Chapter 4 Cell Biology

Chapter 4 Cell Biology I.

Cells – basic unit making up all living things. A. Unicellular = 1 celled B. Multicellular = many celled

II.

History of CELL THEORY A. 1st scope 1600 by Galileo – compound consisting of 2 lenses B. Robert Hooke – 1st observed cork and used the term cells to describe small boxes he saw magnified 20x the eye! 1. Year 1665 C. Anton Can Leeuwenhoek – lens maker, his scopes magnified 200x greater than Hooke’s. 1. 1st to see single-celled creatures swimming in pond H2O. 2. 1st to take scrapings from his teeth and saw creatures. D. Robert Brown – discovered a central structure was in all cells (orchid leaves). Today we call it nucleus. E. Matthew Schneider – observed plant tissue and hypothesized that ALL plants are made of cells. F. Theodore Schwann - observed animal tissue and hypothesized that ALL plants are made of cells G. Rudolf Virchow – cells reproduce to form new cells.

III.

Cell Theory (Pg. 70) A. All organisms are made opf one or more cells B. Cells are the basic unit of structure and function of all organisms

C. New cells come from existing cells by reproduction. IV.

Internal Organization A. Organelles – tiny structures inside cells. specific function.

Each has a

B. 2 basic kinds of cells 1. Prokaryotes – small, simple cells, do not contain membrane bound organelles. 2. Eukaryotes – larger cells containing membrane bound organelles. V.

Cell Structures A. Cell membrane (plasma) 1. Outer layer in animal cells. 2. 2nd layer in plant cells. 3. Functions a. Allows only certain materials in and out of the cell. b. Gives shape 4. Composed of 2 lipid layers and proteins 5. Double layer of phospholipids a. Have polar hydrophilic water loving b. Have nonpolar hydrophobic water hating. a. Allows cell membrane to be selectively permeable c. Between fatty acids is cholesterol. 6. Plasma membrane proteins embedded in lipid layer = integral proteins. a. Cell surface markers – identifies each cell type. (sit on outside only)

b. Receptor proteins – recognizes and bends to substances outside the cell. c. Transport proteins – substances move across cell membrane. B. Nucleus – largest object in the cell, contains the chromosomes. JOB: to control ALL activities of the cell. 1. Nucleoplasm – liquid inside 2. Nuclear envelope (membrane) a. Double layered; regulates materials in and out of the nucleus. 3. Nucleolus – rounded body in nucleus. producing ribosomes.

JOB:

4. Chromatin – very thin strands of DNA.

I.

Cytoplasm Organelles A. Mitochondria – powerhouse of the cell – site of cellular respiration where food is converted to energy. B. Endoplasmic Reticulum (ER) – network of canals. to move materials around inside the cell. C. Ribosomes – found on ER.

JOB:

JOB: makes proteins

D. Golgi apparatus – flat, sac like; found near ER. proteins (packages) and stores them.

JOB:

E. Lysosomes – storage for enzymes to break down organic food particles, foreign matter which invaded the cell (germs) or worn out or damaged cell parts. F. Centrioles – used during cell reproduction. only in animal cells.

Found

G. Microfilaments – very thin, thread like fibers made of protein and found in bundles below cell membrane. JOB: allows more flowing movement of materials within the cytoplasm called cytoplasmic streaming. H. Microtubules – hollow, pipe like; gives shape, also aids in locomotion. (ON OUTSIDE) 1. 2 kinds of microtubules a. Cilia – short, hair like for locomotion b. Flagella – whip like hair for locomotion II.

Organelles found in plant cells A. Large H2O storage vacuoles B. Plastids – large storage areas or chemical factories. 1. Chloroplasts – green bodies mainly found in leaves. JOB: site of photosynthesis. 2. Chromoplasts – contain pigments of red, yellow, red for color. 3. Leucoplasts – storage for oils and starches. C. Cell wall – outer layer in plant cells only composed of cellulose, many, many simple (glucose) sugars (called a polysaccharide).