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Explore the structure and functions of cells, including the organelles involved in synthesis and homeostasis. Learn about cellular size limits, organelles like nucleus and ribosomes, and the role of mitochondria and chloroplasts. Dive into topics such as cytoskeleton composition and cell wall structure in plants.
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Cellular Architecture Or the typical/nontypical cell
I. Limits to cell size • Surface to volume ratio 1. function of membrane 2. relationship of surface area to volume 3. consequences of growing too large
1 mm 2 mm 2 mm 1 mm Figure 4-2Page 68
I. Limits to cell size • Control issues • Informational flow • Transcription • Diffusion • Translation • Cell gets too large, lag time in the control of activities • Analogy
II. Few Generalizations • A. Procaryotic vs. eukaryotic • B. Typical cell • 1. animal • 2. plant • 3. discuss the similarities first
III. Organelles of synthesis • A. Introduction • 1. Going to act as an assembly line • 2. Nucleus • 3. Endoplasmic reticulm • 4. ribosome • 5. Golgi apparatus
III. Organelles of synthesis • Nucleus-headquarters 1. chromatin 2. chromosomes 3. nucleolus 4. double membrane with pores
III. Organelles of synthesis • C. Endoplasmic Reticulum • 1. definition • 2. nickname • 3. types of • Rough • Smooth
III. Organelles of synthesis • D. Ribosomes-protein synthesis • 1. found free in cytoplasm-endogenous use • 2. attached to E.R.-proteins for export • 3. responsible for translation of mRNA into protein
III. Organelles of synthesis • D. Golgi Body or Golgi Apparatus • 1. nick name of bottling center • 2. modifies product • 3. concentrates product • 4. packages product into vesicles • 5. exports via exocytosis
III. Organelles of synthesis • E. Cell membrane with exocytosis
IV. Organelles of homeostasis • A. Mitochondria • Nickname • Structure • Endosymbiosis • More active tissue • Both animal and plant
B. Chloroplasts • Nickname • Structure • Endosymbiosis
Cell wall Plasma membrane Vacuole Granum Stroma Nuclear envelope Nucleolus Smooth ER Nuclear pores Chromatin Rough ER Nucleus Figure 4-7(2)Page 72 Ribosomes Rough and smooth endoplasmic reticulum (ER) Chloroplast
C. Lysosome • Nickname • Structure • Functions
D. Peroxisomes • Similar in appearance to lysosomes • Contain enzymes important in lipid breakdown • Detoxification centers • Possess enzyme catalase important in the breakdown of hydrogen peroxide
E. Cytoskeleton Composed of microtubules and microfilaments
1. Microtubules • “Skeleton” of the cell • Produce the structural framework for cilia and flagella
1. microtubules • Act as a railway along which organelles travel • Microtubules may walk past one another • Motor molecules may transport organelles from one area of the cytoplasm to another
2. microfilaments • “muscles” of the cell • Same proteins that are found in our muscles
Microfilaments (cont) • produce swaying of microvilli • Movements of cytoplasmic streaming
Relationship of the cytoskeleton to the cell membrane and extracellular fibers
F. Cell wall of plant cells • Primary cell wall • Secondary cell wall • Middle lamellae pectin • Importance of plasmodesmata
I. Cilia and flagella • Microtubules • 9 +2 • Triplets in basal body • Form from centrioles?