cell structure and function. all living things share common compounds: water: universal solvent –...

CELL STRUCTURE AND FUNCTION

All living things share common compounds:water: universal solvent – smaller is better

transporthydrolysis

carbohydrates: source of energy cell recognition

(monosaccharides, disaccharides, polysaccharides)lipids: source of energy

does not dissolve in water(saturated, unsaturated, polyunsaturated)

proteins: cellular growth and repair enzymes aid in diffusion and transport

(amino acids)nucleic acids: genetic codes and transmission

DNA: reproduction and function double strand RNA: protein synthesis single strand

All livings need:watershelterenergy- life processes

Photosynthesis: energy from sun stored in chemical bonds of sugarsRespiration: chemical reaction aided by enzymes to break bonds to release energy.

aerobic-oxygen=a lot of energy releasedanaerobic-lack of oxygen=not so much energy

releasedChemosynthesis: unicellular organisms obtain energy from inorganic compounds=minerals=little energy obtained

autotrophsheterotrophs

All living things will: grow(increase in the number of cells) and develop

(organs become more complex, mature) respond to environment: stimulus and appropriate

response reproduce: to continue the species

sexual: 2 cells-2 sets of DNA-similar offspring asexual: 1 cell-1 set of DNA-identical offspring stable internal environment: homeostasis

temperature (rise in could denature enzymes)blood pressurerespiration ratemetabolism rateheart rate

THE CELL!!! THE CELL THEORY1. ALL LIVING THINGS ARECOMPOSED OF CELLS.2. BASIC UNIT OF STRUCTUREAND FUNCTION3. PRODUCED FROM OTHERCELLS.

CELL MEMBRANEthin, flexible barriercholesterol-lipidselectively permeable

CELL WALLrigid, protective barriercellulose –carbohydrate

polysaccharide

Nucleus: brain of the cell contains genetic material – codes for function controls cell’s activities

prokaryotes: cell membrane and cytoplasm NO NUCLEUS

bacteria, staph, ecoli

Eukaryotes: cell membrane, cytoplasm, and nucleus

NUCLEAR ENVELOPE

Double membrane*pores

CHROMATINDNA+protein NUCLEOLUS

Production of proteins

Cytoplasm: jelly like substance that fills the cell 70% water

Cytoskeleton: network of protein filamentsmaintains shape

Microtubules: cell movement = cilia, flagella cell division=centriolesMicrofilaments: structure

Ribosomes: synthesis of proteins using codes from RNA

Endoplasmic Reticulum: movement of materialsrough: synthesis of proteins contain ribosomessmooth: contain enzymes-specialized tasks=

synthesis of lipids

Golgi bodies: package and transport materials in the cell, especially proteins: produced in RER

Lysosomes: cell’s waste disposal system enzymes break down lipids, carbs and proteins digest old organelles

Vacuoles: storage for water, salts, proteins, carbs plants – one large =storage and support**vesicles: small vacuoles used to transport

Chloroplasts: chlorophyll trap sunlight for photosynthesis

contain nucleus=reproduction

Mitochondria: powerhouse of the cell convert energy from food into ATP involved in cell death, cell division cellular respiration. contain nucleus=reproduction inherited from mother two membranes

Cell membrane – selectively permeableprotects, supportstakes in food and water

eliminates wastes structure of membrane: double layer made up of lipids called lipid bilayer=tough, flexible

Diffusion: movement of materials through the membrane based on concentration: high concentration to low concentration**when concentration inside is equal to concentrationoutside the system has reached equilibrium

Molecules will continue to move into and out of the cell to maintain equilibrium.

Osmosis: diffusion of water across a selectively permeable membrane.

Isotonic: equal in outHypotonic: more in than out swollen cellHypertonic: more out than in shrunken cell

Osmotic pressure: force exerted by too much fluid inside a cell-a result of movement of fluid from high concentration to low concentration. This pressure could cause cells to burst.

Freshwater would be a problem for most cells in a living organism because of the salt content in the fluids that surround cells.

In large living organisms, cells do not come in contact with fresh water because these cells are surrounded by fluids such as blood which is isotonic.

Cells that would come in contact with fresh water such as plants and bacteria correct this osmotic pressure in two ways:

1. cell wall prevents cells from expanding2. contractile vacuoles-vacuoles that have the

ability to contract or pump rhythmicallyto push water out of the cell.

Some molecules such as water, alcohol, and small lipids can diffuse or move through the lipid bilayer into the cell. Others cannot-size, polarity.

Facilitated diffusion is a process that uses special proteins to allow these molecules to pass into the cell

http://highered.mcgraw-hill.com/sites/9834092339/student_view0/chapter38/how_facilitated_diffusion_works.html

Summary of diffusion

SODIUMCALCIUMPOTASSIUM

These elements are important for musclecontraction such as the …….

Na

Transportprotein

Active transport-diffusion that requires energy low concentration to high concentration Seen mostly with ions such as potassium and sodium. Concentrations of these ions are lower outside the cell than inside the cell. Special proteins imbedded in the cell membrane act like pumps to pump these ions into the cell.

If a molecule is to be transported from an area of low concentration to an area of high concentration, work must be done to overcome the influences of diffusion and osmosis. Since in the normal state of a cell, large concentration differences in K+, Na+ and Ca2+ are maintained, it is evident that active transport mechanisms are at work.

Two other ways cells bring materials in are: endocytosis: cell membrane engulfs material, forming a vacuole within in the cytoplasm. Size is not a factor and material can be a liquid or a solid

Phagocytosis: engulfs molecules larger than endocytosis materials are solids only

Removal of large amount of material are known as exocytosis- membrane of vacuole fuses with cell membrane and contents are released

Unicellular: prokaryotes and eukaryotes may contain chloroplasts very adaptable reproduce easily and quickly offspring are identical live independently

Multicellular: eukaryotes interdependent specialized cells

Levels of organization: cell tissue organ organ system