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BIOLOGY 2021 - Coggle Diagram

- - - - divides during cytokinesis
    - - 1 prophase chromosomes appear, nuclear membrane disappears, spindle forms
        
        2. metaphase chromosomes line up in a single line across the centre of the cell
        
        3. anaphase, each pair of chromatids separates at the cetromere, each chromatid/ now called a chromosome moves to the opposite pole
        
        4. telophase nuclear membrane reforms
        
        5 cytokinesis cytoplasm divides two daughter cells are produced
        
        interphase normal life of a cell
  - - - gamete is a sex cell (egg or sperm) has half genetic material of the parent cell are haploid
    - - metaphase 1 pairs line up in random orientation with help of spindle fibers, pairs move to centre of the cell
        
        anaphase 1 chromosomes are pulled away by the spindle fibers to opposite poles of the cell
        
        telophase 1 gather at poles two nuclei form with a membrane cytokinesis then splits the cell into two
    - - metaphase 2 chromosomes line up in random orientation in single file instead of pairs
        
        anaphase 2 spindle fibers pull on chromosomes pull single chromatids away to contrasting sides
        
        telophase 2 chromatids gather at opposite poles and nuclei membrane reforms cytokinesis splits the cells into four - results in four daughter cells called gametes each with 23 chromosomes
        
        due to independent assortment and recombination chromosomes line up independently all gametes will be different from themselves as well as parent cells
  - - - g1 - cell growth undergoing cell processes (occupies most of cell life span
      - s phase- genome/ dna replicatoin
      - g2 phase- preparation for separation of the genome/dna
    - - mitosis in which DNA separates so each daughter cell receives the identical genetic code to that of the dividing cell (PMAT)
      - c phase - cytokinesis, division of the cell itself creating TWO daughter cells
- - - - 23 from the female parent, 23 from the male parent
    - - along the length of the chromosome in specific positions are the genes
        
        a gene is a section of DNA that codes information for making proteins- codes for inherited characteristics (such as height in plants) Alleles are different versions of a gene - different sequences of bases in DNA that result in determining a single characteristic they occurs in pairs and that can be classified as a recessive or dominant
        
        GENE can be defined as a region of DNA that controls a hereditary characteristics. usually corresponds to a sequence used to produce specific proteins/RNA
  - - - NITROGEN BASE, SUGAR MOLECULE DEOXYRIBOSE, A PHOSPHATE MOLECULE and one of FOUR types of nitrogen base: ANDENINE, THYMINE, CUTOSINE AND GUANINE
        
        COMPLEMENTARY BASES: ANDENINE - THYMINE and CUTOSINE - GUANINE
        
        when the nucleotides join together they form a long polynucleotide (wind into double helix) called a nucleic acid. DNA is a nucleic acid.
        
        Nucleotides are joined together by sugar + phosphate groups, the sugar of one nucleotide is joined to the phosphate of the next nucleotide - forms sugar phosphate backbone
- - - - are a diagrammatic way to show the inheritance patter of a trait
        
        males are represented by squares
        
        females are represented by circles
        
        marriage = horizontal lines
        
        vertical line leads to offspring
        
        characteristics shown by shading
        
        generation numbers - roman numerals individuals are arabic numbers
    - - sex chromosomes determine the sex of an organism
        
        contain genes that are inherited in a unique way
        
        fathers pass all x chromosomes to all their daughters and all their y chromosomes to their sons
        
        mothers will pass all x chromosomes to their children
        
        autosomes = non sex chromosomes
      - traits carried on the sex chromosomes are said to be sex linked
    - - unique combination of alleles for a gene inherited from parents is the GENOTYPE of an organism
        
        homozygous individuals have 2 IDENTICAL alleles
        
        heterozygous recessive bb
        
        homozygous dominant BB
        
        heterozygous individuals have 2 DIFFERENT alleles
        
        eg for brown eyes Bb
        
        a person who is heterozygous for a recessive trait is said to be a carrier for the trait
      - only a single allele for a trait needs to be present for a dominant trait needs to be present for a dominant trait to appear in the phenotype
        
        can be influenced by the enviroment
      - RECESSIVE traits need to be two copies of the allele before it can be expressed into phenotype
  - - - effect depends on whether it has occured in a non-reproductive or reproductive cells
    - - substitution - POINT MUTATION
      - addition & deletion - FRAMESHIFT MUTATIONS
        
        group of 3 reading (codon) has been shifted along the DNA strand
    - - males - 22 autosomes XY, female - 22 autosomes. XX
      - karyotypes reveal large genetic errors