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41 Cards in this Set
- Front
- Back
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What is the cell cycle? |
The period of time between one cell division to the next. |
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Two major periods of cell growth. |
1. Interphase period of cell growth.
2. Mitotic Phase period of cell reproduction M phase. |
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Interphase? Also steps. |
Metabolic growth phase.
1. G-1 or Gap phase 1. 2. S or Synthesis phase 3. G-2 or gap phase 2
G0 phase means cells have left this cycle.
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Explain Gap Phase 1 |
Interphase step 1 where after cell division
- proteins synthesized - vigorous growth - most growth happens here - at the end centrioles replicate to 4. |
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Explain Synthesis Phase (S) |
Interphase step 2:
DNA replicates in this stage. |
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What are the steps of the DNA replication that takes place in the Interphase Synthesis Phase? (S) |
1. DNA uncoils 2. Hydrogen bonds holding the bases are broken by enzymes 3. DNA seperates into 2 chains 4. new nucleotides attach to the complementary base. 5. Enzymes catalyze hydrogen bonds to hold bases together.
Uses ATP!!! |
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What is the law of complimentary base pairing? |
Basically the dna is split in 2, and nucleotides attach to each half replicating what is there. |
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Steps of DNA replication more detail: |
1. DNA helicase opens short segment of helix.
2. DNA polymerase assembles new strand of DNA next to the old.
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What is a DNA semiconservative replication mean? |
That each replication contains halffrom the parent DNA. |
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What do polymerase molecules do to the 46 chromosomes? |
It replicates them by teaming up with thousands of other polymerase molecules. This takes about 6 to 8 hours. |
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Explain the Interphase gap phase 2 |
Final brief phase of growth!. - Proteins and Enzymes are moved to proper sites. - Interphase ends with this phase and leaves the cell prepared for mitotic process! |
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Explain the Mitotic phase. |
Involves nuclear divison and cell division. 1 cell into 2 with identical copies of DNA. |
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What are the two phases of the mitotic phase? |
Mitosis (nuclear division)
Cytokinesis (Cell division)
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List the 4 phases in the Mitiotic.Mitosis phase |
1. Prophase 2. Metaphse 3. Anaphase 4. Telophase |
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Explain functions of mitiotic.mitosis |
- one cell divides into 2
- Functions + embryonic development + tissue growth + replacement of dead cells + repair of injured tissues |
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Explain mitiotic.mitosis.prophase.1 |
Longest of mitiotic phase.
1. Centrioles move to opposite side of cytoplasm. 2. Chromatin coils into genetically identical paired sister chromatids.
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Explain mitiotic.mitosis.prophase.2 |
1. Nuculear envelope disintegrates. 2. Centrioles sprout microtubules that push them away from each other and towards poles of cell.
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Explain mitotic.mitosis.metaphase |
Short phase when chromosomes cluster towards center of cell. |
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Explain mitotic.mitosis.anaphase |
Shortest phase when the chromosomes split and each chromatid becomes a single chromosone.
Microtubules shorten and move chromozome towards pole of cell. |
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Explain mitotic.mitosis.telophase |
1. Starts when chromatids arrive at poles. 2. Chromatids uncoil 3. New nuclear envelopes formed by rough ER 4. Mitotic spindle breaks down 5. nucleus forms nucleoli |
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Explain Cytokinesis |
Division of cytoplasm into 2 cells.
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Explains steps of cytokinesis |
1. Myosin pulls on microfilaments of actin in the membrane skeleton creating a crase called cleavage furrow.
2. Cell pinches in two.
Moves into G-1 interphase. |
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What causes cell division? |
Surface-Volume relationship... - some critical size is reached where the cell can't hold any more stuff.... and then some biological trigger starts the cell division! |
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When do cells divide? |
1. have enough cytoplasm for 2 daughter cells. 2. dna has replicated 3. enough nutrients 4. open space. |
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When do cells stop dividing? |
1. loss of growth factors or nutrients 2. contact with other cells stops them from growing. (contact inhibition.) |
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What is cell differentiation? |
All cells are highly specialized! This process is not understood and causes cells to be different. |
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Function: DNA |
- Code for protein synthesis. - Composed of genes (sequence of dna to make one protein) - Genome is all the genes that we have. |
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What do proteins do in regards to cells? |
- Proteins determine chemical and physical nature of all cells. |
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What does DNA do in regards to protein? |
Dictates protein construction. |
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What does each gene represent on DNA? |
A sequence of neucleotides.
Carries the instructions for the synthesis of 1 polypeptide chain. |
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What is protein synthesis? |
The creation of proteins that starts in the nucleus and ends in the cytoplasm. |
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What are the 2 processes involved in protein synthesis? |
1. Transcription 2. Translation |
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Process: protein_synthesis.transcription |
Messenger RNA mRNA is formed next to activated gene and then it migrates to the cytoplasm. |
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Process: protein_synthesis.translation |
mRNA is read by ribosomal RNA as amino acids are assembled into a protein molecule.
transfer RNA delivers the amino acids to the ribosome. |
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3 Types of RNA |
messenger: mRNA long, single string of nucleotides.
ribosomal - rRNA - forms part of ribosomes.
Transfer: tRNA - small clover shaped molecule.
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STEPS OF TRANSCRIPTION!: |
1. RNA polymerase binds to DNA 2. RNA polymerase opens DNA and transcribes into pre-mRNA DNA (C) -> mRNA(G) DNA(A) -> mRNA(U) 3. rewinds DNA Helix 4. introns removed, exons connected. 5. exit nucleus |
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What are introns? What are exons? |
"nonsense" in pre-mRNA" "sense" in pre-mRNA
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Final version of transcription of protein synthesis: |
1. DNA molecule uncoils. 2. Strands separate. 3. RNA nucleotides attach to complementary DNA bases. 4. After order of nucleotides established 5. Hydrogen bonds split. 6. New mRNA moves out of nucleus. 7. DNA recoils into helical form. |
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Protein Synthesis: Translation |
1. mRNA carries genetic code from nucleus w/ protein cap passport. 2. tRNA binds mRNA and delivers to ribosome. 3. Ribosome "little reading machines" |
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What is a polyribosome? |
cluster of 10-20 ribosomes reading mRNA at one time. |
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What is Signal peptide? |
begining of chain of amino acids. determines proteins destination within the cell. |
