CELLS & TISSUES Chapter 3 – Pgs. 42-59

1. CELLS & TISSUESChapter 3 – Pgs. 42-59 • Cells vary in size, shape, and function; the shape is closely related to function

2. Composition of CellNucleus, Cytoplasm, Cell Mebrane • Cytoplasmic organelles perform specific function, but the nucleus controls the overall activities of the cell

3. Cell Membrane (fluid mosaic)Fig. 3-1 • forms outermost boundary • selectively permeable – controls movement of substances into and out of cells • mainly phospholipids but also includes proteins, & carbohydrates • molecules lipid soluble will pass easily; barrier to water soluble substances • proteins function as receptors or form channels

5. Cytoplasm is the area between nucleus and cell membrane, contains organelles – Fig. 3-2, Table 3-1, ***Know functions of each organelle***

6. Nucleus • Enclosed in double layered (pores) nuclear envelope that controls the movement of substances between the nucleus& cytoplasm • Nucleolus is a dense body of protein & RNA that functions in the production of ribosomes • Chromatin is composed of loosely coiled fibers of protein and DNA that condenses into the structures known as chromosomes during cell division

8. Movements through cell membranes Passive transport – no energy required, substances move from an area of high concentration to low concentration (concentration gradient) – Fig. 3-2 • diffusion - scattering of molecules or ions from high concentration to low concentration - responsible for the exchange of oxygen and carbon dioxide within the body - rate of diffusion can be increased by short distance, high concentration of diffusion molecules, low molecular weight, & high temperature • facilitated diffusion – carrier molecules (usually proteins) transport a substance from [high] to [low]

11. Osmosis – H2O molecules move from [high] to [low] through a selectively permeable membrane – (Clinical Application pg. 54) • isotonic – a solution that neither gains or loses H2O, has the same concentration of solutes as the solution with which it is being compared • hypertonic – a solution that gains H2O because it has a higher concentration of solutes than the solution with which it is being compared • hypotonic – a solution that loses H2O because it has a lower concentration of solutes than the solution with which it is being compared

15. Filtration – forced – movement of molecules from regions of higher hydrostatic pressure to lower hydrostatic pressure • blood pressure causes filtration of H2O & dissolved substances through porous capillary walls • urine formation – nephrons of kidney

16. Filtration

17. Active Transport – requires energy (ATP) and involves the action of carrier molecules in the cell membrane; moves substance “up the concentration gradient”; from [low] to [high] – Table 3-3

18. Active Transport – requires energy (ATP) and involves the action of carrier molecules in the cell membrane; moves substance “up the concentration gradient”; from [low] to [high] – Table 3-3 • Permease (pump systems) – protein driven transport systems – Fig. 3-4 • Endocytosis – cells take in large molecules from their surrounding • Phagocytosis – large molecules, ex. – white blood cell engulfing bacteria • Pinocytosis – water and small molecules • Exocytosis – cells release materials

20. Sodium Potassium Pump

24. Cell Reproduction & Heredity • Mitosis – a parent cell divides once to produce two genetically identical daughter cells; daughter cells contain the same number of chromosomes as the parent cell; both are diploid in chromosome number (2n) • Meiosis – a parent cell divides twice to produce four cells (gametes) that contain a haploid (n) number of chromosomes; “male” & “female” gametes fuse at fertilization to produce a zygote (2n)

25. Mitosis

26. Meiosis

27. DNA & RNA carry genetic information • DNA – double helix, sugar is deoxyribose adenine (purine) – thymine (pyrimadine) guanine(purine) – cytosine (pyrimadine) • RNA – Single stranded, sugar is ribose, uracil (pyrimadine) replaces thymine • Gene – a segment of a chromosome that is made up of specific base pairs and codes for proteins

30. Protein Synthesis • transcription – synthesis of RNA using a DNA template • translation – the assembly of amino acids to form a polypeptide chain, in a sequence specified by the order of nucleotide in a molecule of mRNA

32. Cell Cycle – Interphase and Mitotic Phase (mitosis & cytokinesis) – Fig. 3-6 • Interphase – cell grows and “does its specific job”, chromosomes are replicated (duplicated) during this phase • Mitosis – division of the chromosomes – Table 3-5 **Know** • Cytokinesis – division of the cytoplasm

34. MITOSIS