Cell Structure and Function

Cell Structure and Function

• Life characteristics include a defined lifespan, growth, reproduction, energy requirements, and waste production, as well as repair.
• All living organisms are composed of cells, the basic organizational units.
• Cells arise from pre-existing cells.
• Cells come in two types, eukaryotic and prokaryotic. 
• Eukaryotic cells are generally larger and are common in multicellular organisms.
• Prokaryotic cells are smaller and have fewer organelles compared to eukaryotes.
• Organelles are structures within a cell that carry out functions to maintain life, and many organelles have specific functions.
• These organelles include, but are not limited to, the Cell membrane, Cytoplasm, Nucleus, DNA, Vacuoles/Vesicles, Mitochondria, Lysosomes, ER and Ribosomes, Golgi apparatus and Cytoskeleton.
• The cell membrane acts as protection and helps move substances in and out of the cells.
• The cytoplasm is the jelly-like substance that fills the cell, holding the organelles and nutrients.
• The nucleus is the control center that manages cell activities and contains DNA.
• DNA holds coded information for protein synthesis.
• Vacuoles and vesicles are membrane-bound sacs that store various substances including water, waste, and nutrients.
• Mitochondria are responsible for converting nutrients into energy for the cell.
• Lysosomes break down waste materials and damaged organelles.
• The endoplasmic reticulum (ER) and ribosomes work in protein production.
• The Golgi apparatus modifies, sorts, and packages proteins and materials.
• The cytoskeleton maintains cell shape and facilitates movement.

DNA and Genes

• DNA is the deoxyribonucleic acid, a crucial molecule that carries genetic instructions.
• DNA's structure is a double helix made up of nucleotides.
• The order of nucleotides in DNA forms a code that dictates protein production.
• Genes are segments of DNA responsible for specific traits, and can be passed down through generations.
• Chromosomes are large DNA molecules with segments of DNA that control various activities.
• Four types of nucleotides are adenine, thymine, cytosine, and guanine.
• These form pairs, and these pairs are on opposite sides to one another naturally.
• The order of these nucleotides in the DNA forms the specific sequence and determines the order of amino acids, thereby determining the protein.

Cell Cycle

• The cell cycle is a series of events that describes a cell's lifetime from formation to reproduction.
• Interphase is the preparatory phase where the cell grows and replicates its DNA.
• Gap 1 (G1), Synthesis (S), and Gap 2 (G2) are phases of the cell cycle
• Mitosis is the division of the nucleus followed by cytokinesis, which divides the rest of the cell.
• Mitosis is further composed of prophase, metaphase, anaphase, and telophase

Cancer

• Cancer is a disease caused by uncontrolled cell division.
• Factors such as lifestyle choices, genetic predisposition, and environmental factors (carcinogens) contribute to cancer development.
• Diagnostics methods including but not limited to blood tests, urine tests, X-rays, CT scans, ultrasounds, PET scans, X-rays and MRIs can help detect cancer cells.
• Treatments include surgery, chemotherapy, and radiation therapy,.
• DNA damage, uncontrolled division, DNA mutation can lead to cancer.

Stem Cells and Tissue Types

• Stem cells are a type of unspeicialized cell in the body that can produce specialized cells.
• Embryonic stem cells have more potential for differentiation, meaning they can develop into more cell types compared to adult stem cells.
• Adult stem cells have a more limited capacity for differentiation and are found mainly in specific regions, such as the bone marrow.
• Stem cells play a important role in tissue repair and regeneration.
• Epithelial tissue is the primary tissue that protects and lines cavities and organs.
• Connective tissue provides structure, support, and protection in various parts of the body.
• Muscle tissue is responsible for movement, and Nervous tissue is essential for communication and coordination in the body.

Plant Structures

• Plant tissues comprise meristematic, epidermal, ground, and vascular.
• Meristematic tissue is for growth.
• Epidermal protects the plant.
• Ground tissue fills space, and vascular tissue performs transport (xylem & phloem).
• Rooted tissues consist of xylem, phloem, cambium and epidermal.