Theme 3 Flashcards
Different Cells
Somatic-differentiated into different tissues, organs-full genetic material
Sex-Sperm, eggs/ova. 1/2 of genetic material, gamete vs zygote
Stem-Not yet differentiated into any type of specialized cell, can be used to treat injuries and diseases.
Prokaryotes vs Eukaryotes
Pro-Single celled organisms, DNA contained within cell walls, appeared 3.7 bya, no nucleas
Euk-Multicellular organisms, appeared 1.5-1 bya, nucleus containing DNA.
Animal Cells
Cell membrane (semi-permeable), cytoplasm, mitochondria, nucleus.
DNA
Mitochondrial (inherited through maternal line), found in every body cell except red blood cells.
Proteins
3 bases=codon. 1 codon=1 amino acid. Chain of amino acids=polypeptide. 20 different amino acids in our bodies. Wide range of functions.
Nucleotide
Sugar phosphate sides+base. 3 Billion bases in human body, 19-20 thousand protein encoding things.
Gene
Section of DNA that codes for the production of a protein.
RNA and protein synthase
Reads the code, mRNA takes the information outside the nucleus for protein synthesis.
Point Mutation
1 small, specific change
Deletion and Insertion
Removing or adding bases
Inversion
Sequence gets twisted around
Mitosis vs Meiosis
Mitosis-Somatic, changes (mutations) don’t get passed on. 2 daughter cells formed.
Meiosis- Gametes, mutations get passed on. 4 daughter cells formed, only 1 kept.
Where does the blood type gene reside?
Chromosome 9 (loci)
Diploid Organisms
Principle of segregation, during meiosis, only one copy of the original chromosome is passed on to the sex cell.
Genotype
Alleles that occur at the locus in that individual
Sex Linked Traits
Information on the Y chromosome is not the same as on the X.
Red-Green Colour Blindness
Female has recessive trait for colour blindness that is passed on via X chromosome to their son. Since the son only has one X chromosome, he will be colour blind.
Hemophilia (Royal Blood Disease)
Female dominant or recessive hemophilia allele will be passed onto their son and the son will become hemophilic due to only having one X chromosome.
Principle of Independent Assortment
Traits separate independently when reproductive cells develop.
Monogenic Traits
Controlled by a single gene, ex) Blood type, tongue rolling (mendelian traits)
Polygenic/Continuous Traits
Controlled by many genes ex) eye colour, hair colou, skin tone.
Pleiotropic Traits
One gene associated with multiple effects (phenotypic traits-ex: phenylketonuria)
Human Genome Project
Aim to sequence entire human genome
Venter
Started his own company to quicken the sequencing of the genome, caused HGP to get more funding. Both were published in June 2000 (draft genomes).
Human Genome
3 billion base pairs and 20000 protein coding genes. Lots of non-coding “junk” DNA. No concrete idea of what it does.
Does the reference genome represent all humans globally?
No. Only identification of the location of genes and their method of ineritance.
Ancient DNA (aDNA)
Started in 1985, DNA from poor quality samples (2000 year old mummies)- discovered origin and spread of human diseases (plague, tuberculosis, syphillis), and human neanderthal evolutionary history (up to 4% of neanderthal DNA in modern humans).
aDNA tropically
Difficult to recover with high amounts of degradation. High levels of contamination, usually about 1% of DNA from a sample is the target DNA.
Lamarck and Weismann
Lamarck-Environment directs variation
Weismann-Identified somatic vs sex cells-genetic variation only occurs through mutation in the sex cells.
Epigenetics
Affect gene expression, changes that occur in the regulation of DNA. Can be passed on to future generations. Can interfere with transcription. Epigenetcs does not change actual DNA-gene must be encoded first so epigenome can act on it.
Epigenetic Tags
Attaches to DNA and inhibits/expreses genes. Talks with environment, tags are influenced by environement and are turned on/off.
Epigenetics and Cortisol
World Trade Centre, 1700 pregnant women directly exposed during attack-38 women were looked at. Lower salivary cortisol (PTSD) in mothers and infants born to these women.
