Biology Chapter 10

If the p53 gene is damaged, tumor suppression is severely reduced. People who inherit only one functional copy of p53 will most likely develop tumors in early adulthood, a disease known as Li-Fraumeni syndrome. p53 can also be damaged in cells by mutagens (chemicals, radiation or viruses), increasing the likelihood that the cell will begin uncontrolled division. More than 50 percent of human tumors contain a mutation or deletion of the p53 gene.

A cell will usually undergo apoptosis if the cell experiences DNA damage that could lead to a tumor. Predict what may happen if a gene that controls apoptosis is damaged

The cell shall remain in the S phase of interphase The scientist halts the DNA synthesis so it can't move past duplication

A scientist treats cells with a chemical that prevents DNA synthesis. In which stage of the cell cycle will these cells remain?

As a cell's size increases, the volume increases more than the surface area. However, the ratio decreases. Notice that the surface area is not increasing as fast as the volume

As a cell's size increases, what happens to the ratio of its surface are to its volume?

Pluripotent Bone marrow cells are adult stem cells that can turn into several different types of cells including blood cells, muscle, bone, etc. They are adult but pluripotent is more descriptive and the better choice

Bone marrow cells that produce blood cells are best categorized as

Cell volume is amount of space inside cell. Length x Width x Height = 4 x 4 x = 64 Cell surface area is the perimeter of the cell. Length x Width x 6 = 4 x 4 x 6 = 96 area/volume = 96/64 .....need to make sure this is correct

Calculate the ratio of surface area to volume of an imaginary cubic cell measuring 4 mm long on each side

For single celled organisms, asexual reproduction is a survival strategy. When conditions are right, they reproduce faster and have a better chance of survival over other organisms using the same resources Sexual reproduction is a different survival strategy. For species that live in environments where seasonal change affect weather conditions and food availability. Sexual reproduction also provides genetic diversity. If an environment changes, some offspring may have the right combination of characteristics needed to survive.

Describe asexual and sexual reproduction as survival strategies

The chromosomes condense. Imagine a white thread in a white bowl, all unraveled. It's hard to see the thread, and it's very fine. It takes up a lot of space because it's not folded up or anything, just in a haphazard cluster in the bowl. This is how the DNA is before the chromosomes start condensing. Imagine tying and folding the string into a rope. The rope is now visible and takes up less space even though there's still the same amount of thread. The chromosomes themselves condense by winding and folding or even coiling around clusters of proteins called histones.

Describe how a eukaryotic cell's chromosomes change as a cell prepares to divide

The major differences in plant and animal cell division are in the assembly of the spindle apparatus. The site of spindle apparatus assembly is the centrosome. In animal cells, a pair of centrioles is at the center of the centromere. In contrast, most plants lack centrioles, but they do have a centrosome. In animal cells, a cleavage furrow forms during cytokinesis, which deepens and then pinches the parent cells in two. Plant cells, which have cell walls, do not have a cleavage furrow. Instead, a cell plate is produced in the middle of the parent cell, which grows toward the perimeter of the cell until it reaches the plasma membrane, dividing the cell in two. A new cell wall then forms from the cell plate.

Describe the differences between cell division in an animal cell and cell division in a plant cell.

cyclins regulates the timings of the cell cycles

Describe the role of cyclins.

There is ongoing research involving adult stem cells as well as stem cells extracted from umbilical tissue. Already this research has resulted in some effective experimental treatments for certain conditions. Some animal research suggests that techniques could be developed to make adult stem cells from the same specialized tissues that embryonic stem cells do.

Describe two ways that technology may address the ethical concerns related to stem cell research.

Cell volume is amount of space inside cell. Length x Width x Height Cell surface area is the perimeter of the cell. Length x Width x 6 Ratio of surface area to volume you can see how the size of the cell's surface area grows compared to its volume. surface area/volume or surface area:volume

Describe what is meant by each of the following terms: cell volume cell surface area ratio of surface area to volume

During the S phase or synthesis phase (part of Interphase)

During which phase of the cell cycle are chromosomes replicated?

Animal cells: cell membrane is drawn inward Plant cells: cell membrane not flexible enough to draw inward because of the cell wall so instead a structure called the cell plate forms halfway between the divided nuclei the cell plate gradually develops into cell membranes that separate to form new cell

How does cytokinesis differ in animal and plant cells?

Embryonic and Adult stem cells are alike since they both have ability to produce/develop differentiated cells. Embryonic and Adult stem cells differ: Embryonic stem cells are pluripotent cells meaning they can produce "ANY" cell type in the human body. For example, embryonic stem cells can differentiate into nerve cells, muscle cells, and even into sperm and egg cells. Adult stem cells are multipotent cells are more limited in their ability and develop into "MANY" (not any)differentiated cell types. For example, adult stem cells of a given organ or tissue produce only the types of cells that are unique to that tissue.

How are embryonic stem cells and adult stem cells alike? How are they different?

Tumor formation occurs due to uncontrolled growth of cell. Uncontrolled growth occurs when any cell cycle regulatory or related proteins get mutated leading to loss of cell cycle control. DNA replication which occurs to heal a injury is highly controlled by internal and external regulatory factors and hence stops once its purpose served

How are the growth of a tumor and the repair of a crape on your knee similar? How are they different?

cancer cells and non-cancer cells follow the same cell cycle processes. However the growth of cancer cells are not regulated such as non-cancer cells.

How do cancer cells differ from noncancerous cells? How are they similar?

Caenorhabdltis elegans is a small organism that has a particular differentiation pattern with a defined number of cells. Embryonic development follows a ridged pattern and is predictable. Mammals do not have a rigid cell differentiation pattern and cell count like the organism C. elegans. It is hard to predict the embryonic development of larger animals because of the sheer number of cells involved. Larger organisms have a more flexible differentiation pattern, and their large cell count makes it difficult to map and trace specific cells, especially if those cells differentiate (slightly) differently per individual.

How does embryonic development and cell differentiation in C. elegans differ from how these processes work in mammals?

Prokaryotes do not have a nucleus . They have a single circular chromosome as genetic material, located in cytoplasm. The DNA is less condensed than eukaryotic DNA, and hence, can not be easily visualized under light microcope. Eukaryotes on the other hand contain multiple pair of linear chromosomes, which are contained within the cellular nucleus.Since, eukaryotic genetic material is quite large it is condensed with help of histone proteins to form chromosomes. Eukaryotic genome/ DNA is very small in comparison to eukaryotic genome.

How does the structure of chromosomes differ in prokaryotes and eukaryotes?

Cancer is a type of disease that originates from a cell's defective cell cycle. The disease arises when a step in a cell cycle is functionally altered. When the alteration in the cell cycle affects the regulation of how often a cell divides, cancer is produced. The tumor(s) that cancerous cells produce can have devastating effects on the entire organism. Cancerous tumors compete for the same resources that healthy tissue needs to thrive. Tumors often take up nutrition that would otherwise be used by healthy tissue, and produce waste that is toxic to the surrounding healthy tissue. If the cancerous cells metastasize (escape into the blood stream), tumors will spread throughout the body, affecting multiple organs and impair the host organism as a whole. Therefore, it is possible for a single cell that stopped responding to internal and external stimuli to multiply into many negatively impacting tumors that affect the entire organism.

How is cancer an example of how changes to a single cell can affect the health of an entire organism?

Prokaryotic cells are simple in structure when compared to eukaryotic cells. They contain non-membranous organelles, lack a cell nucleus, and have a simplistic genome: only one circular chromosome of limited size. Therefore, prokaryotic cell division, a process known as binary fission, is fast. The chromosome is duplicated prior to division. The two copies of the chromosome attach to opposing sides of the cellular membrane. Cytokinesis, the physical separation of the cell Eukaryotic Cells Mitosis: The division of the nucleus, separating the duplicated genome into two sets identical to the parent's. Cytokinesis: The division of the cytoplasm, separating the organelles and other cellular components. Meiosis: The division of the nucleus in sex cells, making one cell into four sex cells identical to the parent sex cell. Eukaryotic cells divide by separating the duplicated chromosomes, through movements directed by microtubules. it protect the organ system of our body.

How is the process of cell division in prokaryotes different from cell division in eukaryotes?

Technological advances will help address the ethical concerns surrounding stem cell research because technology might tweak the results of the cell. Because there dealt with by people and scientists, there might be a possibility that the outcome of the cell/ embryo is different.

How might technological advances help address the ethical concerns surrounding stem cell research?

The larger a cell becomes, the more demands the cell place on its DNA. In addition, a large cell is less efficient in moving nutrients and waste materials across the cell membrane.

Identify two reasons why a cell's growth is limited.

12

If a cell has 12 chromosomes, how many chromosomes will each of its daughter cells have after mitosis and cytokinesis?

The baseball would possess a larger ratio of area of cell membrane to cell volume When the cell increases the ratio begins to get smaller because the surface area is beginning to increase faster than the volume. See text book page 278 to read the question and read the section to get better examples and more information

If the baseball and basketball were cells, which would possess a larger ratio of area of cell membrane to cell volume?

Sexual reproduction; it will introduce new variations in DNA by recombination, by combining different gametes. increased variation leads to better selection. Leading to adaptation

In a changing environment which organisms have an advantage - those that reproduce asexually or those that reproduce sexually? Explain your answer

Duplicate its genetic information

In order for a cell to divide successfully, the cell must first

cell plate

In plant cells, what forms midway between the divided nuclei during cytokinesis?

1) Prophase - the genetic material inside the nucleus condenses and the duplicated chromosomes become visible. Outside the nucleus, a spindle starts to form. 2) Metaphase - the centromeres of the duplicated chromosomes line up across the center of the cell. Spindle fibers connect the centromere of each chromosome to the 2 poles of the spindle. 3) Anaphase - the chromosomes separate and move along the spindle fibers to opposite ends of the cell. 4) Telophase - chromosomes arrive at the poles, the microtubules disappear and the nuclear envelope forms

List the following stages of mitosis in the correct sequence, and describe what happens during each stage: anaphase metaphase prophase telophase

Internal Regulators and External Regulators Internal Regulators are proteins that respond to events occurring "inside" cell. Internal regulators allow the cell cycle to proceed only when certain events have occurred in the cell itself. External Regulators are proteins that respond to events occurring "outside" the cell. External regulators direct cells to speed up or slow down the cell cycle.

Name the two types of proteins that regulate the cell cycle. How do these proteins work?

growth and development and reproduction.

Recall what you learned about characteristics of life in Chapter 1. Explain how cell division is related to two or more of those characteristics.

centromere

Sister chromatids are attached to each other at an area called the

The presence of many nuclei indicates that mitosis has occurred repeatedly without cytokinesis having occurred, because there is still only one cell

Some cells have several nuclei within their cytoplasm. Considering the events in a typical cell cycle, which phase of the cell cycle is not operating when such cells form?

By providing the raw material for virtually every kind of human tissue, new treatments for a wide range of human diseases including diabetes, some forms of cancer, and Parkinson's disease can now be developed.

Summarize the potential benefits and issues of stem cell research.

If nerve cells do not necessarily go through mitosis which doesn't allow for growth and division of cells. Cells that are injured are not replaced hence absence of complete recovery.

The nerve cells in the human nervous system seldom undergo mitosis. Based on this information, explain why complete recovery from injuries to the nervous system does not occur

Humans and most animals and plants reproduce sexually, and so do some single-celled organisms.

What types of organisms reproduce sexually?

Interphase are phases divided into three parts as cell is being prepared for cell division. These three parts are G1, S and G2. G1 Phase is cell growth a period of intense growth and activity. Cells o most of their growing during G1 phase. In this phase, cells increase in size and synthesize new proteins and organelles. The "G" stands for "Gap". S Phase is DNA replication. The G1 phase is followed by S Phase. 'S' stands for "Synthesis". In the S phase, new DNA is synthesized when the chromosomes are replicated. At the end of S Phase the cell contains twice as much DNA as it did at beginning. G2 Phase is preparation for cell division. After completion of DNA replication the cell enter G2 phase which is the shortest of all three phases of interphase. In G2 phase many of the organelles and molecules required for cell division are produced.

Summarize what happens during interphase. Be sure to include all three parts of interphase. Hint: Include all of the main details in your summary.

It most resembles that of an animal because there is no evidence of a cell wall, as there would be in a plant cell. Also this cell has centrioles at the opposite ends of the spindles, and plant cells don't have centrioles.

The diagram shows a phase of mitosis. Use the diagram to answer the following questions. (Diagram on page 301 #20) Is this a plant or animal cell? How do you know?

The two strands carry the same genetic information which is important because the cell needs this information to function

The diagram shows a phase of mitosis. Use the diagram to answer the following questions. (Diagram on page 301 #20) The four chromosomes shown in the center of this cell each have two connected strands. Explain how the two strands on the same chromosome compare with regard to the genetic information they carry. In your answer, be sure to explain why this is important to the cell.

The cell is in metaphase.

The diagram shows a phase of mitosis. Use the diagram to answer the following questions. (Diagram on page 301 #20) Identify the phase of mitosis shown in the diagram

Basketball: R = 12.2 cm the surface area of the basketball is 1870.37 cm and the volume of the basketball is 7607.20 cm the ratio of surface area to volume is 1870.37 cm: 7607.20 cm Baseball: R = 3.6 cm the surface area of the basketball is 162.86 cm and the volume of the baseball is 195.43 cm the ratio of surface area to volume is 162.86 cm: 195.43 cm

The formula for finding the surface area of a sphere, such as a baseball or a basketball, is A = 4 TT r2, where r is the radius. The formula for finding the volume of a sphere is V = 4/3 TT r3. Calculate the surface area and the volume of the baseball and the basketball. Then, write the ratio of surface area to volume for each sphere.

sexual reproduction

The process that increases genetic diversity within a population is

surface area

The rate at which materials enter and leave the cell depends on the cell's

cyclins

The timing in the cell cycle in eukaryotic cells is believed to be controlled by a group of closely related proteins known as

As the temperature increases, the cell cycle takes shorter time to complete.

Use table Effect of Temperature on Length of Onion Cell Cycle pg 302 Given this set of data, what is one valid conclusion the scientist could state?

more than 54.6 hours As the temperature increases, the length of the cell cycle decreases and vise versa.

Use table Effect of Temperature on Length of Onion Cell Cycle pg 302 On the basis of the data in the table, how long would you expect the cell cycle to be at 5 degrees Celsius? a. less than 13.3 hours b. more than 54.6 hours c. between 29.8 and 54.6 hours d. about 20 hours

They are similar because they are both long-lived. They are different because the cells cannot divide.

Use the data table Life Spans of Various Cells on page 302 to answer question Based on the data, in what ways might injuries to the heart and spinal cord be similar? How might they differ fro injuries to smooth muscles?

cancer cells/ long-lived/can divide

Use the data table Life Spans of Various Cells on page 302 to answer question If cancer cells were added to the table, predict what would be written in the Life Span and Cell Division columns. Explain

Cell differentiation is a product of receiving certain signals at certain times and in certain concentrations which will turn on and turn off different genes and will result in a stem cell for instance to become a lung cell or a heart cell. now once cells begin to coalesce or bunch up together into groups and become distant from neighboring groups the signals are able to be differentiated well enough by groups of cells to continuously divide and form tissue.

Use what you learned in this lesson to discuss how cells become specialized for different functions. Include an explanation of now the potential for specialization varies with cell type and how it varies over the life span of an organism.

A chromosome is a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

What are chromosomes?

The unspecialized cells from which differentiated cells develop. These stem cells sit at the base of a branching "stem" of development from which different cell types form.

What are stem cells?

The centromeres would not attach to the spindle fibers and the chromosomes could not be pulled apart during anaphase.

What do you predict would happen if the spindle fi bers were disrupted during metaphase?

Mapping refers to what biologists equates an outcome/result to based on each and every cell division from fertilized egg to adult.

What does "mapping" refer to in the process of cell differentiation?

During the development of an organism, cells differentiate into many types of cells. A differentiated cell has become different from the embryonic cell that produced it and specialized to perform certain tasks/jobs (photosynthesis, protection...etc) that needs to be performed in order for us to stay alive.

What happens during differentiation?

Prophase:genetic material inside nucleus condenses and the duplicated chromosomes become visible; Metaphase:the centromeres of the duplicated chromosomes line up across the center of the cell and spindle fibers connect the centromere of each chromosome to the two poles of the spindle; Anaphase:chromosomes separate and move along the spindle fibers to the opposite ends of the cell; Telophase:chromosomes begin to spread out into a tangle of chromatin and the nuclear envelope reforms around the clusters of chromosomes

What happens during each of the four phases of mitosis? Write one or two sentences for each phase.

Asexual Reproduction is the process of reproduction involving a single parent that results in offspring that are genetically identical to the parent. Sexual Reproduction is a type or reproduction in which cells from two parents unite to form the first cell of a new organism.

What is asexual reproduction? What is sexual reproduction?

a mammalian blastula in which some differentiation of cells has occurred.

What is blastocyst?

Cell differentiation is the process where cells become specialized in structure and function, which means it's when cells decide what kind of cell they are going to be. If there were no cell differentiation, we would have only one type of cell that cannot do all the things that are different cells in her body do. With only one cell, we cannot accomplish all of our daily needs.

What is cell differentiation and how is it important to an organism's development?

It is division of cytoplasm and occurs during the telophase

What is cytokinesis and when does it occur?

The cell cycle is a series of events where a cell grows, prepares for division, and divides to form two daughter cells

What is the cell cycle?

The interphase is the phase of growth of a cell "in-between" its last cell division and the upcoming cell division

What is the relationship between interphase and cell division?

they could grow the cells and put them where the cells were lost in the patient

When researchers discovered how to make skin stem cells pluripotent, how did they apply their discovery to the treatment for heart attack patients?

New cells will grow to replace the cells removed. This is because cells will divide until they fill the space and come in contact with each other, they will stop dividing

When some cells are removed from the center f a tissue culture, will new cells replace the cells that were removed? Explain

B (look at illustration for pg 300 #10) the chromosomes are lined up across the center of the cell

Which of the illustrations best represents metaphase of mitosis? (look at page 300 # 10 illustration)

They respond to events occurring inside a cell

Which statement does NOT describe external regulatory proteins? a. They respond to events occurring inside a cell b. Growth factors are one group of external regulatory proteins c. They can speed up or slow down the cell cycle d. Some can cause cells to slow down or stop their cell cycles.

Totipotent

Which type of cell has the potential to develop into any type of cell?

As organs develop, there must be some mechanism to initiate and stop cell division, or the organ would simply continue to grow beyond what it should.

Why do you think it is important that cells have a "control system" to regulate the timing of cell division?

Because this means that there is an adequate exchange of nutrients, wastes, and other materials. So when the volume of a cell increases it means that this cell can contain and obtain more materials. However, it varies due to the cell membranes bilayer, since it only allows specific material into and out of the cell.

Why is a cell's surface area-to-volume ratio important?

because cancer cells fail to respond to internal and external growth regulators. There is no control over the cell cycle

Why is cancer considered a disease of the cell cycle?

Cyclins help to regulate the timing of the cell cycle, are present in cell mitosis, and promote spindle fiber formation. If cyclins were injected into a cell during mitosis which is a continuous process not a series events could lead to excessive growth and tumor formation. To test hypothesis observe normal mitosis process and record results. Then introduce cyclins during mitosis and record results. Compare results as Mitosis completes for both.

Write a hypothesis about what you think would happen if cyclin were injected into a cell during mitosis. How could you test your hypothesis?

Asexual Reproduction helps in the survival because the faster they reproduce, the better their chance of survival over other organisms using the same resources. Having offspring that are genetically identical is also an advantage as long as the conditions remain favorable. However, a lack of genetic diversity becomes a disadvantage when conditions change in ways that do not fit the characteristics of an organism. Sexual Reproduction is a different type of survival strategy. The process of finding a mate and the growth and development of offspring require more time. However, this can be an advantage for species that live in environments where seasonal changes affect weather conditions and food availability. It also provides genetic diversity. If an environment changes, some offspring may have the right combination of characteristics needed to survive.

what are the advantages and disadvantages of both asexual and sexual reproduction?