BIOL10003 Course Summary Notes
BIOL10003 Course Summary Notes
Table of Contents:
Genetic
Page 2
Mammals
Page 22
Parasites
Page 26
1
Genetics Basic Genetics
Definitions o Gene – unit of inheritance that occupies a specific locus on a chromosome (NB: also in ribosomes and chloroplasts) o Genotype – genetic constitution of an organism o Phenotype – the morphological biochemical and behavioural properties of an organism resulting from its genotype and interaction with the environment o Genome – the total amount of genetic material in a chromosome set o Genome sequencing – determining full genome, used to examine for genetic diseases and susceptibility o Genetic disease – any disease that alters DNA (not necessarily genetically inherited; eg: cancer) o Metabolic block – block of a biosynthetic pathway due to a genetic enzyme defect/inhibition o Methylation – adding methyl (CH3) to bunch up nucleosomes to point where they can’t be transcribed (so not expressed) o Heterogametic – can give 2 different alleles to a gamete (XY (human male) gives X or Y) o Homogametic – all gametes created contain the same chromosomes (XX (human female) can give only X o Mosaic – individual with 2 or more different genotypes in groups of cells, despite having come from a single fertilised egg (caused in heterozygous females who have X-inactivation) o Alleles – different variants on the same gene Genetic Notation o Alleles A/a = mutant allele (can be anything, eg: Ser, wx… etc) A+ = wild type (where mutation is dominant ‘A’) a+ = wild type (where mutation is recessive ‘a’) o Writing A- means – (the dash) is ‘A’ or ‘a’ (irrelevant for phenotype assuming A is completely dominant) Phenotypic Variation o Genetic factors (eg: Huntington’s Disease) Eg: dwarfism – gene releases enzyme causing metabolic block; blocks Phenylalanine from releasing Tyrosine (a key growth hormone) o Environmental factors (eg: foetal alcohol syndrome – mother drinking lots of alcohol during pregnancy) Generally a combination of both – eg: Siamese cats (when colder, extremities go darker) o Epigenetics (a special case) – changes in gene expression that do not involve changes in DNA May be passed from cell to cell, parent to offspring Eg: methylation (adding CH3) of a gene which can prevent gene expression Eg: child abuse can genetically affect people Human Genome o Relatively few genes for so much DNA 3.3 x 109 nucleotide pairs in each length of DNA o Approx 20,000 genes coding for polypeptides and 5000-6000 for RNA Why so many things from so few genes? Can be spliced differently in different tissues Altering genome o Artificial selection “Natural” way of altering population o Genetic engineering Inject DNA into embryo – rarely taken up, need to be performed many times
DNA 2
Double stranded molecule Polynucleotide o Many nucleotides (base, sugar and phosphate) repeated Joined across bases by Hydrogen bonds Strong base or heating breaks bonds (allows for genetic modification) o Base (A, T, C, G) on Carbon 1, Phosphate on Carbon 5 of deoxyribose sugar Antiparallel o 5 Prime (5’) to 3 Prime (3’) sequence runs in opposite directions on opposite strands (5’ and 3’ bond to the phosphate groups)
Chromosomes (condensed chromatin; observable during prophase onwards of cell replication)
Humans: 46 chromosomes (so say 2N = 46) – found in the nucleolus of the nucleus Chromatin made up of nucleosomes (DNA wrapped around proteins (histones)) o Heterochromatin – contains more tighter packed DNA packaging (only found in eukaryotes) o Euchromatin – loosely coiled DNA and protein, found in all cells 3 key features in replication: o Centromere – join between sisters chromatids o Telomeres Protect end of chromosomes by looping or recruiting protective proteins Extends lagging strand to perfectly fit complete Okazaki fragment Ensures DNA is replicated to end of strand Involved in aging Telomeres shorten over our life – may be responsible for again Werner syndrome – shortened telomeres leads to accelerated aging o Origin of replication Above and below centromere (p,q) called chromosome ‘arms’ o (modification can alter genes) Sorting of chromosomes o Karyotype – sorted chromosomes Organised on basis of: Size Centromere position (during replication only) Whether or not nucleolar organiser regions present (small dots seen above chromosome) Banding pattern o Karyogram – a drawing of chromosomes with banding shown o Autosome – chromosome now involved in determining sex of chromosome o Sex chromosome – chromosome involved in determining the sex of organism Change in chromosome number o Aneuploidy – add or subtract 1 or 2 chromosomes (very occasionally 3 or even 4) Could be caused by defect in ‘cohesin’ – protein responsible for making sister chromatids stick together either side of centromere Types: Trisomy 21 – extra 21 chromosome (Down Syndrome) o Different level of severity – depend son level of interaction of extra chromosome Trisomy 18 – extra 18 chromosome Trisomy 13 – extra 13 chromosome (all other trisomy defects NEVER born – ALWAYS miscarry) 3
Table of Contents:
Genetic
Page 2
Mammals
Page 22
Parasites
Page 26
1
Genetics Basic Genetics
Definitions o Gene – unit of inheritance that occupies a specific locus on a chromosome (NB: also in ribosomes and chloroplasts) o Genotype – genetic constitution of an organism o Phenotype – the morphological biochemical and behavioural properties of an organism resulting from its genotype and interaction with the environment o Genome – the total amount of genetic material in a chromosome set o Genome sequencing – determining full genome, used to examine for genetic diseases and susceptibility o Genetic disease – any disease that alters DNA (not necessarily genetically inherited; eg: cancer) o Metabolic block – block of a biosynthetic pathway due to a genetic enzyme defect/inhibition o Methylation – adding methyl (CH3) to bunch up nucleosomes to point where they can’t be transcribed (so not expressed) o Heterogametic – can give 2 different alleles to a gamete (XY (human male) gives X or Y) o Homogametic – all gametes created contain the same chromosomes (XX (human female) can give only X o Mosaic – individual with 2 or more different genotypes in groups of cells, despite having come from a single fertilised egg (caused in heterozygous females who have X-inactivation) o Alleles – different variants on the same gene Genetic Notation o Alleles A/a = mutant allele (can be anything, eg: Ser, wx… etc) A+ = wild type (where mutation is dominant ‘A’) a+ = wild type (where mutation is recessive ‘a’) o Writing A- means – (the dash) is ‘A’ or ‘a’ (irrelevant for phenotype assuming A is completely dominant) Phenotypic Variation o Genetic factors (eg: Huntington’s Disease) Eg: dwarfism – gene releases enzyme causing metabolic block; blocks Phenylalanine from releasing Tyrosine (a key growth hormone) o Environmental factors (eg: foetal alcohol syndrome – mother drinking lots of alcohol during pregnancy) Generally a combination of both – eg: Siamese cats (when colder, extremities go darker) o Epigenetics (a special case) – changes in gene expression that do not involve changes in DNA May be passed from cell to cell, parent to offspring Eg: methylation (adding CH3) of a gene which can prevent gene expression Eg: child abuse can genetically affect people Human Genome o Relatively few genes for so much DNA 3.3 x 109 nucleotide pairs in each length of DNA o Approx 20,000 genes coding for polypeptides and 5000-6000 for RNA Why so many things from so few genes? Can be spliced differently in different tissues Altering genome o Artificial selection “Natural” way of altering population o Genetic engineering Inject DNA into embryo – rarely taken up, need to be performed many times
DNA 2
Double stranded molecule Polynucleotide o Many nucleotides (base, sugar and phosphate) repeated Joined across bases by Hydrogen bonds Strong base or heating breaks bonds (allows for genetic modification) o Base (A, T, C, G) on Carbon 1, Phosphate on Carbon 5 of deoxyribose sugar Antiparallel o 5 Prime (5’) to 3 Prime (3’) sequence runs in opposite directions on opposite strands (5’ and 3’ bond to the phosphate groups)
Chromosomes (condensed chromatin; observable during prophase onwards of cell replication)
Humans: 46 chromosomes (so say 2N = 46) – found in the nucleolus of the nucleus Chromatin made up of nucleosomes (DNA wrapped around proteins (histones)) o Heterochromatin – contains more tighter packed DNA packaging (only found in eukaryotes) o Euchromatin – loosely coiled DNA and protein, found in all cells 3 key features in replication: o Centromere – join between sisters chromatids o Telomeres Protect end of chromosomes by looping or recruiting protective proteins Extends lagging strand to perfectly fit complete Okazaki fragment Ensures DNA is replicated to end of strand Involved in aging Telomeres shorten over our life – may be responsible for again Werner syndrome – shortened telomeres leads to accelerated aging o Origin of replication Above and below centromere (p,q) called chromosome ‘arms’ o (modification can alter genes) Sorting of chromosomes o Karyotype – sorted chromosomes Organised on basis of: Size Centromere position (during replication only) Whether or not nucleolar organiser regions present (small dots seen above chromosome) Banding pattern o Karyogram – a drawing of chromosomes with banding shown o Autosome – chromosome now involved in determining sex of chromosome o Sex chromosome – chromosome involved in determining the sex of organism Change in chromosome number o Aneuploidy – add or subtract 1 or 2 chromosomes (very occasionally 3 or even 4) Could be caused by defect in ‘cohesin’ – protein responsible for making sister chromatids stick together either side of centromere Types: Trisomy 21 – extra 21 chromosome (Down Syndrome) o Different level of severity – depend son level of interaction of extra chromosome Trisomy 18 – extra 18 chromosome Trisomy 13 – extra 13 chromosome (all other trisomy defects NEVER born – ALWAYS miscarry) 3
