cell structure and function biology 103. i. the development of the cell theory 1. robert hooke...

Cell Structure and FunctionBiology 103

I. The Development of the Cell Theory 1. Robert Hooke (1665) - observed cork

2. Anton van Leeuwenhoek (1673) saw microscopic life - blood cells, single cell organisms

3. Mathias Schleiden, Botanist & Theodor Schwann, Zoologist, (1839) published their cell theory …"The cells are organisms, and animals as well as plants are aggregates of these organisms arranged in accordance with definite laws."

4. Rudolph Virchow (1858) "omnis cellula e cellula" --all cells come from cells

II. Cell History1.The first cells were prokaryotic (= “before nucleus”) cells that appeared on the earth about 3.5 to 4.0 BYA.

2. More complex eukaryotic (=“true nucleus”) cells appeared about 1.5 BYA.

| euykaryotes | oxygen | first cells | formation of earth

5 4 3 2 1 0Billions of Years Ago

III. Eukaryotic Cell Structure

1. Cell membrane: surrounds cell, controls the movement of substances in and out, structure:

phospholipid bilayer with protein carrier proteins and receptors embedded (a fluid mosaic)

2. Nucleus: information storage: DNA synthesis, surrounded by nuclear envelope. May contain a nucleolus - indicates active protein synthesis

3. The Cytoplasm is everything in the cell except the nucleus,

4. Mitochondrion (plural = Mitochondria) converts carbohydrates into ATP (high energy molecules) Maternal origin, two compartments

Copyright 2008 John Wiley & Sons

The cell membrane surrounds the cell

The fluid mosaic model of the cell membrane


DNA is stored as chromatin• When not dividing, the nucleus is filled with threads

of chromatin– Chromosomes condense before cellular division


Nuclear Envelop surrounds the chromatin

The nuclear envelop is a double-walled membrane studded with nuclear pores

Most DNA is inside the nucleus


Large Molecules leave the nucleus through nuclear pores


The information in the nuclear DNA is copied to mRNA (messenger RNA). mRNA leaves the nucleus via nuclear pores


Once in the cytoplasm mRNA is used to direct protein synthesis in the rough endoplasmic reticulum

Mitpchondria make most of the ATP in the body

5. Special Mention: Chloroplasts chlorophyll and are the site of photosynthesis. Why are chloroplasts important? 6. Ribosomes: help make proteins during RNA translation, made of protein and RNA - give rough ER its appearance

7. Endoplasmic reticulum (two types): smooth - lipid synthesis rough - protein sorting processing


ER and membrane cycling

8. Golgi Apparatus: Packages and sorts proteins from rough ER for export from cell or to other cell compartments

9. Lysosomes and Peroxisomes: contain digestive enzymes

10. Cilia and Flagella: create movement

11. Centrioles: organize Cilia and Flagella

12.Cytoskeleton: supports cell: a),microtubules; b) microfilaments; and c) intermediate fibers

13. Plants have a cell wall, animal cells do not. Cell walls resist osmotic forces.

IV. Cell Junctions

1. Tight junctions 2. Gap junctions 3. Desmosomes

V. Transport functions

1. Diffusion2. Facilitated Diffusion3. Osmosis4. Active Transport: requires ATP5. Vesicular Transport: Endocytosis and Exocytosis


Diffusion equalizes solute concentrations

• Molecules diffuse down their concentration gradient from areas of high concentration to areas of low concentration.


Facilitated diffusion allows water soluble molecules to cross the

membrane with transport proteins that use no energy


Osmosis: movement of water

• Hypotonic solutions – Cells swell

• Hypertonic solutions– cells shrink

• Isotonic solutions– cells neither shrink nor

swell


Active transport takes ATP


Endocytosis (two types)

a. Pinocytosis (cell drinking)

b. Phagocytosis (cell eating)

Exocytosis Removes products from the

cell

VI. Surface to Volume Ratio

cell structure and function biology 103. i. the development of the cell theory 1. robert hooke...

Documents

surrounds cell

cell junctions

cell theory

cell walls

cell history1

cell compartments

cell membrane copyright

eukaryotic cell structure1