Nucleus & Ribosomes

lysosome

membrane bound vesicles produced by the Golgi apparatus; contains digestive enzymes breaking apart old cell parts or substances entering cell (pathogens with white blood cells)

ribosome

particles conducting protein synthesis

ribosomal RNA

produced in the nucleolus, a dark region of chromatin where rRNA joins with proteins to make the subunits of ribosomes.

endoplasmic reticulum

system of membranous channels and saccules (flattened vesicles) is continuous with the nuclear envelope. form vesicles transporting molecules to other parts of the cell, notably the Golgi apparatus.

messenger RNA

intermediary for DNA, which specifies sequence of amino acids in a protein

central dogma of molecular biology

DNA -mRNA-protein sequence involved in every living cell at some point in their lifespan

transfer RNA

assists with assembly of amino acids into polypeptides by recognizing mRNA and amino acids for protein synthesis.

signal peptide

binds to the SRP which then binds to a receptor on the ER, allowing the ribosome to attach to the endoplasmic reticulum

nucleus

command center of every cell containing genetic information and instructions for protein synthesis and mitosis.

endomembrane system

consists of nuclear envelope, ER membranes, Golgi apparatus, and several vesicles. It restricts particular enzymatic reactions to specific regions, thus increasing overall cell efficiency.

Golgi apparatus

consists of stacked saccules (flattened vesicles); modifies lipids and proteins from the ER , sorts them, and packages them into vesicles.

nuclear envelope

double membrane surrounding the nucleus

rough ER

embedded with ribosomes on the side facing cytoplasm, allowing them to produce proteins. within its lumen it allows proteins to fold into their 3D shape. contains enzymes which can add carbs to proteins (glycoproteins)

polyribosome

groups of ribosomes

chromatin

network of proteins and nucleic acids that condense into chromosomes just before the cell divides.

smooth ER

no ribosomes continuous with nuclear envelope and rough ER with various functions including producing lipids such as testosterone (steroid hormone) in the testes and detoxifying blood in the liver.

chromosome

rodlike structures which carry genetic information, and are created from chromatin prior to cell division; every cell has same number of chromosomes, except the egg & sperm with half this number

nucleoplasm

semi fluid matrix inside the nucleus

nuclear pores

small holes allowing nucleus to communicate with cytoplasm; passage of ribosomal subunits & mRNA out and proteins in

gene

storage unit on chromosomes; basic units of heredity