Monday 22 June 2015

2.3.4: Explain the role of the rough endoplasmic reticulum (rER) and the Golgi apparatus in protein transport within cells and including its role in formation of extracellular enzymes

1.     transcription of DNA to mRNA within the nucleus
2.     mRNA leaves the nucleus through the porous nuclear envelope
3.     DNA translation on the surface of ribosomes produces (primary) proteins, which are packaged and travel to the rough endoplasmic reticulum
4.     the proteins move the the rough endoplasmic reticulum, assuming a 3D shape (secondary and tertiary)
5.     vesicles pinched off the rER contain the protein
6.     proteins enter the Golgi apparatus
7.     proteins are modified within the Golgi apparatus (quaternary)
8.     vesicles pinched off the Golgi apparatus contain the modified protein

9.     the vesicles fuse with the cell surface membrane and release proteins through exocytosis

2.3.2: Distinguish between eukaryotic and prokaryotic cells in terms of their structure and ultrastructure AND 2.3.3: Describe the ultrastructure of an animal (eukaryotic) cell (nucleus, nucleolus, ribosomes, rough and smooth endoplasmic reticulum, mitochondria, centrioles, lysosomes, and Golgi apparatus) and recognise these organelles from EM images


EUKARYOTIC CELL

Mitochondria: used in respiration, where it takes in nutrients and stores the energy as ATP for use within the cell
Smooth endoplasmic reticulum: internal membranes that produce and metabolise lipids, carbohydrates, and some types of hormone
80S ribosomes: small complexes of RNA and proteins, the site of translation in protein synthesis
Golgi apparatus: stacks of flattened vesicles that modify and package proteins and other molecules for export outside the cell

Lysosome: hold enzymes, used for digestion of materials within the cell
Cytoplasm: contains substances needed for cell processes, keeps organelles in suspension
Nucleus: maintains the integrity of genetic material, controls the functions of the cell, and directs protein synthesis and cell replication
Rough endoplasmic reticulum: internal membranes studded with ribosomes that carry out protein synthesis
Centrioles: a pair of nine-sided microtubule bundles that aid in cell movement and replication
Cell surface membrane: a phospholipid bilayer embedded with proteins that allows substances to pass into and out of the cell
PROKARYOTIC CELL
Mesosome: an infolding of the cell surface membrane that contains enzymes used in respiration
Plasmid: a small circle of non-essential DNA that can be exchanged between prokaryotes
Capsule: a slimy layer that protects the cell against dehydration and phagocytosis, enables prokaryotes to stick together, and can act as a food reserve
Pili: protein tubes that enable prokaryotes to adhere to surfaces and each other, used in the transfer of DNA
Flagellum: rotates or lashes to enable to cell to move around, uses energy in the form of ATP
Cytoplasm: contains substances needed for cell processes, keeps organelles in suspension
DNA (nucleoid): maintains the integrity of genetic material, controls the functions of the cell, and directs protein synthesis and cell replication
Cell surface membrane: a phospholipid bilayer embedded with proteins that allows substances to pass into and out of the cell
Cell wall: made of peptidoglycan, provides structural support
-        two types of cell wall: gram negative (thin cell wall with outer lipid layer, stains pink) and gram positive (thick cell wall, stains purple)
70S ribosomes: small complexes of RNA and proteins, the site of translation in protein synthesis
COMPARISON OF EUKARYOTIC AND PROKARYOTIC CELLS
prokaryotic
eukaryotic
small cells
larger cells
always unicellular
often multicellular
no membrane-bound organelles
membrane-bound organelles
DNA is circular
DNA is linear
70S ribosomes
80S ribosomes
no cytoskeleton
cytoskeleton
binary fission
mitosis or meiosis
always asexual reproduction
asexual or sexual reproduction