DP Biology Vocabulary - 1.2 Ultrastructure of cells

Essential vocabulary for the IBO DP Biology course

70S

the size of prokaryotic ribosomes.

80S

the size of eukaryotic ribosomes.

Archaea

a domain of prokaryotes.

Bacteria

a domain of prokaryotes.

Binary fission

method of prokaryotic cell division.

Cell wall

non-living carbohydrate-based extracellular material.

Compartmentalization

seen in eukaryotes; consequence of organelles being membrane-bound.

Endoplasmic reticulum (ER)

site of synthesis of proteins destined for export or for secretion.

Eukaryote

organisms with membrane-bound nuclei.

Exocrine glands

glands that secrete their products into ducts.

Extracellular matrix

a network of material that is secreted by cells that serves to support, strengthen, and organize cells.

Flagellum

a relatively long extension of the cell used in locomotion.

Golgi body

a eukaryotic organelle that modifies proteins after translation.

Histone

a protein associated with DNA that plays a role in gene expression and the packing of DNA.

Lysosome

a cellular organelle involved in cellular digestion.

Naked DNA

DNA not associated with histones or histone-like proteins.

Nucleoid

a region of the prokaryotic cell where DNA is located.

Nucleus

membrane-bound organelle found in eukaryotes that contains DNA; it is the site of replication and transcription.

Organelle

a sub-cellular structure or membrane-bound compartment with a distinct structure and function.

Palisade mesophyll

photosynthetic tissue below the epidermis in a leaf.

Pilli

extensions of the prokaryotic cell surface membrane used for reproduction.

Plasmid

extra-chromosomal DNA in a prokaryote.

Prokaryote

category of a cell without a membrane-bound nucleus: archaea and bacteria.

rER

rough ER - ER with ribosomes attached.

Resolution

the ability to see adjacent objects or structures as distinct from each other.

Ribosome

organelle involved in protein synthesis.

Scanning electron microscope

an electron microscope that generates a three-dimensional image.

sER

endoplasmic reticulum that synthesizes new membrane and does not have ribosomes attached.

Svedberg unit

unit of molecule size based on the position that material settles out in a centrifuge tube after spinning. Larger particles tend to settle out faster and so have higher Svedberg values.

Transmission electron microscope

an electron microscope that produces two-dimensional images.

Ultrastructure

the detailed structure of a biological entity.