Agenda: 2/19 To investigate cells macroscopically –After the lab Cells – structure and function...

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