organelles Flashcards
what is an organelle
they are to a cell what organs are to a complex organism,they have a defined function
what does compartmentalisation mean
separating organelles using cell membrane
what is the purpose of compartmentalisation in a cell
to have the correct condition for each organelle e.g.pH levels
how does an electron microscope work
uses a beam of electrons to create an image of the specimen
advantages of electron microscopes
greater resolving power and higher magnification
disadvantages of electron microscopes
needs a specially designed room and training to operate them - expensive -
describe the structure and function of the nucleus
bounded by two membranes which together make the nuclear envelopehas pores to allow mRNA to pass throughgranular material in the nucleus is nucleoplasm. it contains chromatin made of coils of DNAthe nucleolus is within the nucleus
describe the structure and function of the nucleolus
spherical bodysites of formation of rRNA a constituent of ribosomesdarker heterochromatin - made from densely packed DNAlighter euchromatin - less dense, DNA acts as a template for RNA synthesis
describe the structure and function of rough endoplasmic reticulum
is an elaborate system of parallel double membrane forming interconnected flattened sacs called cisternaehas ribosomes on the outer surface which is what gives it a rough look. present in large amounts in cells that make proteinsribosomes transport the proteins made
describe the structure and function of the ribosomes
made up of two subunits - a small and a large onethey are the ‘protein builders’ of the cellfound floating in the cytoplasm or attached to rERinvolved in protein synthesis
describe the structure and function of the golgi body
stack of flattened double membrane sacs called cisternaesurrounded by spherical membranes called vesicles involved ni the modification of proteinspackage proteins into vesiclesbuilds lysosomes
describe the structure and function of lysosome
spherical vesicle containing enzymes made by the golgi body pinching off a small specific vesicleinvolved in digesting material that enters the cell
describe the function and structure of the centriole
help the cell in mitosis and meiosis groups of threads attached called mitotic spindle made of microtubules go to poles of nucleus when cell is dividing
describe the structure and functions of cilia and flagella
cilia — 9 pairs of microtubules around edge and 2 in centrehair like organelles that line surfaces of cells and beat in rhythmic wavesflagella — ‘organ’ of movement need liquid environment to move
describe the structure and function of cell membrane
proteins and phospholipids make up the membranemembrane is made up of 3 ‘bands’ which can be seen as a lighter band sandwiched between two dark onescontrol movement in and out
describe the structure and function of mitochondrion
has an inner and outer membrane inner membrane layers fold over to form cristae and improve surface area matrix pattern of inner membrane containing ribosomes and circular DNAcellular respiration - keep the cell full of energy muscle cells have lots of mitochondria
describe the structure and function of chloroplasts
outer and inner membrane containing starch/sugars, stroma and thykaloid stacks or granaproduce food for the cell chlorophyll is on the surface of each thykaloid stack to capture light thykaloid stacks are held together by storm lamellae which keep the stacks a safe distance away and increases efficiencystroma - where carbon is fixed and sugars are synthesisedchlorophyll - common structure called porphyrin ring
what does magnification mean
the degree to which the size of an image is larger than the image itself
what does resolution mean
the degree to which it is possible to distinguish between two objects that are very close together
how can you work out the actual size of a specimen
magnified size/ magnification x actual size
how can you convert between a)cm to mm b) mm to micrometres c) micrometres to nanometres
a) x10b) x 1000c) x 1000
describe the process of protein trafficking
protein synthesised of ribosome of ERprotein enters the cisternae of the RERprotein is folded into a 3d shapevesicles containing protein pinch of the ERvesicles travel to golgi body vesicles fuse with golgi bodyprotein is modified vesicles pinch off golgi body vesicles move to cell membrane and fusecontents of vesicle is released
what is exocytosis
vesicles move to cell membrane and use with it to become part of the membrane, contents leave vesicle
what is an organelle
they are to a cell what organs are to a complex organism,they have a defined function
