Unit 2: More on Matter & Energy in Ecosystems. Macromolecules to Organelles to Cells

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2 Unit 2: More on Matter & Energy in Ecosystems Macromolecules to Organelles to Cells

3 Where are cells on the biological scale? Sub-Atomic Particles Atoms Molecules Macromolecules (proteins, lipids, nucleic acids, carbohydrates) Organelles Cells Let s scale up! Tissue Organs Organ System Organism Population Community Ecosystems Biome Biosphere Solar System Universe Atom Molecule Macromolecule Organelle Cell Tissue Organ System Organism Population Ecosystem Biome Biosphere Community

4 A sense of scale between living cells and atoms. Each diagram shows an image magnified by a factor of 10 in a progression from a thumb, to skin cells, to a ribosome, to a cluster of atoms forming part of one of the many protein molecules in our bodies.

5 I. Macromolecules Make up the Organelles of a Cell A. Proteins B. Carbohydrates C. Lipids D. Nucleic acids Cell Organelles

6 II. Cell Organelles A.Nucleus a.has a nuclear envelope and a nucleolus b.contains DNA c. Controls all cell activities

7 B. Mitochondria a.double membrane; football shape b. Power House of the cell 1. Food converted into ATP energy (adenosine triphosphate= gasoline of cells ) 2. Uses Oxygen, produces CO 2

8 C. Endoplasmic Reticulum a. Site where cell membrane and proteins are made b. Two types of ER membrane: Rough (ribosomes attached) and Smooth c. Highways of the cell

9 D. Golgi Apparatus - Receives and modifies proteins E. Lysosomes a. Cellular digestion b. Breakdown of waste

10 F. Cytoplasm (cytosol) - Water based, gel-like material where chemical reactions occur G. Cytoskeleton - Filaments Move organelles and the cell H. Vesicles - Sacs of material from the cell membrane, ER, and Golgi

11 I. Chloroplast (plant cells only) a. Bean-shaped; with numerous membranes b. Contains chlorophyll c. Where photosynthesis takes place

12 J. Ribosomes a. tiny molecular machine made of two subunits b. the site of protein synthesis

13 K. Cell Membrane (plasma membrane) a. Encloses cell and organelles b. Membrane is fluid-like and is constantly in motion c. Made of a phospholipid bilayer d. Phospholipids have non-polar, hydrophobic (water hating) ends that stick together and polar, hydrophilic (water loving) ends

14 II. Importance of the Cell Membrane a. Proteins on the surface and embedded in the cell membrane interact with lipid bilayer b. Membrane and proteins control what goes in and out of cell c. Proteins act like pores, channels, pumps and carriers d. Many enzymes in the cell membrane speed up chemical reactions e. Carbohydrate antenna embedded in membrane allows cells to communicate carbohydrates

15 III. Crossing the Cell Membrane A. The membrane is selectively permeable which means some things can and some cannot get through. B. Small, polar molecules pass through the membrane with ease Ex: Water, carbon dioxide, and oxygen C. Large, non-polar molecules and ions do not pass through without help Ex: glucose

16 Lets Review

17 1. What are the subunits for carbohydrates?

18 OUT: Cell Membrane Activity

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20 IV. Cells Respond to their Environment A. Homeostasis cells maintain a constant internal environment in response to environmental changes B. Assures balance and equilibrium to keep cells healthy

21 V. Maintaining Cell Homeostasis with and without Energy A. Passive Transport (Requires no Energy) a. Diffusion Molecules move from an area of higher concentration to an area of lower concentration b. Simple Diffusion Molecules move directly through the membrane. Molecules move with the concentration gradient (a difference in the concentration of molecules across a distance.)

22 c. Facilitated Diffusion carrier proteins help transport larger molecules and ions WITH their concentration gradient (from HIGH to LOW concentration)

23 d. Osmosis water molecules diffuse across a cell membrane 1. Water moves from an area of higher (water) concentration to an area of lower (water) concentration. 2. Water always moves in the direction of high solute. Solute molecule being dissolved Solvent the substance that dissolves the solute; usually water. Add to your notebook!

24 3. Osmosis affects cells. Types of Solutions: Hypotonic Solute concentration is lower outside the cell compared to inside the cell. (water moves in) Hypertonic Solute concentration is higher outside the cell compared to inside the cell. (water moves out) Isotonic Solute concentration is equal inside and outside the cell.

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26 B. Active Transport (Requires Energy) a. Carrier proteins move molecules against concentration gradient b. From LOW to HIGH

27 b. Movement in Vesicles - Some molecules are too large to transport through carrier proteins. 1. Endocytosis cell membrane pinches in and creates a vesicle enclosing macromolecules and large particles Ex: food and bacteria 2. Exocytosis - membrane vesicle fuses with cell membrane and releases material outside cell Ex: proteins, waste, and toxins Need Energy