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Lab #5
Mitosis and Gene Action
Question | Answer |
---|---|
Mitosis | A form of cell division. The genetic material of the nucleus duplicates and becomes separated into two nuclei. |
Karyokinesis | The division of the nuclear material. |
Cytokinesis | The cytoplasm is then divided into two new cells. |
1) Interphase | Time for growth and activity between divisions. There is a distinct nuclear membrane, chromatin material and one or more nucleoli. Duplication of DNA |
2) Prophase | Disappearance of the nuclear membrane and the formation of chromosomes from the chromatin. Each chromosome consists of two chromatids held together by a centromere. Centrioles move apart. |
3) Metaphase | The alignment of the chromosomes along the equatorial plane of the cell and by the symmetrical spindle. In human cells - 92 chromatids during prophase and metaphase. Chromatid pairs line up along the mid-line of the cell. |
4) Anaphase | Separation of chromatids to become chromosomes and by the migration of these chromosomes along the spindle fibers to opposite poles of the cell. Two separate groupings of chromosomes. Cleavage furrow and two nuclei are visible. |
5) Telophase | Completes the mitotic process. Two identical sets of chromosomes are clustered at each pole. Two daughter cells are formed as a result. Chromosomes move to the opposite poles of the cell. |
Gene | Is a piece of DNA that carries the instructions for making one polypeptide (protein). Can be up to 1,000 genes on one chromosome. |
Nucleotides | Structural units of DNA and RNA. Each nucleotide consists of three components - a phosphate group, five-carbon sugar and a base. |
Deoxyribose | Sugars in DNA |
Ribose | Sugars in RNA |
DNA/RNA base | Contain nitrogen and are either purines or pyrimidines. |
Purine bases | Adenine and Guanine |
Pyrimidine bases | Cytosine, Thymine and Uracil (ONLY IN RNA) |
(A) Adenine in DNA | (T) Thymine |
Adenine in RNA | (U) Uracil |
(C) Cytosine | (G) Guanine |
mRNA | Messenger RNA, involved in TRANSCRIPTION. Used to separate the gene involved into two separate strands. |
tRNA | Transfer RNA, used to pair up the separate strand with its corresponding strand. |
Codon | Three adjacent nucleotides. Usually specifies one of the 20 amino acids. There are a possible 64 codon combinations. |
Anticodon | tRNA carries a specific codon which will then match up with the corresponding mRNA. Translation occurs when the two are then bonded. |
Methionine | codon is AUG, always starts a new sequence |
Stop | UAA, UAG or UGA, stopping point |