Cell Composition Mrs. Higgins, LVT Locust Trace Agriscience Center Veterinary Assistant Program

Chemical Composition Chemical composition plays an important role in cellular function. Composition of protoplasm consists of: Water: 85% Protein: 10% Lipids: 2% Inorganic matter: 1.5% Other (including carbs): 1.5%

Water Each cell is about 60-65% water Intracellular fluid is about 40% water Inside the cell Extracellular fluid is about 20% Outside the cell surrounding it Might also hear the term interstitial fluid (cerebrospinal fluid, fluid in joints, in the eyes, and visceral spaces)

Water % is going to vary between species Also varies because of: Age, condition, and state of hydration How do we replace water in our body? _____________ How do we eliminate water from our body? _______________ and ______________ Drinking Sweating Urinating

Proteins Next largest component of cell Complex, high weight molecules Proteins are made of amino acids Classified in one of two ways Structural: fibrous proteins like collagen, elastin, and keratin Reactive: enzymes, protein hormones, and contractile proteins (muscle cells)

Proteins Proteins are also found on the cell membrane. Serve a variety of functions: Membrane receptor for hormones and drugs Contributing to transport of water and particles in and out of cell **Serving as markers to permit the immune system to recognize cells as normal or abnormal body components

Lipids Fatty substance Insoluble in water Consist of carbon, hydrogen, and oxygen

Carbohydrates Carbon, hydrogen, and oxygen (CHO) Simple sugars (monosaccharide) Glucose: most prevalent simple sugar in body Disaccharide (two simple sugars combined) Sucrose (table sugar, glucose + fructose) Lactose (milk sugar, glucose + galactose)

Carbohydrates Glucose: source of all cell energy Glycolysis: enzymatic pathway that metabolizes glucose to produce energy Multiple glucose molecules can be linked together to form a polysaccharide called glycogen Two sites of glycogen synthesis Liver: stored glycogen can be broken down into glucose to be used by the liver or secreted into the bloodstream Skeletal muscle: glycogen stores can be used as an immediate source of energy for muscles (not able to be released into bloodstream)

Inorganic Matter 1-1.5% of cell composition There are 24 elements represented in the body (cell). 20 of them represent <1% of the make-up Electrolyte: also called “ion” Any molecular substance that in solution dissociates into its electrically charged components NaCl ->> Na+ and Cl-

Parts of the Cell

Parts of the Cell Parts of the cell includes: Cell membrane Cytoplasm Organelles Golgi apparatus Endoplasmic reticulum Mitochondria Lysosomes Nucleus

Cell Membrane Outer layer of the cell Cell membrane varies among different types of cells (proteins) Functions Transport substances across membrane Site for binding with substances in extracellular fluid Cell to cell junctions Recognition of other cells

Cell Membrane How do things get across the membrane? Type of Movement Description Simple Diffusion Passive movement; Distribution of a substance in a solvent (water) so it becomes evenly concentrated (greater concentration to lesser concentration) Facilitated Diffusion Same except it requires a carrier system (see picture) Osmosis Movement of water across membrane. Must move through channels formed by proteins Active Transport Molecules can move against concentrations because of charge *requires energy* Endocytosis and Exocytosis In previous notes

Cytoplasm Material filling inside of the cell Contains intracellular organelles and nucleus

Organelles The intracellular structures that are organized for a particular job (all of the “things” inside the cell) Example: Golgi apparatus, endoplasmic reticulum, ect.

Golgi Apparatus Varies in size and location in different cell types Looks like a “stacked” membranous sac Functions: Cite of synthesis and packaging for secretory products. The Golgi encloses the product in a vesicle for release by exocytosis

Endoplasmic Reticulum Membranous network found through cytoplasm. Rough endoplasmic reticulum: has ribosomes attached. Production of proteins Smooth ER: no ribosomes, stores lipids and steroids (carbohydrates)

Mitochondria Oval shaped organelle Double wall provides large surface area Produce energy for the cell Produces ATP (adenosine triphosphate)

Lysosomes Membrane-bound vesicle of digestive enzymes Must be in a membrane or the enzymes would kill the cell itself Can engulf cell organelles that are damaged and remove them. Can you name a cell that doesn’t have lysosomes?? ___________________ Red Blood Cells

Nucleus Contains the genetic material of the cell encoded in molecules of DNA Functions: Regulate protein synthesis Ensure the passage of genetic material (chromosomes) to subsequent generations of cells

Cell Division Mitosis Division of somatic cells to produce to identical daughter cells (all cells in body except sperm and eggs) Divided into periods Interphase Prophase Metaphase Anaphase Telophase

Cell Division Meiosis Division of reproductive cells Reduces the number of chromosomes to half prior to fertilization Like chromosomes are paired from each parent cell

Assignment