BIO Unit Exam 4
environmental contributors to cancer
-Uv energy can cause DNA damage -radiation from X-ray machines Carcinogens: --smoking --asbestos --chemicals found in pesticides and herbicides --nitrates -viruses- HPV and Hepatitis C virus
cancer prevention
-foods high in fiber -increases of vegetables high in vitamin A and C -drink alcohol in moderation -Maintain a healthy weight -get vaccinated against HPV and Hep C.
signal transmission at the synapse
-neurotransmitters can be excitatory or inhibitory -they return to presynaptic neurons via re-uptake pumps
the synapse
-the events at the synapse: --nerve signals travel along an axon and reach an axon terminal --neurotransmitter (housed in vesicles in axon terminal) are released into the synaptic cleft and diffuse across to the receiving membrane and bind to receptors
cells divide
60-70 times and eventually undergo apoptosis. cancer cels are immortal and keep on dividing for an unlimited number of times -cancer cells are undifferentiated
What occurs in S?
A copy is made of all the DNA in the cell. DNA replication occurs, so each chromosome consists of two identical DNA double helix molecules. These molecules occur in the strands called sister chromatids.
G1- what occurs during this checkpoint?
Cell cycle main checkpoint. If DNA is damaged apoptosis will occur. Otherwise, the cell is committed to dividing when growth signals as present and nutrients are available.
what is a tumor?
Cells derived from a single mutated cell that has repeatedly undergone cell division
G0- when would the cell go into G0?
Cells go into Go if the cell is damaged, and G0 acts as a holding phase; if the DNA can be repaired, the cell may reenter the cell cycle if not then the internal mechanism cause the cell to undergo apoptosis.
why are checkpoints important?
Checkpoints are important because cells can't move through them until they meet certain conditions, failure of the cell cycle control mechanism may result in unrestricted cell growth or cancer
Tumor suppressor genes: what do these genes do regarding the cell cycle?
Code for proteins that inhibit the cycle and promotes apoptosis.
Proto-oncogenes: what do these genes do regarding the cell cycle?
Code from proteins that promote the cell cycle and prevent apoptosis from occurring.
Normal cells exhibit contact inhibition, explain what this means. Do cancer cells exhibit contact inhibition?
Contact inhibition means that when the cell comes in contact with a neighbor, they stop dividing. Cancer cells do not have contact inhibition they pile on top of one another.
Chemotherapy
DNA synthesis disruption
interphase
G1 phase- the cell grows larger, prepares for DNA replication S- DNA replication (synthesis0 -G2 phase- Growth, final preparations for cell divison
What are gametes? Do gametes have homologous chromosomes? What type of cell division produces gametes?
Gametes are haploid sex cells that join in fertilization to form a zygote. Haploid cells containing a single copy of each homologous chromosome are found only within games. Gametes are produced by meiotic cell division.
How many chromosomes are there in human cells? How many pairs of chromosomes? How many pairs of autosomes versus how many pairs of sex chromosomes?
Humans have 46 chromosomes which are in 23 pairs. There are 22 pairs of autosomes verses and one pair of sex chromosomes.
what is cancer?
Is a disease characterized by uncontrolled cell growth.
malignancy, primary tumor, and metastatic tumor
Malignancy occurs when cancer cells are found in nearby lymph nodes, the primary tumor is where the tumors point of origin, and a tumor has metastasized when nee tumors are found far from the primary tumor.
What are homologous chromosomes?
Member of a pair of chromosomes that are alike and come together in synapsis during prophase of the first meiotic division.
G2- what occurs during this checkpoint?
Mitosis checkpoint. Mitosis will occur if DNA has replicated properly. Apoptosis will occur if the DNA is damaged and cannot be repaired.
Do all cells move from G1 to s?
Not all cells move from G1 to S, some cells such as nerve and muscle cells typically do not complete the cell cycle and are permanently arrested in G1 because in neurons there is no cell cycle.
We say that one becomes cancerous when it is 'turned on' and one becomes cancerous when it is 'turned off', which is which?
Proto-oncogenes become cancerous when they are turned on whereas tumor suppressor genes become cancerous when they are turned on.
What are some environmental carcinogens?
Radiation, organic chemicals, smoking, pollutants, viruses, and dietary choices
What is G0?
Represents a holding stage outside the cell cycle where nondividing cells like neurons and muscles live.
What occurs in G1?
The cell returns to normal size and resumes its function in the body. A cell doubles its organelles, and it accumulates the materials needed for DNA synthesis.
What occurs in G2?
The cell synthesizes the protein needed for cell division, such as the protein found in microtubules.
Explain how genes on a pair of homologous chromosomes are for the same traits but can be of different types.
The chromosomes in a homologous pair each have the same genes in the same order, but there may be variations between them, resulting in different alleles
What divides during cytokinesis?
The cytoplasm and organelles divide during cytokinesis.
what divides in mitosis?
The nucleus divides into a parent cell and a daughter cell
What happens when a proto-oncogene becomes oncogenes?
When a proto-oncogene becomes oncogenes it becomes a cancer-causing mutation.
If a proto-oncogene is like a gas petal in the cell cycle, what happens to this gas petal when an oncogene is formed? How does this promote cancer?
When an oncogene is formed the mutation becomes very dominant which causes the cell to lose control of the cell cycle causing cancer, and since it acts as a gas pedal that means there is no brake to slow the mutation down.
What occurs when a tumor suppressor gene is mutated? Think of this as losing the brake on a car. What does this imply in terms of the cell cycle?
When an oncogene is formed the mutation becomes very dominant which causes the cell to lose control of the cell cycle causing cancer, and since it acts as a gas pedal that means there is no brake to slow the mutation down.
If cells are damaged your body programs them to go into apoptosis. Why would your body intentionally cause your cells to go into apoptosis?
Your body would intentionally cause apoptosis if the cell was damaged or mutated so that it could not divide and take over.
inhibitory
activates K+ channels
excitatory
activates Na+ channels
mitosis
body cell -the timing of cell division is tightly regulated -errors in cell division can lead to cancer
tumor suppressor gene
brake
malignant tumors
can invade surrounding tissues and their cells don't resemble normal cells. the tumor can spread throughout the body by traveling in blood or lymphatic vessels.
lymphomas
cancers of lymph tissue
leukemias
cancers of the blood
Radiation
cell cycle disruption
cytokinesis
division of the cytoplasm and the cell membrane
nerve signals
electrochemical changes that convey information within the nervous system
carcinomas
epithelial tissue (skin, lung, breast)
Immunotherapy
expose immune cells to antigen on cancer cells
proto-oncogene
gas petal
types of neurotranmitters
inhibitory- GABA, Serotonin (Mood) excitatory- acetylcholine both- Dopamine (Mood) -all thoughts, feelings, and actions are dependent on neurotransmitters -drugs control transmission of neurotransmitters thus, can alter mood, emotional state, behavior and personaility
cancer
is the result of multiple mutations progression from a single mutation to a tumor
what are neurotransmitters
molecules that transmit the neuron impulses
sarcoma
muscle and connective (bone)
G0
nondividing cells
contact inhibition
normal cells stop dividing when neighboring cells are senses -cancer cells have lost contact inhibiton, they pile up on one another and grow in multiple layers forming tumors
meiosis
produces gamates
turns on
proto-oncogene
mitosis
separation of the duplicated DNA and division of the necleus
benign tumor
surrounded by a connective tissue capsule, which prevents the tumor from invading adjacent tissue, resemble normal cells
neurons
transmit nerve impulses
turns off
tumor suppressor gene