| A | B |
|---|
| Nucleotide | a 5-carbon sugar, a phosphate group, and a nitrogen base. |
| Adenine | pairs with thymine |
| Adenine | pairs with Uracil |
| Cytosine | pairs with guanine |
| guanine | pairs with cytosine |
| thymine | pairs with adenine |
| Uracil | pairs with adenine |
| Adenine-Thymine | two hydrogen bonds join them together |
| Cytosine-Guanine | three hydrogen bonds join them together. |
| double-helix | two strands twisted around a central axis. |
| hydrogen bond | forms between purines and pyrimidines. |
| purine | a double ring of carbon and nitrogen atoms. |
| pyrimidine | single rings of carbon and nitrogen. |
| replication | the process of duplicating DNA. |
| transcription | the process of making RNA from DNA |
| translation | the process of assembling protein molecules from information encoded in mRNA |
| mRNA | transmits information from DNA for use during protein synthesis. |
| tRNA | each of the 20 types has the ability to bond to only one specific amino acid. |
| rRNA | recently, scientist have found that it helps produce enzymes needed to bond amino acids together during protein synthesis. |
| genetic code | the system that contains information needed by cells for proper functioning. |
| protein synthesis | the formation of proteins using information coded on DNA and carried out by RNA. |
| translation | the process of assembling protein molecules encoded in mRNA. |
| codon | a specific group of three sequential bases of mRNA. |
| anticodon | complementary to the codon of mRNA |
| AUG | The start codon |
| Methionine | always the first amino acid in the chain. |
| histones | when wrapped with DNA this protein forms a chromosome. |
| centromere | the point where chromatids are attached. |
| chromatids | two identical chromosomes |
| homologous chromososmes | the two members of a pair of chromosomes. |
| diploid | cotins both chromosomes of a homologous pair. |
| haploid | contains one chromosome of a homologous pair. |
| mitosis | the division of the cell nucleus which ends in two daughter cells. |
| cell cycle | the sequence of events that occurs in a cell from mitosis to mitosis. |
| Interphase | a period of cell growth |
| Interphase | Precedes mitosis and follows cytokenesis. |
| cytokenesis | the division of the cytoplasm. |
| G1 phase | the cell doubles in size |
| G1 phase | enzymes and organelles double in number |
| S phase | DNA replicates |
| G2 phase | the cell undergoes rapid growth |
| G2 phase | the cell synthesizes enzymes and structures for mitosis |
| prophase | in this phase chromatin coils and forms chromosomes |
| prophase | in this phase the nucleolus and the nuclear membrane breakdown |
| prophase | in this phase in organisms other than plants, two dark dots appear next to the disappearing nucleus. |
| centrioles | move to opposite ends of the cell. |
| polar fibers | spindle fibers that that extend across the cell from centriole to centriole. |
| kinetichore | spindle fibers that extend from the centromere to the centriole. |
| kinetichore | controls chromosome movement |
| metaphase | kinetichore fibers move the chromosome to the center of the cell. |
| metaphase | characterized by the arrangement of all chromosomes along the equator of the cell. |
| anaphase | the centromere divides |
| anaphase | the chromatids separate |
| telophase | two identical sets of chromatids are clustered at opposite sides of the cell. |
| telophase | the centrioles ans spindle fibers dissapear. |
| telophase | the chromatids unwind and elongate to form chromatin. |
| telophase | a nuclear membrane forms around each mass of chromatin |
| telophase | a nucleolus appears. |
| cell plate | the membrane across the middle of a plant cell during cytokenesis.. |
| meiosis | the process of nuclear division that reduces the number of chromosomes by half. |
| Meiosis I | homologous chromosomes are separated into separate cells. |
| Meiosis II | the chromatids of homologous chromosomes are segregated into separate cells. |
| tetrad | a group of two chromosomes |
| synapsis | the pairing of homologous chromosomes. |
| crossing-over | when portions of chromosomes are exchanged between two homologues or between sister chromatids. |
| Prophase I | synapsis occurs. |
| Prophase I | crossing-over occurs |
| Prophase I | tetrads form |
| gametes | sexual reproduction |
| ootid | the egg cell |
| polar bodies | receive little or no cytoplasm. |
| sexual reproduction | the production of offspring through meiosis and subsequent fusion of gametes. |
| asexual reproduction | the production of offspring from one parent, without the union of gametes. |
| genetic recombination | new cominations of genes. |
