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27 terms

Anth 21 Lecture 4

bio-anth Westin
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Prokaryotes
cells that do not contain nuclei 3.4 bya
Eukaryotes
organisms made up of one or more cells that have a nucleus and membrane-bound organelles 1.5 bya
Somatic Cells
any cell in multicellular organism except an egg or sperm (mitosis- growth or repair)
Gametes
reproductive cells, have only half the number of chromosomes as body cells (meiosis-reproduction)
Nucleotide
subunits of nucleic acid formed from a simple sugar, a phosphate group, and a nitrogenous base- Adenine & Thymine Guanine & Cytosine
Codon
a specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid
Chromosomes
threadlike structures made of DNA molecules that contain the genes (coiled DNA prior to cell division)
Homologous Chromosomes
Chromosomes that are similar in size, shape, and genetic content (same size/location of centromere
genes for same traits
not identical)
Diploid
an organism or cell having two sets of chromosomes or twice the haploid number (# chromosomes in somatic cells)
Haploid
An organism or cell having only one complete set of chromosomes (Gametes)
Chromatid
one of two identical strands into which a chromosome splits during mitosis
Centromere
a specialized condensed region of each chromosome that appears during mitosis where the chromatids are held together to form an X shape
Autosome
any chromosome that is not a sex chromosome
Sex Chromosomes
one of the 23 pairs of chromosomes in the human, contains genes that will determine the sex of the individual
Gene
(genetics) a segment of DNA that is involved in producing a polypeptide chain (codes for a protein- occurs at a locus)
locus
the specific site of a particular gene on its chromosome
allele
one of the alternative forms of a gene that governs a characteristic, such as hair color
Genotype
the particular alleles at specified loci present in an organism
phenotype
what an organism looks like as a consequence of its genotype
homozygous
having identical alleles at corresponding chromosomal loci
heterozygous
having dissimilar alleles at corresponding chromosomal loci
mutation
any event that changes genetic structure (change in nitrogen base ONLY source of NEW genetic material)
silent mutation
A type of base substitution mutation that changes a single nucleotide, but does not change the amino acid created.
Beneficial Mutation
is a mutation that increases fitness of the organism, or which promotes traits that are desirable. (Fuel for Natural Selection)
Deleterious Mutation
A mutation that is harmful to its host; most mutations are this. (protein is not made or does not work)
Point Mutation
mutation that effects a single nucleotide (base), usually by substituting one for another- sickle cell anemia
Frame-shift Mutation
Mutation that involves the insertion or deletion of a nucleotide (base) in the DNA sequence-codons shifted