Cancer, DNA, RNA, Transcription and Translation

• Cancer arises from the body's inability to control cell division, leading to a cellular disease.
• A tumor is a mass or lump of cancer cells.
• Benign tumors do not spread to other parts of the body.
• Malignant tumors can break off and spread.
• Metastasis is the spread of cancer from the primary site to other areas in the body.
• DNA consists of two strands joined in a double-helix structure and is composed of nucleotides.
• Semi-conservative replication involves DNA strands unwinding, with each acting as a template for a new strand.
• RNA is a single-stranded nucleic acid, comprised of ribose sugar, phosphate, and a nitrogenous base.
• DNA provides the instructions for the cell to make proteins.

Transcription and Translation

• Transcription uses DNA information to produce RNA.
• During transcription, one strand of DNA is read to create a strand of messenger RNA.
• After editing, the RNA exits the nucleus.
• Translation involves RNA moving from the nucleus to ribosomes, where it is translated into a protein.
• The messenger RNA is used to make protein.

Cancer Types

• Melanoma affects the skin.
• Leukemia affects white blood cells in the bone marrow.
• Carcinoma affects the lining of internal organs or skin.
• Sarcoma affects connective tissue, such as bone.
• Lymphoma affects cells and tissues of the immune system.

Body Systems

• The nervous system regulates and coordinates activities of all other systems and responds quickly to stimuli.
• The endocrine system secretes hormones to regulate and coordinate other systems, working more slowly than the nervous system.
• The respiratory system supplies blood with oxygen and removes carbon dioxide, while also regulating the blood's acid-base balance.
• The cardiovascular system transports oxygen and nutrients to tissue cells and removes waste, while also transporting hormones.
• The digestive system supplies blood with nutrients and water and removes nondigestible remains.
• The urinary system excretes waste and regulates water-salt and acid-base balance of the blood.
• The lymphatic system maintains blood volume, defends against disease, and collects excess interstitial fluid.
• The muscular system produces heat, protects and supports internal organs, and enables movement.
• The integumentary system helps maintain body temperature and protects internal organs.

Cell Cycle

• The cell cycle order is G1, S, G2, and M.
• G1 is the major growth phase of the cell cycle.
• During the S phase, DNA replicates, producing chromosomes with two sister chromatids attached at the centromere.
• In G2, chromosomes coil further, preparing for mitosis, and the mitotic spindle forms.
• Cell centrioles grow out spindle fibers (mitotic spindle) that attach to each sister chromatid.
• Mitosis includes eukaryotic nuclear division and cytokinesis (cell division).

Mitosis (PMAT)

• Prophase: Chromosomes condense, the nucleus breaks down, and the mitotic spindle forms and attaches fibers to each chromatid.

• Metaphase: Mitotic spindle fibers move chromosomes to line up in the middle of the cell.

• Anaphase: Mitotic spindle fibers pull one copy (chromatid) to each side/pole of the cell, separating them.

• Telophase: Chromatids reach opposite sides of the cell, the mitotic spindle breaks down, the nucleus reforms, chromosomes decondense, and the cell divides.

• Checkpoints regulate the cell cycle's speed, ensuring the cell is ready for division.

• Tumor-suppressor genes prevent unregulated cell growth by slowing down cell cycle progression.

• Mutations are changes to the nucleotide sequence of DNA, caused by chemicals, radiation, or viruses.

• Proto-oncogenes speed up the cell cycle.

• Mutations can cause proto-oncogenes to become oncogenes, leading to continuous division.

• Oncogenes trigger cancer.

Cancer Stages

• Stage 1: Cancer is limited to a small area and has not spread.
• Stage 2: Cancer has become invasive in more than one tissue but is still close to the original location; lymph may be involved.
• Stage 3: Cancer is in the lymph nodes but has not spread to distant organs.
• Stage 4: Cancer has fully metastasized.

Cancer Detection

• Complete blood tests assess normal blood cells and basic blood chemistry.
• Polymerase chain reaction (PCR) is used to make copies and determine genes of interest.
• DNA sequencing identifies mutations that increase the risk of cancer.
• CT scans provide 3D x-ray images of internal tissues.
• PET scans use radioactive tracers to measure cell metabolism; cancer cells are more active.
• MRI uses radio waves and magnets to detail soft tissue images.
• Mammograms are x-rays used to screen the breasts.

Cancer Treatment

• Chemotherapy uses chemicals to treat diseases by targeting the cell cycle of fast-growing cancer cells.
• Radiation with shorter wavelengths has more energy.
• Radiation therapy uses high-energy gamma rays and x-rays.
• External radiation uses x-rays or gamma rays to target a specific area of cancer.
• Internal radiation involves placing high doses of radioactive material in the body.
• Immunotherapy involves stimulating the body’s immune system to identify and eliminate cancer cells as "nonself".
• Cancer can occur when immune cells do not recognize cancer cells and do not destroy them.