Genetics review exam 1

Genetics review exam 1 - Caroline or Halley Cell Division...

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Caroline or Halley Cell Division Justin I. The relationship between volume and surface area of the Cell - Volume expands faster than surface area…so as a cell grows there is proportionately less surface area of the membrane, which makes it harder to remove waste and obtain nutrients…there is a point at which the cell becomes inefficient -cells divide so that they maintain a proper SA:V ratio; otherwise, cells would have insufficient surface area to absorb nutrients in great enough quantities to provide the necessary energy for their large volume. II. Procaryotic (bacterial) cell division - also called Binary fission is asexual; the organism splits directly into two equal-sized offspring, each with a copy of the parent's genetic material. The copies are separated by a mesosome, “middle body” or membrane hook that grabs on to each copy as the cell elongates. - Genetic material must be copied, separated, and divided. A cell revolves around genes of cell, because cell encodes all information needed to make cell membrane, cytoplasm, organelles, and all other essential factors for cell to function. - Differences between Prokaryotes and Eukaryotes: Eukaryotes have 4X more DNA; has several DNA molecules in its nuclear membrane; they are more complex; posses a nucleus and membranes bounded organelles such as chloroplast and mitochondria III. Chromosomal morphology A. Chromatids- Either of the two daughter strands of a replicated chromosome that are joined by a single centromere and separate during cell division to become individual chromosomes B .Centromeres- Arrangement of proteins which hold chromatids together, protein tubulin aid in holding chromatid together. 1. Metacentric – Centromere is centered in middle of two chromosomes. 2. Acrocentric (sub-metacentric)- Centromere is offset to either side of the middle of the chromosome. 3. Telocentric - The centromere is at the very end of the chromosome by the telomere. - Spindle – an array of tubulin proteins that attach to the kinetochore and pull the chromadits apart. B. Secondary constrictions and satellites IV. The cell in interphase A. The nuclear membrane -during interphase the chromosomes unravel, rendering indistinguishable segments of DNA.
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- A cell in Interphase spends about 85% of its life in interphase, and whether or not the cell enters a new phase is controlled by Cyclin-Dependent Kinases. B . Chromosome structure in interphase 1. "Beads on a string"- many histone cores with DNA wrapped around them resemble a string of beads. It is important to note that the DNA is mostly unraveled so that replication can take place. 2. Nucleosomes - after the DNA is wrapped around the histones, each unit is called a nucleosome a. DNA DNA remains partially condensed, even during most of interphase. b.
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This note was uploaded on 02/23/2009 for the course BIO 2306 taught by Professor Durhkopf during the Spring '08 term at Baylor.

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Genetics review exam 1 - Caroline or Halley Cell Division...

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