ch 3 Flashcards
(17 cards)
genetics
the study of genes and how traits are transmitted from one generation to the next
genes
sequences of DNA that code for proteins
nuclear DNA
DNA found within the nucleus of a cell
mutations
alterations to genes or chromosomes; a change in one base of the gene sequence; can be caused by exposure to chemicals, sunlight, radiation; most are neutral, some are beneficial, sometimes can be harmful
protein synthesis
the process by which amino acids are assembled to form proteins; certain types of amino acids must come from the diet
ribosomes
structures found in cells that are involved in the assembly of proteins
RNA
ribonucleic acid; the RNA molecule is single-stranded and has uracil instead of thymine as one of its bases; it also contains a different type of sugar
messenger RNA/ mRNA
a form or RNA that carries the genetic instructions of a DNA molecule to the site of protein synthesis
mitosis
- division of the somatic cells resulting in the production of two identical daughter cells; .
- The first step in mitosis is the replication of these chromosomes, resulting in 46 double-stranded chromosomes
- These duplicate pairs line up at the center of the cell and then diverge so that the strands are separated.
- The individual strands move toward opposite ends of the cell, the cell membrane constricts in the middle, and two new cells are formed, each containing 46 single-stranded chromosome
mutation
recombination (crossing over)
major sources of variation on which natural selection acts; development of recombinant DNA technology in the 1970s allowed scientists to insert pieces of DNA from one organism into the DNA of another. This technique has allowed for the manufacture of insulin and other substances that can be used for medical treatment
alleles
factors that are responsible for traits; alternative forms of a gene
monogenetic traits
traits that are controlled by genes at a single locus
polygenic traits
phenotypic characteristics influenced by multiple genes; also known as continuous traits; include eye color, stature, body weight
Ancient DNA/ aDNA
DNA in ancient (ie nonmodern) remains recoverable from hard tissues (bones and teeth) and in exceptional cases of preservation, from hair and soft tissues
Heritability
the proportion of a phenotypic variation that can be ascribed to genotypic variation in a specific population
Mechanisms of inheritance
how traits are inherited by offspring; geneticist Gregor Mendel and his 2 principles of inheritance
Principle of segregation: the separation of alleles during the production of sex cells so that each sex cell contains only one allele from each parent
The principle of independent assortment: the distribution of one pair of alleles into the sex cells does not influence the distribution of another pair of alleles
