Week 4 Cell Highlights PDF

Week 4 tutorial ANAT 1005 Quiz this week is for marks Questions about the mini lectures? Tutorial today will focus more on the cell’s organelles plus other material not covered on the mini-lectures Structure of the Plasma Membrane Extremely thin (6 n m -10 n m )...

Week 4 tutorial ANAT 1005 Quiz this week is for marks Questions about the mini lectures? Tutorial today will focus more on the cell’s organelles plus other material not covered on the mini-lectures Structure of the Plasma Membrane Extremely thin (6 n m -10 n m ) ano eter ano eter Plasma Membrane Components Lipid bilayer containing phospholipids, steroids, proteins, and carbohydrates – Lipids Functions – Proteins Isolation; protection; sensitivity; – Carbohydrates support; controls entry and exit of materials Cytosol (distributes materials by diffusion) Figure 3.2 Anatomy of a Model Cell Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Figure 3-7 Osmotic Flow Across a Plasma Membrane a Isotonic solution b Hypotonic solution c Hypertonic solution In an isotonic saline solution, no osmotic In a hypotonic solution, the water flows In a hypertonic solution, water moves flow occurs, and the shape of the red into the red blood cell. The swelling may out of the red blood cell. The cell blood cell (RBC) appears normal. continue until the plasma membrane shrivels and becomes crenated. ruptures, or lyses. Water molecules Solute molecules SEM of a normal RBC SEM of an RBC in a SEM of crenated RBCs in an isotonic solution hypotonic solution in a hypertonic solution Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved A Summary of Transport Processes (1 of 2) Table 3-2 A Summary of Passive and Active Membrane Transport Processes Process Description Factors Affecting Rate of Substances Involved Movement Diffusion Passive: molecular movement of Steepness of concentration Small inorganic ions; most solutes; direction determined by gradient,molecular size, electric gases and lipid-soluble relative concentrations charge, lipid solubility, temperature, materials (all cells) and presence of channel proteins Osmosis Passive; movement of water Concentration gradient, opposing Water only (all cells) molecules toward solution osmotic or hydrostatic pressure containing a relatively higher solute concentration across a selectively permeable membrane Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved A Summary of Transport Processes (2 of 2) Table 3-2 [continued] Carrier-mediated transport Process Description Factors Affecting Rate of Substances Involved Movement Facilitated Passive; carrier proteins Steepness of gradient, temperature, Glucose and amino acids diffusion passively transport solutes down and availability of carrier proteins (all cells) a concentration gradient Active Active: carrier proteins actively Availability of carrier proteins, Na+, K+, Ca2+, Mg2+ (all transport transport solutes regardless of substrate, and ATP cells); other solutes by any concentration Gradients specialized cells Vesicular transport Process Description Factors Affecting Rate of Substances Involved Movement Endocytosis Active; formation of vesicles Type depends on substance Fluids, nutrients (all cells); containing extracellular fluid or solid being moved into cell; requires debris, Pathogens material A TP (specialized cells) Exocytosis Active; fusion of intracellular vesicles Type depends on substance Fluids, debris (all cells) with plasma membrane to release being carried; requires A TP fluids and/or solids from the cell Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Figure 3.2 Anatomy of a Model Cell (1 of 2) Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Figure 3.2 Anatomy of a Model Cell (2 of 2) Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved The Nucleus (1 of 2) Usually the largest structure in a cell (mature RBCs have no nucleus and so they disintegrate in 3-4 months) Control center of the cell – Dictates cell function and structure by controlling protein synthesis Nuclear envelope – Double membrane that surrounds the nucleus – Separates nucleoplasm from cytosol Nuclear pores – Allow movement of substances into and out of the nucleus Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Microvilli Microvilli are small, finger- Microvilli shaped projections of the plasma membrane on exposed Plasma membrane extensions containing microfilaments surface of some cells Function Have internal core of Increase surface microfilaments for support area to aid absorption of extra- cellular materials Increase surface area of membrane Figure 3.2 Anatomy of a Model Cell Found on cells that are absorbing lots of materials from the extracellular fluid Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Cilia and Flagella Cilia Cilia (not shown in model cell) – Relatively long, slender extensions of plasma Cilia are long extensions of the plasma membrane containing membrane microtubules. There are two types: motile and primary. – Multiple motile cilia use ATP to move substances across cell Function surface Multiple motile cilia move materials over cell surfaces. A – Single, nonmotile primary solitary primary cilium acts as a sensor. cilium acts as signal sensor Flagella Figure 3.2 Anatomy of a Model Cell – Look like long cilia, but are used to move the cell through its environment Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Ribosomes Ribosomes Ribosomes – Manufacture proteins RNA + proteins; fixed ribosomes bound to rough endoplasmic reticulum, free ribosomes – Consist of small and large scattered in cytoplasm subunits Functions – Two major types Protein synthesis 1. Free ribosomes that are spread throughout Figure 3.2 Anatomy of a Model Cell cytoplasm 2. Fixed ribosomes attached to endoplasmic reticulum (ER) Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Endoplasmic Reticulum Network of intracellular Endoplasmic reticulum (ER) membranes Network of membranous Rough ER channels extending modifies and Continuous with nuclear throughout the cytoplasm packages newly synthesized proteins Functions envelope Synthesis of secretory products; intracellular storage and transport Smooth ER Forms hollow tubes, synthesizes lipids and carbohydrates flattened sheets, and chambers (cisternae) Figure 3.2 Anatomy of a Model Cell Two types: 1. Smooth endoplasmic reticulum (SER) 2. Rough endoplasmic reticulum (RER) Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Endoplasmic Reticulum Functions Four major functions: 1. Synthesis of proteins, Nucleus carbohydrates, and lipids 2. Storage of materials, Rough endoplasmic reticulum with fixed isolating them from the Ribosomes (attached) ribosomes cytosol Cisternae 3. Transport of materials Smooth through the cell endoplasmic reticulum 4. Detoxification of drugs or toxins Figure 3-13 The Endoplasmic Reticulum Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Mitochondria Provide energy for the cell – Number varies with cell’s energy demands Have a double membrane – The outer surrounds the organelle – The inner is folded to form the cristae ▪ Cristae increase surface area exposed to fluid matrix ▪ Enzymes in this matrix catalyze energy-producing reactions Mitochondria Double membrane, with inner membrane folds (cristae) enclosing important metabolic enzymes Functions Produce 95% of the ATP required by the cell Figure 3.2 Anatomy of a Model Cell Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Stages of a Cell’s Life Cycle (2 of 2) INTERPHASE S DNA replication, synthesis of histones G2 G1 Protein Normal synthesis cell functions plus cell growth, THE duplication of CELL organelles, CYCLE protein synthesis MITOSIS AND CYTOKINESIS (see Fig. 3-23) Figure 3-21 Stages of a Cell’s Life Cycle How is meiosis different from mitosis? Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Tumors Tumor or neoplasm is mass produced by abnormal cell growth and division – Benign tumors ▪ Usually and rarely life threatening – Malignant tumors ▪ Spread from original location or primary tumor through a process called invasion ▪ May also spread to distant tissues forming secondary tumors – Migration called metastasis Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved Cellular Differentiation Cellular specialization due to gene activation or repression All somatic cells in the body have the same chromosomes and genes – Yet develop to form a wide variety of cell types Differentiation – Occurs when specific genes are turned off, leaving the cell with limited capabilities – A collection of cells with specific functions is called a tissue Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved So What? What is the relevance of the cellular level of organization for nurses? Next week = tissue level of organization Copyright © 2020, 2017, 2013 Pearson Education, Inc. All Rights Reserved