Biology Midterm 3 Part 1 Flashcards
Define cancer
Cancer is a disease that occurs when cells in the body grow and spread uncontrollably. Cancer can start in almost any tissue or organ in the body.
indentify and decribe the casues of cancer
Over 90% of cancers are observed to have some type of genetic alteration. Some of these alterations are inherited, while others are sporadic, which means they occur by chance or occur from environmental exposures (usually over many years)
identify methods of cancer treatment and prevention
Surgery: Removes cancerous cells and some nearby tissue
Chemotherapy: Uses strong medicines to kill cancer cells
Radiation therapy: Uses high doses of radiation to kill cancer cells and shrink tumors
Immunotherapy: Uses substances made by the body or in a lab to help the immune system fight cancer
Hormone therapy: Uses supplemental hormones to prevent or stop the growth or spread of tumors
Targeted therapy: Targets changes in cancer cells that help them grow, divide, and spread
Ablation: A non-invasive procedure that can use radiofrequency, microwave, high-intensity focused ultrasound, or cryoablation to damage tissue
describe the key stages of the cell cycle (interphase and miotic phase) and its relation to cancer
The cell cycle consists of two primary phases: interphase, where the cell grows and replicates its DNA, and the mitotic phase, where the cell divides into two daughter cells; the key point regarding cancer is that uncontrolled cell division arises from disruptions in the cell cycle checkpoints within interphase, allowing damaged cells to replicate and proliferate abnormally.
outline and diagram the steps of transcription and translation
Transcription and translation are the two key steps in gene expression, where genetic information from DNA is converted into a functional protein; transcription involves copying the DNA sequence into a messenger RNA (mRNA) molecule, while translation then uses the mRNA to assemble amino acids into a polypeptide chain, forming the protein
interpret and determine protein sequences (amino acids) from DNA/RNA
To interpret and determine protein sequences (amino acids) from DNA or RNA, you need to “translate” the nucleotide sequence into a chain of amino acids by reading the sequence in groups of three called codons, where each codon corresponds to a specific amino acid according to the genetic code table; essentially, the order of nucleotides in the DNA/RNA dictates the order of amino acids in the resulting protein
point mutations
a genetic mutation that occurs when a single base in a DNA or RNA sequence is changed, inserted, or deleted. Point mutations are the most common type of mutation
describe and contrast tumor suppressor genes and oncogens
Oncogenes are genes are mutated versions of proto-oncogenes, which are normal genes that stimulate cell growth and division. Oncogenes cause cells to grow and divide too quickly, which can lead to cancer. Tumor suppressor genes are genes normally inhibit cell proliferation and tumor development. They slow down cell division, repair DNA damage, and promote apoptosis, or programmed cell death. When tumor suppressor genes are mutated or inactivated, cells can grow out of control and lead to cancer
describe the basic structure of a chromosome, including how it is packaged into an elaborate, multilevel system of coiling and folding
A chromosome is essentially a long strand of DNA tightly coiled around proteins called histones, forming a complex, multi-level structure through a series of winding and folding mechanisms, allowing the vast length of DNA to be condensed into a compact unit within the nucleus of a cell; this packaging process begins with the formation of nucleosomes, which then further coil into thicker fibers, ultimately creating the visible chromosome structure, particularly noticeable during cell division
recognize the phases of mitosis from diagrams and micrographs
in prophase, chromosomes become visible and condense; in metaphase, chromosomes line up in the middle of the cell; in anaphase, sister chromatids separate and are pulled to opposite poles; and in telophase, new nuclear membranes form around the separated chromosomes; with the most distinct visual difference being the alignment of chromosomes at the metaphase plate and their separation during anaphase
outline and describe the pahses of mitosis
Prophase: Chromosomes coil up, Metaphase: Sister chromatids line up along, Cytokinesis: The cell splits up into two daughter cells, each with identical copies of DNA., Anaphase: Daughter chromosomes migrate to the opposite ends of the cell, Telophase: Chromosomes begin to uncoil, nuclear membrane reforms.
frameshift mutation
a genetic mutation that occurs when a DNA sequence is altered by the insertion or deletion of a number of nucleotides that is not a multiple of three
silent mutation
A silent mutation is a DNA change that doesn’t cause a noticeable effect on an organism’s phenotype. Silent mutations are also known as synonymous or samesense mutations.
nonsense mutation
A nonsense mutation occurs in DNA when a sequence change gives rise to a stop codon rather than a codon specifying an amino acid. The presence of the new stop codon results in the production of a shortened protein that is likely non-functional.
missense mutation
A genetic alteration in which a single base pair substitution alters the genetic code in a way that produces an amino acid that is different from the usual amino acid at that position. Some missense variants (or mutations) will alter the function of the protein.
