Cell Structure and Function

1. Cell Structure and Function • 1. The Cell Theory • A. All organisms composed of one or more cells • B. Cell is smallest living organizational unit • C. Cells arise only from division of other cells

2. Attributes of cells A. Plasma membrane B. DNA C. Cytoplasm D. Obtain energy and nutrients from their environment

3. Cell Size • 1–100µ • Cell Size • A. Limitations of molecular diffusion • 1. Faster passage through small cell • 2. More efficient communication • B. Limitations of surface-to-volume ratio • 1. With increase in size, greater increase in volume than surface area • a. Interaction with outside occurs only at surface • b. Insufficient exchange of materials at plasma membrane for survival

4. tallest trees adult human chicken egg frog embryo most eukaryotic cells mitochondrion most bacteria virus proteins diameter of DNA double helix atoms

5. Cell types Prokaryotic—no nucleus, circular DNA, ribosomes, peptiglycon-prokayotic cell wall • a. Carbohydrate matrix cross linked with peptide units • Eukaryotic—larger, nucleus, linear chromosomes, membraned organelles, • Compartmentalization • Include true bacteria • On earth 3.8 million years • Found nearly everywhere • Spores in each breath; intestines • Naturally in soil, air, hot springs

6. nucleoid (DNA) ribosomes food granule prokaryotic flagellum plasma membrane cell wall cytoplasm

7. Eukaryotic Cells • Have numerous internal structures • Various types & forms • Plants, animals, fungi, protists • Multicellular organisms Nucleus is control center of the cell • 1. Membrane bound (nuclear envelope) • 2. Contains nucleoli; synthesizes ribosomal RNA • 3. DNA in chromosomes (DNA and proteins)

8. 1. Plant cells • a. Square-geometric shaped • b. Cell wall- cellulose • c. Chloroplast • d. No centrioles • e. Large vacuoles

9. microtubules (part of cytoskeleton) mitochondrion chloroplast Golgi complex central vacuole smooth endoplasmic reticulum vesicle cell wall rough endoplasmic reticulum plasma membrane nucleolus nuclear pore nucleus chromatin nuclear envelope intermediate filaments free ribosome ribosomes

10. Animal Cells • a. Irregular shaped • b. Just Cell membrane • c. Small vacuoles • d. Centrioles

11. nuclear pore chromatin (DNA) nucleus nucleolus nuclear envelope flagellum intermediate filaments cytoplasm plasma membrane rough endoplasmic reticulum ribosome lysosome microtubules smooth endoplasmic reticulum Golgi complex free ribosome vesicle mitochondrion vesicle

12. nuclear envelope nucleolus nuclear pores chromatin

13. nucleus nuclear pores

14. chromatin chromosome

15. 0.05 micrometers

16. Eukaryotic cell structure • Organelles • Endoplasmic reticulum consists of folded membranes attached to the nucleus • Rough ER is site of protein synthesis and protein secretion. Proteins made here are processed and shipped out of the cell

17. Eukaryotic Cell Structure • Ribosomes assemble amino acid into polypeptide chains • a. Associated with the ER • b. Composed of RNA and proteins • Proteins for inside the cell

18. ribosomes rough endoplasmic reticulum 0.5 micrometers

19. vesicles smooth endoplasmic reticulum 0.5 micrometers

20. Eukaryotic Cell Structure • Golgi apparatus are membranous sacs associated with ER • Processing and transport of proteins, lipids exported from the cell • Synthesis and transport of polysaccharides • Lysosomes are Golgi-derived vesicles containing digestive enzymes

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22. vesicles from ER vesicles leaving Golgi complex Golgi complex

23. Energy sources for cell activities • Mitochondria provide energy for cellular functions (respiration) • a. Matrix/cristae • b. Have their own DNA and ribosomes; self- replicate • C. Bounded by double membrane-numerous • a. Outer membrane is smooth • b. Inner membrane is folded into contiguous layers called cristae • 1. Cristae are stuffed with 100,000 enzymes • 2. Site of cellular respiration-Oxidation • 3. Divides into inner matrix and outer compartment • 4. Associated with proteins of oxidative metabolism

25. 5 micrometers

26. Energy sources for cell activities • Chloroplasts—function in photosynthesis • 1) Green—contain chlorophyll pigment • 2) Stroma/grana (thylakoid stacks) • 3) Have their own DNA and ribosomes; self-replicate • 4) Up to 100 per cell • 5) Become leucoplasts when deprived of light • a. Specialized amyloplasts store starch • b. Plastids are derived from proplastids

29. Cytoskeleton • Cytoskeleton • Internal infrastructure • a. Actin filaments-microfiliments • a. Muscle movement • b. Pinches cell when it divides during cytokinesis • b. Microtubules • 1. Hollow tubes of 13 protein protofilaments-made of tubulin • 2. Function • a. Help move materials within the cell itself • b. Skeletal System • c. Aides in cell Division-spindle • d. Cilia, Flagella, sperm tails c. Intermediate filaments Surface structures extensions of the plasma membrane aid in movement of simple organisms

30. actin subunits subunit tubulin subunit

33. Prokaryotes & Eukaryotes • Similarities & differences • Both surrounded by plasma membrane, but very different • Prokaryotes – Archaebacteria and Eubacteria • Eukaryotes – everything else

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35. Evolution of Eukaryotic cell Endosymbiotic Hypothesis • Similarities between bacteria, mitochondria and chloroplasts • Self-reproducing by binary fission • Size of organism and genome • Single circular naked DNA • Proportion of (G & C) to (A & T) • Same sized ribosome • Protein synthesis inhibited by antibiotics • Enzymes for synthesis of DNA, RNA and protein • Electron transport system

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38. Plant & Animal Cells • Similarities Both constructed from eukaryotic cells ________________________________________________________________________________ Both contain similar organelles __________________________________________________________________________________ Both surrounded by cell membrane _________________________________________________________________________________

39. Plant & Animal Cells • Differences • Plants have • Cell wall – provides strength & rigidity • Have chloroplasts, photosynthetic • Animals have • Other organelle not found in plants (lysosomes formed from Golgi) • Centrioles, important in cell division

40. Brief Look at Viruses • Viruses are acellular • Not considered to be living • Cause serious diseases in most organisms