Biopsy, Tumors and Cancer

• Biopsy is the removal and examination of tissue samples from a living body for diagnostic purposes.
• Tumors are abnormal masses of tissue that can be benign or malignant.
• Cancer is a disease caused by uncontrolled division of abnormal cells in a part of the body.
• Malignant tumors are cancerous and can invade and destroy nearby tissues and spread to other parts of the body.
• Benign tumors are non-cancerous and do not spread to other parts of the body.
• Metastasis is the spread of cancer cells from the primary site to other parts of the body.
• Somatic cells are any biological cells forming the body of a multicellular organism other than gametes, germ cells, gametocytes or undifferentiated stem cells.
• Gametes are mature haploid male or female germ cell that is able to unite with another of the opposite sex in sexual reproduction to form a zygote.
• Eukaryotes are organisms whose cells have a nucleus and other membrane-bound organelles.
• Prokaryotes are single-celled organisms that do not have a nucleus or other membrane-bound organelles.

Characteristics of Cancerous Cells vs Normal Cells

• Cancer cells have uncontrolled growth and division.
• They lack differentiation.
• They have the ability to invade other tissues.
• Cancer cells can induce angiogenesis (growth of new blood vessels).
• Normal cells have controlled growth and division.
• They have specific functions and structures.
• Normal cells undergo apoptosis (programmed cell death) when damaged.

Stages of Cell Cycle

• Interphase: The cell grows and replicates its DNA
• Prophase: Chromosomes condense and become visible, the nuclear membrane breaks down, and the spindle apparatus forms.
• Metaphase: Chromosomes line up along the metaphase plate.
• Anaphase: Sister chromatids separate and move to opposite poles of the cell.
• Telophase: Chromosomes arrive at opposite poles, the nuclear membrane reforms, and the cell begins to divide.
• Cytokinesis: The cytoplasm divides, resulting in two identical daughter cells.
• Homologous chromosomes are chromosome pairs (one from each parent) of approximately the same length, centromere position, and staining pattern, for genes with the same corresponding loci.
• The centromere is the region of a chromosome to which the microtubules of the spindle attach, via the kinetochore, during cell division.

Location and Function of DNA Replication

• It occurs in the nucleus.
• DNA replication is the process of copying a double-stranded DNA molecule.

Location and Function of Transcription

• It occurs in the nucleus.
• Transcription is the process of synthesizing RNA from a DNA template.

Location and Function of Translation

• It occurs in the cytoplasm on ribosomes.
• Translation is the process of synthesizing a protein from an mRNA template.

Role of mRNA

• Messenger RNA (mRNA) carries the genetic code from DNA in the nucleus to ribosomes in the cytoplasm.

Role of rRNA/Ribosomes

• Ribosomal RNA (rRNA) is a component of ribosomes
• Ribosomes are the site of protein synthesis

Role of tRNA

• Transfer RNA (tRNA) carries amino acids to the ribosome for protein synthesis.
• RNA polymerase synthesizes RNA from a DNA template, and DNA polymerase synthesizes DNA from a DNA template.

Mutations

• Point mutation: A change in a single nucleotide base in DNA.
• Frameshift mutation: Insertion or deletion of nucleotides that alters the reading frame of the genetic code
• Insertion: Addition of one or more nucleotide base pairs into a DNA sequence.
• Deletion: Removal of one or more nucleotide base pairs from a DNA sequence.
• Substitution: Replacement of one nucleotide base pair with another in a DNA sequence.