Science 10-Q3 EXAM (W/SUB)

• DNA

  • Deoxyribonucleic acid
  • Is a double strand / double helix
  • belong to a type of molecule called nucleic acid
• Nitrogenous bases

  • are molecules that contain nitrogen and have the chemical properties of a base
• James Watson and Francis Crick (1953)

  Discovered that DNA is double strand / double helix
• Double Strand / Double Helix

  • Also known as a backbone
• Nucleic acid

  Long chains of nucleotides
• • Adenine is paired with Thymine (A,T)
  • Cytosine is paired with Guanine (C,G)
• 5¹ = 5 prime
• Type of sugar in DNA

  Deoxyribose
• 3¹ = 3 prime
• RNA

  • Ribonucleic acid
  • single strand
  • has no thymine, but it has Uracil
• There are 3 types of RNA

  mRNA

  tRNA

  rRNA
• Messenger RNA (mRNA)

  • transcribes the DNA nucleotide bases to RNA nucleotide bases
• Ribosomal RNA (rRNA)

  • binds the mRNA and tRNA to ensure that codons are translated correctly
• Transfer RNA (tRNA)

  • translates the mRNA codons into the correct amino acids
• There are two stages of protein synthesis: 1. Transcription 2. Translation
• Replication

  the process of making copies of DNA
• Replication

  1. Helicase breaks the bond between nitrogenous bases
  2. Complementary nucleotides are added to strands by DNA polymerase to form new strands.
  3. Two new DNA molecules, each with a parent strand and a new strand are formed.
• Human have

  • 46 chromosomes
  • 23 pairs of chromosomes
  • 2 sex chromosomes
• 2 sex chromosomes

  • XX - female
  • XY - male
• Chromosomes

  • First 22 pairs of chromosomes are called autosomes
  • The 23rd pair is a sex chromosomes (XY/XX)
• Protein

  • Proteins are made in the ribosomes in a process called protein synthesis
• Protein

  • Proteins are made up of organic compounds called amino acids
• Protein

  • different proteins are made by forming combinations from any of the 20 amino acids
• Protein

  • A chain of amino acids is linked together by peptide bonds and is called a polypeptide.
• Protein

  • One or more of these polypeptides make up a protein
• Protein

  • Amino acids and proteins are the building blocks of life.
• Mutations - are changes or alterations in DNA sequences. They usually manifest on our physical characteristics
• two types of mutations

  • Hereditary/Germline
  • Acquired/Somatic
• Hereditary/Germline mutations

  • these are inherited from parents, like color blindness. They are present in almost all the cells in bodies because they are inherited
• Acquired/Somatic mutations

  • these occur usually because of lifestyle or environmental factors like exposure to chemicals or diseases. These can also occur due to errors during cell division. Acquired mutations in somatic cells are inherited.
• Different types of chromosomal mutation

  • Duplication
  • Inversion
  • Deletion
  • Insertion
  • Translocation
• Duplication - an extra copy or a gene is repeated. (Pallister Killian)
• Inversion - a segment is broken off and inverted. (Hemophilia)
• Deletion - a segment is lost. (Cri-du-chat)
• Insertion - extra pairs are inserted into a new place.
• Translocation - part of one chromosome attaches to another chromosome
• The backbone of the nucleotide chain called a polynucleotide
• Nitrogenous bases

  molecules that contain nitrogen and have the chemical properties of a base.
• two different types of proteins according to structure:

  • Fibrous
  • Globular
• Fibrous

  these have an elongated shape, and usually for structure and support. They form muscles, bones, tendons, and connective tissue.