chapter 7 – the cell i.a view of the cell a.contributing scientists who came up with ideas about...
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Chapter 7 – The Cell
I. A View of the CellA. Contributing Scientists who came
up with ideas about the cell:1. Hooke (1665) – first saw cork
cells & named the tiny boxes “cells” after monk’s rooms in a monastery
2. Leeuwenhoek (1683) – saw cells using a microscope which he invented
3. Schleiden (1838) – said cells compose every part of a
plant
4. Schwann (1839) – said cells compose every part of an animal
5. Virchow (1855) – said cells only come from other cells
B. The Cell Theory – 3 parts:
1. All organisms are made of 1+ cells
2. Cells are the basic unit of structure & organization of all living organisms (a cell is the simplest living part)
3. All cells come from pre-existing cells, & pass copies of genetic information on to daughter cells
C. 2 Cells Types:
1. Prokaryote – No true nucleus nor organelles; DNA not separated by a membrane (only Bacteria)
2. Eukaryote – has a true nucleus and organelles (all cells, besides Bacteria)
II. The Cell is like a Factory
A. Cell/Plasma Membrane (Doors):
maintains homeostasis by regulating what goes in & out of the cell (selectively
permeable)
B. Nucleus (Boss): contains directions for the cell’s operations
C. Nucleolus (Boss’ Assistant): inside nucleus, it makes ribosomes
D. Chromatin (Blueprints): inside nucleus; are strands of DNA with directions for cell
E. Cytoplasm (Air): jellylike fluid that fills the cell
F. Mitochondria (Generator): makes energy (ATP) for the cell/our body
G. Golgi Body (Assembly Line): packages cell products
1. Vesicles (trucks): distribute
cell products
H. Centriole (Boss’ wife): helps in cell reproduction
I. Cytoskeleton (steel frames in brick walls): stick-like microtubules & microfilaments support the cell like a skeleton
J. Lysosome (cleanup crew w/ garbage cans): digest wastes
K. Ribosomes (Cooks): make protein
L. Endoplasmic Reticulum (Vending
Machines):
1. Smooth ER (olive oil): no ribosomes, makes fats
2. Rough ER (cheese): has ribosomes, makes proteins
III. Parts found only in Plant Cells:
A. Cell Wall (Bricks): – rigid for support
B. Vacuole (Warehouse): – filled w/ fluid & stores water and waste
C. Chloroplast (Solar Panels): makes glucose through photosynthesis; green due to chlorophyll
Let’s check out these for Review:
The Cell Song https://www.youtube.com/watch?v=rABKB5aS2Zg
Cells Cells – Parts of the Cell https://www.youtube.com/watch?v=-zafJKbMPA8
Cells from Other Cells https://www.youtube.com/watch?v=BTicXXxzQA4
Chapter 7 – The Microscope
Before microscopes were invented, people believed that diseases were caused by curses and spirits
I. Types of Microscopes (2)A. Light Microscope – has a series of
lenses to magnify objects in steps1. light passes thru object being observed2. object can be living or dead3. magnifies up to 1500x (ours 400x)4. Total Magnification = Eyepiece x Lens
B. Electron Microscope (EM) – a beam of electrons is focused by magnets to enlarge an image
magnifies objects up to 500,000x object is placed in a vacuum, so it is
often dead when viewed costs about $25,0001. Transmission EM (TEM) –
electrons pass thru object; 2D views
2. Scanning EM (SEM) – electrons bounce off surface of
object; 3D views
3. Scanning Tunneling EM (STM) – electrons “tunnel” through living specimens; sees
atoms
4. Atomic Force Microscope (AFM) – measures force b/t probe and specimen
Changes the objectives
Magnify the image
Holds slide in place
Controls amount of light
Illuminates the specimen
Used to carry the microscope
Supports the slide
Rough focus for low & medium
Detailed focus
Supports the microscope
Magnifies image
III. Using the Microscope1. Turn the light switch on and put the
slide onto the stage2. Start with the lens in low power3. Focus the specimen using coarse,
then fine adjustment4. Rotate the nosepiece to medium
power5. Focus the specimen using coarse,
then fine adjustment6. Rotate the nosepiece to high power7. Focus the specimen using FINE
adjustment ONLY