Cellular Structures (Ch. 4 - BSC2010)

plasma membrane

bilayer of phospholipids and proteins that forms a barrier between interior of cell and its external environment

nucleoid

location of genetic material in a prokaryotic cell

ribosomes

synthesis of proteins or polypeptides

bacterial cell wall

protective layer made of peptidoglycan

capsule

thick protective layer found in some prokaryotes that enable them to attach to surfaces and to evade host immune system

pili

prokaryotic appendages used for horizontal gene transfer

cytosol

region within an eukaryotic cell that is outside the organelles but inside the plasma membrane where metabolic chemical reactions take place

cytoskeleton

a network of fibers composed of different types of proteins with different functions in cells

microtubules

type of cytoskeletal element made of tubulin; present in cilia and flagella; important in cell division and intracellular transport

intermediate filaments

type of cytoskeletal element made of keratin; present in cells that are subject to stretch; also present inside nucleus for support

microfilaments

type of cytoskeletal element made of actin; thin fibers important in muscle contractions and amoeboid movement

centrosome

structure inside cell from which microtubules originate from

motor proteins

proteins that use energy of ATP to promote various types of cellular movements

cilia

short, hairlike projections used for movement; numerous in a cell

flagella

long, whip-like projection used for movement

nucleus

command center of cell; place where genetic material is located

endomembrane system

a network of internal membranes that include the nuclear envelope, the endoplasmic reticulum, Golgi apparatus, lysosome, peroxisomes, vacuoles, and plasma membrane

nuclear envelope

a double membrane that surrounds the nucleus in the cell

nuclear pores

structures in the nuclear envelope that allow passage of certain materials between the cell nucleus and the cytoplasm

chromosome

piece of DNA that contains information to build proteins

nucleolus

found inside the nucleus and produces ribosomal subunits

rough endoplasmic reticulum (rough ER)

the portion of the endoplasmic reticulum that has ribosomes attached to it; important in protein synthesis and sorting

smooth endoplasmic reticulum (smooth ER)

the portion of the endoplasmic reticulum that does not have ribosomes attached to it. Involved in synthesis and secretion of lipids; detox; Calcium balance; and glycogen metabolism

Golgi apparatus

part of the endomembrane system; in charge of receiving, modifying, packaging, and sorting

central vacuole

organelle found in plant cells used for storage and support

contractile vacuole

structure found in unicellular protozoans that pumps water out of cell; used for osmoregulation

peroxisomes

contain enzyme catalase used to break down hydrogen peroxide into water and oxygen

mitochondria

powerhouse of the cell; ATP production; cellular respiration

matrix

innermost compartment of the mitochondrion

cristae

folds in the inner membrane of mitochondria

chloroplast

site of photosynthesis; contain chlorophyll; conversion of light energy into chemical energy

thylakoids

a flattened membrane sac inside the chloroplast, used to convert light energy to chemical energy.

granum

one stack of thylakoids

stroma

fluid portion of the chloroplast; outside of the thylakoids