Biological Anthropology Chapter 3

Front 1

prokaryotes

Back 1

single-celled organisms, such as bacteria, in which genetic material is not separated from the rest of the cell nucleus.

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eukaryotes

Back 2

a cell that possesses a well-organized nucleus

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nucleus

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in eukaryotic cells, the part of the cell in which the genetics material is separated form the rest of the cell (cytoplasm) by a plasma membrane

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cytoplasm

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in a eukaryotic cell, the regio within the cell membrane that surrounds the nucleus; it contains organelles, which carry out the essential functions of the cell, such as energy production, metabolism, and protein synthesis

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somatic cells

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the cells of the body that are not sex cells

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gametes

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the sex cells: sperm for males and eggs (ova) in females

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stem cells

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undifferentiated cells found in the developing embryo that can be induced to differentiate into a wide variety of cell types and tissues. also found in adults although adult stem cells are not as totipotent as embryonic stem cells

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Deoxyribonucleic acid

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a double-stranded molecule that is the carrier of genetic material. each strand is composed of a linear sequence of nucleotides: the two strands are held together by hydrogen bonds that form between complementary bonds

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proteins

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complex molecules formed from the chains of amino acids (polypeptide) or from a complex of polypeptides. they functions as structural molecules ad transport molecules antibodies, enzymes, and hormones

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protein synthesis

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the assembly of proteins from amino acids that occurs in ribosomes in te cytoplasm and is based on information carried by mRNA

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ribonucleic acid

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single-stranded nucleic acid that performs critical functions during protein synthesis and comes in three forms: messenger, transfer, and ribsomal

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mitochondria

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organelles in the cytoplasm of the cell where energy production for the cell takes place. contains its own DNA

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ribosomes

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structures composed primarily of RNA that are found on the endoplasmic reticulum. they are the site of protein synthesis

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nucleotide

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molecular building block of nucleic acids DNA and RNA; consists of a phosphate, sugar and base

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base

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variable component of the nucleotides that form the nucleic acids DNA and RNA. in DNA, the bases are adenine, guanine, thymine, and cytosine. in RNA uracil replaces thymine

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enzyme

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a complex protein that is a catalyst for chemical processes in the body

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amino acids

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molecules the form the basic building blocks of proteins

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polypeptides

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a molecule made up of a chain of amino acids

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genetic code

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the system whereby the nucleotide triplets in DNA and RNA contain the information for synthesizing proteins from the twenty amino acids

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codon

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a triplet of nucleotide bases in mRNA that specifies an amino acid or the initiation or termination or a polypeptide sequence

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gene

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the fundamental unit of heredity. consists of a sequence of DNA bases that carries the information for synthesizing a protein (or Polypeptide) and occupies a specific chromosomal locus

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mRNA

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strand of RNA synthesized in the nucleus as a complement to s specific gene. it carries the information for the sequnce of amino acids to make a specific protein into the cytoplasm, where at a ribosome it it read and a protein molecule synthesized.

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tRNA

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RNA molecules that bind to specific amino acids and transport them to ribosomes to be used during protein synthesis

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mitosis

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somatic cell division in which a single cell divides to produce two identical daughter cells

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meiosis

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cell division that occurs in the testes and ovaries that leads to the formation of sperm an ova

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chromosome

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discrete structures composed of condensed DNA and supporting proteins

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homologous chromosomes

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members of the same pair of chromosomes. homologous chromosomes undergo crossing over during meiosis

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locus

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the location or a gene on a chromosome. the locus for a gene is identified by the number of the chromosomes on which it is found and its positions on the chromosomes

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alleles

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alternative versions of a gene. different alleles are distinguished from one another b their different effects on the phenotypic expression of the same gene.

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homozygous

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having the same allele at the loci for the gene on both members of a pair of homologous chromosomes

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heterozygous

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having two different alleles at the loci for a gene on a pair of homologous chromosomes

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crossing over

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exchange of genetic material between homologous chromosomes during the first prophase of the meiosis; mechanism for genetic recombination

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recombination

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the rearrangement of genes on homologous chromosomes that occurs during crossing over in meiosis. source of variation arising out of sexual reproduction; important for increasing rates of natural selection

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autosomes

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any of the chromosomes other than the sex chromosomes

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sex chromosomes

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in mammals, chromosomes X and Y, with XX producing females and XY producing males