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Pack 5 Nucleic acids, ATP and Cells Arise from other cells : - Coggle…

- - - - Releases energy instantaneously
      - Can be rapidly re-synthesised
      - Hydrolysis of ATP releases relatively small amount of energy (little energy lost, low chance of thermal death)
      - Does not leave the cell
      - Phosphorylates other compounds, making them more reactive
    - - Movement
      - Active transport
      - Metabolic processes (building up macromolecules: Proteins, DNA, Glycogen)
      - Secretion (forming lysosomes/vesicles)
- - - - DNA is double stranded - it twists to form a double helix. the sugar phosphate backbone on the outside, the complementary base pairs on the inside
      - Functions
        
        Very stable molecule- it doesn't change, information can be passed on accurately
        
        Very large molecule - holds lots of information
        
        Sugar phosphate backbone - Stability and strength, protects bases from damage
        
        Coiled helix structure - compact
        
        Sequence of nitrogen bases - allows information to be stored, sequence codes for polypeptides
    - - Semi-conservative Meselsohn and Stahls experiment - E.coli replicating in 15N then transferred to 14N
      - Enzyme DNA Helicase "unzips" the double helix: hydrogen bonds between complementary bases are broken
        
        Free nucleotides are attracted to the exposed bases. Base paring takes place and hydrogen bonds form between complementary bases
        
        Enzyme DNA polymerase joins nucleotides together along the sugar-phosphate backbone. 2 identical new DNA molecules are formed, each containing one of the original strands
  - - - Similarities
        
        A pentose sugar, Nitrogen containing base (A, G, C) Phosphodiester bond
      - Deoxyribose (no oxygen on C2)
      - Ribose sugar
      - Bases: Adenine, Thymine, Guanine, Cytosine (A,T, G, C)
        
        Adenine and Thymine always pair with 2 hydrogen bonds
        
        Guanine and Cytosine always pair with 3 hydrogen bonds
      - Bases: Adenine Uracil, Guanine, Cytosine (A, U, G, C)
        
        Adenine and Uracil always pair with 2 hydrogen bonds
        
        Guanine and Cytosine always pair with 3 hydrogen bonds
      - Nucleotides joining up
        
        Two mononucleotides can join to form a dinucleotide by condensation reaction between the OH group on C3 of one and the phosphate group attached to C5 on the other. Creates Phosphodiester bonds. Nucleotides join to from a long chain called a polynucleotide
    - - Main types of RNA
        
        Ribosomal RNA (rRNA)
        
        Associated with proteins, makes up the ribosomes
        
        Transfer RNA (tRNA)
        
        Carries specific amino acids to the ribosomes during protein synthesis
        
        Messenger RNA (mRNA)
        
        Transfers information from the DNA to the ribosomes
- - - - Mitosis - Replicated chromosomes are split into 2 new nuclei
        
        Anaphase
        
        Centromeres divide, half spindle fibres contract pulling sister chromatids apart
        
        Chromatids move to opposite poles of the cell
        
        Prophase
        
        Chromosomes become visible Chromosomes shorten and thicken
        
        Centrioles (in animal cells) move to opposite poles
        
        Spindle fibres develop forming spindle apparatus
        
        Nucleolus disappears + Nuclear envelope breaks down
        
        Telophase
        
        Chromosomes reach the poles
        
        Chromosomes become longer and thinner and are no longer visible
        
        Spindle fibres disintegrate
        
        Nuclear membrane and nucleoli re-form
        
        Metaphase
        
        Some spindle fibres attach to centromeres, others span pole to pole
        
        Chromosomes line up along the equator of the cell
        
        Chromosomes clearly seen to be 2 sister chromatids joined by centromere (X shape)
      - Interphase - Cell spends most of the time in this stage; Growing, Replicating organelles and DNA, Carrying out Cell function
        
        G2 - Growth stage 2
        
        Cell "double checks" chromosomes for errors and repairs any, replicates centrioles
        
        G1 - Growth stage 1
        
        Cell duplicates contents(organelles, cytoplasm) excluding chromosomes
        
        S - Synthesis
        
        Each of the 46 chromosomes is duplicated - 2 sister chromatids held at a centromere
      - Cytokinesis
        
        Cytoplasm divides forming 2 genetically identical daughter cells
    - - Carry the genes that control protein synthesis in living organism
        
        Cells of higher plants and animas have pairs of chromosomes called homologous chromosomes - they are said to be diploid
        
        Pairs of homologous chromosomes carry copies of the same genes in the same locus (position) on each of the pairs although there may be different alleles (versions) on each gene
        
        Humans have 23 pairs of chromosomes, diploid number 23
    - - Mitosis is a controlled process. Cancer refers to a group of diseases that result in mutations to the genes that regulate mitosis
        
        Most mutations = cell death, cells that do survive start to uncontrollingly grow and divide leading to tumours
        
        Malignant
        
        A tumour that can spread to surrounding tissues / where some caner cells can break off and travel in the blood forming new tumour sites
        
        Benign
        
        Tumours that tend to grow more slowly and less likely to be life threatening
      - Treatment
        
        Often treated by controlling cell division. Highly toxic chemicals which block some parts of the cell cycle
        
        Also affects normal cells but cancer cells divide more rapidly, they become more damaged
        
        Affects: -Hair(always growing from follicle)
        -Bone marrow(constantly producing blood)
        -Skin and lining of digestive system (Constantly renews itself)
  - - - Cell elongates an circular DNA is replicated - both DNA molecules attach to the cell membrane. Plasmids replicate
        
        Cell wall and plasma membrane begin to divide. Membrane grows between the DNA molecules dividing the cytoplasm
        
        Cross- wall formed completely around divided DNA
        
        Cells separate and new cell wall formed
        
        Two daughter cells formed, each with a single copy of circular double stranded DNA and a variable number of plasmids
  - - - Infected host cell produces all the components of the virus which are assembled in to new viral particles in a T helper cell