Chapter 3 Flashcards
DNA
Traits coded by Genes => on chromosomes => made of DNA (discovered by Crick + Watson, humans + chimps share 99% of DNA)
(DNA->chromosomes->genes->Genome!
Prokaryotes!
3.5 byo
Single-Celled bacteria
No nucleus or organelles (a cell wall aorund disorganized DNA)
Eukaryotes!
1.2 byo
Some single-celled, all multi-cellular organisms (humans!)
DNA in nucleus, has organelles (mitochondria)
Somatic cells
Body cells (brain, blood, bone, skin)
Have full set of DNA (46 chromosomes)
Mitosis (my toes! Split + creating two copies)
Gametes
Sex cells
Eggs (ova) + sperm
Half DNA (23 chromosomes)
Meiosis (split + only half of DNA)
Chromosomes
DNA packaged in chromosomes
Chromosome # varies by species, are same size and arrange in pairs
DNA structure - DOUBLE HELIX!
sugar + phosphate = “sides” of ladder (outside)
Nucleotide base =
Adenine + Thymine
Guanine + Cytosine
Chromosome types
A set = karyotype Homologous pairs -autosome (22 pairs) -sex chromosome (1 pair) - X+Y male determines sex
MITOSIS (my toes…hihi)
Diploid
chromosomes replicated = c have same karyotype = switching process that turns on specific c (2 separate entities, 46 becomes 46)
MEIOSIS
Haploid: 23 chromosomes (no pairs)
Recombination via crossing over (haplotypes)
Mitosis => then replicate again
Law of Independent Assortment
Mendel’s peas- Inheritance of one trait does not affect inheritance of other traits.
Protein synthesis
DNA codes for proteins = Enzymes catalyze chemical reactions. Ie. Lactase! Folks who aren’t lactose intolerant are mutants!
Structural proteins = tissues (collagen, skin + bone)
Gas transport (to tissues)
Antibodies ( immune syst.)
Hormones (regulate metabolism)
Mechanical proteins (actine+myosine)
Nutrients
Transcription
DNA transcribed into mRNA in the nucleus of the cell
Transcription - translation - replication
Translation
mRNA (messengerRNA) translated into an amino acid chain at the ribosomes
(Transcription - translation - replication)
Regulatory Genes
On/off switches for genes• Marfan syndrome• (BIG HANDS) Chicken teeth• Human hair• Lactose intolerance or persistence!!!!! MUTANTS!!!!
Polymorphisms
Variations in specific gene. Presence of 2 or more alleles at a locus.
Law of segregation
2 alleles for any given gene (or trait) are inherited, one from each parent; during gamete production, one of the two alleles will be present in each ovum or sperm.
Homeotic genes (Hox)
Regulatory genes responsible for form + arrangement of tissues.
Codominance
2 diff. alleles that are equally dominant, both are expressed in phenotype.
Polygenic traits + pleiotropy
Many traits are polygenic
(multiple genes)
Many genes are pleiotropic (influencing diff. phenotypes)
ALL TRAITS product of genes + env.
Phenotype vs. Genotype
Expressed outwardly (expression of genotype) vs. expressed genetically (combination of alleles)
Epigenetics
chemical changes genome affecting how DNA is used in production of proteins, without altering the DNA sequence.•Environmental change
Methylation
Attachment of methyl group to DNA; affects gene expression.
impact env. on foetus
Polygenic Inheritance
Continuous traits governed by alleles at two or more loci. Phenotypal.
Mitochondrial Inheritance
powerpacks of c, has own DNA, mtDNA is matriarchal, only changes with mutations)
