Biology - Regulating the cell cycle & Cell differentiation

how do cancer cells differ from other cells?

-Cancer cells don't respond to the signals that regulate the growth of most cells. -the cells divide uncontrollably. -they do not perform apoptosis

what is cloning?

-Cloning is a type of asexual reproduction. It produces cells that are genetically identical to an original cell. -when the nucleus is removed from a somatic cell and is implanted into an enucleated egg cell. these are then incubated until they are a blastocyst which can then be inserted into the surrogate (mother)

relationship between MPF and the cell cycle?

-Cyclin binds with an enzyme to produce MPF Cyclin, and as its concentration rises, it promotes mitosis. -(the more cyclin/MPF, the faster cells divide)

How do the mutated (cancer) cells show evidence that they do not respond to contact inhibition? how would this result in the spread of cancerous cells?

-Rather than dividing until the cells come in contact with one another, the mutated cells continue dividing after having come in contact with one another, forming a tumor-like demonstration. -When a cancerous cell lacks contact inhibition, it will continue to divide after coming into contact with other cells, and therefore, it will continue to grow and spread in the form of tumor(s). These cancerous cells also have the ability to spread through the blood stream, nervous system, etc.

what happens if cell cycle regulators don't function properly?

-an organism may end up with too few or too many cells -can cause health issues

cyclin...RIP: process

-apoptosis step 1: the cell and its chromatin shrink step 2: parts of the cell's membrane break off step 3: neighboring cells clean up the cell's remains

What is the difference between cancer cells and normal cells?

-cancer cells lack the ordered arrangement of normal cells -cancer cells divide more rapidly than normal cells -cancer cells absorb nutrients that normal cells need to survive -cancer cells may stop organs from functioning properly while normal cells help them to function properly -cancer cells sometimes have multiple nuclei or have an abnormally shaped one

totipotent

-cells that are able to develop into any type of cell found in the body (including cells that make up the placenta) -think "totally" -toti = entirely

pluripotent

-cells that are capable of developing in to most, but not all, of the body's cell types -pluri = several

embryonic stem cells vs adult stem cells

-embryonic stem cells can be totipotent or pluripotent (can differentiate into any type of cell) Adult stem cells are multipotent (can only differentiate into different types of blood cells) -adult stem cells are found in the bone marrow -embryonic stem cells are found in early human embryos

cancer

-excessive cell growth and division -some of the body's cells lose the ability to control growth -lack of apoptosis -cancerous cells can create a tumor -absorb nutrients necessary for other healthy cells -can spread through the blood stream, nervous system, etc.

regeneration

-growth of a new lost tissue, destroyed part, or organs -think of starfish

what are some possible benefits and issues associated with stem cell research?

-hold potential cures for hundreds of immune system and genetic disorders -medical risks -conflicts with legal or ethical standards

what signals cells to tell them what they will become? their fate?

-internal signals: cytoplasmic factors -external factors: cell-to-cell interactions

adult stem cells

-multipotent -giver rise to a limited variety of cell types -mainly produce cells for tissues in the blood and skin that have a limited life span and must be constantly replaced

what regulators push the cell cycle forward? what regulators make things stop?

-positive (go) -negative (stop)

apoptosis

-programmed cell death -helps regulate cell population and tissues

cyclin

-proteins that help regulate the timing of the cell cycle in eukaryotic cells -when injected into non-dividing cells, spindle fibers form -cyclin = a mitosis promoting factor (MPE) -have a rise and fall pattern

internal regulators

-proteins that respond to events occurring inside of the cell -serve as checkpoints -does not allow cell cycle to continue until each checkpoint is successfully completed

external regulators

-proteins that respond to events occurring outside of the cell -directs cells to speed up or slow down the cell cycle -prevent excessive cell growth and keeps body tissues from disrupting one another, while also allowing cells to grow a healthy amount (growth factors)

name 5 examples of different types of cells and their function

-red blood cell: specialized in carrying oxygen throughout the body -white blood cell: specialize in treating infections -skin cell: produce vitamin D, heal wounds -nerve cell: specialize in communication -pancreatic B cell: produce insulin

stem cells and zygotes

-stem cells are categorized based on their potency, or the diversity of cell types they can become as they differentiate -the zygote is known to be totipotent -after about 4 days of development, a human embryo forms into a blastocyst

growth factors

-stimulate the growth and division of cells -extremely important when it comes to embryonic development and wound healing -type of external regulator

how do some cells become specialized for different functions?

-through the process of differentiation -unspecialized cells develop into specialized cells when stem cells go through many cell divisions (begin as totipotent and move down the line) -daughter cells from each division follow a specific path toward the role of a specific kind of cell -stem cells --> embryonic stem cells --> specialized cell

stimulate

-to encourage something to become active, grow, develop

1) what cells do not divide once they have developed? 2) what cells grow and divide throughout their life?

1) muscle cells, nerve cells 2) skin cells, blood producing cells, digestive tract cells

How does apoptosis relate to cancer cells?

In cancer cells, too little apoptosis occurs, resulting in malignant cells that will not undergo programmed cell death.

Gurdon inserted the nucleus of a differentiated tadpole cell into an enucleated frog egg, meaning the nucleus was removed. The frog egg then developed into a normal frog embryo. Which conclusion is supported by these results?

Factors in the nucleus of the egg cell affect cell development.

cell cycle checkpoints

G1: is the cell growing well enough? is the DNA damaged? does the cell have proper resources G2: if DNA is replicated properly, is cell is growing well enough, if cell has proper resources M: ensures chromosomes are lined up in the middle correctly and are attached to the spindles

what does the p53 protein do?

initiates apoptosis

the blastocyst is the fertilized egg that implants in the uterine wall. the outer layer becomes the placenta. What is the name of the inner part that will develop into a living organism?

inner cell mass/embryotic stem cells

tumor

mass of rapidly dividing cells that can damage surrounding tissue

is an adult stem cell totipotent, multipotent, or pluripotent?

multipotent

proteins involved in negative regulation

p53 (initiates apoptosis)

are embryonic stem cells totipotent, multipotent, or pluripotent?

pluripotent

differentiation

process in which cells become specialized in structure and function

treatments for cancer

surgery, radiation, treatment with chemical compounds

During the development of a multicellular organisms, which cells are totipotent?

the fertilized egg and the cells produced by the first few cell divisions

is a zygote totipotent, multipotent, or pluripotent?

totipotent

what are stem cells?

unspecialized cells from which differentiated cells develop

When does the Mitosis-promoting factor (Cyclin concentration) decline during a typical cell cycle in clam eggs?

when the cell nucleus divides

What is the relationship between mutation, the cell cycle, and cancer? Select all statements that apply. a) Mutated genes typically allow cells to respond to checkpoint proteins that halt the cell cycle, thus avoiding formation of tumors. b) As a result of unregulated cell cycles, cells may become cancerous, meaning that the cells grow and divide uncontrollably. c) Cancerous cells may form malignant tumors that invade and destroy surrounding healthy tissue. d) Mutated, defective genes may cause cells to become unable to respond to signals that regulate the cell cycle.

b, c, d

2 proteins involved in positive regulation

cdk (enzyme), cyclin

multipotent

cell with limited potential to develop into many types of differentiated cells

embryo

developing stage of a multicellular organism

true or false: cells grow as you grow bigger

false: cells do not grow, they divide into more cells by reproduction/mitosis

blastocyst

a hollow ball of cells with a cluster of cells inside, known as the inner-cell mass

Which is the most likely application of stem cell research?

a treatment for macular degeneration, in which cells of the eye are damaged or killed

By regulating the cell cycle, multicellular organisms gain which of these benefits? a) eliminating unnecessary genes b) healing wounds effectively c) replacing lost cells d) preventing communication among cells

b and c

How is the cell cycle regulated?

The cell cycle is controlled by regulatory proteins both inside and outside the cell.