HC1- evolution and genes Flashcards
Out of africa theory
humans have neanderthal dna, everyone is 99.9% identical
Evolution theory
all organisms have a common ancestor.
support: bigeography, fossil records, structural similarities, embryology, molecular biology
bigeography
organisms are indegenous to environments
natural selection
traits beneficial for survival and reproduction become more common
karotype
organised set of chromosomes in cell nucleus (46 chromosomes -> 22 identical pairs + 23rd is XY or XX)
genome
complete set of DNA in an organism
chromosome
long DNA strand wound on histones
telomere
Region at the tip of a chromosome that protects DNA during cell division
histones
Proteins used to fold the DNA so it doesn’t become tangled
gene
part of dna with instructions to make proteins on a chromosome
allele
two alternative forms of a gene controlling the same trait found on the same place on a chromosome
genotype
influenced by a single gene, following a pattern of inheritance. presence or absence of a disease, unaffected by the environment (huntingtons)
phenotype
no pattern of inheritance, observable based on the environment and genes (ADHD, manifests based on evironment)
mendelian inheritance
inheritance based on dominant and recessive genes (huntingtons is AA or Aa)
mitosis
cellular division after fertilization to complete an organism. the basis of variation(tiny differences in DNA). the chromosomes can cross over, break, and rejoin, producing a variation in the genetic code
Deoxyribo Nucleic Acid
DNA, double strand of nucleotides with instructions to make proteins and to replicate itself
nucleotides
form pairs (A-T, C-G)
replication(DNA function)
two strands of nucleotide bases unravel, the exposure attracts complement from unattached bases in the nucleus. the unravelled strand now has a full complement of attached nucleotide bases therefore identical to the original
Protein synthesis (DNA function)
transcription -> splicing -> translation -> processing
transcription
1st step, in the nucleus a piece of DNA is copied into RNA (shorter so can leave nucleus)
translation
3rd step, mRNA turn into amino acids because of ribosome. each mRNA merges with transferRNA anticodon
splicing
2nd step, spliceosomes split introns (stay in nucleus) and exons (exit nucleus) RNA -> mRNA
mRNA
connects with the ribosome and merges with tRNA -> anticodon -> protein
anticodon
complementary codon to the mRNA on the tRNA (T=U)
post-translational protein processing
4th step, large proteins are cut into smaller proteins, making multiple proteins from one gene
protein functions
building blocks, NT or hormone receptors, form ribosomes, fuel for energy and heat production, muscle contraction, kill invaders, transport O2 in rbc, enzyme to metabolise chemical reactions
enzyme
molecular glue/scissors, biological catalyst
polymorphism
differences in dna sequences in individuals, increases risk for a disorder
Single Nucleotide Polymorphism
polymorphism with long stretches of DNA
Mutations
change in a single gene that is rare and can manifest gene difference
tandem repeats
sequences of DNA where a specific pattern of nucleotides is repeated consecutively. These repeated units are adjacent to each other and can vary in size, sequence, and number of repetitions. Tandem repeats are a common feature of the genome and can be found in both coding and non-coding regions of DNA.
epigenetics
functional modification of the genome that do not involve a change in de DNA sequence. Phenotypical changes in response to environmental exposure. can switch genes on or off
