Genetics
- Created by: Sophie
- Created on: 22-02-14 13:51
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- Genetics, the Cell Cycle and Differentiation
- DNA
- Made of nucleotides
- A phosphate, a sugar and a base.
- Base contains nitrogen
- A phosphate, a sugar and a base.
- 2 polynucleotide strands join to form a double helix
- Sugar-phosphate backbone
- Specific base pairing
- Long and coiled up tightly so lots of genetic info fits in a small space in the nucleus
- Paired structure- for self-replication
- Stable in cell
- Made of nucleotides
- EUKARYOTIC
- Linear
- Associated with proteins
- DNA wound up around histones, both coiled up to form a chromosome
- Associated with proteins
- Introns are sections don't code for amino acids
- Introns removed during protein synthesis
- DNA also contains sections of multiple repeats
- e.g CCTTCCTT
- Linear
- PROKARYOTES
- Circular
- Not
- Shorter
- Supercoiled to fit in cell
- Shorter
- Not
- Circular
- DNA triplet
- Amino acid
- Order of amino acids to make a protein
- Enzymes are proteins, control metabolism and growth etc.
- Non functional proteins can be the result of gene mutations
- Mutations are a change in the base sequence
- Non functional proteins can be the result of gene mutations
- Enzymes are proteins, control metabolism and growth etc.
- Order of amino acids to make a protein
- Amino acid
- Genes can exist in more than one form- allele.
- Order of bases is slightly different, so they code for slightly different versions of the same thing
- MEIOSIS
- Gametes
- haploid
- DNA unravels and replicates so there are 2 copied of each chromosome
- DNA condenses to form a double armed chromosome made from 2 sister chromatids
- Meiosis I- chromosomes arrange themselves into homologuous pairs
- H-Pairs separated, halving chromosome number
- Meiosis II- Pairs of sister chromatids seperate
- FOUR haploid cells produced
- Meiosis II- Pairs of sister chromatids seperate
- As the homologous pairs pair up, the chromatids twist round each other and bits swap over, giving different allele combos
- Also independent segregation of chromosomes- random chromosomes from parents
- H-Pairs separated, halving chromosome number
- Meiosis I- chromosomes arrange themselves into homologuous pairs
- DNA condenses to form a double armed chromosome made from 2 sister chromatids
- Gametes
- Genetic diversity
- Mutations
- Gene flow- new individuals migrating and reproducing
- Genetic bottlenecks reduce this as a big reduction in population, reduced alleles
- The Founder effect- new colony, fewer alleles and more inbreeding
- The Cell cycle
- Interpahse, G1, S, G2
- G1- Protein synthesis
- S- Replication of DNA
- G2- Organelles grow and divide, energy stores increased
- Nucelar division
- Mitosis or meiosis
- Cell division
- Interpahse, G1, S, G2
- Relication- Interphase
- DNA helicase breaks H-bonds
- Polynucleotide strands unzip to form single strands
- Free floating nucleotides join the exposed bases by specific base pairing
- DNA Polymerase joins the nucleotides on the new strand. New H-bonds between old and new strand
- Semi conservative as each new DNA molecule has half of the news strands of DNA from the original.
- DNA Polymerase joins the nucleotides on the new strand. New H-bonds between old and new strand
- Free floating nucleotides join the exposed bases by specific base pairing
- Polynucleotide strands unzip to form single strands
- DNA helicase breaks H-bonds
- Mitosis
- Clones
- Repair
- Interphase
- Prophase
- Chromosomes become visible
- nuclear envelope disappears
- Metaphase
- Chromosomes arrange themselves at equator of cell
- Anaphase
- Each of the 2 chromatids migrate to opposite poles of the cell pulled by spindle fibres
- Telophase
- Nuclear envelope reforms
- Chromosomes become visible
- Prophase
- DNA
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