unit 2: the cell - welcome to ms. thompson's class...

Unit 2: The Cell

This unit will be broken up into two separate parts, each with its own test. However, both parts are from the same standard.

Standard B-2: The student will demonstrate an understanding of the structure and function of cells and their organelles.

Part 1The first half of this unit will focus on the following standards:

B-2.1 Recall the three major tenets of cell theory (all living things are composed of one or

more cells; cells are the basic units of structure and function in living things; and all presently existing cells arose from previously existing cells).

B-2.2 Summarize the structures and functions of organelles found in a eukaryotic cell (including the nucleus, mitochondria, chloroplasts, lysosomes, vacuoles, ribosomes, endoplasmic reticulum [ER], Golgi apparatus, cilia, flagella, cell membrane, nuclear membrane, cell wall, and cytoplasm).

B-2.3 Compare the structures and organelles of prokaryotic and eukaryotic cells.

B-2.5 Explain how active, passive, and facilitated transport serve to maintain the homeostasis of the cell.

You will have a test on the above standards.

Part 2The second half of this unit will focus on the following standards:

B-2.4 Explain the process of cell differentiation as the basis for the hierarchical organization of organisms (including cells, tissues, organs, and organ systems).

B-2.6 Summarize the characteristics of the cell cycle: interphase (called G1, S, G2); the phases of mitosis (called prophase, metaphase, anaphase, and telophase); and plant and animal cytokinesis.

B-2.7 Summarize how cell regulation controls and coordinates cell growth and division and allows cells to respond to the environment, and recognize the consequences of uncontrolled cell division.

There will be a test on the above standards.

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The Cell


Indicator B – 2.1: Recall the three major tenets of cell theory (all living things are composed of one or more cells; cells are the basic units of structure and function in living things; and all presently existing cells arose from previously existing cells).

Indicator B – 2.3: Compare the structures and organelles of prokaryotic and eukaryotic cells.

Key Concepts:Cell Theory Unicellular Organisms vs. Multicellular Organisms Prokaryotes vs. Eukaryotes

It is essential for you to know: All living things are composed of one or more cells. Cells are the basic unit of structure of all living things. All presently existing cells arose from previously existing cells. Prokaryotic cells do not have a true nucleus whereas eukaryotic cells do have a true nucleus.

Objectives:Recall the major tenets of the Cell theory.Compare unicellular organisms and multicellular organisms. Differentiate between prokaryotic cells and eukaryotic cells.

*******************************************************************************************************************You and all other organisms are made of cells. A cell’s structure is closely related to its function.

Today, we know that cells are smallest unit of life that can carry out all processes required for life.

However, before the 1600s, people had many other ideas about the basis of life.

Using either your book, read through the following and fill in the blanks.

Life is ____________________.

ATP stands for ______________________________. It is what organisms

use for ____________.

Cells take sugar (________) from food to turn it into ________.

The History of Cell BiologyA person who studies cells is called a ____________________. The study of cells is ____________.

The following scientists contributed to the Cell Theory.

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Anton van Leeuwenhoek

RobertHooke

Matthias Schleiden

TheodorSchwann

RudolfVirchow

The Cell TheoryA cell is the basic unit of _____________.

The 3 parts to the Cell Theory are:

1) _________________________________________________________________________

2) _________________________________________________________________________

3) _________________________________________________________________________

Prokaryotes and EukaryotesBiologists divide cells into two categories: _________________ and _________________

Fill out the chart about prokaryotes and eukaryotes.

Prokaryotic Cells Eukaryotic Cells

Where is the DNA in a prokaryote found?

Where is the DNA in a eukaryote found?

Unicellular and Multicellular Organisms

Sometimes just one cell is the entire _____________________.

They do everything that you would expect a living thing to do.

Includes both prokaryotes and eukaryotes.

Prokaryote examples

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Eukaryote examples

Multicellular organisms are comprised of __________________________.

Cells are ____________ to perform particular functions. This is called ___________________.

Levels of OrganizationIn a multicellular organism, there is a certain order to how cells are organized. What is the correct order?

__________________ ________________ __________________ ____________________

Can You Tell the Difference?

Determine if each of the following describes a prokaryotic cell, eukaryotic cell, or both.

1. Mostly unicellular, like bacteria

2. Contains organelles (specialized structures)

3. DNA found within a membrane-bound nucleus

Use the picture to the left.

According to the levels of organization in a multicellular organism, what do you think each of the following would be.

Cell: ____________________

Tissue: ____________________

Organ: ________________________

Organ System: _________________

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4. Has ribosomes (for making proteins)

5. DNA found suspended in the cytoplasm of the cell in a plasmid

6. Has cytoplasm

7. Has a cell membrane

8. The DNA is organized into structures called chromosomes

9.

10.

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Indicator B – 2.2: Summarize the structures and functions of organelles found in a eukaryotic cell (including the nucleus, mitochondria, chloroplast, lysosomes, vacuoles, ribosomes, endoplasmic reticulum [ER], Golgi apparatus, cilia, flagella, cell membrane, nuclear membrane, cell wall, and cytoplasm).

Key Concepts:Organelles

It is essential for you to know: That an organelle is a cell structure that performs a specialized function within a cell. The structure and function of various organelles within a eukaryotic cell. How to locate and identify each organelle when presented with a scientific drawing, diagram,

or model of a eukaryotic cell.

Objectives:Describe the functions of the major cell organelles.Identify the structures of various cell organelles.

*******************************************************************************************************************Your body is highly organized. It contains organs that are specialized to perform particular tasks. For example, your skin receives sensory information and helps prevent infection. Your intestines digest your food while your kidneys filter wastes. Your bones support and protect your organs, while allowing you to walk upright and move. On a much smaller scale, your cells have a similar division of labor. They contain specialized structures that work together to respond to stimuli and efficiently carry out other necessary processes.

CELL ORGANELLES

All cells have three things:

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Cells have an internal structure that gives it its shape and supports it. A ________________, which is

a network of proteins that are constantly changing to meet the needs of a cell. This is composed of

_______________ and _________________.

Several organelles are involved in making proteins.

The ________________ contains the chromosomes which are

composed of ________, a chemical called deoxyribonucleic

acid. The __________ is responsible for the genetic information

of the cell. There are two parts to the nucleus. The

____________ _____________, which is found around the nucleus and contains thousands of tiny

holes called ____________. This is how RNA and other materials can get out of the nucleus. There is

also a dense region within the nucleus called the ____________, where ribosomes are made.

____________ is the actual organelle where proteins are made. They may

be freely floating around the cell or attached to ________________

_______________ (ER). When they are attached to ER, it is called

_________ _______________ ______________, but when there are no

ribosomes attached to ER, it is called

____________ __________________

_________________.

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Once a protein is made, it must be packaged before it is delivered to it appropriate place. The

organelle responsible for this is the ________________ _____________. It is a stack of membranes

that lie directly outside the endoplasmic reticulum.

Once a protein is packaged and ready for delivery, it must have a method of

getting to its destination. ___________ are the organelles responsible for this.

In a plant cell, there is a large central _______________, but in animal cells,

there are many smaller ones.

Other organelles have various functions.

The organelle which contain chemicals called enzymes are necessary for

digesting certain materials of the cell. They can also remove debris from

the cell. They are called _________________.

When your cell needs energy in the form of ATP, the

____________________ is an organelle that releases the energy

from the food taken in. It is very unique in that it contains its own DNA

and can reproduce on its own. It is thought that at one time, this

organelle was actually an organism that lived a unicellular life. The

DNA found within this organelle is different from the DNA found within

the nucleus of the cell.

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________________ are cylinder-shaped organelles made of microtubules that

aid in mitosis or meiosis. They are not found in __________ cells. They lie

right outside the nucleus.

Plant cells have specialized structures not found in animal cells.

_______________ are organelles that use energy from sunlight to

make ATP. Like mitochondria, they also contain their own DNA and

can reproduce on their own.

Around the cell membrane of a plant cell, lies an extra layer of protection

called the __________ _________. Unlike the cell membrane, the

_________ __________ is rigid.

Cells Move Too! ____________ are short hair-like structures that aid animal cells and

protists in movement whereas a ______________ is a long whip-like

structure found on some animal cells, bacteria, and protists.

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Label the following parts of

the animal cell to the left.

Try not to use your notes.


Indicator B-2.5: Explain how active, passive, and facilitated transports serve to maintain the homeostasis of the cell. Key Concepts:Homeostasis Passive transport Active Transport

It is essential for you to know: Materials needed for cellular processes must pass into cells so they can be utilized. Waste materials from cellular processes must pass out of cells as they are produced. The cell membrane regulates the passage of material into and out of the cell. Each individual cell exists in a fluid environment, and the cytoplasm within the cell also has a

fluid environment. A cell membrane is semipermeable. Materials can enter or exit through the cell membrane by passive or active transport.

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Objectives:Identify the main functions of the cell membrane.Describe what happens during diffusion.Explain the processes of osmosis, facilitated diffusion, and active transport.

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Cell MembranesAll cells have a _______ _____________. The environment of individual cells and the cytoplasm

make it possible for substances to move _______ and _______ of the cell.

Structure and FunctionTwo functions of the cell membrane are for ________________ and ______________. To maintain

homeostasis, the membrane ____________ what enters and leaves the cell.

The structure of the cell membrane is described as a _________ ___________ or two layers of

________________. The _______________ head is polar or ________ ________. The non-polar or

________ _________ends consist of _________ _________. Finally, ___________ are embedded in the

membrane. Cell membranes have holes or __________ that make them _____________ _____________

or ________ _______________, allowing some thing to _________ into the cell and other things to

_________ out.

Types of Cellular TransportIn ______________ transport, the cell ______ _____ use energy or ______. Types of

_______________ transport are __________, ___________ ___________, and ___________.

In __________ transport, the cell ________ use energy, _________. Types of ___________

transport include _________ __________, ________________, and ________________.

Passive Transport In passive transport, cells use _______ energy, molecules move ___________ and

spread out from an area of ________ concentration to an area of _______

concentration or a ____________ ____________ (a difference in concentrations

across a ___________ _____________). High Low

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1. Diffusion is the random ___________ of particles from an area of ________

concentration to an area of _______ concentration and continues until all __________ are

evenly spread out or have reached _______________. Once equilibrium is reached, the

molecules will continue to ________, but stay ______ out. ______ ______

2. Facilitated Diffusion occurs when specific particles move through ________

_______ found in the cell ____________. The “facilitation” is provided by the ________

________ which are _____________ or specific regarding the molecules that they move

across the membrane. They can transport _________ molecules or ________ molecules.

3. Osmosis is the ____________ of _________ through a selectively permeable

membrane.

Active TransportIn active transport, the cell uses ___________ as it actively moves _____________ to where

they are needed. The reason this transport is “active and requires _________ is because the

movement is from an area of ________ concentration to an area of _________concentration

(against gradient). ______ ______

1. Protein Pumps require __________ to do work. They change ____________ to

move molecules. Example: Sodium/Potassium pumps in nerve

responses.

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2. Endocytosis takes bulky material ________ the cell. This process referred to as

“______ __________” uses energy as the cell membrane __________

around a food

particle, forms a food ____________ and __________ food.

Example: white blood cells digesting bacteria

3. Exocytosis ___________ material out of cell in

bulk. In this process, the

membrane surrounding the material to be moved ___________ with the cell

membrane and changes ___________. This requires energy. Example:

Hormones or wastes removed from the cell.

Some Other Important Aspects of Osmosis

Osmosis is the diffusion of __________ through a __________ __________ membrane.

Water is such a _________ molecule that the cell cannot control its __________ through the cell

membrane.

Semi-permeable refers to the ability of water, the ____________ to diffuse across a cell membrane,

but not ________ molecules.

Dissolved molecules such as glucose, salt, and starch are called __________.

The dissolving medium, such as water is called the _____________.

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When the amount of water and solute are equal on both sides of the cell membrane, the environment

is __________________ (same) and water flows both in and out of the cell without changing the

___________ concentrations. The cell remains ___________.

When the amount of solute inside the cell is high and the amount of water is low (inside), water will

move into the cell to equalize the concentrations. This describes a cell that is _________________

(high solute, low solvent) to its external environment. The cell may __________ or burst if too much

water comes into the cell. When the amount of solute inside the cell is low and the amount of water is

high (inside), water will go out of the cell to equalize the concentrations. This describes a cell that is

________________ (low solute, high solvent) to its external environment. The cell may

________________ (shrink) if too much water leaves the cell.

Water Water Water concentration is concentration is concentration is greater outside the same inside greater inside the cell than and outside the the cell than inside so water cell so there is no outside so water moves into the net movement moves out of the cell of water. cell.

For each of the following solution, draw arrows, showing which way the WATER will move.

Underneath the picture, explain why it will move in that direction.

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Answer each of the following.1. A cell with a concentration of 20% glucose is placed in a solution with 50% glucose. Which way

will water move and why? Sketch this out.

2. A cell with a concentration of 50% glucose is placed in a solution with 20% glucose. Which way


3. A cell with a concentration of 20% glucose is placed in a solution with 20% glucose. Which way


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Indicator B-2.4: Explain the process of cell differentiation as the basis for the hierarchal organization of organisms (including cells, tissues, organs, and organ

systems). Key Concepts:Cell Division Stem Cells

It is essential for you to know: In the development of most multicellular organisms, a single cell (fertilized egg) gives rise to

many different types of cells, each with a different structure and corresponding function. Nearly all of the cells of a multicellular organism have exactly the same chromosomes and

DNA. Stem cells are unspecialized cells that continually reproduce themselves and have, under

appropriate conditions, the ability to differentiate into one or more types of specialized cells.

Objectives:Explain the process of cell differentiation.Recall that all of the cells of a particular organism contain all of the genetic code.Summarize the unique characteristics of embryonic and adult stem cells.

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Each of us enters this world as a screaming infant. At

first, the ability to eat solid foods of take a step draws

forth great praise. These general skills rapidly lose their

wonder, however, and by the time you reach the age of

18, everyone wants to know what you plan to do with

yourself. Will you build houses or design clothing or treat

patients? What will your specialty be? Cell, too, undergo

specialization to carry out the complex functions required by the body.

Cell Tissue Organ Organ System

All life starts with a single cell. This cell is a __________ _____, or

_______________. Sperm, from the male enters the membrane of the

egg from the female. This ___________ ______ then gives rise to many

different types of cells in that organism. Each of these cells has a

particular structure and function. This is referred to as ____________

_________________.

The fertilized egg can give rise to many different cells through CELL DIVISION. However, the

process of cell division itself only gives rise to many cells that are genetically identical, it doesn’t

specialize any cells. As cell division continues, the cells not only increase in number but they also

begin to ______________, meaning they become _____________ in structure and function. These

specialized cells then arrange themselves into tissues which are organized into organs, and

ultimately, organ systems.

Cells within a multicellular organism also come in many different shapes and sizes.

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Even though these cells are all different sizes, shapes, and

perform different functions, they all contain the same

__________ in their nucleus. During the process of

_______________, only specific parts of the ____________

are activated. The parts that are activated determine the

_______________ and specialized ______________ of the

cell. Because all cells contain the same _____, all cells

initially have the potential to become any type of cell.

However, once a cell _____________ the process CANNOT

BE ______________.

There is a type of cell that is unspecialized and can continually reproduce themselves under the

appropriate conditions. They are called ___________ ____________. They have the ability to

differentiate into one or more types of specialized cells. There can be classified based on

_______________ and __________________.

Potential Origin

Totipotent

Pluripotent

Embryonic Stem Cells

Adult Stem Cells

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Multipotent


Indicator B-2.6: Summarize the characteristics of the cell cycle: interphase (called G1, S, G2); and the phases of mitosis (called prophase, metaphase, anaphase, and

telophase); and plant and animal cytokinesis. Key Concepts:Cell Cycle Interphase Mitosis Cytokinesis

It is essential for you to know: The cell cycle is a repeated pattern of growth and division that occurs in eukaryotic cells. The cell cycle has three phases: Interphase, Mitosis, and Cytokinesis

Objectives:Summarize the characteristics of the cell cycle. Identify the phases of the cell cycle. Recall the events that occur in each phase of the cell cycle.

*******************************************************************************************************************

Cell Cycle and MitosisTHE CELL CYCLEThe cell cycle, or cell-division cycle, is the series of events that take place in a eukaryotic cell between its

formation and the moment it replicates itself. These events can be divided in two main parts: interphase (in

between divisions phase grouping G1 phase, S phase, G2 phase), during which the cell is forming and carries

on with its normal metabolic functions; the mitotic phase (M-Phase), during which the cell is replicating itself.

Thus, cell-division cycle is an essential process by which a single-cell fertilized egg develops into a mature

organism and the process by which hair, skin, blood cells, and some internal organs are formed.

1. What is meant by the cell cycle or cell division cycle?

2. In what type of cells --- prokaryotes or eukaryotes --- does the cell cycle occur?

3. Name the 2 main PHASES of the cell cycle.

4. __________ is in between the times when a cell is dividing.

5. What is occurring in a cell during interphase?19

6. What is occurring during the mitosis phase?

7. A fertilized cell develops into a ___________ organism during the cell cycle.

8. Name three things that form during the cycle.

INTERPHASE

Interphase is a phase of the cell cycle, defined only by the absence of cell division. During interphase, the cell

obtains nutrients, and duplicates (copies) its chromatids (genetic material). The genetic material or

chromatids are located in the nucleus of the cell and are made of the molecule DNA. Cells spend the

majority of their time in interphase. By the end of interphase, the cell has two full sets of DNA (chromosomes)

and is large enough to divide.

9. What is the longest phase of the cell cycle?

10. Cells obtain ______________ and duplicate or copy their ___________ or genetic material during interphase.

11. Where are chromatids found in a cell?

12. Chromatids are made of a molecule called ___________.

Label the parts of a chromosome.

The two types of chromosomes are __________

chromosomes and ___________. A picture of all of the

chromosomes of an organism is called a ____________.

How many pairs of sex chromosomes do humans have?

___________ How many pairs of autosomes do humans

have? ___________

Diploid cells:

Haploid cells:

Most eukaryotic cells spend most of their time in

interphase. For example, human skin cells, which divide about once a day, spend roughly 22 hours in 20

1.

2.

3.

4.

http://en.wikipedia.org/wiki/Image:Chromosome.png

interphase. About 90 percent of cells are in interphase. Some cells, such as nerve cells, can stay in

interphase for decades. There are 3 parts of interphase: G1 (growth 1 in which the cell creates organelles and

begins metabolism), S phase (DNA synthesis in which the chromosomes of the cell are copied) and G2 (growth 2 in which the cell grows in preparation for cell division). In what PHASE do most cells spend the

majority of their lifetime?

13. How often do human skin cells divide each day?

14. How many hours per day is a human skin cell in interphase?

15. What type of cell may spend decades in interphase instead of dividing?

16. Name the 3 stages in interphase.

17. What does G1 stand for and what occurs in this stage?

18. What does S stand for and what occurs in this stage?

19. What does G2 stand for and what occurs in this stage?

Sometimes the cells exit the cell cycle (usually from G1 phase) and enter the G0 phase. In the G0 phase, cells are alive and active, but do not divide. In this phase cells do not copy their DNA and do not prepare for cell

division. Many cells in the human body, including those in heart muscle, eyes, and brain are in the G0 phase.

If these cells are damaged they cannot be replaced.

20. From what stage of the cell cycle do cells sometimes EXIT?

22. What happens to cells that enter the G0 stage?

23. Name 3 types of cells that enter the G0 phase when they are mature?

24. What happens if these cells are damaged during your lifetime?

The G1 phase is a period in the cell cycle during interphase, after cytokinesis (process whereby a single cell

is divided into two identical daughter cells whenever the cytoplasm is divided) and before the S phase. For

many cells, this phase is the major period of cell growth during its lifespan. During this stage new organelles are being synthesized (made).

25. What stage occurs after cytokinesis?

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26. What part of the cell is divided during cytokinesis?

27 What are the new cells called and how do they compare with each other?

28 What is major thing happening to a cell during G1?

29 What cell structures are made in G1?

30. Since proteins and ____________ are being made during G1, there is a great amount of protein _______________ occurring.

The S phase, short for synthesis phase, is a period in the cell cycle during interphase, between G1 phase and the G2 phase. Following G1, the cell enters the S stage, when DNA synthesis or replication occurs. At

the beginning of the S stage, each chromosome is composed of one coiled DNA double helix molecule, which

is called a chromatid. At the end of this stage, each chromosome has two identical DNA double helix

molecules, and therefore is composed of two sister chromatids.

31. What does the S phase stand for?

32. What happens during the S phase?

33. Each chromosome originally is made of how many DNA molecules and how does this molecule appear in the chromosome?

34. At the end of S phase each chromosome has how many coiled DNA molecules?

35. What structure holds the duplicated chromosomes together and is also copied during the S phase?

G2 phase is the third, final, and usually the shortest stage during interphase within the cell cycle in which the

cell undergoes a period of rapid growth to prepare for mitosis. It follows successful completion of DNA

synthesis and chromosomal replication during the S phase, and occurs during a period of often four to five

hours. Although chromosomes have been replicated they cannot yet be distinguished individually because they

are still in the form of loosely packed chromatin fibers. The G2 phase continues growth of the cell and

prepares the cell for mitosis (M phase) by producing all of the enzymes that the cell will need in order to divide.

After the G2 phase of interphase, the cell is ready to start dividing. The nucleus and nuclear material (chromosomes made of DNA) divide first during stage known as MITOSIS.

36. What is the final and shortest phase of interphase?

37. About how long would a typical cell be in the G2 phase?

38. How is the cell prepared for mitosis during the G2 phase?

39. What follows the G2 phase?

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40. What part of the cell is actually dividing in mitosis?

MITOSIS – NUCLEAR DIVISION

Mitosis is the process in which a eukaryotic cell separates its already duplicated chromosomes (copied

during the S phase) into two sets of chromosomes so there will be two identical nuclei. It is generally

followed by cytokinesis which divides the cytoplasm and cell membrane. This results in two identical cells

(both have an identical set of chromosomes) with an equal distribution of organelles and other cellular

components. The mitosis and cytokinesis together are called cell division (M phase), the division of the

parent cell (original) into two daughter cells (new cells), each with the same genetic information (chromosomes) as the parent cell. Mitosis does NOT occur in prokaryotic cells that do NOT have a

nucleus. In multicellular organisms, the somatic cells (body cells) undergo mitosis, while germ cells — cells

destined to become sperm in males or ova (eggs) in females — divide by a related process called meiosis.

Prokaryotic cells (bacteria), which lack a nucleus, divide by a process called binary fission.

41. When are chromosomes duplicated --- before or during mitosis?

42. What process follows mitosis?

43. The nucleus is divided during ______, while cytoplasm of the cell is divided during _______.

44. How do the two new cells compare with each other?

45. The two new cells are called _____________ cells.

46. Does mitosis occur in prokaryotes? Explain why or why not.

47. What process is used by bacteria to divide and reproduce?

48. Body cells are called ___________ cells, while reproductive cells are known as __________ cells.

The process of mitosis (division of the nucleus) is divided into four stages (Prophase, Metaphase, Anaphase, and Telophase). Immediately following nuclear division (mitosis), the cell membrane must also

divide (cytokinesis). Animal cells divide the cytoplasm by constricting the cell membrane in the middle to form

a cleavage furrow. Plant cells form a cell plate in the center to divide the cytoplasm. At Interphase, there is

only one cell, but after cytokinesis there are two identical cells.

49. Name the 4 mitotic stages.

50. How does cytokinesis occur in an animal cell? Plant cell?

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The Cell Cycle

Name each numbered stage in the plant cell cycle diagram:(interphase, prophase, metaphase, anaphase, or telophase)

1. 7. 13.2. 8. 14.3. 9. 15.4. 10. 16.5. 11. 17.6. 12. 18.

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Plant Cells in Mitosis


Indicator B-2.7: Summarize how cell regulation controls and coordinates cell growth and division and allows cells to respond to the environment, and recognize the consequences of uncontrolled cell division.

Key Concepts:Chemical Control System: internal signal, external signal, checkpointCancer Cells: malignant tumor, benign tumor

It is essential for you to know: The cell cycle is driven by a chemical control system that both triggers and coordinates key

events in the cell cycle. Recognize consequences of uncontrolled cell division.

Objectives:Identify internal and external factors that regulate cell division. Explain cancer in terms of the cell cycle.

Vocabulary Words:Define the following vocabulary words in the space provided.

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1. growth factor

2. apoptosis

3. cancer

4. benign

5. malignant

6. metastasize

7. carcinogens

You have already learned that cells in different parts of the body divide at different rates. For

example, cells in the lining of the stomach divide at a much faster rate than most of the other cells in

your body. Some cells, like neurons, will not divide at all. Signals from within the cell and from the

cell’s environment control a cell’s division.

Internal and External Factors Regulate Cell DivisionExternal factors come from the _____________ of the cell.

They may be messages from nearby ____________ or from distant ________ of the body.

Internal factors come from the _____________ of the cell.

They include several types of molecules found in the ___________ of the cell.

External FactorsIncludes both ___________ and ____________ signals.

A physical signal would be _____ to ______ contact.

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Many cells release chemical signals that tell other cells to ___________.

This would include _________ _________, a group of proteins that

stimulate cell division. In general, cells grow and divide in response to a

combination of different ____________ __________, not just one. Various

hormones may also stimulate the __________ of certain cell types. In

particular, __________ ___________ results in bone growth and also

affects your ________ and ________ metabolism.

Internal FactorsWhen external factors bind to their receptors, they can trigger ___________ factors.

There are two main types in eukaryotic cells: ___________ and _____________

Kinases are :

Cyclins are:

ApoptosisJust as some cells need to ___________ and _________, other cells need to _____.

__________ is programmed cell death. It occurs when __________ or __________

signals activate genes that help produce _________________ enzymes.

Most mammal cells grown in the lab form a single layer on the bottom of a culture or Petri dish as seen in the picture to the left. Once a cell _________ another cell, it stops __________. The exact reason for this phenomenon is ___________.

The picture to the left shows a classic

example of APOPTOSIS. In the early

stages of development, __________

embryos have ___________ between

their fingers and toes. Before the

baby is born, those cells typically go

through ___________. Most babies

are born with little _________ fingers

and toes.

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Cell Division is Uncontrolled in Cancer___________ is the common name for a class of diseases characterized by uncontrolled cell division.

Unlike healthy cells, ___________ cells grown in a culture (Petri) dish continue to divide even when

surrounded by neighboring cells. Cancer cells form disorganized clumps called ___________.

Tumors can be either ____________ or ____________. If they are benign, they tend to stay in one

place and are relatively ____________. They can usually be cured by ___________ them.

If they are malignant, some of the cancer cells can _________ _________ or metastasize. This

means they can leave their original place of origin and travel elsewhere in the body. They can be

carried via the ________ stream of the __________ system.

Cancer cells do not perform the __________ functions

needed by the __________. For example, if there is

cancer in the lungs, they will not exchange __________

and __________ __________. Cancer cells come from

___________ cells that have suffered ____________ to

the genes that help make proteins involved in cell cycle

regulation. There can be many reasons why a cell turns

cancerous. Substances known to produce or promote

the development of cancer are called ____________.

These include ___________ smoke and certain ________ pollutants, which are both associated with

lung cancer. Sometimes they can be carried by a ________, such as the one known to cause cervical

cancer. Standard cancer treatment involves both ____________ and ___________.

Blood Stream

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unit 2: the cell - welcome to ms. thompson's class...

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