CELL STRUCTURE & FUNCTION

CELL WALL Main function –

provide support & protection for the cell

Made of cellulose (carbohydrates) and protiens

Located outside the cell membrane of plant, fungi, and some protist cells

CELL MEMBRANE Main function – outer boundary of cell;

regulates what can enter and exit the cell Composed of a phospholipid bilayer w/

proteins embedded in the membranes; carbohydrates may attach to proteins

CYTOPLASM Main function –

substance where organelles are suspended; site of many chemical reactions

Fluid substance that fills the space between the cell membrane and the nucleus

NUCLEUS Main function – controls

most cell processes and contains hereditary information (DNA)

Composed of a Nuclear membrane Nuclear pores Nucleolus Chromatin/Chromosomes

Located in all eukaryotic cells

Scanning ↑Transmission ↓

CHROMATIN/CHROMOSOMES Chromatin – DNA &

Protein when it is loose and thread-like; granular looking; most of the time

Chromosomes – DNA & Protein when it condenses to form distinct structures; when cells are dividing

NUCLEOLUS Main function –

production / assembly of ribosomes

Dense region within the nucleus

NUCLEAR MEMBRANE Main function –

surround and protect the contents of the nucleus

Double membrane layer

Dotted with thousands of nuclear pore which allow material to move into and out of the nucleus

CYTOSKELETON Main function – help the

cell maintain its shape; also involved in many forms of cell movement

Network of protein filaments Microfilaments –

smallest; movement & support

Intermediate filaments – medium sized

Microtubules – largest; transport; cilia; flagella

RIBOSOMES Main function – site

of protein synthesis Composed of RNA

and protein Can be free floating

in the cytoplasm or attached to endoplasmic reticulum

ENDOPLASMIC RETICULUM Rough ER Main

function – manufacture and distribution of proteins; ribosomes are attached

Smooth ER Main function – manufacture of lipids and break down toxins; NO ribosomes are attached

GOLGI APPARATUS Main Function –

modifies, packages, and distributes material in the cell; Material is received from the ER, modified in the Golgi, then sent to the cell or out of cell.

Stack of membranes

LYSOSOME Main function –

break down food and/or worn out organelles

Small sack containing digestive enzymes

VACUOLE Main function –

store materials such as water, salts, proteins, and carbohydrates

Plants have a large central vacuole that help the plant stand upright

Saclike structures

CHLOROPLASTS Main function – use

energy from sunlight to make energy-rich food molecules; site of photosynthesis

Double membrane structure that contain large states of green membranes; green color is due to the pigment chlorophyll

MITOCHONDRIA Main function – use

energy from food to make high-energy compounds that eh cell can use to power growth, development, and movement

Double membrane structure; inner membrane is highly folded

ENDOSYMBIOSIS

Theory that states - mitochondria and chloroplasts are descendents from ancient prokaryotic cells that were engulfed by other cells; the two cells formed a symbiotic relationship where both cells benefited. Evidence = mitochondria & chloroplasts have DNA, ribosomes, and can divide independently of the cell