Principles of Biology - Biology 110
Lake Tahoe Community College
Intro to Cell and Molecular Biology
Instructor: Sue Kloss
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Ch. 4 - Introduction to Cells/Organelles, Structure, Movement
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I. Introduction to cells
A. Cell size relates to function
B. Natural limits on cell size
C. Prokaryotic cells (bacteria and archaea) most are 2 - 8 um in length
D. Eukaryotic cells avg. about 20 - 80 um in length
1. Variety of structures in cytoplasm
2. organelles
3. cellular metabolism - occur in organelles or on surfaces
4. partitioning
5. Eukaryotic cells have about 10x the diameter of prokaryotes,
6. Plant and Animal cell differences
Both have
Nucleus
Rough ER
Smooth ER
Ribosomes
Peroxisome
Cytoskeleton
Plasma membrane
Golgi apparatus
Mitochondrion
Only Animal Cells
(some exceptions)
Lysosomes
Flagella
Centriole
Only Plant Cells
Cell Wall
Central vacuole
Chloroplast
E. Membrane structure and function
1. fluid mosaic of lipids and proteins
2. selectively permeable
III. Eukaryotic cells - Organelles of the Endomembrane system
A. Nucleus - genetic control center
1. chromatin
2. chromosomes
3. nuclear envelope
4. nucleolus
B. Endomembrane system
1. many organelles work together in synthesis, storage and export of imp. molecules
C. Endoplasmic reticulum
Continuous membrane constitutes:
1. rough er - studded with ribosomes;
2. smooth er C. Golgi apparatus - close partner to ER
D. Lysosomes (Gr. - breakdown body)
1. produced by ER and Golgi apparatus
2. consists of hydrolytic enzymes (Digestive) in a membranous sack
3digestive functions
E. Vacuoles function in genl
IV. Organelles that convert energy
A. Chloroplasts - convert light to chemical energy in plants and some protists and algae
B. Mitochondria - convert chemical energy from one form to another e.g. food to ATP
1. ATP main currency
2. 2 membranes
3. mitochondrial matrix
V. Cytoskeleton - meshwork of fine fibers for structure and movement
A. Microfilaments
1. help cells change shape
2. interact w. other proteins
B. Intermediate filaments - varied group
1. act as reinforcing rods
2. hold certain organelles in place
C. Microtubules -straight hollow tubes
VI. Cilia and flagella move when microtubules bend
A. Cilia - short numerous appendages
B. Flagella - longer less numerous for propulsion
VII. Cell Surfaces and Junctions
A. Cell walls in plants
B. Cell junctions connect one cell to another
1. Plasmodesmata in plants
2. () Extracellular matrix in animal cells -
Due: Second meeting week 3
Homework Questions/Lesson Objectives for Chapter 4 - A Tour of the Cell
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1. Define cell theory.
2. Explain why cell size and shape varies.
3. Explain why there are both upper and lower limit to cell size.
4. Distinguish between prokaryotic and eukaryotic cells.
5. Explain why compartmentalization is important in eukaryotic cells.
6. Compare the structures of plant and animal cells.
7. Describe the structures and functions of the organelles of the endomembrane system - the nucleus, endomembrane
system, rough and smooth endoplasmic reticulum, Golgi apparatus, and lysosomes.
8. Compare the structures and functions of the energy converting organelles - mitochondria and chloroplasts.
9. Compare the structures and functions of cytoskeleton structures - microfilaments and microtubules.
10. Explain how structures of cilia and flagella relate to their functions.
11. Compare structures of cell surfaces and intracellular junctions in animals and plants.