1 BASIC UNITS OF LIFE Cells General Structure

1 BASIC UNITS OF LIFE Cells

General Structure of a Cell 2 Cells are basic structural and functional units of life. There are many different kinds of cells, which are specialized to carry out particular functions. Could be viewed as a factory with different departments carrying out specialized tasks.

Cell Parts 3 Cells – the basic unit of life Organelles - small structures inside a cell with specific functions.

In General 4 Extracellular Fluid – an aqueous (waterbased) solution that bathes the cells and surrounds them Cytosol – the aqueous solution INSIDE the cells

Membranes 5 Cell membrane Head Tail Membranes are made up of a double layer (bilayer) of fat molecules called phospholipids. Phospholipids have a head and tail.

Membranes 6 Each phospholipid can move around and “flows” past each other, so the membrane is said to be fluid Membranes also have other molecules (proteins and carbohydrates) stuck inside them Function: Regulates materials entering and exiting the cell. Structure: Two layers of phospholipids, proteins A flexible, skin-like layer surrounding cells and organelles

Nucleus 7 Nucleus 1. 2. Function: “Control Center. ” Regulates DNA & RNA actions. Structure: membrane bound, contains DNA

Nuclear Envelope 8 Nuclear Envelope 1. Function: Regulates what enters or exits the nucleus. 2. Structure: Double Layer of Lipids

Nucleolus 1. Function: Produces RNA, which are used to make all proteins. 2. Structure: Inside Nucleus, separate from DNA 9

DNA – Deoxyribonucleic acid DNA (chromatin) 1. Function: information on how to make proteins. a. Chromatin – unorganized DNA (normal state) b. Chromosomes – organized DNA (present before cell division 2. Structure: Made up of nucleotides, locked in the nucleus 10

Cytoplasm 11 Cytoplasm 1. 2. Function: All cell contents that lie between the cell membrane and the nucleus. (organelles + cytosol) a. Cytosol = liquid portion/non-organelles. Structure: made up of fluid and organelles except for nucleus

Ribosomes Free Ribosomes 1. Function: Makes proteins (protein synthesis). 2. Structure: small circular organelles 12

Endoplasmic Reticulum Rough ER Smooth ER 1. Function: Transportation route for proteins. a. Rough ER: has ribosomes b. Smooth ER: no ribosomes 2. Structure: tubes and channels 13

Vacuoles & Vesicles Function: Storage for water, nutrients or waste. In plants turgor pressure helps keep the cell membrane pressed firmly against cell wall. Structure: small membrane-bound organelle. 14

Golgi Apparatus 1. Function: Packages then sends fats and proteins out of the cell in vesicles. 2. Structure: Pancake-shaped layered organelle 15

Lysosomes (only in animal cells) Lysosomes 16 Function: packets of enzymes that break down materials in a cell. If the cell is old or sick, it will “commit suicide” in a process called apoptosis Structure: Small membrane-bound organelles

Mitochondria Function: Produce energy for the cell Cristae – folds where chemical reactions occur for cellular respiration Matrix – fluid where chemical reactions also occur Structure: Double membrane-bound, smooth outer and a highly folded inner one 17

Cytoskeleton Microfilaments Microtubules 1. Function: Provide support and structure for the cell. a. Microfilaments b. Microtubules 2. Structure: Tubules 18

Centrioles (Animals Only) Centrioles 1. Function: microtubules that help divide the cell during cell division. • Structure: Tubules 19

Cilia & Flagella Cilia 1. Function: provides movement for the cell or objects moving by the cell. 2. Structure: a. Flagella – 1 long fiber b. Cilia – many short fibers 20

Chloroplasts (Plants only) Chloroplasts 21 Function: site of photosynthesis (converting sun and CO 2 into sugar). Thylakoid – a membrane bound compartment found in chloroplasts Granum – stacks of thylakoids Stroma – protein rich fluid Structure: Membrane bound organelles that contain chlorophyll

Cell Wall (Plant cells only) Cell Wall 1. Function: Provides support for the cell and the plant. 2. Structure: Made of cellulose 22

Cell Parts Analogy 23 Create an analogy for the cell and its parts Possible ideas: � Stadium � School � Country � Restaurant � House � Mall � Waterpark

Stadium Example: 24 Cell membrane: wall of stadium, gates Cytoplasm: everything inside the stadium. Nucleus: the control room for the stadium. Etc… Animation of a Cell http: //www. ted. com/talks/david_bolinsky_anim ates_a_cell. html