Cell Communication and Cell Cycle

• Mitosis involves four stages: prophase, metaphase, anaphase, and telophase.
• Benign and malignant tumors can be compared based on their characteristics.
• There are various ways to treat cancer.
• Cell-to-cell communication is essential for multicellular organisms, such as nerve cells must communicate with muscle cells for muscle contraction to occur.
• Chemical signals can pass from the cytosol of one cell to another through junctions like Gap Junctions & Plasmodesmata.
• Immune cells interact by cell-cell contact.
• Local regulators, also known as messenger molecules, travel only short distances and include hormones used in long-distance signaling.
• Hormones bind to receptor proteins in the cytoplasm, acting as a transcription factor by binding to a gene and turning it on.
• Hydrophobic hormones diffuse across the membrane and bind to intracellular receptors.
• Protein hormones are hydrophilic, so they bind to receptors found on the cell surface.
• Signal transduction pathway is a series of steps linking a chemical signal molecule to a particular cellular response.
• Humans have two sexes: females (XX) and males (XY).
• The sex-determining region Y (SRY) gene is ordinarily found on the Y-chromosome in placental and marsupial mammals.
• The SRY gene encodes a protein (transcription factor) that is involved in activating genes that leads to the development of male gonads (testes) and prevents the development of female reproductive features (uterus and fallopian tubes).
• Lack of the SRY gene leads to the formation of a female.
• A chromosome is a threadlike, gene-carrying structure found in the nucleus.
• Each eukaryotic chromosome is made of chromatin.
• During interphase, the DNA is found in the loose Chromatin state so the genes can be accessed easily.
• During prophase of mitosis, the chromatin coils and folds tightly into condensed chromosomes, so the sister chromatids can be separated easily during mitosis.
• A duplicated chromosome consists of 2 sister chromatids that are connected at the centromere and contain identical copies of original DNA.
• Signal transduction pathways can be initiated by direct contact or chemical signaling (local or long distance).
• Signal transduction stages include Reception, Transduction, and Response.
• Reception in signal transduction is the binding between a signal molecule (ligand) and a receptor, which is highly specific.
• Ligands bind to receptor proteins found in the plasma membrane, causing the intracellular domain of the receptor to change shape, allowing the receptor to interact with molecules relaying the message to the interior of the cell.
• There are three main types of membrane receptors: G protein-coupled receptors, Receptor tyrosine kinases, and Ligand-gated ion channel receptors.
• Ethylene is a hormone gas released by plant cells that promotes fruit ripening and has a positive feedback mechanism.
• Leaf abscission, or leaf drop in Autumn, is an example of apoptosis.
• The endocrine system consists of hormone-producing glands that regulate various bodily functions.
• Protein and lipid-based hormones differ in their mechanism of action.
• The hypothalamus, anterior pituitary, and the thyroid gland work together to regulate your metabolic rate.
• Homeostasis and negative feedback are terms used in the regulation of blood glucose levels.
• Positive feedback differs from negative feedback in that it promotes an increase in the initial stimulus.
• Cell division is an ordered series of events that occurs in a cell leading to its division into two cells.
• Interphase is the time when the cell is not dividing, but is preparing for division.
• Mitotic Phase is the cell division stage where mitosis and cytokinesis occur.
• Genome is the entire collection of an organism’s DNA.
• There are two main types of chromosomes: sex chromosomes and autosomes.
• Females are organized to receive genetic material, while males are organized to transmit genetic material.
• The sex-determination system varies based upon the species.
• Hermaphrodites, such as earthworms, have both functional male and female gonads (testes and ovaries).