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· Deoxyribose Nucleic acid ­ information caring molecule, carries genetic code
· Nucleotide deoxyribose, phosphate group, base (nitrogen)- adenine, guanine, thymine ,cytosine
· Condensation polynucleotide ­ sugar phosphate backbone
Structure related to function:
1.Carries code in bases ­ triplet/ unzip P synthesis/ strong backbone = stable/ large
carry info
2.Can replicate prior to cell division
DNA Helicase unzips complimentary base pairing with fee nucleotides to
exposed bases backbone formed. DNA Polymerase joins the bases.
·Semi conservative ­ conserves half old DNA in each new molecule (1new, 1old)
Genetic code
Gene ­ section DNA - coded info sequence of AA polypeptide protein determining development
Genetic code ­ relationship between base sequence in DNA and sequence of AA in protein
Triplet (3base=1code), degenerate (some have +1code + stop codons), non overlapping (1st doesn't
dictate next), universal all organisms use it.
Change in DNA sequence different protein
·Different AA altered tertiary structure enzyme ineffective (metabolic pathway, end product = no
·Beneficial allele formed better survival
·Can cause cancer ­ spread metastasis. Treated by chemo (Spindle form inhibited), surgery,
radiation…read more

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Cell division
The cell cycle
Interphase ­ (G1) growth, protein synthesis, (S) DNA replication, (G2) grow and divide
Nuclear division ­ nucleus divides
Cytokinesis ­ cytoplasm divided form new cell
Produces 2 genetically identical daughter cells ­ differentiation (specialisation) growth + repair asexual
Sister chromatids…read more

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Produces 4 genetically different
gametes haploid
Crossing over
Breakage +rejoining of DNA between
non-sister chromatids
recombination of genetic material.
Independent segregation
Homologous chromosomes orientate
randomly on equator during
metaphase 1 separate
independently different gene
Mutations during replication…read more

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Intron ­ non-coding region of a gene not expressed
Exon ­ expressed region of a gene
Molecule of DNA associated with protein ­ numbers vary for species (humans ­ 46, 23pairs)
Eukaryotic ­ large, linear DNA. Each choromo at fixed position. Has introns
Prokaryote ­ small, circular. No protein. No intorns
Intra(between), Inter(within) specific
Causes: genetic (crossing over etc) / environmental
Twin studies - determine if variation environmental or genetic. ID same geno, enviro/non different
geno, same enviro
Genetic Diversity
Selective breeding ­ beneficial alleles selected up yield/ reduced diversity, up risk of recessive allele
Founder Effect ­ small pop colonise new area (small %alleles) less diversity. inbreeding, no variation
Genetic Bottleneck ­ pop suffers dramatic drop disaster survivor (small variety) inbreeding…read more

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Variety of life
· 4polychains containing haem load + unload O2 at various partial pressures.
· Has high affinity when pp high (lungs), low when pp is low (tissue)
· During respiration CO2 carboxylic acid, denatures enzyme readily release O2 Bohr Shift R
· In low O2, high metabolic rate, foetal + myoglobin to left
Starch ­ polymer alpha glucose, stored as grains in cytoplasm +
chloroplasts. High in storage organsStarch ­ polymer alpha glucose,
stored as grains in cytoplasm + chloroplasts. High in storage organs
Glycogen ­ carb energy store in animals cytoplasm as granules. High
in liver + muscle (branched)
Adaption: easily hydrolysed/ large (no osmotic effect), compact shape
store lots
Cellulose ­ polymer beta glucose, structural support in cell wall to
prevent osmotic damage. (chained)
Adaption: large, insoluble/ microfibrils ­ cellulose fibres high tensile
strength (hydrated gaps apoplast)
Plant structures
Chloroplasts ­ found in palisade, to photosynthesise. Contain stroma
(enzymes, sugar, starch), Granum/thylakoid membranes ­ chlorophyll
filled structures
Adaption: biconcave large SA/ stroma stuff needed/ thylakoid
membrane light absorbing pigment
Xylem ­ transport water + ions, long, tubular strengthened and protected by Lignin (woody, waterproof)
End walls disintergrate continous flow. Ligning pitted sidewards movement.…read more

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