Genetic Information

• Who is the teacher presenting the biology video?

  Miss Estrich
• What is the purpose of the video presented by Miss Estrich?

  To provide a revision boost for topic four in biology
• How can viewers navigate to specific topics in the video?

  By looking at the time codes on the bottom
• What has Miss Estrich been doing for over 10 years?

  Helping students with challenging biology topics
• What has Miss Estrich prepared for students during their revision period?

  Essential revision resources
• What should students do if they struggle with timing in their revision?

  Use the revision notes created by Miss Estrich
• What does the active recall workbook help students with?

  Testing their knowledge and improving memory
• What is the function of the revision timetable maker?

  To help students create a personalized study schedule
• What are the key similarities and differences between eukaryotic and prokaryotic DNA?

  Similarities:

  • Both made of DNA nucleotides
  • Both contain deoxyribose, a phosphate group, and a nitrogenous base
  • Nucleotides joined by phosphodiester bonds

  
  

  Differences:

  • Eukaryotic DNA is longer and linear; prokaryotic DNA is circular
  • Eukaryotic DNA is associated with histones; prokaryotic DNA is not
• What is the organization of DNA in a eukaryotic cell?

  DNA is tightly coiled into chromosomes within the nucleus
• What is the purpose of the DNA in mitochondria and chloroplasts?

  To transcribe and translate enzymes needed for photosynthesis and respiration
• What is a gene and what does it code for?

  • A gene is a sequence of DNA
  • It codes for the amino acid sequence of a polypeptide
  • It also codes for functional RNA, such as mRNA
• What is the definition of locus in genetics?

  Locus is the exact position of a gene on a chromosome
• What are the three features of the genetic code?

  1. Degenerate code
  2. Universal
  3. Non-overlapping
• Why is the genetic code considered degenerate?

  Because multiple triplets can code for the same amino acid
• How many possible codes are there with three DNA bases?

  64 possible codes
• What is a codon?

  A codon is three bases on mRNA that codes for a specific amino acid
• What is the role of introns and exons in DNA?

  Introns do not code for polypeptides, while exons do
• What is a start codon?

  A start codon is three bases that initiate translation
• What is a stop codon?

  A stop codon is three bases that signal the end of translation
• What is the difference between a genome and a proteome?

  • Genome: Complete set of genes in an organism
  • Proteome: Full range of proteins produced by a cell
• How many DNA base pairs are in the human genome?

  Three billion DNA base pairs
• What is the function of mRNA?

  To carry the genetic code from DNA to the ribosome
• What is the structure of tRNA?

  It has a cloverleaf shape with an amino acid binding site
• What is the role of the ribosome in translation?

  To hold tRNA molecules in place for amino acid bonding
• What are the key steps in transcription?

  1. DNA helix unwinds
  2. One strand acts as a template
  3. RNA nucleotides align opposite DNA bases
  4. RNA polymerase joins RNA nucleotides
  5. mRNA is modified and leaves the nucleus
• What happens during splicing in eukaryotes?

  Introns are removed from the pre-mRNA
• What are the key steps in translation?

  1. mRNA binds to a ribosome
  2. tRNA aligns with complementary codons
  3. Amino acids are joined by peptide bonds
  4. Ribosome moves along the mRNA
  5. Translation ends at the stop codon
• What is a gene mutation?

  A change in the base sequence of DNA
• What can cause gene mutations?

  Exposure to mutagenic agents like radiation and chemicals
• What are the two types of chromosome mutations?

  1. Polyploidy: Change in whole sets of chromosomes
  2. Aneuploidy: Change in the number of individual chromosomes
• What is non-disjunction?

  Failure of chromosomes to separate properly during meiosis
• What is an example of aneuploidy?

  Down syndrome, caused by an extra chromosome 21
• How does polyploidy occur in plants?

  By having multiple copies of every chromosome
• What happens during non-disjunction in meiosis I?

  Homologous chromosomes fail to separate
• What happens during non-disjunction in meiosis II?

  Sister chromatids fail to separate
• What is the result of non-disjunction during meiosis?

  It can lead to gametes with an abnormal number of chromosomes
• What is aneuploidy?

  Aneuploidy is a condition with changes in the number of individual chromosomes.
• How does non-disjunction lead to Down syndrome?

  Non-disjunction on chromosome 21 results in three copies of that chromosome.
• What happens during non-disjunction in meiosis I?

  Homologous pairs of chromosomes fail to separate, leading to one gamete with an extra chromosome.