Biology - Chapter 11

This is talking about Cell Division

What is cell division?

A process where a cell divides in two.

What is interphase?

Cell growth and preparation.

What does G1 phase do?

The cell growth to create more space for organelles.

What does S phase do?

DNA replication where 2 copies are needed before division.

What is G2 phase do?

The preparation for mitosis; reorganizing and moving of organelles.

How many phases are there in M Phase?

5 phases

What is prophase?

The nucleus condenses and chromosomes become visible and spindle fibers forms.

What is metaphase?

The chromosome line up in the center of cell, pulled apart by the centrioles and spindle fibers.

What is anaphase?

The chromosomes move apart with opposite pulls. The cell elongates.

What is telophase?

The cell begins to split; one cell but two times the parts.

What is cytokinesis?

Nuclear envelopes are formed, chromatids uncoil to form chromatin, and cytoplasm pinches in two.

What is the abbreviation to remember the order of the phases?

PMATC

What is the purpose of cell division in multicellular organisms?

Produce two daughter cells, the cell must replicate DNA before cell division, and dividing to make more smaller cells keep area to volume ratio higher.

How does cell division differ in prokaryotes and eukaryotes?

Prokaryotes DNA is packaged into a singular, circular chromosome, and in eukaryotes DNA is packaged into multiple chromosomes, found inside the nucleus.

How does cell division differ in plant and animal cells?

In animal cells the cell membrane is pinched until split in two. And in a plant cell a cell plate forms half way through the cell.

What is surface area?

The amount of “covering” of the object.

What is volume?

The amount of space inside the object.

What is the surface area to volume ratio? What does the number tell you about the cell?

The surface area to volume ratio is when they do not increase at the same rate. The numbers tell you that the smaller the cell the larger the ratio, the more efficient it is.

What cell has the largest surface area to volume ratio and why?

Smallest cell/cube, because the numbers of the ratio have a bigger difference in numbers.

What cell has the smallest surface area to volume ration and why?

Largest cell because the numbers of the ratio are closer together.

What is apoptosis and why does it happen?

Apoptosis is a process of programmed cell death. It happens because there has been an accident or the cells might be programmed to die.

What are some examples of Asexual Reproduction?

Bacteria and Hydra

What are some examples of sexual reproduction?

Animals and Plants

What are some advantages of Asexual Reproduction?

• Produce many offspring in a short period.

• Don’t need to find a mate.

• In stable environments genetically identical offspring thrive.

What are some disadvantages of Asexual Reproduction?

• If conditions change, offspring are not well adopted.

What are some advantages of Sexual Reproduction?

• In a changing environment genetic diversity can be beneficial (natural selection).

What are some disadvantages of Sexual Reproduction?

• Relatively fewer offspring;growth takes more time.

• Need to find a mate.

• And offspring may be less well adapted to current conditions (birth defect).

The cell cycle is controlled by what both inside and outside of the cell.

Regulatory Proteins

What are internal regulators?

They respond to events inside the cell. Let cell cycle proceed only when certain steps have happened.

What are external regulators?

They respond to events outside the cell cycle. Direct cells to speed up or slow down the cell cycle and growth factors wound healing and embyonic development.

What are growth factors?

Protein that stimulates the growth and division of cells.

What are cyclins?

Protein that regulates the cell cycle.

What are Stem Cells?

The unspecialized cells from which differentiated cells develop.

How many types of stem cells are there?

3: Totipotent, pluripotent, and multipotent.

Totipotent is located where and what is its’ function?

In fertilized eggs; Can develop into any type of cell in the body, including the cells that make up the extraembryonic membranes and placenta.

Pluripotent is located where and what is its’ function?

In blastocyst; Cells that are capable of developing most, but not all of the body’s cell type.

Multipotent is located where and what is its’ function?

Located mainly in bone marrow and hair follicles. Also in some brain, heart, and skeletal muscle; Limited potential to develop into many different types of differentiated cells.

CANCER CELLS

They do not respond to the signals that regulate the growth of most cells. As a result, the cell cycle is disrupted, and cells grow and divide uncontrollably.

NORMAL CELLS

They respond to the signals that regulate the growth of most cells. And as a result, the cell cycle is not disrupted, and the cells grow and divide as they should.

Definition of centromere?

The middle where two daughter cells come together and meet.

Definition of Centrosome?

They hold the tiny structures where centrioles are located.

Definition of Chromosomes?

Genetic information is bundled together into DNA.

Definition of Chromatin?

The complex of DNA and proteins that condenses into chromosomes.

Definition of Chromatid?

The name of the two daughter cells.

What are the limits to cell size?

The limits to cell size are the larger a cell becomes, the less efficient it is in moving nutrients and waste materials across the membrane. In addition, as a cell grows it places increasing demands on its own DNA.

How does surface area to volume ratio provide evidence for cell division?

Surface area to volume ratio provides evidence for cell division by allowing you to see how the size of the cell’s surface area grows compared to its volume.

Why does a cell divide?

A cell divides because with the cell dividing a more efficient exchange of materials between the cell and its environment can occur.

What is the difference between sexual and asexual reproduction?

Sexual reproduction is when 2 parents which involves the fusion of two separate parent cells. And asexual reproduction is when a single parent produces genetically identical offspring.

Which form of reproduction is better? Why?

Asexual reproduction is better because there are more positives than negatives while in sexual reproduction there are more negatives than positives.

Where and in what form is DNA within a cell?

DNA is in the nucleus in the form of a chromosome.

How do prokaryotic cells divide?

Prokaryotic cells go through binary fission. Once their DNA has been replicated, the two molecules move to different regions of the cell membrane. And then the cell slowly pinches to divide.

How do eukaryotic cells divide?

Eukaryotic cells go through four stages: G1, S, G2, and M. G1 is when the cell is growing, S is when the DNA is being replicated, G2 is when the cell is being prepared for mitosis, and M is when the cell divides. M phase consists of cytokinesis and mitosis.

How do chromosomes, chromatid, and chromatin and centromere relate?

They all relate by being combined together to make the bundles of DNA which is also known as chromosomes.

What are the phases of the cell cycle?

Interphase

Prophase

Metaphase

Anaphase

Telophase

Cytokinesis

How does cell division differ in plant and animal cells?

In animal cells the cell membrane is drawn inward until the cytoplasm is pinched into 2. While in plant cells a cell plate forms halfway between the divided nuclei then gradually hardens into the cell wall creating daughter cells.

What controls cell division?

Normal growth/ development and need/ repair control cell division.

What are the differences between internal and external regulators?

Internal regulators respond to events inside the cells and let the cell cycle proceed only when certain steps have happened. While external regulators respond to events outside the cell, direct cells to speed up or slow down the cell cycle, and growth factors wound healing and embryonic development.

Why is apoptosis an important process in cells?

Apoptosis is an important process in cells because it has an important role in structuring tissues in growth and development.

How do cancer cells differ from healthy cells?

Cancer cells spread rapidly while healthy cells spread controllably.

What are the different kinds of tumors and treatments?

The different kinds of tumors are benign- non cancerous, because it does not spread, and malignant- cancerous, because it invades, adds and destroys healthy tissue. The treatments are surgery to remove a localized tumor, radiation to destroy cancer cells DNA, and chemotherapy to kill cancer cells or slow their growth.

When and why does cell differentiation happen?

Cell differentiation happens when normal development and repair happens. It happens because the cells become specialized.

What are different stem cells and their functions?

Totipotent- can develop into any type of cell in the body, including the cells that make up the extraembryonic membranes and placenta.

Pluripotent- Cells that are capable of developing into most, but not all of the body’s call type. (Turn into any except embryo).

Multipotent- Limited potential to develop into many different types of differentiated cells.

What parts of stem cell research have ethical questions?

The parts of stem cell research that have ethical questions are adult human cells are not controversial because of the donor and embryonic human stem cells are controversial because of arguments for and against life and death.

What would happen if the cell was missing organelles like spindle fibers or centrioles?

If cells didn’t have organelles such as spindle fibers and centrioles then the cytoplasm would not get pulled apart to go through the specific function needed to divide.