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What is DNA?
Nucleic acids that contain genetic information, base pairs
Where is DNA stored?
in the nucleus of eukaryotic cells
What is a gene?
a section of DNA that provides information to make a protein
What are proteins?
made of amino acids that are arranged into structure
What are DNA sequences?
the specific order of nucleotides (ATCG) that make up the DNA
What is non-coding DNA?
control gene expression and maintain genome structure, during gene splicing they are taken out
What is an allele?
variants of a specific gene
What is a phenotype?
the physical appearance or state of an organism
What is a genotype?
the allele present genetically, RR or Rr or rr
How many chromosomes do humans have in total? How many matching sets?
46, 23
What are homologous chromosomes?
pairs of chromosomes with the same type of genetic informatiom
How many alleles for each gene are present in an organism with 2 sets of chromosomes?
2
What is a gene pool?
all genes present in any population or species
Where does genetic variation come from?
mutations, the change in sequence of DNA
What are point mutations?
single nucleotide (base) changes,
What are frameshift mutations?
insertions or deletions cause a change in the way the coding sections are read during translation
What are chromosomal mutations?
changes to large chunks of genes (deletion, translocation, duplication, and inversion)
What is a frameshift silent mutation?
no change in amino acid sequence
What is a frameshift missense mutation?
change in 3rd amino acid
What is a frameshift nonsense mutation?
change in 4th amino acid which causes termination
What is evolution?
the change in allele frequency over time
What were some of the major revolutions in evolutionary theory over the 1800s and 1900s?
inheritance of traits, old earth, uniformitarianism,
What was particularly revolutionary about Darwin’s ideas?
unity of life, diversity of life, ecology, evolution through natural selection
·What are the four major principles of evolution by natural selection?
heritable variation, individuals compete, differential reproductive success, evolution over time
What does it mean to lose an allele? Is it reversible?
allele is no longer present in the population, no
What is adaptation?
Individuals with traits that help them survive and will pass on traits
What do we mean when we say there is selection for or against a trait? What kinds of things can cause “selection” in populations?
environmental factors, predators
How does antibiotic resistance in bacteria occur?
when bacteria has a genetic mutations that allows the small population of resisting bacteria to grow
What are the three types of natural selection?
directional selection (dark colored moths), stabilizing selection (Siberian husky), disruptive selection (beak size)
What is non-random mating?
mates are chosen or limited (preference or physical location)
What is gene flow?
caused by the movement of individuals between populations (immigration or emigration)
How does mutation relate to natural selection?
mutation can create new alleles, natural selection determines how common they are
What is genetic drift?
random changes in allele frequency due to chance events
What are bottleneck events?
events that kill large amounts of individuals
What are the 6 main forms of evidence for evolution by natural selection? How does each of these provide support and help us understand how the current diversity of life was produced?
1. Direct observation and strong inference
2. Fossils
3. Homologies: Comparative anatomy
4. Vestigial structures
5. Biogeography + Geology
6. Genetic
What was the earliest view of how offspring traits are determined? How do these ideas contrast Mendel’s ideas about particulate inheritance?
people originally thought it was blending inheritance, contrasting Mendel’s particulate inheritance
What is a monohybrid cross?
crossing organisms that differ in just one trait
What is meant by parental generation (P), F1 generation, and F2 generation?
p=original cross of traits, F1=inherited traits first generation, F2= second generation after
What is the law of segregation?
during meiosis, each gene separates so that each gamete carries one allele for each gene
What is a locus?
the alleles location on the chromosome
What is meiosis?
a type of cell division that produces egg and sperm cells
What is a gamete?
a cell containing half of the parental DNA (egg and sperm)
What are the outcomes of meiosis 1 and 2? What is produced?
4 haploid daughter cells that are not genetically identical
When does crossing over occur and why does it generate diversity in gametes?
in prophase 1 and genetic exchange occurs, results in recombinant genes
What is a test cross?
crossing a specific trait with the recessive gene
What is a dihyrbid cross?
crossing an organism with two traits (16 Punnett square)
What is incomplete dominance?
when the traits merge together (purple+white=whitish purple)
What is codominance?
two versions of the trait are expressed equally (blood types)
What is pleiotropy?
one gene affecting many traits
What is heterozygous advantage?
the two different alleles allow the organism to have a higher survival advantage
What is epistasis?
phenotypic expression of one gene
is influenced by another gene
What is genetic linkage?
the tendency of genes located close together on the same chromosome to be inherited together during meiosis
What are recombinant genotypes?
genotypes that do not look like the parental genotypes
What are complex traits?
characteristics that are influenced by many genes and environmental factors
What are x-linked traits?
genes carried on the x chromosome
What is phenotypic plasticity?
through an organisms lifetime, being able to change the phenotype based on the environment
What is a pedigree?
Trace inheritance along family trees, often rare alleles
What is autosomal recessive/dominant in disease inheritance patterns?
non-sex chromosomes, parent is unaffected (recessive) or affected (dominant)
What is x-linked dominant in disease inheritance patterns?
rare, affected females pass traits to sons and daughters
What is x-linked recessive in disease inheritance patterns?
more common, affected males will significantly outnumber affected females, trait often goes from unaffected carrier mother to
affected sons
Why might alleles that cause abnormalities/disease stay in the population? Why don’t they disappear?
heterozygous advantage, doesn’t affect survival, trait appears well after child bearing age
What are the 5 conditions of the Hardy-Weinberg (HW) theorem/model?
Frequencies of alleles and genotypes in a
population’s gene pool remain constant over
generation if-
1. Infinitely large population
2. No mutation
3. Random mating
4. Isolated from other populations
5. All individuals survive & reproduce
equally (no natural selection)
math equations — put on cheat sheet
p+q=1… etc
