Structure Of Cells Flashcards
What is the ultra structure of prokaryotic cells
-made up of bacteria and cyanobacteria (photosynthetic bacteria)
-most extremely small with smaller ribosomes that eukaryotic
-DNA not associated with any histone proteins and lies freely within the cytoplasm
-no membrane bound organelle
-always a cell wall present
Cell wall and is it always/sometimes present in prokaryotic
Tough outer layer of cell made up of peptidoglycan which provides strength and support, always present in prokaryotic cells
Flagella and is it always/sometimes present in prokaryotic
Whip-like structure found on bacterial cells that is used for cell movement and propels cell forward using a corkscrew motion, sometimes present
Capsule and is it always/sometimes present in prokaryotic
Polysaccharide layer that surrounds bacterial cells and provides strength and prevents cell from drying out and helps adhesion to surfaces, sometimes present
Pili and are they always/sometimes present in prokaryotic cells
Small hair-like projections on the surface of bacterial cells used to adhere to other cells, sometimes present
Plasmids and are they always/sometimes present in prokaryotic cells
Loops of DNA found in the cytoplasm of prokaryotic cells used in DNA replication and transferring DNA between bacteria, sometimes present
What is a prokaryotic cell
A type of cell that does not contain any membrane bound organelles or a nucleus
Ribosomes and are they always/sometimes present in prokaryotic cells
Organelles involved in the synthesis of proteins, always present in prokaryotic as they are not membrane-bound but smaller that in eukaryotic cells
Mesosomes and are they always/sometimes present in prokaryotic cells
Inward folds in the membrane of bacterial cells used for aerobic respiration, sometimes present
Ultrastructure of eukaryotic cells
Cells that contain discrete membrane bound organelles and have a membrane-bound nucleus
-larger than prokaryotic cells and have larger ribosomes
What are centrioles
Structure found in cytoplasm made of microtubules that produce the spindle fibres during mitosis which are found in pairs close to the nucleus at right angles so are involved in cell division
Role of Golgi apparatus and how this occurs
Organelle found in eukaryotic cells that is involved in the modification and packaging of proteins with flat curved fluid filled sacs surrounded by vesicles
-proteins enter Golgi apparatus modification of the protein occurs inside the Golgi apparatus, protein then packaged into secretory vesicles which fuse with the cell surface membrane
Role of lysosomes
Membrane-bound vesicles found in the cytoplasm of eukaryotic cells that contain hydrolytic enzymes which breakdown any of the cells waste and destroy disease causing organisms that enter the cell
Role of mitochondrion
Organelle found in eukaryotic cells that are the site of aerobic respiration, structure is bound by a double outer membrane which is folded to increase its surface area
What is the nuclear envelope
Double membrane that surrounds the nucleus
