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29 Cards in this Set
- Front
- Back
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Chromatin |
- The material of which the chromosomes of organisms other than bacteria are composed - Consisting of protein, RNA, and DNA |
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Centrioles |
- Organize spindle fibres for movement of chromosomes during meiosis and mitosis - Located in a specialized region called the centrosome in animal cells |
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Spindle Fibres |
- Cytoskeletal structures that form during cell division to separate sister chromatids between daughter cells |
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Alleles |
- Alternative forms of the same gene - Arise by mutation - Found at the same place on the same chromosome |
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Interphase |
- Resting phase between mitotic divisions or first and second divisions of meiosis - Include G0, G1, G2, and S phases |
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G0 Phase |
- A period in the cell cycle in which cells exist in a quiescent state - G0 phase is viewed either as an extended G1 phase, where the cell is neither dividing nor preparing to divide, or a distinct stage that occurs outside of the cell cycle - A cell may remain for long periods of time in this stage - A cell in this stage has either: a) Postponed making a decision to divide b) Or made the decision to never divide again |
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G1 Phase |
- The first of four phases in the cell cycle - Part of interphase where the cell synthesizes mRNA and proteins in preparation for subsequent steps leading to mitosis |
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G2 Phase |
- The third and final stage of interphase - Follows the successful completion of S phase - Directly precedes mitosis |
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S Phase |
- Occurs between G1 and G2 phases - DNA is replicated |
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Karyokinesis |
The partitioning of genetic material into daughter cells during nuclear division |
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Cytokinesis |
Cytoplasmic division |
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Prophase (mitosis) |
- Centrioles divide and move apart - Nuclear envelope breaks down - Chromosomes condense and become visible |
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Prometaphase (mitosis) |
Chromosomes move to equatorial plane of the cell |
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Metaphase (mitosis) |
- Centromeres, chromosomes are aligned at the equatorial plane - Spindle fibres bound to kinetochores associated with centromeres are responsible for chromosome movement |
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Kinetochores |
The protein structure on chromatids where the spindle fibres attach during cell division to pull sister chromatids |
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Anaphase (mitosis) |
Sister chromatids separate from each other and migrate to opposite poles |
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Daughter Chromosomes |
Separate sister chromatids |
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Telophase (mitosis) |
- Cytokinesis - Uncoiling of the chromosomes - Re-formation of the nuclear envelope |
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Cyclins |
- A family of regulatory proteins that control the progression of cells through the cell cycle by activating Cdks |
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Cdks |
- Cyclin-dependent kinases - A family of protein kinases that play a role in regulating the cell cycle - Involved in regulating transcription, mRNA processing, and the differentiation of nerve cells - Binds the regulatory protein, cyclin - Cyclin-Cdk complex is an active kinase |
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Transcription |
- The first step of gene expression - A particular segment of DNA is copied into RNA (mRNA) by the enzyme RNA polymerase |
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Translation |
- The process by which a sequence of nucleotide triplets in a mRNA molecule gives rise to a specific sequence of amino acids during synthesis of a polypeptide or protein |
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RNA / DNA Polymerase |
Enzyme used to assemble DNA and RNA molecules by copying a DNA or RNA template strand using base-pairing interactions |
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Sense Strand |
The strand of DNA that has the same sequence as the mRNA, which takes the antisense strand as its template during transcription, and eventually undergoes (typically, not always) translation into a protein. |
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G1/S Checkpoint |
- Also known as the G1 checkpoint - A control mechanism that ensures proper division of the cell - At this checkpoint, conditions of the cell are assessed - Either delays G1 phase to enter G0 phase or proceeds past the restriction point |
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G2 Checkpoint |
- Also known as the G2/M checkpoint or the DNA damage checkpoint - Ensures the cell went through all the necessary changes during the S and G2 phases and is ready to divide |
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Metaphase Checkpoint |
- Occurs at the point in metaphase where all the chromosomes should have aligned at the mitotic plate |
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Tumour Suppressor Genes |
- Encode many cell checkpoint proteins |
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Checkpoint Proteins |
- Many are encoded by genes known as tumour suppressor genes - Detect abnormalities such as DNA breaks and improperly segregated chromosomes - Check the integrity of the genome and prevent cells from progressing past a certain point of the cell cycle if there is damage - Prevent mutations / mutant cells from surviving or dividing that otherwise may lead to uncontrolled cell proliferation and cancer |
