3.2.1.1 Structure of Eukaryotic cells

What is the functions of the nucleus?

• Site of DNA replication and transcription (making mRNA)

• Contains the genetic code for each cell

What is the structure & function of the nucleus envelope?

S. double membrane

F. Controls entry and exit of molecules & contains reactions

What is the structure & function of the chromatin?

S. made of liner DNA with histones

F. forms chromosomes

What is the structure & function of the nucleoplasm?

S. granular, jelly-like material

F. suspension substance

What is the structure & function of the nuclear pores?

S. 40-100nm diameter

F. allows large molecules (e.g., mRNA) out of the nucleus

What is the structure & function of the nucleolus?

S. smaller sphere

F. production of rRNA & ribosomes

Whats the two type of ER structures & their differences/similarities ?

Rough and smooth ER

• Both have folded membranes called cisternae

• Rough have ribosomes on the cisternae

Whats the function of the RER?

Protein synthesis

Whats the function of the SER?

Synthesis & store lipids and carbohydrates

What is the structure of the golgi apparatus and vesicles?

• folded membranes making cisternae

• secretary vesicles pinch off from the cisternae

What is the function of golgi apparatus and vesicles?

• Add carbohydrates to proteins to form glycoproteins

• produce secretory enzymws

• secrete carbohydrates

• transport, modify and store lipids

• form lysosomes

what is the structure of lysosomes?

• bags of digestive enzymes - can contain 50 different enzymes

what is the function of lysosomes:

• Hydrolyse pathogens in phagosomes

• completely breaks down dead cells (autolysis)

• Exocytosis: release enzymes to outside of cell to destroy material

• digest worn-out organelles for reuse of materials

what is the structure of mitochondria:

• double membrane

• inner membrane called the cristae

• fluid centre called the mitochondrial matrix

• loop pf mitchondria DNA

• 70s ribosomes

What is the function of the mitochondria?

• Site of aerobic respiration

• Site of ATP production

• DNA to code for enzymes needed in respiration

What is the structure of ribosomes?

• Small, made up of two sub-units of protein and rRNA

• 80s - larger ribosome found in eukaryotic cells (25nm)

• 70s - smaller ribosomes found in prokaryotic cells, mitochondria and chloroplasts

What is the function of ribosomes?

protein synthesis

Structure of vacuole?

filled with fluid surrounded by a single membrane called a tonoplast

function of a vacuole?

• make cells turgid and therefore provide support

• temporary store of sugars and amino acids

• the pigments may colour petals to attract pollinators

What is the structure of chloroplasts?

• Surrounded by a double membrane called

• contains thylakoids (folded membranes embedded with pigment)

• fluid filled stroma contains enzymes for photo synthesis

• found in plants

What is the function of chloroplasts?

Site of photosynthesis

What is the structure of the cell wall?

• In plant and fungi cells

• Plants- made of microfibrils of the cellulose polymer

• Fungi- made of chitin, a nitrogen-containing polysaccharide

What is the function of cell wall?

Provide structural strength to the cell

What is the structure of plasma membrane?

• Found in all cells

• Phospholipid bilayer- molecules embed within and attached on the outside(proteins, carbohydrates, cholesterol)

What is the function of plasma membrane?

Controls the entrance and exit of molecules