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bio exam3
| Question | Answer |
|---|---|
| codominant | allele that are both expressed when they occur together in the heterozygous state (example are A and B alleles in the ABO blood groupings) |
| codon | group of 3 mRNA bases each of which specifies an amino acid when translated |
| complementary | a fundamental process in which adenosine pairs with thymine and guanine with cytosine |
| adenosine pairs with what in DNA? | Thymine |
| Thymine pairs with what in DNA/RNA? | Adenosine |
| Cytosine pairs with what in DNA/RNA? | Guanine |
| Guanine pairs with what in DNA/RNA? | Cytosine |
| adenoine pairs with what in RNA? | Uracil |
| cytokinesis | cytoplasmic division that occurs during mitosis and meiosis |
| diploid | having 2 copies of each chromosome. |
| what is the diploid number for human chromosomes | 46 |
| DNA | double helix, contains a nitrogenous base pairs, made of sugar deoxyribose, sugar-phosphate backbone |
| exon | portions of the genes that encode for amino acids, retained |
| dominant | an allele that is expresed in the same way in a single copy as in a double copy |
| gamete | haploid germ cell ex. sperm and ovum |
| promoter | before every structural gene this exists. dna sequence located 5' of a gene to which rna polymerase binds to begin transcription |
| enhancers | increase the production of a particular protein....regulatory gene...ex.proto-onco genes |
| silencer | turns of expression of a gene. ex. proto-onco genes |
| gene | fundamental unit of heredity, information used to produce/codes for a protein |
| genotype | indivdual's allelic constiution at a locus |
| haploid | refer to the cells that have one copy of each chromosome, the typical state for gametes |
| what is the haploid number for humans? | 23 |
| heterozygous | individual who has 2 different alleles at a locus |
| homologous | dna/amino acids sequence highly similar to one another. refers to chromosones that pair during fertilization (1 from mom, one from dad) |
| homozygous | individual with two alleles at the locus are the same |
| intron | noncoding part of mrna,spliced out |
| meiosis | cell division process in which haploid gametes are formed from diploid germ cells |
| metaphase | stage of mitosis/meosis in which homologous chromosomes are arranged on the equatorial plane of the cell |
| mitosis | cell division process in which 2 identical progency cells are produced from a single parent cell |
| nucleotide | basic unit of dna or rna consisting of one deoxyribose (ribose in RNA case) one phosphate, and one nitrogenous base |
| phenotype | observed characteristics of an individual, produced by the interaction of genes and enviroment |
| polymorphism | a locus in which 2 or more alleles have gene frequencies greater than 0.01 in a population |
| prophase | first stage of mitosis and meosis |
| recessive | an allele that is masked by the dominant allele when the two occur in a heterozygote |
| repetitive DNA | DNA sequences that are found in multiple copies in the genome |
| ribosomes | site of translation of mature mesenger rna into amino acids sequences |
| satellite dna | a portion of the dna that differs enough in base composition so that it form a distinct bond on a cesium, usually contain highly repeptitive dna sequences |
| somatic | a cell other than those of the gamete-forming germline, in humans those are called haploid |
| structural gene | genes that encode protein products |
| telophase | a final major stage of mitosis and meiosis in which the daughter chromosomes are located on oppoite edges of the cell and new nuclear envelope is formed |
| transcription | process in which mRNA sequence is sythesized from DNA template |
| allele | refers to the different form or DNA sequences, that a gene can have in a population |
| anaphase | one of the stages of cell division, in which sister chromatids seperate and move toward opposite ide of the cell |
| anticodon | 3 nucleotides dna sequence in a trna molecule that undergoes complementary base pairing with mRNA codon |
| autosome | the 22 pairs of chromosomes excluding the sex chromosomes (x and y) |
| centromere | the region of a chromosome that seperates the two arms; site of attachment for the sspindle fibers during cell division |
| chromosome | threadlike structure consisting of chromatin |
| mRNA | is transcribed from a DNA template, and carries coding information to the sites of protein synthesis: the ribosomes. Here, the nucleic acid polymer is translated into a polymer of amino acids: a protein |
| tRNA | is a small RNA molecule (usually about 74-95 nucleotides) that transfers a specific active amino acid to a growing polypeptide chain at the ribosomal site of protein synthesis during translation |
| rRNA | RNA component of the protein manufacturing machinery of all living cells.provides a mechanism for decoding mRNA into amino acids and interacts with tRNAs during translation by providing peptidyl transferase activity |
| translation | is the third stage of protein biosynthesis (part of the overall process of gene expression). Where mRNA is decoded to create a protein. |
| splicing (mRNA) | is a modification of an RNA after transcription, in which introns are removed and exons are joined. |
| regulatory gene | is a gene involved in controlling the expression of one or more other genes. A regulator gene may encode a protein, or it may work at the level of RNA, as in the case of genes encoding microRNAs. |
| examples of regulatory genes | promoter – bind RNA polymerase-before every structural gene properly orient the polymerase, give start point enhancer silencer |
| disjunction | the seperation of chromosomes during cell division |
| chromatid | is one of the two identical copies of DNA making up a duplicated chromosome, which are joined at their centromeres, for the process of cell division (mitosis or meiosis). |
| antiparallel | In biochemistry, two molecules are that run side-by-side in opposite directions. 5 to 3 prime end |