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Agenda: 2/19
• To investigate cells macroscopically– After the lab
• Cells – structure and function – Presentation – Video
Homework: Thursday – Lab notebooks with Dissecting Egg
Friday Test: Cell function & structure
“Dissecting a “Cell” and Examining Its Components
Lab procedurespp. 14-16
Biotechnology Laboratory ManualEllen Daughtery
After Lab Review
A bird ovulates a single egg cell at a time.
The egg cell is what we call the yolk.
Most eggs are too small to be seen without the aid of a microscope.
However, we can study the chicken egg macroscopically.
“Dissecting a “Cell” and Examining Its Components
What do you think these eggs represent?
(Sized to scale)
Composition of a chicken egg
SHELL Bumpy and grainy in texture, an eggshell is covered with as many as 17,000 tiny pores. Eggshell is made almost entirely of calcium carbonate (CaCO3) crystals. It is a semipermeable membrane, which means that air and moisture can pass through its pores. The shell also has a thin outermost coating called the bloom or cuticle that helps keep out bacteria and dust.
INNER AND OUTER
MEMBRANES
Lying between the eggshell and egg white, these two transparent protein membranes provide efficient defense against bacterial invasion. If you give these layers a tug, you’ll find they’re surprisingly strong. They’re made partly of keratin, a protein that’s also in human hair.
ALBUMEN
The egg white is known as the albumen, which comes from albus, the Latin word for “white.” Four alternating layers of thick and thin albumen contain approximately 40 different proteins, the main components of the egg white in addition to water.
CHALAZAE Opaque ropes of egg white, the chalazae hold the yolk in the center of the egg. Like little anchors, they attach the yolk’s casing to the membrane lining the eggshell. The more prominent they are, the fresher the egg.
VITELLINEMEMBRANE
The clear casing that encloses the yolk.
YOLK The yolk contains less water and more protein than the white, some fat, and most of the vitamins and minerals of the egg. These include iron, vitamin A, vitamin D, phosphorus, calcium, thiamine, and riboflavin. The yolk is also a source of lecithin, an effective emulsifier. Yolk color ranges from just a hint of yellow to a magnificent deep orange, according to the feed and breed of the hen.
Main constituents (%) of edible part of a medium chicken egg:(Total caloric value 77 Kcal)
White %
Yolk %
Protein 10.9 16.5
Fats trace 32.0
Carbohydrates 1.0 1.0
Water 87.0 49.0
Nutrient content of large egg
Carbohydrate
Definition
Any of the group of organic compounds consisting of carbon, hydrogen, and oxygen, usually in the ratio of 1:2:1, hence the general formula: C H2 O. Examples include sugar, starch, cellulose and gums.
Indicator Tests
• Biology Labs ~ KCC Distance Learning Object
• Indicators: solutions that change color in the presence of another type of moleculePositive test
Negative test – no color change
Lugol’s Iodine Solution for Starch
• Turns from yellowish brown to blue-black in the presence of starch
Biuret indicator for proteinInterpret the colors
Observations and Interpretation
Biuret indicator for protein
Observations and Interpretation
Positive test: blue to purple = protein presence blue to pink = amino acids (building blocks of proteinsNegative test: remains blue
Date Topic Page
2/10 Inside the Cell – Table
2/10 What is a cell? Notes from video & presentation
2/11 Warm-up: Probe: Speculation on what happened
2/19 Types of cells- prokarylotic & eukaryoticcompare plant & animal cells
2/19 Cells Structure and Function - Organelles
2/19 Voyage into the cell – video notes
Class notebook
Cell Structure & Function
http://koning.ecsu.ctstateu.edu/cell/cell.html
Cell Theory
• All living things are made up of cells. • Cells are the smallest working units of all
living things. • All cells come from preexisting cells
through cell division.
Definition of Cell
A cell is the smallest unit that is capable of performing life
functions.
Examples of Cells
Amoeba Proteus
Plant Stem
Red Blood Cell
Nerve Cell
Bacteria
Two Types of Cells
•Prokaryotic•Eukaryotic
Prokaryotic
• Do not have structures surrounded by membranes
• Few internal structures
• One-celled organisms, Bacteria
http://library.thinkquest.org/C004535/prokaryotic_cells.html
Eukaryotic• Contain organelles surrounded by membranes
Plant Animal
http://library.thinkquest.org/C004535/eukaryotic_cells.html
How do plant and animal cells differ?
Examine the following slides. Compare and contrast the cells.
“Typical” Animal Cell
http://web.jjay.cuny.edu/~acarpi/NSC/images/cell.gif
http://waynesword.palomar.edu/images/plant3.gif
“Typical” Plant Cell
Cell Parts
Organelles
Surrounding the Cell
Cell Membrane
• Outer membrane of cell that controls movement in and out of the cell
• Double layer
http://library.thinkquest.org/12413/structures.html
Cell Wall
• Most commonly found in plant cells & bacteria
• Supports & protects cells
http://library.thinkquest.org/12413/structures.html
Inside the Cell
Nucleus
• Directs cell activities• Separated from cytoplasm by nuclear
membrane• Contains genetic material - DNA
Nuclear Membrane
• Surrounds nucleus• Made of two layers• Openings allow
material to enter and leave nucleus
http://library.thinkquest.org/12413/structures.html
Chromosomes
• In nucleus• Made of DNA• Contain instructions
for traits & characteristics
http://library.thinkquest.org/12413/structures.html
Nucleolus
• Inside nucleus• Contains RNA to build
proteins
http://library.thinkquest.org/12413/structures.html
Cytoplasm
• Gel-like mixture• Surrounded by cell membrane• Contains hereditary material
Endoplasmic Reticulum• Moves materials around
in cell• Smooth type: lacks
ribosomes• Rough type (pictured):
ribosomes embedded in surface
http://library.thinkquest.org/12413/structures.html
Ribosomes
• Each cell contains thousands
• Make proteins• Found on
endoplasmic reticulum (ER) & floating throughout the cell
http://library.thinkquest.org/12413/structures.html
Mitochondria
• Produces energy through chemical reactions – breaking down fats & carbohydrates
• Controls level of water and other materials in cell
• Recycles and decomposes proteins, fats, and carbohydrates
http://library.thinkquest.org/12413/structures.html
Golgi Bodies
• Protein 'packaging plant'
• Move materials within the cell
• Move materials out of the cell
http://library.thinkquest.org/12413/structures.html
Lysosome• Digestive 'plant' for
proteins, fats, and carbohydrates
• Transports undigested material to cell membrane for removal
• Cell breaks down if lysosome explodes
http://library.thinkquest.org/12413/structures.html
Vacuoles
• Membrane-bound sacs for storage, digestion, and waste removal
• Contains water solution
• Help plants maintain shape
http://library.thinkquest.org/12413/structures.html
Chloroplast
• Usually found in plant cells
• Contains green chlorophyll
• Where photosynthesis takes place
http://library.thinkquest.org/12413/structures.html
Voyage Inside the Cell
• http://www.youtube.com/watch?v=Ao9cVhwPg84
Cells 101: Business Basics
• Inside the Cell• Read and take Cornell notes
Using a Light Microscope to Study Cells
• A light or compound microscope used light and 2 or more lenses to enlarge and focus on an image.
• The eyepiece contains the ocular lens– Magnifies 10X
• The rotating lenses are 4X, 10X, 40X & 100X
• What magnification can be achieved?
Parts of the Microscope
See your notes: diagram and function