein.
• What is an allele?


  Different variant of the same gene expressed in an organism.
• What does Homozygous mean?


  Having two identical alleles for a particular gene.
• What does Heterozygous mean?


  Having two different alleles for a particular gene.
• what is a genotype?


  The genetic makeup of an organism.
• what is a zygote?


  Fertilized egg. (Diploid).