When a pigment absorbs light, electrons of certain atoms in the pigment molecules are boosted to a higher energy level. The energy of an absorbed photon is converted to the potential energy of the electron that has been raised to an excited state. In most pigments, the excited electron drops back to its ground-state, or normal orbit, and releases the excess energy as heat. Some pigments, including chlorophyll, emit light as well as heat after absorbing photons.
In the chloroplast, these excited electrons jump from the chlorophyll molecule to a protein molecule in the thylakoid membrane, and are replaced by electrons from the splitting of water. The energy thus transferred, is used in carbohydrate production.
This release of light is called fluorescence. Chlorophyll will fluoresce in the red part of the spectrum, and also give off heat. In this lab, you will observe this fluorescence by separating the chlorophyll from the thylakoid membrane.
MATERIALS
Spinach leaves
Flashlight or small lab light
Mortar and pestle
Test tube
Acetone
Filter paper
25-mL graduated cylinder
Funnel
Ring stand or funnel rack
Safety goggles
PROCEDURE
1. Grind the spinach leaves using a mortar and pestle.
2. Add acetone to the ground leaves, using enough acetone and spinach leaves to get between 10 and 15 mL of extract.
3. Set up your filtering apparatus, and using proper filtering technique, filter the extract to a test tube. NOTE: Use a small amount of acetone to wet the filter paper, to hold it into place, instead of water.
4. Shine a flashlight, or other similar light source, through the test tube and extract.
5. Observe the fluorescence of the chlorophyll at a 90 degree angle to the flashlight.
All chordates have a notochord, dorsal nerve cord, pharyngeal pouches, & postanal tail at some time in their life
Notochord is a firm, flexible rod of tissue located on the dorsal side of the body that becomes part of the endoskeleton in vertebrates
Dorsal nerve cord is a hollow tube lying dorsal to the notochord that becomes the brain & spinal cord in vertebrates
Pharyngeal pouches are small outpockets of the anterior part of the digestive tract that become gills in aquatic chordates & jaws, inner ear, & tonsils in terrestrial chordates
Postanal tail consists of muscle tissue & lies behind the posterior opening of the digestive tract
Subphyla of Chordates
The Phylum Chordata includes all of the vertebrates, as well as two groups of marine animals that lack backbones and are called invertebrate chordates
The phylum is divided into three subphyla, determined by the development of the notochord
Subphylum Cephalochordata contains about 24 species of blade-shaped animals known as lancelates that retain the notochord, dorsal nerve chord, pharyngeal pouches, and postanal tail throughout their life
Subphylum Urochordata contains 2,000 species commonly called tunicates because their bodies are covered by a tough covering, or tunic
* Called sea squirts because they shoot out a stream of water when touched
*Sessile, barrel-shaped, filter feeding animals that live on the sea bottom
*Adults have a pouch-like pharynx with slits
*Adults do not have a notochord, dorsal nerve cord, or postanal tail
Subphylum Vertebrata is the largest subphylum in which the notochord is replaced with vertebrae
* Skeletons consist of bone &/or cartilage
* Brain is protected by a cranium
* Well developed 4 chambered heart with a closed circulatory system
* Includes fish, amphibians, reptiles, birds, & mammals
Indicate whether the sentence or statement is true or false.
1.
Organelles enable eukaryotic cells to specialize.
2.
Chromatin carries a cell’s genetic information.
3.
Nucleoli produce the RNA of ribosomes
4.
Cells within a tissue carry out a common function.
5.
The ribosome is the site of protein synthesis within a cell.
6.
A unicellular organism is at a disadvantage when compared to a multicellular organism because a unicellular organism is unable to perform all life functions that a multicellular organism can.
7.
Cell membranes are totally permeable.
8.
As a cell gets larger, its volume increases at a faster rate than its surface area.
9.
ATP is produced primarily in mitochondria.
10.
The only difference between a plant cell and an animal cell is that plant cells have chloroplasts.
Multiple Choice
Identify the letter of the choice that best completes the statement or answers the question.
11.
Which of the following is not a function both multicellular and unicellular organisms can perform?
a.
coordinate the activities of organs
c.
produce other cells
b.
synthesize new living material
d.
regulate water balance
12.
Structures that support and give shape to cells are
a.
Golgi bodies
c.
basal bodies
b.
microtubules
d.
chloroplasts
13.
Which of the following functions are performed by both multicellular and unicellular organisms?
a.
regulating water balance
c.
producing other cells
b.
reacting to changes in the environment
d.
all of these
14.
What structures are associated with cell division?
a.
mitochondria
c.
Golgi bodies
b.
chloroplasts
d.
centrioles
15.
A complex network of membranes lying between the nuclear membrane and the cell membrane is
the
a.
mitochondria
c.
cristae
b.
chromosomes
d.
endoplasmic reticulum
16.
A particularly active cell might contain large amounts of
a.
chromosomes.
c.
mitochondria.
b.
vacuoles.
d.
walls.
17.
The cell membrane
a.
allows all substances to pass into and out of the cell
c.
is composed mainly of a protein bilayer
b.
prevents all substances from passing into and out of the cell
d.
is composed mainly of a lipid bilayer
18.
Sometimes these organelles are attached to the endoplasmic reticulum to form rough ER
a.
chloroplasts
c.
mitochondria
b.
ribosomes
d.
centrioles
19.
One difference between prokaryotes and eukaryotes is that
a.
nucleic acids are found only in prokaryotes.
b.
mitochondria are found in larger quantities in eukaryotes.
c.
Golgi vesicles are found only in prokaryotes.
d.
prokaryotes have no nuclear membrane.
20.
Cigar-shaped bodies in the cytoplasm known as centers of ATP production are
a.
Golgi bodies
c.
ribosomes
b.
mitochondria
d.
chloroplasts
21.
Which of the following cells would probably contain the greatest number of mitochondria
a.
stomach cells
c.
bone cells
b.
muscle cells
d.
red blood cells
22.
Any cell component that performs specific functions is called:
a.
an organelle
c.
a eukaryote
b.
a nucleus
d.
a microorganism
23.
Hooke’s discovery of cells was made observing
a.
living algal cells.
c.
dead plant cells.
b.
living human blood cells.
d.
dead protist cells.
24.
When the volume of a cell increases, its surface area
a.
increases at the same rate.
c.
increases at a faster rate.
b.
remains the same.
d.
increases at a slower rate.
25.
Cells that have a high energy requirement generally have many
a.
nuclei
c.
mitochondria
b.
flagella
d.
microfillaments
26.
Which organelles are a pathway for transport of materials
a.
endoplasmic reticulum
c.
mitochondria
b.
ribosomes
d.
Golgi bodies
27.
Which organelle selectively destroys tissue to shape the bodies of animals during early
development?
a.
lysosome
c.
cell membrane
b.
mitochondria
d.
ribosome
28.
The ends of this structure pinch off to form lysosomes
a.
endoplasmic reticulum
c.
Golgi bodies
b.
mitochondria
d.
centrioles
29.
A cell that can change its shape would be well suited for
a.
receiving and transmitting nerve impulses.
b.
covering the body surface.
c.
moving to different tissues through narrow openings.
d.
All of the above
30.
Which organelles store cellular secretions?
a.
endoplasmic reticulum
c.
Golgi bodies
b.
ribosomes
d.
centrioles
31.
Which of the following is not a specialized activity found in cells of Volvox (green algae) colonies?
a.
photosynthesis
c.
movement
b.
transmission of messages
d.
reproduction
32.
Ribosomes are
a.
surrounded by a double membrane
c.
composed of proteins and RNA
b.
manufactured in the cytosol
d.
attached to the smooth endoplasmic reticulum
33.
Lysosomes function in cells to
a.
recycle cell parts
c.
shape developing body parts
b.
destroy viruses and bacteria
d.
all of the above
34.
An example of a prokaryotic cell is a(n)
a.
animal cell.
c.
bacterium.
b.
tree cell.
d.
“animalcule.”
35.
Which of the following associations between a type of animal tissue and its primary function is incorrect?
a.
connective tissue—transport of substances around the body
b.
epithelial tissue—protective surface coverings
c.
muscle tissue—contraction
d.
nervous tissue—receiving and transmitting messages
36.
Which of the following is not part of an animal cell?
a.
protoplasm
c.
cell wall
b.
nucleus
d.
cell membrane
37.
The organelles associated with photosynthesis are the
a.
mitochondria.
c.
Golgi apparatus.
b.
chloroplasts.
d.
vacuoles.
38.
The cell theory states that
a.
Unicellular organisms are exceptions to the rule
b.
cells come from other cells
c.
cell membranes have a fluid mosaic structure
d.
A and B
39.
One early piece of evidence supporting the cell theory was the observation that
a.
only plants are composed of cells
c.
cells come from other cells
b.
only animals are composed of cells
d.
animal cells come from plant cells
40.
The semifluid that fills most of the cell outside the nucleus is called:
