Bio- Unit 4 AOS2, Ch. 9, 10, & 11

gene pool

the complete set of alleles present within a particular population

gene

a section of DNA that carries the code to make a protein

allele

an alternative form of a gene

population

a group of individuals of the same species living in the same location

allele frequency

the proportion of certain alleles in a gene pool

genotype

the genetic composition of an organism at a particular gene locus

phenotype

the physical or biochemical characteristics of an organism that are he result of gene expression and the environment

mutation

permanent changes to the DNA sequence of an individual and can occur either spontaneously or be induced by agents known as mutagens. when mutations occur, they can have a significant downstream effect on the expression of the gene by altering the folding and functionality of the protein. they can be classified as advantageous, neutral, or deleterious

mutagen

an agent that can cause mutations in DNA

deleterious

alleles that have an overall negative effect on individual fitness when expressed

advantageous vs. deleterious

if the mutation leads to the production of an abnormally functioning protein, then it’d be classified as deleterious. However, if it led to the production of a protein that enhances the survivability of an individual, then it’d be classified as advantageous.

heritability

the transmission from parent to offspring. for a mutation to be heritable, it must occur in an individual’s germline cells. If the mutation occurs in a somatic cell, then it’s not heritable

germline cell

a cell involved in the generation of gametes in eukaryotes

somatic cell

any cell in an organism that’s not a germline cell

point mutation

a mutation that alters a single nucleotide in a DNA sequence. they can include silent, missense, nonsense, and frameshift mutations.

silent mutations

a mutation that occurs when a nucleotide is changed, but due to our DNA being degenerate, the same amino acid is produced, resulting in the same protein.

missense mutations

conservative: a change in an amino acid, altering the primary structure of the polypeptide, however they can be tolerated due to the amino acid having similar properties.

non-conservative: a change in an amino acid, altering the primary structure of the polypeptide, resulting in abnormal functioning due to the amino acid having different properties

nonsense mutations

a single base change that results in the production of a STOP codon, resulting in a shorter protein and therefore affecting the protein’s function. these mutations are generally considered the most dangerous

insertion frameshift mutations

a mutation that alters the reading frame of all downstream nucleotides, by inserting one or two nucleotides into the DNA sequence. This causes all codons and therefore amino acids to be potentially altered, disrupting the structure and function of the protein.

deletion frameshift mutations

a mutation that alters the reading frame of all downstream nucleotides, by removing one or two nucleotides into the DNA sequence. This causes all codons and therefore amino acids to be potentially altered, disrupting the structure and function of the protein.

block mutations

mutations that affect a large chunk of DNA, or an entire gene. It involves deleting, duplicating, inverting, or translocating a cluster of nucleotides. these mutations usually occur during the process of meiosis

degenerate

a property of the genetic code which means that a single amino acid can be coded for by more than one codon

reading frame

the order in which nucleotide triplets or codons are divided into a consecutive, non-overlapping sequence

deletion mutation

the removal of a section of DNA

duplication mutation

the replication of a section of DNA, lengthening the DNA

inversion mutations

the reversal of a section of DNA

translocation mutations

the switching of two sections of DNA on different chromosomes

aneuploidy

a chromosomal abnormality in which an organism possesses an incorrect number of total chromosomes caused by the addition or loss of an individual chromosome

polyploidy

a chromosomal abnormality in which an organism has an incorrect number of sets of each chromosome, there is an entire set of chromosomes added or missing