Biology AHSGE

Standard IV- Cell Organelles

Biology AHSGE• Biology Standard 4. Describe similarities and

differences of cell organelles, using diagrams and tables.

A. Identify cell structures including cell membrane, cell wall, nucleus, ribosome, smooth endoplasmic reticulum, rough endoplasmic reticulum, Golgi body, vacuole, chloroplast, and mitochondrion.

B. Classify organisms as prokaryotic or eukaryotic.

Cells

• Cells- the smallest unit of life– Discovered by Robert Hooke

• The Cell Theory- All living things are composed of cells, cells are the basic unit of structure for all life, and all cells come from other cells.– Developed by Schwann, Schleiden

and Virchow

Cells • Unicellular- Organism composed of only one cell

– Kingdoms: Monera (Archaebacteria and Eubacteria) and Protista

• Mutlicellular- Organism composed of more than one cell– Kingdoms: Fungi, Plantae and Animalia

• Prokaryotic- Cells without a nucleus or membrane-bound organelles– Kingdom Monera (Archaebacteria and

Eubacteria)- bacteria, blue-green algae and viruses

• Eukaryotic- Cells containing a true nucleus and membrane-bound organelles– Kingdoms: Protista, Fungi, Plantae, and

Animalia *** Remember pro-no; eu-true

Cells

Organelles- Structures found within or on a cell which contain specific functions

• Nucleus- “Control Center” – Controls all intracellular

activity– Contains DNA (genetic

material, hereditary information, chromosomes, chromatin)

– Nucleolus- Center of nucleus where transcription occurs

– Nuclear membrane (envelope)- Outer covering of a nucleus which controls materials passage into and out of cell

Organelles• Cell Membrane (Plasma Membrane)- Outer

covering of a cell– Gives cells their shape– Protects the cell by controlling the passage of

materials into and out of the cell– Composed of a phospholipid bilayer and proteins

•Fluid mosaic model- creates a sea in which molecules can float

• Bilayer is tail to tail• Heads are on the outside, polar and attracted to water

which is also polar• Tails make up the non-polar middle of the bilayer which

repels water-soluble substances

Organelles• Cell Membrane cont’d:

– Receptors- proteins found on the outside of the membrane which transmit signals into the cell

– Inner surface proteins anchor the membrane to the cell’s internal support structures giving it shape

– Transport proteins- move needed substances or waste materials through the membrane

– Cholesterol- Prevents the fatty-acid tails from sticking together aiding the fluidity of the membrane

– Carbohydrates aid the receptors in identifying chemical signals

Cell Membrane

Organelles

• Cytoplasm (cytosol)- Jelly-like substance that fills the cell– Cushions and

protects the organelles from damage

– Allows for organelles to float

Organelles

• Endoplasmic reticulum- – Membrane system of folded

sacs and interconnected channels that serves as a site for ribosome attachment

– Always some attached to the outside of the nucleus

– Smooth- Has no ribosomes– Rough- Contains ribosomes

• Associated with protein synthesis

Organelles

• Ribosomes- Responsible for protein synthesis– Use amino acids

from RNA code

Organelles

• Mitochondria- “Power house”– Produces energy

(ATP) from glucose– Adenosine

triphosphate (ATP) is stored energy

• Converted to ADP (Adenosine diphosphate) to release energy from the broken bond

Organelles

• Golgi Complex (body, apparatus)- “Factory” or Warehouse”– Modifies, sorts, and

packages proteins into sacs called vesicles

– Vesicles fuse with membrane to release materials to the outside environment during active transport (exocytosis)

Organelles

• Lysosome- Digest excess or worn-out organelles and food particles– “Suicide sacs”

Organelles

• Cytoskeleton- A supporting network of long, thin protein fibers form a framework for the cell and provide an anchor for the organelles inside the cell– Microfilament- Thin, protein

threads that help give cell shape and parts to move

– Microtubule- Long, hollow protein cylinders that form a rigid skeleton and assist in movement of substances

Organelles

• Centrioles- Groups of microtubules that that function during cell division– Not found in plant

cells

Organelles• Vacuole-

Membrane-bound, fluid-filled organelle responsible for storage– Sometimes for

ingestion, digestion, excretion, and expulsion of excess water

Organelles

• Chloroplasts- Organelles that contain chlorophyll which captures energy from sunlight– Convert light energy from

sun into chemical energy (glucose) during photosynthesis

– Thylakoids- Inside/many small disk-shaped compartments of chlorophyll

– Belong to a group of cells called plastids

– Not found in animal cells

Organelles

• Cell Wall- Thick, rigid mesh of fibers that surrounds the plasma membrane for extra structure and support– Allows plants to

stand at various heights

– Made of cellulose

Organelles• Cilia (cilium)- Short, numerous projections on

the outside of some cells that look like hairs– Wave movement for locomotion– Found on respiratory tract and fallopian tubes– Paramecium

• Flagella (flagellum)- Long, less numerous projections on the outside of some cells that look like tails – Whip-like movement for locomotion– Found on sperm cells– Euglena

Plant vs. Animal