Download bsaa processes in plant cells worksheet

PROCESSES WITHIN THE
PLANT CELLS
Student Learning Objectives. Instruction in this lesson should result in
students achieving the following objectives:
1 Describe a plant cell’s components and their function.
2 Describe the structure and function of the nucleus.
3 Describe the structure of DNA.
4 Explain protein synthesis.
5 Explain the steps involved in cellular replication.
6 Explain diffusion.
7 Explain osmosis and osmotic potential.
Anticipated Problem: What are the components of a plant cell and what do they do?
I. Plant cells are made up of cell walls, membranes, cytoplasm, and a variety of
organelles.
A. The cell wall is a protective layer made of cellulose which surrounds the cell.
B. The cell membrane is a thin film comprised of two fatty layers that surrounds the cell
and regulates the movement of material into and out of the cell.
C. Cytoplasm is the semi-fluid inside the cell membrane that surrounds the organelles.
D. Organelles are small structures inside the cell which carry out the physiological
processes of the organism. These are the plant’s organelles and their functions:
1. Chloroplasts, membranes filled with chlorophyll, are the site of photosynthesis.
2. Chromosomes are found inside the nucleus and are made of DNA. The site of the
genetic blueprint of the organism, chromosomes direct all functions of the cell,
including protein synthesis.
3. The endoplasmic reticulum is a system of tubes that moves compounds through the
cell to the ribosomes for protein synthesis.
4. The Golgi apparatus processes, packages, and transports compounds through the
cell.
5. Mitochondria are the site of cellular respiration.
6. The nucleus contains the chromosomes. It is surrounded by a membrane that allows
the materials needed for protein synthesis to pass through.
7. Ribosomes assemble amino acids into proteins.
8. The vacuole is a large storage compartment filled mostly with water.
Anticipated Problem: What is the structure and function of the nucleus?
II. The nucleus is a porous membrane surrounding chromosomes.
A. The membrane allows the passage of fluid carrying chemical messages between the
cytoplasm and the nucleus.
B. Chromosomes are made of chromatin. Chromatin is long strands ofDNAtightly coiled
around protein. A section of this DNA strand codes for a specific protein to be made.
This functional section of DNA is called a gene. Chromosomes exist in pairs, one from
each parent.
Anticipated Problem: What is the structure of DNA?
III. DNA stands for DeoxyriboNucleic Acid. It exists as a double-stranded spiral called a
double helix. It looks like a twisted ladder. The steps of the ladder are made of chemicals
called nucleotides. The nucleotides are made from: a nitrogen base, a sugar
(deoxyribose), and a phosphate group. There are only four possible nitrogen bases:
A. Sugar (deoxyribose)
B. Phosphate group
C. Nitrogen bases (only four possible)
1. Adenine (A)
2. Thymine (T)
3. Guanine (G)
4. Cytosine (C)
D. These base pairs will only match up A with T and G with C across the DNA strand.
E. Following along the strand, the bases are looked at in groups of three called codons.
Specific codons signal the formation of a specific amino acid.
Anticipated Problem: How are proteins synthesized in the cell?
IV. There are two basic steps in protein synthesis, transcription and translation.
A. Transcription takes place in the nucleus and involves the following steps:
1. The DNA strand opens up or unzips.
2. Messenger RNA (mRNA) duplicates the sequence of bases from the DNA strand,
substituting uracil for thymine.
3. mRNA passes through the nuclear membrane and endoplasmic reticulum to the
ribosome.
B. Translation takes place in the ribosome. This concludes with the formation of a
specific protein.
1. Transfer RNA (tRNA) reads the sequence of codons on the mRNA.
2. tRNA assembles the amino acids coded from the DNA.
3. The amino acids are chemically bound together to form the protein.
Anticipated Problem: What are the steps in cellular replication?
V. The survival of an organism depends on its ability to accurately copy DNA before the
cell divides. This occurs as the nucleus divides. After the DNA replicates itself, the cell
divides. The process of nucleus division is called mitosis, and it involves four phases.
After mitosis, a fifth stage, cytokinesis, takes place to complete cell division. These are
the five steps in cell division, with the first four making up mitosis:
A. Prophase: During this phase, the nuclear membrane begins to break down, spindle
fibers appear at each end of the cell, and chromosomes become visible as paired bundles.
B. Metaphase: During this phase, spindle fibers attach to the chromosomes as they group
together.
C. Anaphase: During this phase, the chromosomes divide and separate, moving to
opposite ends of the cell.
D. Telophase: During this phase, new nuclear membranes are formed around the groups
of chromosomes, the spindle fibers disappear, and the chromosomes uncoil.
E. Cytokinesis: In this final phase, the organelles move to the new nuclei and the cell
completes division by forming a plate between the two new complete cells.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 6
Anticipated Problem: What is diffusion and how does it occur?
VI. Because the environment inside the cell is very different from the environment
outside the cell, the cell restricts the movement of material into and out of it. This is
accomplished through the process of diffusion.
A. The cell membrane acts as a filter, letting some molecules pass through and keeping
others out. This characteristic is referred to as selective permeability. Diffusion involves
the passage of molecules through this semi-permeable membrane.
B. During diffusion, molecules move from areas of high concentration to areas of low
concentration, as long as they can pass through the membrane. They will continue to
move until they reach a state of equilibrium on both sides of the membrane.
Anticipated Problem: What is osmosis and how does it occur? What is osmotic
potential?
VII. Osmosis is the phenomenon where water molecules move from an area of high
concentration to an area of low concentration. Osmosis is the diffusion of water across a
differentially permeable membrane.
A. If a cell is placed in a solution with a higher concentration of dissolved chemicals than
it has inside itself, an imbalance exists. The solution inside the cell has fewer dissolved
chemicals than the solution outside the cell. The chemicals outside the cell will move
into the cell, as long as they can move through the cell membrane, in order to form a
state of equilibrium. If the dissolved chemical cannot get into the cell, water will move
out of the cell in order to achieve this equilibrium. Likewise, if a cell contains more
dissolved chemicals than its external environment and the molecules cannot exit the cell,
the cell will take in water to dilute this chemical concentration. This concept is called
osmosis.
B. The level of dissolved chemical in a cell affects the amount of water the cell will
absorb. The greater the concentration of dissolved chemicals in the cell, the more water
the cell will absorb. A measurable physical force is demonstrated in this situation. The
force of the cell to absorb water in order to reach equilibrium with its environment is
osmotic potential, or osmotic pressure. If the environment exerts more osmotic potential
than the cell, the cell will lose water.
PROCESSES WITHIN THE PLANT CELLS
Part One: Matching
Instructions: Match the word with the correct definition.
a. Cell wall
b. Cell membrane
c. Cytoplasm
d. Organelles
e. Chloroplast
f. Chromosome
g. Mitochondria
h. Endoplasmic reticulum
i. Nucleus
j. Ribosome
k. Vacuole
l. Golgi apparatus
_______1. A large storage compartment filled mostly with water
_______2. Found inside the nucleus; made of DNA
_______3. A protective layer made of cellulose which surrounds the cell
_______4. A system of tubes which move compounds through the cell
_______5. Small structures inside the cell which carry out physiological processes
_______6. Assemble amino acids into proteins
_______7. A thin film comprised of two fatty layers that surrounds the cell
_______8. Processes, packages, and transports compounds through the cell
_______9. The site of photosynthesis
______10. The site of cellular respiration
______11. The semi-fluid inside the cell that surrounds the organelles
______12. Contains the chromosomes
Part Two: Fill in the Blank
Instructions: Complete the following statements.
1. DNA is made up of three basic components, the nitrogen bases, _____________________,
and ________________ ________________.
2. The strand of DNA that functions to code for a specific protein is called a ______________.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 10
3. The four possible nitrogen bases that make up DNA are: ____________________,
____________________, ____________________, and ____________________.
4. ____________________ is long strands of DNA tightly coiled around a protein to form a
chromosome.
5. Reading along a DNA strand, the nitrogen bases are looked at in groups of three called
_______________.
Part Three: Multiple Choice
Instructions: Circle the letter of the correct answer.
_______1. The process of nucleus division that involves five phases
a. Meiosis
b. Mitosis
c. Miata
d. Mycosis
_______2. During this phase, spindle fibers attach to the chromosomes as they group together.
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
_______3. During this phase, the chromosomes divide and separate, moving to opposite ends of
the cell.
a. Cytokinesis
b. Metaphase
c. Anaphase
d. Telophase
_______4. During this phase, the nuclear membrane begins to break down, spindle fibers appear
at each end of the cell, and chromosomes become visible as paired bundles.
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
_______5. In the final phase of cell division, the organelles move to the new nuclei, and the cell
completes division by forming a plate between the two new complete cells.
a. Cytokinesis
b. Metaphase
c. Anaphase
d. Telophase
_______6. During this phase, new nuclear membranes are formed around the groups of
chromosomes, the spindle fibers disappear, and the chromosomes uncoil.
a. Prophase
b. Metaphase
c. Anaphase
d. Telophase
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 11
_______7. This involves the passage of molecules through a semi-permeable membrane from an
area of high concentration to an area of low concentration.
a. Permeability
b. Solute potential
c. Osmosis
d. Diffusion
_______8. This is the phenomenon in which water molecules move from an area of high
concentration to an area
of low concentration.
a. Permeability
b. Solute potential
c. Osmosis
d. Diffusion
_______9. In the DNA strand, the nitrogen base represented by the letter “A” will always pair up
with which other nitrogen base?
a. U
b. G
c. T
d. C
______10. In the DNA strand, the nitrogen base represented by the letter “C” will always pair up
with which other nitrogen base?
a. A
b. G
c. T
d. U
Part Four: Short Answer
Instructions: Answer the following statements.
There are two basic steps in protein synthesis, transcription and translation.
1. Explain the process of transcription.
2. Explain the process of translation.
3. Explain the concept of osmotic potential.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 12
Assessment
TS–A
Technical Supplement
PROCESSES WITHIN THE
PLANT CELLS
It is important to know the parts of a cell, because this provides a basic vocabulary with
which to discuss physiological processes. When studying photosynthesis, for example, it
is helpful to know what a chloroplast is and where it is found. Likewise, when looking at
protein synthesis, it is good to know the architecture of the cell involving this complex
process. Diffusion and osmosis are concepts which help to explain processes including
germination, plant/soil water relations, transpiration, nutrient uptake, pesticide
absorption, turgor, drought response, and stomata function, to name a few. Understanding
diffusion and osmosis, students are better able to explain the phenomenon observed in
nature. A knowledge of how the cell functions is important to people doing research in
biotechnology. When we identify a specific trait in an organism, we are really identifying
proteins that perform some desired function. By manipulating an organism’s DNA, we
make changes to the protein synthesis pathway. The cell codes for new proteins.
Understanding this process gives students a better appreciation of the objectives and
challenges of biotechnology. When we change some function within the cell, we are able
to create unique and useful products for agriculture. We have created plants that produce
their own pesticide, plants that are able to withstand certain pesticide applications, and
still others that can produce enhanced levels of protein. We have manipulated bacteria to
produce human insulin and improved the microorganisms which produce cheese. All of
these advances in technology started with an understanding of the cell.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 33
What are the components of a plant cell and what do they do?
All organisms are made up of cells. These units of life are able to reproduce, and cells
can only come from existing cells. All basic functions of life take place inside the cell.
Plant cells are made up of cell walls, membranes, cytoplasm, and a variety of organelles.
Following is a list of these plant cell components and their function:
A. The cell wall is a protective layer made of cellulose which surrounds the cell.
B. The cell membrane is a thin film comprised of two fatty layers that surrounds the
cell and regulates the movement of material into and out of the cell.
C. Cytoplasm is the semi-fluid inside the cell membrane which surrounds the
organelles.
D. Organelles are small structures inside the cell which carry out the physiological
processes of the organism. These are the plant’s organelles and their function:
1. Chloroplasts, membranes filled with chlorophyll, are the site of photosynthesis.
2. Chromosomes are found inside the nucleus and are made of DNA. Chromosomes
are the site of the genetic blueprint of the organism, and they direct all
functions of the cell including protein synthesis.
3. The endoplasmic reticulum is a system of tubes which moves compounds
through the cell to the ribosomes for protein synthesis.
4. The Golgi apparatus processes, packages, and transports compounds
through the cell.
5. Mitochondria are the site of cellular respiration.
6. The nucleus contains the chromosomes. It is surrounded by a membrane
that allows the movement of materials needed for protein synthesis to pass
through.
7. Ribosomes assemble amino acids into proteins.
8. The vacuole is a large storage compartment filled mostly with water.
It takes a continual flow of energy for a cell to remain intact and functional. In the case of
plants, this energy is provided by the chloroplast during photosynthesis. This energy is
utilized by the other cell components after it is converted by the mitochondria during
respiration. The cell components work together to bring life and function to the cell and,
subsequently, to the whole plant.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 34
What is the structure and function of the nucleus?
The nucleus is important because it stores the genetic information that directs cell
function. It also expresses the heredity of the plant. Each cell contains a complete copy of
that organism’s genetic code. The function of the nucleus is regulated by its simple
structure. The nucleus is a porous membrane surrounding chromosomes.
A. The membrane allows the passage of fluid carrying chemical messages between
the cytoplasm and the nucleus.
B. Chromosomes are made of chromatin. Chromatin is long strands of DNA tightly
coiled around protein. A section of this DNA strand codes for a specific protein to
be made. This functional section of DNA is called a gene. Chromosomes exist in
pairs, one from each parent.
What is the structure of DNA?
DNAstands for DeoxyriboNucleic Acid. It exists as a double-stranded spiral called a
double helix. It looks like a twisted ladder. The steps of the ladder are made of chemicals
called nucleotides. The nucleotides are made from: a nitrogen base, a sugar
(deoxyribose), and a phosphate group. There are only four possible nitrogen bases:
Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). These base pairs will only
match up A with T and G with C across the DNA strand. Following along the strand, the
bases are looked at in groups of three called codons, such as ATG. Specific codons signal
the selection of a specific amino acid. In the example ATG, the amino acid tyrosine is
selected. It is the combination of these amino acids that form protein molecules.
How are proteins synthesized in the cell?
The expression of a gene is the production of a protein. These proteins are synthesized
within the cell based on the instructions found in the DNA. There are two basic steps in
protein synthesis, transcription and translation. Transcription takes place in the nucleus
and involves the following steps:
1. The DNA strand opens up or unzips.
2. Messenger RNA (mRNA) finds the start codon and duplicates the sequence of
bases from the DNA strand, substituting uracil for thymine, ending at a stop
codon. The mRNA copies A as U, T as A, G as C, and C as G.
3. mRNA passes through the nuclear membrane and endoplasmic reticulum to the
ribosome.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 35
Translation takes place in the ribosome. Transfer RNA will assemble the various amino
acids into the desired protein. This construction is based on the code or blueprint it reads
from the mRNA. Translation involves the following steps.
1. Transfer RNA (tRNA) reads the sequence of codons on the mRNA.
2. tRNA assembles the amino acids coded for by the DNA.
3. The amino acids are chemically bound together to form the protein.
What are the steps in cellular replication?
The survival of an organism depends on its ability to accurately copy DNA before cell
division. This occurs as the nucleus divides. After the DNA replicates itself, the cell
divides. The process of nucleus division is called mitosis, and it involves four phases.
After mitosis, a fifth stage, called cytokinesis, takes place to complete cell division.
These are the five steps in cell division, with the first four making up mitosis:
A. Prophase: During this phase, the nuclear membrane begins to break down, spindle
fibers appear at each end of the cell, and chromosomes become visible as paired
bundles.
B. Metaphase: During this phase, spindle fibers attach to the chromosomes as they
group together.
C. Anaphase: During this phase, the chromosomes divide and separate, moving to
opposite ends of the cell.
D. Telophase: During this phase, new nuclear membranes are formed around the
groups of chromosomes, the spindle fibers disappear, and the chromosomes uncoil.
E. Cytokinesis: In this final phase, the organelles move to the new nuclei and the cell
completes division by forming a plate between the two new complete cells.
What is diffusion and how does it occur?
Because the environment inside the cell is very different from the environment outside
the cell, the cell restricts the movement of material into and out of it. This is
accomplished through the process of diffusion. The cell membrane acts as a filter, letting
some molecules pass through and keeping others out. This characteristic is referred to as
selective permeability. Diffusion involves the passage of molecules through this semipermeable membrane. During diffusion, molecules move from areas of high
concentration to areas of low concentration, as long as they can pass through the
membrane. They will continue to move until they reach a state of equilibrium on both
sides of the membrane.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 36
What is osmosis and how does it occur? What is osmotic potential?
Osmosis is the phenomenon in which water molecules move from an area of high
concentration to an area of low concentration. Osmosis is the diffusion of water across a
differentially permeable membrane. If a cell is placed in a solution with a higher
concentration of dissolved chemicals than it has inside itself, an imbalance exists. The
solution inside the cell has fewer dissolved chemicals than the solution outside the cell.
The chemicals outside the cell will move into the cell, as long as they can move through
the cell membrane, in order to form a state of equilibrium. If the dissolved chemical
cannot get into the cell, water will move out of the cell in order to achieve this
equilibrium. Likewise, if a cell contains more dissolved chemicals than its external
environment, and the molecules cannot exit the cell, the cell will take in water to dilute
this chemical concentration. This concept is called osmosis. The level of dissolved
chemical in a cell affects the amount of water the cell will absorb. The greater the
concentration of dissolved chemicals in the cell, the more water the cell will absorb.
There is a measurable physical force that is demonstrated in this situation. The force the
cell exerts to absorb water in order to reach equilibrium with its environment is osmotic
potential, or osmotic pressure. If the environment exerts more osmotic potential than the
cell, the cell will lose water as in transpiration.
Illinois Biological Science Applications in Agriculture Lesson B1–1 • Page 37