Parts of the Cell

Bio201A

Ribosomes

function in protein synthesis (On the granular ER or in the cytoplasm)

Protoplasm

Living part of the cell

Cytoplasm

Area between nucleus and plasma membrane

Cytosol

Semi-fluid matrix in cytoplasm

Organelles

Subcellular structures with specific functions, most are membrane-bound

Nucleus

Directs metabolism, growth, development, and reproduction by directing protein synthesis

Nucleolus

Site of synthesis of ribosomal subunits and rRNA

Chromatin

DNA associated with proteins, in dividing cells they condense into chromosomes

vesicles

Short lived sacs enclosed by membrane, often used to transport molecules

Rough ER

Protein packaging and Protein secretion

Smooth ER

detoxifies drug and poisons, calcium ion storage

Golgi apparatus

relabels molecules for transport, modifies phospholipids

Lysosomes

Programs cell death and digests old macromolecules

Food vacuoles

store and break apart food in some protists

Contractile vacuoles

expel excess water in some protists

Central vacuoles in plants

helps maintain turgidity of cells, stores organic compounds and inorganic ions, break down organic molecules, stores pigments, dumping ground for toxic wastes

Endomembrane System

includes nuclear envelope, rER, sER, Golgi apparatus, lysosomes, vacuoles, and plasma membrane

Peroxisomes

contain catalase to break down hydrogen peroxide, detoxify alcohols

Mitochondria

site of aerobic cellular respiration, food is broken down to make ATP

Plastids

organelles in plants

Amyloplasts

store starch

Chromoplasts

plastids with colored pigments other than chlorophyll

Chloroplasts

photosynthesis, contain their own DNA and ribosomes

Thylakoids

internal membrane enclosed sacs, where light dependent reactions occur

Grana

stacks of thylakoids

Stroma

semi-fluid region outside of thylakoids where light independent reactions occur

Endosymbiosis

theory-

that mitochondria and chloroplasts are ancient prokaryotes that took up residence in the precursors of eukaryotic cells, survived, and started to divide independently of eukaryotic cell precursor. some of their genes are thought to have been moved into the nucleus of the host cell

evidence-

many symbiotic relationships between prokaryotes and eukaryotes are known to exist

mitochondria and chloroplasts are similar to bacteria in size and shape

both have their own single circular DNA not associated with histones mitochondria and chloroplasts both have ribosomes that are like prokaryotic ribosomes mitochondria and chloroplasts both divide independently of host cell and they divide like prokaryotes

inner membranes of both have enzymes and transport systems that are homologous to those found in living prokaryotes

Cytoskeleton

network of fibers throughout the cytoplasm that functions in movement and regulation

Microtubules

organelle movement and vesicle movement                   

Centrioles

help organize spindle apparatus that moves chromosomes during cell division

plant cells lack centrosomes with centrioles

Cilia

Many and short hair-like structures that move cell or move things past cell

Flagella

Few and long, hair-like structures that move cell or move things past cell

Microfilaments

cell division and organism movement

Intermediate Filaments

cell adhesion and holds organelles in place

Cell Wall

cell protection and support

Extracellular Matrix

provide tracks for cell movement and cell signaling

Plasmodesmata

functions in cell-to-cell communication

Desmosomes

cell adhesion, holds cell together

tight junctions

membranes of neighboring cells are fused with help of proteins, holds cells together tightly and forms a seal, function is cell adhesion

gap junctions

protein channels lined up between cells, function is cell to cell communication