Lecture 1 Notes

Lecture 1 Notes - Lecture 1(September 28 Introduction 1(Genetics and Cell Nucleus Chapters 1 4 5 6 7 Chapter 1 The single cell vehicle for the

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Lecture 1 (September 28): Introduction 1 (Genetics and Cell Nucleus) - Chapters 1, 4, 5, 6. 7 Chapter 1 - The single cell – vehicle for the hereditary information that defines the species – specified by this information, the cell includes the machinery to gather raw materials from the environment, and to construct out of them a new cell in its own image, complete w a new copy of the hereditary information the hereditary information in the fertilized egg cell determines the nature of the whole multicellular organism - Primordial eukaryotic cell was possibly a predator, living by capturing other cells and eating them o o (Figure) a) Didinium is a carnivorous protozoan, belonging to the group known as ciliates . It has a globular body, about 150 um in diameter, encircles by 2 fringes of cilia – sinuous whiplike appendages that beat continually; its front end is flattened except for a single protrusion, rather like a snout. b) Didinium normally swims around in the water at high speed by means of the synchronous beating of its cilia. When it encounters a suitable prey, usually another type of protozoan, it released numerous small paralyzing darts from its snout region. Then, the Didinium attaches to and devours the other cell by phagocytosis, inverting the like a hollow ball to engulf its victim, which is almost as large as itself. - A predatory way of life helps to explain another feature of eukaryotic cells – Almost all such cells contain mitochondria – these small bodies in the cytoplasm, enclosed by a double layer of membrane, take up oxygen and harness energy from the oxidation of food molecules – such as sugars – to produce most of the ATP that powers the cell’s activities. Mitochondria are similar in size to small bacteria, and, like bacteria, they have their own genome in the form of a circular DNA molecule, their own ribosomes that differ from those elsewhere in the eukaryotic cell, and their own transfer RNAs. It is now generally accepted that mitochondria originated from free- living oxygen-metabolizing (aerobic) bacteria that were engulfed b an ancestral eukaryotic cell that could otherwise make no such use of oxygen (that is, was anaerobic). – these bacteria evolved in symbiosis w the engulfing cell and its progeny, receiving shelter & nourishment in return for the power generation they performed for their hosts – partnership is thought to have been established 1.5 billion years ago, when the Earth’s atmosphere first became rich in oxygen
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o - Many eukaryotic cells – specifically, those of plants and algae – also contain another class of small membrane-enclosed organelles somewhat similar to mitochondria – the chloroplasts. Chloroplasts perform photosynthesis using the energy of sunlight to synthesize carbohydrates
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This note was uploaded on 11/22/2010 for the course BIOLGY BICD 110 taught by Professor Yiminzou during the Spring '10 term at UCSD.

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Lecture 1 Notes - Lecture 1(September 28 Introduction 1(Genetics and Cell Nucleus Chapters 1 4 5 6 7 Chapter 1 The single cell vehicle for the

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