Cell Structure Flashcards
(21 cards)
Structure of nucleus
Has nucleolus , nuclear envelope , chromosomes
Role of nucleus
Has chromosomes that carry genes to code specific polypeptides , has nucleolus to make ribosomes , transcription of genes to make mRNA , nuclear envelope protect DNA from being damaged by enzymes
Structure of mitochondria
Circular DNA
70s ribosomes
Cristae
Sausage shape
Double membrane
Function of mitochondria
Production of ATP and aerobic respiration
Structure of chloroplast
Biconvex
70s ribosomes
Double membrane
Circular dna
Function of chloroplast
Absorb light for photosynthesis
Formation of organic molecules
Formation of atp
Ribosomes
Non membranous organelle
20-25nm
Made of two subunits that are made of protein and rRNA
Large subunit has two binding sites for 2 tRNA
Small subunit has a binding site to mRNA
Function of ribosomes
Polypeptide synthesis
Exocytosis
Polypeptide chains formed by ribosomes enter RER where they are modified then shuttle vesicle fuse with Golgi body then proteins are modified then vesicles move to CSM fuse with it and release proteins
Lysosomes store inactive hydrolytic enzymes as lysozyme
Structure of RER
Flattened fluid filled sacs called cisternae
80s ribosomes
More regular than SER
Function of RER
Transport protein to Golgi
Modifies proteins
Structure of SER
Tubular fluid filled sacs
Interconnected
More irregular than RER
Function of SER
Synthesis of lipids,cholesterol and steroids such as sex hormones
Transport steroids to Golgi apparatus
Breaks down toxic substances in liver
Structure Golgi apparatus
Membranous organelle
Flattened fluid filled sacs called cisternae
Arranged in a stack parallel to each other
Swollen at both ends with Golgi vesicles surrounding them
Function of Golgi
Processing chemical modification and glycosylation of proteins
Packaging of protein in secretory vesicles and lysosomes
Structure of lysosomes
Spherical membranous organelle
Has hydrolytic enzymes
Measures 0.5um
Function of lysosomes
Stores inactive hydrolytic enzymes for phagocytosis
Phagocytosis
Lysosomes move to phagocytic vesicle guided by microtubules of cytoskeleton using ATP then fuse with it as both are fluid in nature releasing hydrolytic enzymes as protease and lipase into it then kill and digest bacteria
Structure of centrioles
Made of two hollow cylinders
Each cylinder is made of nine triplets of microtubules
The two cylinders are perpendicular to each other
Measures 0.4um
Structure of cell wall
1ry cell wall cellulose microfibers
Hemicellulose,pectin,soluble proteins
2ry cell wall cellulose,hemicellulose,many contain lignin
Rigid
Middle lamella has pectin
Function of cell wall
Cell to cell adhesion
Provides strength and flexible to allow growth
Support
