40 Questions
What is a necessary condition for a gene to be cancer-inducing?
Both copies of the gene must be affected
What is the primary function of the immune system?
To surveil the human body to destroy viruses and foreign cell types
Which cells of the immune system engulf and destroy foreign particles?
Macrophages and natural killer cells
What is the reason why normal human cells have a finite ability to undergo mitosis?
Due to the shortening of telomeres
What enables cancer cells to exceed Hayflick's limit and continue to undergo mitosis?
The ability to elongate telomeres using telomerase
What is the role of PDL-1 and PDL-2 antigens in cancer cells?
To inhibit T cells that would normally attack cancer cells
What is the definition of metastasis?
The process by which tumor cells move from the primary tumor to a different organ via lymph and/or blood
What is the function of the tumor suppressor gene p53?
To stop the cell cycle upon detection of DNA damage
What is the term for the state of being able to metastasize?
Metastatic
How do normal cells respond to abundant DNA damage and other cellular stresses?
They initiate apoptosis
What is a hallmark of cancer cells?
The ability to proliferate due to over-active oncogenes
What is the characteristic of benign tumors?
They are unable to invade neighboring tissue and metastasize
How do cancer cells divert metabolites?
By diverting metabolites for useful processes such as mitosis
What is the most common secondary site for cancer metastasis?
Lung and liver
What is the primary tumor growth characterized by?
Cells grow uncontrollably until they become a mass
What is the difference between normal cells and cancer cells in terms of glucose breakdown?
Normal cells break down glucose to pyruvate, while cancer cells break it down to lactate
What is the primary cause of cancer in the human body?
Abnormal cell division in a specific part of the body
What type of cancer arises from epithelial tissue in organs or glands?
Carcinoma
What is the effect of an activating mutation on a gene?
It causes the gene to be expressed at the wrong time, at the wrong level, or with a new function
What type of mutation is inherited from parents and present in germ cells?
Germline mutation
What is the Two Hit Hypothesis in relation to genetic mutations?
Both alleles of a gene must be mutated for cancer to occur
What is the main difference between somatic and germline mutations?
Germline mutations are inherited, while somatic mutations are acquired
What is the increased risk associated with inheriting a BRCA1/2 mutation?
Breast cancer
What is the type of cancer that arises from connective tissue?
Sarcoma
What is the main premise of the scientific theory of evolution?
That all living organisms on Earth descended from a common ancestor
What is the primary mechanism driving the process of evolution?
Natural selection
Which of the following is a key principle of Darwinian evolution?
Variation exists among individuals within a population
What is the term for a trait that improves an organism's chance of survival and reproduction?
Adaptation
What is the ultimate outcome of natural selection acting on a population over time?
The population evolves into a new species
What is the estimated percentage of species that have ever lived on Earth that have become extinct?
99%
Which of the following is a key aspect of gradualism?
Species originate through a gradual change of adaptations
What is the term for the process by which an organism's genes and their frequencies change over time?
Evolution
What is the primary mechanism by which genetic changes occur in punctuated equilibrium?
Rapid genetic changes in response to environmental pressures
What is the primary goal of artificial selection in genetic engineering?
To create genetically modified organisms with desired traits
What is the primary difference between inbreeding and hybridization in genetic engineering?
Inbreeding involves breeding within a species, while hybridization involves crossing two species
What is the primary risk associated with inbreeding in genetic engineering?
The increased risk of recessive genetic disorders
What is the primary purpose of cloning in genetic engineering?
To create an exact genetic copy of an organism
What is the primary characteristic of punctuated equilibrium in terms of the fossil record?
A rapid and episodic record of evolutionary changes
What is the primary difference between genetic engineering and traditional breeding practices?
Genetic engineering involves the use of biotechnology to modify genes, while traditional breeding practices rely on natural selection
What is the primary advantage of genetic engineering over traditional breeding practices?
Genetic engineering is faster and more precise than traditional breeding practices
Study Notes
Cancer
- Cancer is caused by an uncontrolled division of abnormal cells in a part of the body.
- It is caused by an accumulation of detrimental variations in the genome over the course of a lifetime.
Types of Cancer
- There are four main types of cancer:
- Carcinoma: Arises in epithelial tissue that is found in the internal and external lining of the body.
- Sarcoma: Arises from connective tissue that is found in bones, tendons, cartilage, muscle, and fat.
- Leukemia: Cancers of the blood that originate in bone marrow.
- Lymphoma: Cancers of the lymph system.
Mutations
- Activating mutations: Cause the gene to be expressed at the wrong time, at the wrong level, or with a new function.
- Inactivating mutations: Cause reduced function of a gene (less RNA or protein is made).
Somatic and Germline Mutations
- Somatic mutations: Acquired by a somatic cell (all cells except eggs or sperm) that are passed on to daughter cells during cell proliferation.
- Germline mutations (inherited mutations): Present in a germ cell (egg or sperm) and are inherited by offspring.
Two Hit Hypothesis
- For a gene to be cancer-inducing, both copies of the gene must be affected.
- The second "hit" may alter the DNA (mutation) or alter the expression of the DNA (epigenetic).
Hallmarks of Cancer Cells
- Cancer cells can greatly exceed "Hayflick's limit" and continue to undergo mitosis.
- Cancer cells are able to do this because they can elongate their telomeres using an enzyme called telomerase.
Tumor Suppressor Genes
- A Tumor Suppressor Gene, p53, functions as a central regulator of cell death because it stops the cell cycle upon detection of DNA damage.
Cancer Cell Characteristics
- Cancer cells have the ability to proliferate due to the aforementioned Hallmarks 1--4 as well as to over-active oncogenes.
- Cancer cells have altered metabolism, and are able to divert metabolites for useful processes such as mitosis.
- Cancer cells can protect themselves by inhibiting T cells that would normally attack these cancer cells by having the PDL-1 (Programmed Death Ligand -1) or PDL-2 antigen which deflects the immune response.
Metastasis
- The process by which tumor cells move from the primary tumor to a different organ via lymph and/or blood.
- Cancer cells can metastasize to a secondary site, such as the lung and liver.
Evolution and Genetic Engineering
- Evolution: Change in populations over time.
- Important principles of Darwinian Evolution include variation, heritability, and reproductive advantage.
- Genetic Engineering: Changing the DNA in living organisms to create something. These organisms are called Genetically Modified Organism (GMO).
Learn about the causes of cancer, and the different types of cancer, including carcinoma, sarcoma, and leukemia.
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