BIOLOGY 171 Lecture Notes - Lecture 4: Cell Adhesion, Eukaryote, Phloem
Document Summary
Within eukarya, organisms are grouped into superkingdoms. Protists are eukarya that are not plants, animals, or fungi. Multicellularity has evolved independently at least six times in eukarya. Plants use vascular tissues (xylem and phloem) and animals use bulk transport (circulatory systems) Cell-to-cell communication allows for complex multicellular processes to occur. Certain genes are turned on or off depending on the cell"s function. Add, delete, or change nucleotides in dna sequences. Can affect one base pair, a few base pairs, or large regions of chromosomes. Can alter coding sequences (genes) or noncoding sequences. Mutations can be neutral (most common), deleterious, or beneficial (rarest) Can be passed to offspring if they occur in the germ-line (gametes). In coding sequences, amino acids can be changed or not by mutations offspring if mutation occurs in somatic cell. *nonsense: shorter than normal protein (early stop codon) *duplication: two copies of a gene or stretch of dna.
