To investigate cells macroscopically Agenda: 2/19 Homework: Thursday – Lab notebooks with Dissecting Egg Friday Test: Cell function & structure To investigate cells macroscopically After the lab Cells – structure and function Presentation Video

“Dissecting a “Cell” and Examining Its Components Lab procedures pp. 14-16 Biotechnology Laboratory Manual Ellen Daughtery

After Lab Review

“Dissecting a “Cell” and Examining Its Components What do you think these eggs represent? (Sized to scale) 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.

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.

VITELLINE MEMBRANE 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 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 molecule Positive 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 protein Interpret the colors Observations and Interpretation                                                                                                                                     Biuret indicator for protein Interpret the colors

Biuret indicator for protein Observations and Interpretation                                                                                                                                     Biuret indicator for protein Positive test: blue to purple = protein presence blue to pink = amino acids (building blocks of proteins Negative test: remains blue

Class notebook Date Topic Page 2/10 Inside the Cell – Table What is a cell? Notes from video & presentation 2/11 Warm-up: Probe: Speculation on what happened 2/19 Types of cells- prokarylotic & eukaryotic compare plant & animal cells Cells Structure and Function - Organelles Voyage into the cell – video notes

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 Bacteria Red Blood Cell Nerve Cell

Prokaryotic Eukaryotic 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

“Typical” Plant Cell http://waynesword.palomar.edu/images/plant3.gif

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